MWM Splinter 1
Aug 10 09:00-14:00
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Session Chair Meeting 1
Aug 10 09:00-10:00
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Session Chair Meeting 2
Aug 10 16:00-17:00
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Plenary 1
Aug 11 10:00-11:30
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10:00 - Juna Kollmeier - SDSS V Overview10:30 - Michael Blanton - SDSS IV Synopsis11:00 - Yue Shen - SDSS V: BHM Overview
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AGN 1
Aug 11 12:00-14:00
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12:00 - Edgar Cortes Suarez - Type-1 AGN host galaxy global properties in MaNGA12:15 - Hector Javier Ibarra-Medel - A first study of the AGNs host galaxy stellar populations with the SDSS-V12:30 - Alenka Negrete - Type-1 AGN spectral characterization in MaNGA12:45 - Moire Prescott - Extended Gaseous Nebulae around Fading AGN
abstract
Using a flux ratio method, between the continuum and a region where Ha broad component is expected to be detected, we found 47 type-1 AGNs. In this work, we show some Host Galaxy global properties such as their distribution in stellar mass, age, color, and morphological type. We found strong bars signatures that seem to be participating in the type-1 AGN feeding mechanism. Exploring multiwavelength luminosities in X-ray, IR, and radio, we found a strong correlation between them and the Ha broad component luminosity.abstract
We will present a first study of the AGNs host galaxy stellar populations with the SDSS-V. For that objective, we will use optical spectra within a redshift range of 0.1 to 0.9 and execute a set of stellar population synthesis, disentangling the non-thermal component from the host-galaxy. The analysis tries to test the feasibility to retrieve the stellar masses, star formation quantities, ages, synthetic colors, etc., for the host galaxies in the SDSS-V. And second, if there is evidence of a possible impact in the host galaxy star formation efficiencies when a galaxy has or hasn't a strong non-thermal component along the star formation main sequence. This work will generate data products such as stellar masses, star formation rates, star formation histories, and stellar free quasar spectra. This work is part of the SDSS-V project Number 18abstract
We present a simple method based on the Hbeta Lick index (I_Hb) and an index defined in the CaII K-band absorption line region (I_K; which is also sensitive to the Balmer jump). The objective is to characterize the contribution level between the host galaxy (HG) and the active galactic nuclei (AGN) emission, for a selected sample of type-1 AGN of the MaNGA survey. For the case of AGN spectra dominated by HG emission, the I_Hb and I_K indices will indicate the characteristic absorptions of the stellar component. For intermediate AGN where the nuclear emission is stronger but the HG contribution is still visible, I_Hb is expected to be partially observed in emission, but I_K will still be observed in absorption. For dominant AGN, both indexes will be in emission, where H_gamma line will dominate I_K. This distinction is important when separating the host galaxy from the nuclear emission because this process can become degenerate.abstract
A rare sample of spatially extended emission line nebulae at z~0.3, nicknamed Green Beans, was discovered in SDSS imaging thanks to strong [OIII] emission. Subsequent evidence suggested that these nebulae may be associated with recently faded AGN and that they are local cousins of the Lyman-alpha (Lya) nebulae found at high redshift. We are using follow-up APO/DIS spectroscopy to better understand these low-z Lya nebulae and how they compare to other strong emission line sources. Our spectroscopic data has shown that low-z Lya nebulae have emission line ratios, line widths, sizes, and kinematics that resemble other Type 2 AGN at the same redshift, confirming that they are powered by Type 2 AGN with typical ionizing continua. Low-z Lya nebula systems may be drawn from the high luminosity end of the Type 2 AGN distribution, with higher nuclear activity driving high [OIII] equivalent widths and more central star formation leading to bluer optical continua. By studying these low-z Lya nebulae, we can better understand the conditions associated with a rapid ramp-down in AGN ionizing output as well as their relationship with the Lya nebula population at high redshift.Data 1
Aug 11 12:00-14:00
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12:00 - Juan Pablo Alfonzo - Exploring the Link Between the Star Formation History and the Morphology of Galaxies12:15 - Yanping Chen - Estimate Stellar parameters of MaStar using theoretical atmospheric atmosphere12:30 - David W Hogg - Extremely precise spectrophotometric distances for red-giant stars12:45 - Eduardo Lacerda - The new version of Pipe3D pipeline of analysis of Integral Field Spectroscopy data13:00 - Alfredo Mejia-Narvaez - CoSHA: Code for Stellar properties Heuristic Assignment13:15 - Lorenza Nanni - iMaNGA: forward-modelled mock MaNGA galaxies based on IllustrisTNG-50 cosmological simulations and MaStar stellar population models13:30 - Aarya Patil - Functional Data Analysis for extracting the Intrinsic Dimensionality of Spectra: Prospects for Chemical Tagging
abstract
On galaxy-wide scales, the appearance morphology of galaxies is correlated with their past star formation activity. On the smallest scales within galaxies, the local star formation rate is correlated with the local gas density (also referred to as the Kennicutt-Schmidt law). We study the connection between the factors regulating star formation in galaxies on different spatial and temporal scales and connect morphological features (such as bars, bulges and spiral arms) with their integrated star formation on different timescales. This is being done using machine learning methods, specifically using convolutional neural networks (CNNs) trained on galaxies in the SDSS-IV MaNGA DR16. We focus on interpretability of the trained network using Gradient-weighted Class Activation Mapping (Grad-CAM), to see what parts of galaxy images the network is focusing on to make its predictions. With this, we can explore which morphological features of galaxies have the greatest impact on predicted star formation history parameters, and use it to gain insights on the links between the underlying physical processes regulating star formation in galaxiesabstract
We report the stellar atmospheric parameters for spectra contained in the MaStar with MPL11 release. In this work, we determined the basic stellar parameters: effective temperature (Teff), surface gravity (log g), metallicity ([Fe/H]), and alpha abundance ([alpha/Fe]), which best fit the data using mainly the BOSZ stellar atmosphere. For the cooler stars we use the MARCS stellar atmospheric models. We tested the robustness of the method using the BOSZ spectra itself and verified the method. We also provide the comparison with literature parameters to show the systematic consistency and possible offsets. We show the parameter distribution and open to our community to collaborate with.abstract
Precise mapping of the MW disk requires precise distances to luminous stars. We find that we can use something very close to pure linear regression (that is, not even really machine learning) to predict good distances for red-giant stars. The precision varies from the few-percent level in the best parts of the CMD to ten-ish percent at the worst. The training data are from ESA Gaia observations and WISE, 2MASS, and APOGEE; there is no involvement of stellar gastrophysics anywhere in the method. Methodological innovations over previous projects include building different models in every one of many small CMD neighborhoods (of sizes set by the data themselves), and a Fourier-domain regularization that prevents the model from using spectral information at spectral scales smaller than the spectrograph resolution limit. Code is open-source; we intend to release our distances with/after DR17; and we will build a pipeline useful for SDSS-V (Work with Adrian Price-Whelan.)abstract
We present the new version of Pipe3D, the pipeline of analysis of the properties of the stellar populations and the ionized gas. This new implementation includes also an update of the main fitting tool, FIT3D, improving its performance, the accuracy and precision in estimated parameters. The new package is now written in python version 3 with an update in the philosophy of the code, facilitating the production of analysis, data-exploration and interactive scripts. pyFIT3D is used to the analysis of each singular spectrum and pyPipe3D is the new pipeline implemented with in-loop calls of pyFIT3D. Both are fully tested with data of tyhe most recent IFS data surveys (e.g., CALIFA, MaNGA, AMUSING++, SAMI).For the evaluation of the accuracy and precision of the recovered parameters of the new code we create two sets of simulated data. Together, we compare the outputs of the analysis of the same IFS data cube for both, previous and present, version of the code, in order to inspect the behaviour of the new implementation of the new code under real data.abstract
We introduce CoSHA, a machine learning method to compute atmospheric parameters for stellar spectral libraries. Using CoSHA, we estimate Teff, log(g), [Fe/H] and [alpha/Fe] for the MaStar stellar library and validate the resulting distributions through a series of internal and external tests. We recover the well-known trends in the [alpha/Fe] versus [Fe/H] plane with great statistical confidence.abstract
We create MANGA-type galaxy simulations based on the IllustrisTNG-50 cosmological simulations which will allow us to compare galaxy formation theories to MaNGA observations in the closest possible way, as described below, and investigate various processes in astrophysics. We prepare a MaNGA-like sample of galaxies in IllustrisTNG-50, by selecting simulations in M_i and redshift. We create Integral Field Unit (IFU) datacubes with 0.5'' as pixel size, and use the Monte Carlo Radiative Transfer code SKIRT to simulate dust if present. We generate the IllustrisTNG-50 simulated galaxy spectra with the new MaStar stellar population models. The resulting simulations cover the wavelength range ~ 0.36-1.03 micron with a spectral resolution of R~1800 and share the same resolution and flux calibration of the MaNGA galaxies. To further improve the realism of the simulations, we add several observational effects typical of MaNGA observations adopting a forward-modelling approach. Our current mock datacubes include the information within 1.5 R_eff, as in the MaNGA primary sample. We then analyse these mock MANGA datacubes as if they were real observations, by applying Voronoi binning with target S/N=10 and adopting the FIREFLY full spectral fitting code to derive the stellar population properties, age, metallicity, stellar mass, the star formation history and their radial gradients.abstract
High-resolution spectroscopic surveys have entered the Big Data regime, and have opened avenues for solving outstanding questions in Galactic Archaeology. Automated inference of stellar properties from noisy spectroscopic data involves several steps, each inducing systematic errors into the inference due to underlying assumptions. We focus on minimizing these systematics through thoughtful statistical treatment of spectra. We bypass the use of ~8,000 discrete wavelengths in APOGEE spectra in favor of its intrinsic ~10-dimensional structure. This structure is effectively disentangled from systematics and instrumental noise through the use of Functional Principal Component Analysis (FPCA) on a sample of ~20,000 giant spectra. Our results enable direct usage of spectra to study properties of stellar populations and demonstrate that FPCA, a PCA technique that incorporates domain knowledge, is a powerful tool for astronomy. To demonstrate that our functional PCs incorporate stellar information, we apply them to dimensionally reduce the spectra of 28 giant stars in open cluster M67 and then infer their stellar parameters abundances. We perform Sequential Neural Likelihood, a simulation-based inference method that uses Neural Networks to learn complex likelihood functions. Using uninformative priors, we put stringent constraints on the chemical homogeneity in M67. In this talk, I will discuss spectral dimensionality reduction using FPCA, and its application to M67.Milky Way 1
Aug 11 12:00-14:00
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12:45 - José Fernández Trincado - Tons of interesting results in the heavily obscured bulge globular clusters with APOGEE-212:00 - Doug Geisler - CAPOS, the bulge Cluster APOgee Survey12:15 - Meszaros Szabolcs - Homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code12:30 - Dominic Taylor - Is Terzan 5 the remnant of a building block of the Galactic bulge? Evidence from APOGEE
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I will present Tons of interesting results in the heavily obscured bulge globular clusters with the NIR spectroscopy of the Apogee-2S and Apogee-2N survey.abstract
We will present initial results from CAPOS, the bulge Cluster APOgee Survey, designed to obtain detailed abundances and kinematics for as complete a sample of bona fide members in true bulge globular clusters as possible. The goals are to greatly improve our knowledge of their formation and chemical evolution as well as that of the underlying Galactic bulge population they trace. We will also search for multiple populations in bulge globular clusters. We will show results for a number of clusters and discuss future research.abstract
We investigated the Fe, C, N, O, Mg, Al, Si, K, Ca, Ce and Nd abundances of 2283 red giant stars in 31 globular clusters from high-resolution spectra observed in both the northern and southern hemisphere by the SDSS-IV APOGEE-2 survey. This homogeneous dataset allowed us to discuss the intrinsic Fe spread, the shape and statistics of Al-Mg and N-C anticorrelations as a function of cluster mass, luminosity, age and metallicity for all 31 clusters. In this talk we will overview our results published in three different papers to date.abstract
Prior research has hypothesised the globular cluster Terzan 5 to be the surviving remnant of a primordial building block of the Milky Way bulge, mainly due to the spread in age and metallicity of its stellar members. We put this hypothesis to test by comparing the detailed chemical compositions of Terzan 5 with those of their field bulge counterparts. Adopting a novel random sampling technique, we contrast the abundance pattern of Terzan 5 with that of stars in the bulge field, finding that they differ at statistically significant levels. We thus conclude that the APOGEE data argues against Terzan 5 being a remnant of a building block of the Galactic bulge.Lightning 1
Aug 11 14:10-14:30
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- Michael Blanton - Selection effects in AGN identification - Jonathan Trump - The Year 1 SDSS-V BHM Data - Juan Pablo Alfonzo - Exploring the Link Between the Star Formation History and the Morphology of Galaxies - Andreas Filipp - - Alejandro Miguel MunguÃa-Córdova - Multicomponent Fit of Spatially Resolved Spectra and Indirect Estimation of Black Holes Masses of Galaxies From the MaNGA Catalog. - Alejandra Zaavik Lugo Aranda - pyHIIExplorerV2 a tool for detecting and extracting physical properties from HII regions. - Bárbara Rojas-Ayala - Challenges in the derivation of stellar parameters via spectrum synthesis of APOGEE M dwarf stars - Valeria RamÃrez - Spectral Classification of Intermediate and High Mass Stars: The Empirical Sequence Using SDSS-IV/APOGEE Near-IR Data - Sina Babaei Zadeh - Building galaxies from the bottom up: how uniquely does galaxy assembly determine their present day properties? - Alexander Stone-Martinez - Parameter based distances and masses using simple neural nets - Hugh Sharp - Exploring The Accretion Disk Size Problem Through SDSS-RM Quasars
abstract
Active galactic nuclei span a large range of luminosities. Determining the distribution of luminosities and how it depends on galaxy host properties is complicated by selection effects. In the case optical line detection of AGN, this leads to difficulties finding AGN in star forming galaxies whose star formation related lines may overwhelm the AGN lines. The same effect may be at work when selecting AGN from radio or X-ray emission. I'll discuss recent work on measuring AGN luminosity distributions from optical selection and ideas for extending the same methods to radio and X-ray detection.abstract
I will present a brief summary and advertisement of the year 1 SDSS-V Black Hole Mapper (BHM) data, including an assessment of how well each of the BHM experiments are progressing along their stated survey goals.abstract
On galaxy-wide scales, the appearance morphology of galaxies is correlated with their past star formation activity. On the smallest scales within galaxies, the local star formation rate is correlated with the local gas density (also referred to as the Kennicutt-Schmidt law). We study the connection between the factors regulating star formation in galaxies on different spatial and temporal scales and connect morphological features (such as bars, bulges and spiral arms) with their integrated star formation on different timescales. This is being done using machine learning methods, specifically using convolutional neural networks (CNNs) trained on galaxies in the SDSS-IV MaNGA DR16. We focus on interpretability of the trained network using Gradient-weighted Class Activation Mapping (Grad-CAM), to see what parts of galaxy images the network is focusing on to make its predictions. With this, we can explore which morphological features of galaxies have the greatest impact on predicted star formation history parameters, and use it to gain insights on the links between the underlying physical processes regulating star formation in galaxiesabstract
Strong lensing-enabled studies have provided essential insights into galaxy evolution, the nature of dark matter, the interplay between dark and baryonic matter, fundamental physics and cosmology in general. However, the current strong lens sample is heavily biased against star-forming galaxies. We aim to extend strong lensing galaxy evolution analyses to star-forming galaxies by enlarging the sample of star-forming galaxy lenses. We constructed an ELG strong lens catalog based on DR17 eBOSS spectra that will be released as a VAC catalog.abstract
In this Lightening Talk , we present the results of comparing the direct estimations of supermassive black hole masses (BHMs) available in the literature with those that we derived using an indirect method based on single epoch spectroscopy. We use Integral Field Spectroscopic (IFS) observations from the Mapping Nearby Galaxies at APO (MaNGA) to carry out our analysis. IFS observations are useful as they provide spatially resolved spectroscopic information for extended objects, which in the case of MaNGA, it can be resolved up to kpc scales. For a small sample of galaxies, we exploit the spatially resolved information from MaNGA to derive BHMs estimations at different apertures and compare them with the directly derived masses available. We discuss the differences obtained applying the chosen indirect method, and how IFS data could help to correct the BHMs estimations done with it.abstract
We present a new tool called pyHIIexplorer V2 to explore and exploit the information provided by integral-field spectroscopy technique in the optical range. The code detects clumpy regions of Halpha maps (candidates for HII regions) and extracts as much spectroscopic information as possible (for both the underlying stellar populations and emission lines). Simultaneously during the detection and extraction of the clumpy regions, pyHIIexplorer V2 builds a diffuse ionized gas model (DIG). The construction of DIG will allow us to decontaminate the information of the HII regions candidates.abstract
In Sarmento et al. 2021, we present a method to derive stellar parameters for M dwarfs using high-resolution H-band spectra via spectrum synthesis using iSpec, Turbospectrum, MARCS models atmospheres, and a custom-made line list including over 1000000 water lines. The method was developed to provide reliable spectroscopic parameters from the spectra of current and future NIR high-resolution spectrographs. We derived the spectroscopic parameters ($T_eff$, [M/H], log g, $v_mic$) for a sample of 313 M dwarfs in the APOGEE DR16 and compared them to the ones obtained by ASPCAP and previous values derived from NIR and optical data. In this Lighting Talk, I will discuss the challenges still present related to the derivation of spectroscopic parameters for ultra-cool dwarfs with this technique, hoping to find other interested colleagues on the subject.abstract
We present a semi-empirical spectral classification scheme for normal B and A-type stars using near-infrared spectra (1.5−1.7μm) from the Sloan Digital Sky Survey (SDSS) Apache Point Observatory Galaxy Evolution Experiment (APOGEE2) data release 16 (DR16) database. We found that there is a relation between the spectral features available on the NIR and the spectral type for intermediate-to-low mass stars. This relation works for high mass stars, such as B-type (RamÃrez-Preciado et al. 2020) and apparently extend down to A-type stars (RamÃrez-Preciado et al. in prep). To verify the above, we classified a sample of 316 B-type and 322 A-type stars, using the Morgan Keenan methodology and optical data from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey. By first obtaining an accurate spectral classification of the sources using the LAMOST spectra and the canonical spectral classification scheme, we found a linear relation between optical spectral types and the equivalent widths of the hydrogen lines of the Brackett series in the APOGEE2-N NIR spectra. This relation extends smoothly from a similar relation for O and early B stars found by Roman-Lopes et al. (2018). With our classification scheme and the relation proposed, we show that it is possible to classify high and intermediate-to-low mass star using only NIR spectra on young regions where optical data is not available.abstract
An important question in astrophysics is how to predict the future state of galaxies, and to determine if two evolving galaxies will share the same properties given their assembly history. In an attempt to answer this, we look at the EAGLE simulation (Evolution and Assembly of GaLaxies and their Environments) which contains data on about one million galaxies, and their defining properties. Our research utilizes the assembly history in order to answer this question. By analyzing and grouping similar assembly histories, we look to analyze the properties of the galaxies in a particular group to see if their likeness in assembly history can predict their likeness in other properties. Using this bottom-up approach, we hope to be able to predict the properties of galaxies like our own Milky Way in a few billion years in the future. This analysis complements the work done in the reverse direction, which attempts to predict the assembly history given the present-day properties of a particular galaxy.abstract
We created a value added catalog for DR17 that contains predicted distances to APOGEE stars and, for evolved stars, masses and ages that are derived from the ASPCAP parameters. We use simple neural networks to accomplish this. Distances are trained from stellar parameters using GAIA EDR3 distances and literature distances for star clusters. Masses/ages are trained from stellar parameters and abundances using APOKASC asteroseismic masses and, for subgiants, isochrone masses, using isochrones to transform from mass to age. We also present Bayesian isochrone-based distances based on the observed effective temperatures, surface gravities, and metallicities.abstract
Continuum reverberation mapping studies have often shown inconsistencies between observed and theoretically predicted accretion disk sizes, with the observed size 2-3 times larger than the model. To further investigate the cause of this disparity, we studied 95 SDSS-RM quasars to investigate how a broad range of quasar properties relate to over-sized and under-sized accretion disks.Speed Geeking
Aug 11 15:00-16:00
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Plenary 2
Aug 11 16:00-17:30
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16:00 - Guillermo Blanc - The SDSS-V Local Volume Mapper (LVM): Project Description, Status and Opportunities16:30 - Jennifer Johnson - SDSS V: MWM Overview17:00 - Rachael Beaton - APOGEE Legacy
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I will present the LVM survey, an ambitious project to create the first optical IFU data-cube of the Milky Way and the Magellanic Clouds at an unprecedented spatial resolution, resolving the interface between the ISM and individual sources of feedback and ionization. The LVM will produce a revolutionary dataset for the study of star-formation, feedback, chemical abundances and ISM physics in general. To conduct the survey the LVM team is deploying a new facility at Las Campanas Observatory in Chile, and planning for first-light in mid 2022. I will provide an update of the current project status, and discuss opportunities for SDSS-V members to engage in the development, commissioning, operations, and early-science phases of the project.abstract
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Galaxies 1
Aug 11 18:00-20:00
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18:00 - Vladimir Avila-Reese - Evolution of mass-to-light structural ratios of MaNGA Ellipticals: have they been significantly more compact and concentrated in the past? 18:15 - Stephanie Campbell - Incorporating Cold Gas into Dynamical Models of Galaxies in MaNGA18:30 - Brian DiGiorgio - NIRVANA: Non-axisymmetric velocity field models of MaNGA galaxies18:45 - Shuai Feng - The Morphology of Halpha Velocity Field in MaNGA Galaxies19:00 - Luis Garma-Oehmichen - Bar pattern speed in Milky Way-like galaxies19:15 - Hector Javier Ibarra-Medel - The fossil record study of MaNGA Ellipticals: global and radial inferences of the evolution of stellar mass and light properties19:30 - Sebastian Francisco Sanchez Sanchez - Pipe3D exploration of the full MaNGA dataset
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We discuss the archaeological reconstruction of a MaNGA sample of red and quenched Elliptical galaxies. Our study focuses on the evolution of the ratio between mass and light structural properties: effective radii, concentration, and effective surface densities. We find that the stellar mass and light radial distributions evolve differently, with small differences at high redshifts, then the differences increase up to low redshifts, after which the the light distribution tends to follow the mass distribution, as expected for galaxies in the long-term global quenching regime. The above trends differ systematically with mass. After comparing our results with those of direct observations of quiescent/early-type galaxies at different redshifts, we conclude that a significant part of the strong increase in size and puffing-up reported for these galaxies is photometric (evolution of the M/L ratio gradient) rather than intrinsic.abstract
Dynamical modelling allows us access to information about the internal structure of galaxies which we otherwise would not have. One part of this is the mass distribution within the galaxies, and the fraction which comes from dark matter. Integral Field Spectroscopy surveys such as MaNGA give us the observational information required to create these models, but in order to model the dark matter component as accurately as possible we require kinematics from the most dark matter dominant regions, which are beyond the extent of the stars. This has been achieved previously using spatially resolved observations of cold neutral Hydrogen which extends out into these regions, but such observations are only available for a handful of galaxies. In this talk I present the work I have been doing to explore the possibility of using unresolved single dish Hydrogen observations from the HI-MaNGA survey (Masters et al, 2019; Stark et al, 2020) to improve the dynamical models, while being applicable for a statistically significant sample of galaxies.abstract
Representing the largest sample of kinematic maps obtained to date, the MaNGA data provide an unprecedented opportunity to study the internal motions of galaxies. Building on work by Leung (2018), we will forward model each rotating MaNGA galaxy with a nonaxisymmetric kinematic model that decomposes MaNGA velocity fields into the radial and tangential modes up to second order for both ionized gas and stars. This approach allows us to quantify the influence of noncircular, bisymmetric features like bars and warps, as well as producing kinematic geometries, rotation curves, and velocity-dispersion profiles. Our results show successful fits of both circular and noncircular rotational features, including strong bar and spiral distortions. Ultimately, we aim to publish a catalog of our modeling results in the next year, providing basic kinematic parameters of interest for MaNGA galaxies, useful for sample selection and follow-up analysis.abstract
With the help of IFS observation, the morphology of velocity fields provide an excellent discription of galaxy kinematics. However, the physical implication of those morphological features are poorly known. In this talk, we focus on the asymmetric feature in Halpha velocity field, analyze its dependancy and explore its origin. Based on the large sample of MaNGA, we find the galaxy-galaxy interaction play a dominant role in shaping the morphology of velocity field. Using the kinematic asymmetry, we can further identify the merging stage. For isolated galaxies, the combination effects of graviational potential, bar-driven gas inflow and gas accretion determine the asymmetric degree of velocity field. Besides, we notice that the dust attentuaiton can also induce the asymmetry of velocity field.abstract
We compiled a sample of Milky-Way Analogs (M-WAs) from the DR15 ManGA sample by constraining the stellar mass to (log M ~ 10.5 - 11), the morphological types to (SBb - SBc) and the inclination to $i < 70$. We estimate the bar pattern speed of 35 M-WAs using the Tremaine-Weinberg method. With a careful sampling of the geometric parameters errors and using three independent measurements of the disc PA, we can recover the bar pattern speed with relative errors lower than 30% in 80% of the sample. We also estimate the effects of different rotation curve shapes, and how they affect the bar rotation classification. Our preliminary results show a smooth distribution in the bar pattern speed of M-WAs of ($\Omega{Bar}=25.6^{+11.71}{-8.78}) and in the rotation rate ($\mathcal{R} = 1.31^{+0.71}_{-0.43}$).abstract
Using the fossil record method, we explore the global and radial evolution of red and dead elliptical galaxies. We implement the fossil reconstruction methods to obtain resolved stellar mass and light maps across several lock-back times. For this study, we analyzed well-classified MaNGA elliptical galaxies with red colors and retired. We obtain information about the stellar mass and star formation evolution of these galaxies as well as their mass and light structural evolution, which provides us with several restrictions on galaxy evolutionary models.abstract
We present the main properties of the full MaNGA dataset extracted from the new version of the Pipe3D pipeline. This new version present fundamental modifications. Among them the most relevant are: (1) the use of an improved version of the fitting algorithms, fully coded in pythin; (2) the use of new set of synthetic stellar populations created from using the MaStar library; (3) an improved list of analyzed emission lines. We summarize the main integrated, characteristic, and spatial resolved properties of the galaxies, which will be the core of the DR17 Pipe3D VAC.ISM 1
Aug 11 18:00-20:00
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18:00 - Xihan Ji - Correlation Between the Gas-phase Metallicity and Ionization Parameter in Spatially-resolved Star-forming Regions18:15 - Marina Kounkel - Low Mass YSOs in the SDSS-V data18:30 - Kevin McKinnon - Evidence of Diffuse Interstellar Bands in Residuals of Data-Driven Models of APOGEE Stellar Spectra18:45 - Carlos Román-Zúñiga - The Great APOGEE-YSO Exhibit19:00 - Elizabeth Watkins - Tracking the evolution of Milky Way molecular clouds
abstract
The gas-phase metallicities and ionization parameters are important measurables that reflect the physical conditions of star-forming regions. By studying the dynamical evolution of HII regions with theoretical models, people found a strong negative correlation between these two quantities as a consequence of the change in the output energy of the central stars. However, observations of star-forming galaxies have produced contradicting results. While some works support the theoretical predictions, many recent studies based on spatially-resolved data favor instead a positive correlation between the metallicity and ionization parameter. Part of the reason behind this discrepancy is related to the calibrations of these measurables. By studying the spatially-resolved star-forming regions in MaNGA, we compute a self-consistent photoionization model that reproduces most strong emission lines for the majority of the data. With this model, we measure the metallicities and ionization parameters for our sample through Bayesian inference. The results show that a positive correlation exists between the gas-phase metallicity and ionization parameter regardless of which combinations of emission lines are used for calibrations. This correlation indicates missing physics in the current dynamical model and might be related to how the formations of HII regions are regulated as galaxies evolve.abstract
We present the overview of the preliminary results from the plate observations from SDSS-V YSO program. Specifically, we discuss the complex targeting strategy, as well as the efforts of characterization of the optical spectra - from extracting fundamental stellar properties, to the methods based on which the youth of the sample can be established. Finally, we examine some of the trends in the properties of the stars as a function of age.abstract
We create a data-driven spectral model using ~15,000 red clump stars in the APOGEE dataset. The continuum-normalized flux at each pixel is a 2nd order polynomial of the stellar labels, namely, Teff, log g, [Fe/H], [alpha/Fe], and age. This model successfully describes the stellar spectra within the observed uncertainties for many APOGEE pixels, but there are also many pixels where the residuals are distinctly non-Gaussian. These poorly-modelled regions reveal residual absorption features that are not in the rest frame of the stars, and the strongest of these residual features corresponds to previously-known Diffuse Interstellar Bands (DIBs); in total, there are ~50–100 features (in emission and absorption) in the residual spectra at the level of 1%–2% in flux on average and 4%–5% at worst. Many of these features occur in the wavelength windows that APOGEE uses to determine chemical abundances, which is why it is important to characterize and remove these sources of stellar-spectral contamination to reach the precision required for chemical tagging experiments. Proper characterization of these features will benefit Milky Way ISM science and the upcoming Milky Way Mapper program of SDSS-V which will use the APOGEE spectrograph.abstract
We present the result of the combined study of thousands of young stars distributed across eleven Galactic stellar nurseries. These comprise a variety of projects that made use of Science Goal, Ancillary and BTX time, and include both nearby low-mass forming environments (e.g. Taurus) and massive star forming complexes (e.g. Cygnus-X). APOGEE-2 spectra combined with GAIA EDR3 and near-IR photometry allowed us to determine precise spectral parameters (Teff, logg, [Fe/H]) using the APOGEE Net neural network (Onley+20), physical properties (L/Lsun, M/Msun, Av, ages) and statistics of evolutive stages from circumstellar emission. This wonderful dataset paves the way for the MWM YSO program and demonstrates the capabilities of APOGEE to study the origin population.abstract
Star formation is a multiscale process that heats up surrounding cold gas and powers large scale processes in the interstellar medium. Tracking the full star forming lifecycle therefore provides strong constraints on these effects. However, the long timescales over which stars form limit investigations of molecular clouds (MCs) to a single snapshot. To overcome this, we use Herschel-HiGAL to catalogue 12000 MCs in the southern galactic plane, and using Spitzer 8μm, we define the infrared bright fraction, fIRB—the area of a MC that appears bright against the background—as a proxy for time evolution. We show MCs evolve down two paths. Down path one, MCs increase their mass and column density as fIRB increases. But at later stages (fIRB>0.5), MCs decrease in mass while retaining a constant column density and dissipate after fIRB>0.9. Down path two, the MCs instead experience an extreme period of growth, increasing their mass by two orders of magnitude. MCs evolving down this path remain fIRB< 0.5. To explain this behaviour, we propose stellar feedback processes dominate MC evolution after half of the MC becomes star forming, showing early feedback sets the maximum amount of star formation by limiting their mass reservoir. We also show how this catalogue can be used to trace the impact of feedback using the WISE-HII catalogue. With the extra constraints on ionised sources provided by the upcoming LVM survey, we can improve these results to get a comprehensive picture of feedback.Stars 1
Aug 11 18:00-20:00
Zoom Link TBC
18:00 - Lyra Cao - Spots and Pre-MS Stellar Characterization from APOGEE DR17 Spectra18:15 - Chih-Chun Dino Hsu - Precise Radial and Rotational Velocities of Ultracool Dwarfs with the APOGEE High-Resolution Spectrometer18:30 - Nicolás Medina - The photometric NIR amplitude of accreting young sources.18:45 - Mathieu Vrard - Combining APOGEE with precise seismology from TESS CVZ data19:00 - Fábio Wanderley - Characterization of Hyades M dwarf stars from the APOGEE Survey
abstract
We apply a two-temperature synthetic spot model for identifying spot filling factor and spot temperature contrasts to APOGEE DR17 spectra in a selection of young star clusters, simultaneously fitting for spot parameters and effective temperature, Vsini, metallicity, and surface gravity. Spot presence and spot parameters in our stars are inferred by comparing observed stellar spectra to synthetic spectra with two temperature components and checking the quality of the fit against synthetic single temperature spectra. Our clusters are chosen from the K2 field spanning an age range from ~1 Myr to 2.7 Gyr, with kinematic membership information from Gaia EDR3, and literature period estimates from K2 light curves. With independent period information, this technique probes spot-activity relations, spot evolution, and radius anomalies across a wide range of ages. We also describe the synthesis of this technique with existing photometric techniques, such as the inference of starspots with light curves or with color-based spectral energy distribution fitting. Finally, we quantify the effects of a detailed starspot analysis on the inferred HR Diagram positions of these stars by comparing the outcomes of classical models with our SPOTS tracks.abstract
Ultracool dwarfs (UCDs) are stellar and substellar objects with effective temperatures below 3,000 K, spectral types later than M6, and masses below 0.1 solar masses. Precise measurements of ultracool dwarf radial and rotational velocities are important for mapping local stellar kinematics, identifying close binaries and measuring their orbits, identifying new members from young associations, and tracing angular momentum evolution. However, the current compilation of UCD high-resolution spectra is relatively small. We have compiled 184 UCDs observed with APOGEE DR17, ranging in spectral type from M5 to L2, the majority of which currently lack robust ASPCAP radial and rotational velocities. Using a Markov Chain Monte Carlo forward-modeling approach, we measure radial and rotational velocities for APOGEE UCD to median precisions of 0.3 km/s and 0.4 km/s and determine effective temperatures and surface gravities. Most of our sources are members of the Galactic thin disk, but we also identify 11 members of the intermediate thin/thick disk and 1 member of the halo. From 142 sources with multiple epochs, we identified 47 candidates with significant radial velocity variations. Our sample has a velocity dispersion of 35.2±0.2 km/s, equivalent to 2.6±0.2 Gyr based on empirical age-velocity dispersion relations, reflecting the sample bias toward young clusters. Our sample has a median vsini of 16 km/s, compared to APOGEE minimum vsini of 5 km/s.abstract
Researching the link between the young-stellar objects (YSOs) photometric near-infrared (NIR) variability and their accretion, we designed three APOGEE-2 plates that cover a big field of view in the Carina star-forming region. Several confirmed YSOs were observed, allowing us to go deeper into the photometric variability in young sources with broad-emission lines in the APOGEE-2 range. Using the VVV survey to quantified the NIR variability, and the multi-epoch spectra from APOGEE-2, we have found that, in general, sources that display signs of active accretion presents low photometric amplitude in Ks-band and a scattered profile in their Ks-band time series.abstract
Since its launch in 2018, the TESS satellite has observed hundreds of thousands of stars. The longest stellar observations occurred in the South and North Continuous Viewing Zones (CVZ) where the light-curve lengths can go as far as one year. This length allow us to perform precise seismology on those objects and use it to deduce precise stellar characteristics. In this talk we will present the first evolutionary status determination of red giant stars from the TESS South CVZ data and its merge with APOGEE data. We used a sample of more than 5000 stars for which oscillations were already detected and the global seismic parameters already determined. We gathered the results of different evolutionary status determination techniques on these data and found a consensus for more than 2000 stars. The agreement between the different techniques was around 20%, lower than for Kepler. We combined those data with the APOGEE measurements allowing a finer confirmation of the stars evolutionarys status. These results assess the possibility of determining the evolutionary status of red giant stars with TESS and pave the way for further combined spectroscopic and seismic red clump star identification which will be crucial to determine the age of stellar populations.abstract
APOGEE has observed a large sample of M dwarfs in the young (600 Myr) slightly metal rich Hyades open cluster. In this study we derive effective temperatures, surface gravities, metallicities and oxygen abundances for a sample of M dwarfs covering a Teff range from 3000 - 3700 K. The methodology adopted in the analysis is independent from ASPCAP, although based on the same 1-D plane-parallel LTE MARCS atmosphere models, the radiative transfer code Turbospectrum and the APOGEE DR17 linelist. Open clusters are excellent laboratories to test chemical homogeneity and metallicities as a function of stellar parameters. We will compare our metallicities with spectroscopic results for hotter Hyades stars from the literature. The results obtained will be compared with DR17 and potentially serve as calibrators to ASPCAP results.Plenary 3
Aug 12 10:00-11:30
Zoom Link TBC
10:00 - Cheng Li - MaNGA Legacy10:30 - Eleonora Zari - Hot Stars 10111:00 - Becky Smethurst - Quenching 101
abstract
abstract
Luminous hot stars dominate the stellar energy input to the interstellar medium throughout cosmological time, they are used as laboratories to test theories of stellar evolution and multiplicity, and they serve as luminous tracers of star formation in the Milky Way and other galaxies. For these reasons, one of the goals of SDSS-V is to provide a multi-epoch spectroscopic census of luminous and hot stars across the Galaxy, providing spatial and dynamic information together with estimates for masses, ages, metallicity, multiplicity, and other spectroscopic information. In this talk I will present an all-sky sample of such hot luminous OBA-type stars, which will provide targets for spectroscopic follow-up with SDSS-V. I will describe the distribution of such sample across the Galactic disc, and show that the spatial picture of the Milky Way's young disc structure is complex, and suggests that most young massive stars in our Galaxy are not neatly organised into distinct spiral arms. I will conclude by illustrating how the comprehensive spectroscopy to come from SDSS-V (yielding velocities, ages, etc.) will be crucial to investigate the dynamical properties of young massive stars, and the nature of spiral arms themselves.abstract
Galaxies 2
Aug 12 12:00-14:00
Zoom Link TBC
12:00 - Abhijeet Anand - The cool circumgalactic medium in SDSS galaxies12:15 - Gustavo Bruzual - Using the MaStar stellar library in population synthesis models12:30 - Mariana Cano-DÃaz - MaNDala: MaNGA Dwarf galaxy Sample VAC presentation12:45 - Catherine Fielder - Constraining the Milky Way's Ultraviolet to Infrared SED with Gaussian Process Regression: Is the Milky Way a Red Spiral13:00 - Jacob Ider Chitham - Spectroscopic follow-up of eROSITA Galaxy Clusters within SDSS-V13:15 - Nimisha Kumari - Exploring radiation hardness using SDSS-MaNGA survey13:30 - Jose Antonio Vazquez-Mata - An overview of the MaNGA Visual Morphology DR17 catalogue.
abstract
In order to study the circumgalactic medium (CGM) of galaxies we develop an automated pipeline to estimate the optical continuum of quasars and detect intervening metal absorption line systems with a matched kernel convolution technique and adaptive S/N criteria. We process ~ one million quasars in the latest Data Release 16 (DR16) of the Sloan Digital Sky Survey (SDSS) and compile a large sample of ~ 160,000 MgII absorbers, together with ~ 70,000 FeII systems, in the redshift range 0.35< z{abs}< 2.3. Combining these with the SDSS DR16 spectroscopy of ~1.1 million luminous red galaxies (LRGs) and ~200,000 emission line galaxies (ELGs), we investigate the nature of cold gas absorption at 0.5< z< 1. These large samples allow us to characterize the scale dependence of MgII with greater accuracy than in previous work. We find that there is a strong enhancement of MgII absorption within ~ 50 kpc of ELGs, and the covering fraction within 0.5r{vir} of ELGs is 2-5 times higher than for LRGs. Beyond 50 kpc, there is a sharp decline in MgII for both kinds of galaxies, indicating a transition to the regime where the CGM is tightly linked with the dark matter halo. The MgII covering fraction correlates strongly with stellar mass for LRGs, but weakly for ELGs, where covering fractions increase with star formation rate. Our analysis implies that cool circumgalactic gas has a different physical origin for star forming versus quiescent galaxies.abstract
I use the MaStar stellar library, as calibrated by MejÃa-Narváez et al. (2021), to build an updated version of the Bruzual & Charlot (2003) evolutionary synthesis models. I will compare the resulting models with models built with the same stellar evolutionary tracks but different stellar libraries to quantify the gains achieved by using MaStar.abstract
In this talk I will present the first version of the MaNGA Dwarf galaxy Sample (MaNDala) VAC. In this version of the sample we have 125 dwarf galaxies (M* < 109 MSun), for which we have performed a detailed photometric analysis using DESI Legacy images in three bands. In addition to the main photometric results, I will briefly explain the set of spectroscopically derived results using MaNGA data that are also available in our VAC. Finally I will present a few examples of the science cases that we will be able to study using this sample, which range from studies about the Star Formation Histories of this population of galaxies to their kinematics and behaviour within the fundamental relations of galaxies in the local Universe.abstract
Improving our knowledge of the global properties of the Milky Way (MW) is critical for connecting the detailed measurements only possible within our own galaxy to our understanding of the broader galaxy population. We train GPR models to map from galaxy properties that are well-measured for both the MW and external galaxies to broadband fluxes in a wide variety of photometric bands. The galaxy properties we use to predict photometric characteristics are stellar mass, apparent axis ratio, star formation rate, bulge-to-total ratio, disk scale length, and bar vote fraction. We use these models to estimate the global UV (GALEX FUV/NUV), optical (SDSS ugriz) and IR (2MASS JHKs and WISE W1/W2/W3/W4) photometric properties for the MW as they would be measured from outside, resulting in a full UV-to-IR spectral energy distribution (SED). Previously we established that the MW must lie in the star-forming regime in standard UV and IR diagnostic diagrams, in contrast to its position in the green valley in optical colour-mass diagrams. We find that this is characteristic of the population of red spiral galaxies, suggesting that the MW may be a member of that class. Even though each GPR model only predicts one band at a time, we find that the resulting MW UV-IR SED is in good agreement with SEDs of local spirals with characteristics broadly similar to the Milky Way, suggesting that we can combine the individual band fluxes with confidence.abstract
The final eROSITA all-sky survey (eRASS:8) will detect 10^5 clusters of galaxies via their extended X-ray emission. In order utilise the eROSITA cluster sample as a cosmological probe, it is necessary to precisely measure the redshift of each system. On average, eROSITA cluster redshifts measured from SDSS-IV/V optical spectroscopy are ten times more precise than those derived from photometry alone. This presentation includes details of the all-sky photometric follow up program used to obtain spectroscopic targets for SDSS-IV/V as well as results from spectroscopically confirmed clusters in the eROSITA Final Equatorial-Depth Survey (eFEDS).abstract
In this contribution, we use integral field spectroscopic data from the MaNGA survey to investigate radiation hardness within a representative sample of 67 nearby galaxies. The large wavelength range of MaNGA allows us to study the observational softness parameter (Vilchez & Pagel 1988) which is the ratio of the two emission line rations [OIII]/[OII] and [SIII]/[SII]. We analyze the relation between radiation hardness and various diagnostics sensitive to gas-phase metallicity, electron temperature and density, ionization parameter, effective temperature and age of ionizing populations. Low metallicity is found to be accompanied by hard radiation field though we do not find any direct evidence between radiation hardness and other nebular parameters. A comparison of MaNGA data with the photoionization models suggests that hard radiation fields from hot and old low-mass stars within or around star-forming regions might significantly contribute to the observed values of softness parameters in these star-forming galaxies. Such detailed studies and lesson learnt from them are useful in investigating the radiation hardness in high-redshift low-metallicity galaxies targeted by future ground and space-based telescopes such as James Webb Space Telescope and European Extremely Large Telescope.abstract
In this talk I will present a summary of the new data presented in the MaNGA Visual Morphology catalogue. This catalogue contains a direct visual morphological classification based on the inspection of image mosaics generated from a combination of SDSS and DESI Legacy Imaging Surveys images, for all the ~10 200 galaxies in the MaNGA DR17. After a digital image post-processing, we exploit the advantages of these images to identify inner structures, as well as external low surface brightness features for an homogeneous classification. We also provide a new estimate of the structural CAS parameters (Concentration, Asymmetry and Clumpiness) based on the DESI images. Finally, a general characterisation of these galaxies, in terms of their morphology, is also presented.ISM 2
Aug 12 12:00-14:00
Zoom Link TBC
12:00 - Enrico Congiu - Classification of emission-line nebulae in the PHANGS-MUSE sample12:15 - Carlos Espinosa-Ponce - Physical properties of HII regions of CALIFA survey12:30 - Sean Fillingham - Molecular Gas Content of a BreakBRD-MaNGA Galaxy12:45 - Adam Schaefer - Exploring the local scaling relations for N/O and their implications for galaxy evolution
abstract
Recent surveys like PHANGS-MUSE, SIGNALS, and soon LVM, offer us an unprecedented view of the ionized interstellar medium (ISM) of nearby star-forming galaxies. Their spatial resolution and spectral range allow us to identify, isolate and study in details single emitting clouds, while keeping a galactic scale view thanks to the large area covered. A correct classification of the ionized nebulae (e.g., HII regions, planetary nebulae, supernova remnants) is a critical step to properly study the ionized ISM and its role in galaxy evolution. Many classification schemes are available in the literature. Still, none of them can take advantage of all the information provided by integral-field spectrographs such as MUSE and LVM. In this talk, I will present the first results of a new algorithm that aims to reliably and objectively classify nebulae using the Bayesian principle of the odds ratio to compare each region to models representing the different classes of nebulae. The algorithm is applied to the nebulae identified in the PHANGS-MUSE survey to produce the most extensive catalog of classified ionized nebulae available in the literature. This catalog is part of the preparatory work aimed at developing a robust machine learning-based classification algorithm capable of identifying and classifying nebulae directly in the datacube, and that will be instrumental in analyzing data of future surveys of nearby galaxies, such as the LVM survey.abstract
The last catalog released of HII regions from CALIFA survey comprises the information of 27000 objects. In previous work, we explored the dependence on the distribution of HII regions sample on the BPT diagram with the morphological type and galactocentric distance. We found a relation between the strong emission lines of nebulae and the subjacent stellar populations' properties. In this work, we present the physical properties from HII regions sample: oxygen abundance, ionization parameter, the fraction of young stellar population, nitrogen-oxygen ratio, electronic density, and dust extinction (Av). We analyzed the dependence between the physical properties and the galactocentric distance, the morphological type, and the stellar mass of the respective host galaxies. We found a relation between the oxygen abundance of HII regions and the age and metallicity of underlying stellar populations.abstract
The BreakBRD sample of galaxies have disk morphologies that are characterized by centrally concentrated star formation and quiescent disks. Preliminary analysis suggests these galaxies are in the midst of “outside-in†quenching, which is fairly unusual for galaxies in this stellar mass range. Here we report the detection of CO in one of the BreakBRD galaxies that is also part of the SDSS IV - MaNGA sample. These new observations were carried out as part of a pilot Green Bank Telescope observing program in 2019B (PI: Dave Stark). This work will characterize the total cold gas content in this galaxy in an effort to better understand the nature of the cold gas reservoir and the mechanisms that are leading to the observed, centrally concentrated star formation distribution.abstract
The measured chemical abundances in galaxies are useful for constraining their formation histories and the details of their evolution. The abundance of oxygen has been shown to trace the buildup of stellar mass in galaxies on both global and local scales. Nitrogen, however, is produced on different timescales as oxygen, and therefore may provide a secondary constraint on our galaxy evolution models. I use data from the SDSS IV: Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey to investigate whether similar scaling relations hold for nitrogen as for oxygen. I find that the observed abundances cannot be explained by simple models for the evolution of nitrogen in galaxies. Contrary to previous literature, the ratio of N/O depends on the star formation rate, total stellar mass and sizes of galaxies. These results pose problems for the universal applicability of some optical gas-phase metallicity calibrations. They also hint that our understanding of how nitrogen is produced and dispersed within galaxies may require revision.Stars 2
Aug 12 12:00-14:00
Zoom Link TBC
12:00 - Katie Breivik - Where are APOGEE’s black hole companions?12:15 - Julio Chanamé - Exploring and exploting the coevality of the components of wide binaries12:30 - Christine Daher - A Closer Look at Stellar Rotation and the Close Binary Fraction through APOGEE12:45 - Matthew Green - 50000 Ellipsoidal Binary Candidates with TESS and SDSS-V13:00 - Thomas Masseron - The BACCHUS VAC: analysis of weak-lined features in APOGEE DR17 spectra13:15 - Nicholas Troup - Radial Velocity Monitoring in SDSS-IV & SDSS-V - -
abstract
The observation of gravitational waves from ~50 pairs of merging black hole and neutron star binaries by the LIGO-Virgo Collaboration offers the potential to use these populations as tools to study the formation of compact objects in binary systems. However, such mergers only account for a tiny fraction of all stellar-origin black holes formed in the Universe and could originate through pathways other than isolated binary star evolution. The population of black holes orbiting stars in the Milky Way offers an opportunity to study compact object formation with radial velocity and astrometric surveys that have complementary selection biases to gravitational wave detection. Since the detection of stars orbiting black holes is driven by the properties of the binary orbit and evolutionary phase of the observed star, direct connections to intermediate phases of binary evolution can be made, ultimately adding to our understanding of how binary stars evolve from birth all the way through to compact object merger. In this talk I will discuss how the relatively few black hole binary candidates observed by APOGEE can inform the distributions of natal kicks and initial mass ratios of compact object binary progenitors.abstract
The components of very wide binaries are expected to be stars of common origins, meaning that they should have very similar chemical compositions and share the same age. These simple properties make wide binaries extremely versatile tools for a variety of astrophysical tests, on areas as diverse as the determination of fundamental parameters of single field stars (metallicities, ages, etc.) to the testing and calibration of chemical tagging as an archaeological tool. However, only the co-chemical nature of their components has been largely validated by independent obervational means, while their coevality has been relatively harder to tackle. I will provide a review of what we know, empirically, about the degree of coevality of the components of wide binaries, and, in doing so, I will focus on two of the most recent applications of these objects: their use for constraining the initial-to-final mass relation of white dwarfs, and studying the reliability of recently proposed chemical clocks for the age dating of field stars.abstract
A number of stellar properties are derived from the high-quality spectra delivered by APOGEE, including a limited amount of rotational broadening in primarily main sequence (MS) stars. We have estimated additional rotational broadening for APOGEE Data Release 14 MS stars and red giants and have combined this information with APOGEE radial velocities and stellar ages derived via isochrone fitting (Sanders and Das 2018) to create a rich dataset for exploring stellar rotation’s relationship to stellar multiplicity. I will present our observed correlations between rotational speed vsini and the close binary fraction, as well as describe the connection between vsini, stellar age, and the close binary fraction and its relation to gyrochronology.abstract
Binaries with small orbital separations display photometric signatures that result from the tidal distortion of their component stars, as well as from Doppler beaming and from reflection. These signatures can be used to identify candidate non-eclipsing binary systems, producing a sample whose selection effects differ from those of any eclipsing binary catalogue. Confirmation of these binaries requires spectroscopic follow-up. We used the BEER algorithm (Faigler et al. 2011, 2013, 2015a, 2015b), which fits for BEaming, Ellipsoidal modulation and Reflection, to select 50,000 candidate binaries with orbital periods < 7 days. These candidates will be followed up by SDSS-V as part of an open fibre science proposal. In our talk we will present an overview of this sample, and show how it can be used to illuminate the underlying population of short-period binaries, in particular the distributions of periods and masses. We will also discuss the selection effects and contaminants of the sample, and show how SDSS-V spectroscopy will be vital for improving the sample purity. In addition, hidden among the sample are likely to be a number of binaries with non-accreting neutron star or black hole companions. We will demonstrate how we have selected promising candidates for such compact binaries, present our preliminary attempts to follow up on these candidates, and discuss the prospects for discovery of compact objects among our sample with SDSS-V.abstract
Weak-lined species in APOGEE spectra have been challenging and in some cases, could not be done with the standard ASPCAP pipeline as they require a boutique analysis in order to measure their abundances precisely. We have created a catalog containing approximately 120,000 high signal-to-noise giants from APOGEE DR17, for which we derive Na, V, S, Cu, Ce, Nd abundances and the 12C/13C isotopic ratio. An updated version of the BACCHUS (Brussels Automatic Code for Characterizing High accUracy Spectra; Masseron et al. 2016) code has been employed in the derivation of these abundances, relying on ASPCAP fundamental stellar parameters but also employing a dedicated set of individual line quality flags and a prescription for identifying upper limits. Using these newly derived abundances and ratios, we show how they compare to literature values, and provide examples of scientific projects that can be done with APOGEE and our new catalog, ranging from nuclear physics to Galactic chemical evolution and Milky Way population studies.abstract
In this presentation, we give an overview of the APOGEE-2 radial velocity monitoring programs. By re-observing select fields from APOGEE-1, these programs collected radial velocity measurements of ~4400 stars over a nine-year temporal baseline. Furthermore, all stars selected for these programs acquired a sufficient number of radial velocity measurements for Keplerian orbit fitting. We give a brief census of the types of stars observed and their constituent environments, and some interesting companions found orbiting these stars. In the course of discussing the overall quality of the data, we also discuss sources of short- and long-term instrumental causes of RV variations, as well as the challenges of combining data from multiple instruments and survey modes. Finally, we give an overview of the radial velocity monitoring programs slated for SDSS-V in the Milky Way Mapper program, as well as initial results from the early SDSS-V plate observations.abstract
Lightning 2
Aug 12 14:10-14:30
Zoom Link TBC
- Josh Speagle - Modelling Stochastic Star Formation Histories using Gaussian Processes - Elliott Khilfeh - Strong Accretion Signatures in the APOGEE Spectra - Adrian Diaz-Espinoza - Characterization of green valley galaxies in MaNGA survey - Benjamin Gibson - Untangling the Chemodynamics of the Stellar Populations in M31 - Yuanhao Shi - Label transfer between APOGEE, BOSS and LAMOST - Paula Jofre - Two sequences in the age-metallicity diagram - Lingfeng Wei - The stellar mass and 3-D velocity around the core of Orion Nebula Cluster - Julie Imig - 3D density modeling of the Galactic disk with APOGEE - Dilpreet Kaur - Metal-Poor Stars in APOGEE - Mirko Krumpe - HE SPATIAL CLUSTERING OF ROSAT ALL-SKY SURVEY ACTIVE GALACTIC NUCLEI V. The evolution of broad-line AGN clustering properties in the last 6 Gyr.
abstract
Recent work has shown that simple, random walk-inspired models for various components of star formation, gas cycling, and other self-regulatory mechanisms produce characteristic timescales and behaviors that appear to be a good match to simulations and observations. I will present an extension of this approach as a physics-based Gaussian Process that enables quick simulation and inference over star formation histories, and present preliminary results on using expected observational signatures to constrain portions of the model.abstract
Young stars possess strong magnetic fields that channel ionized gas from the interior of its circumstellar disc to the surface of the star. Upon impacting the stellar surface, the gas cools down, recombining and emitting hydrogen spectral lines. Measuring these emission lines can allow for the determination of the temperature and density of the gas in those accretion streams, and whether those parameters depend on the accretion rate. We present measurements of equivalent widths and line ratios for lines 11 − 20 of the Brackett series from APOGEE DR17 spectra of pre-main sequence stars. We identify the subset of these stars with strong detections of multiple lines, and fit the resultant line ratios to predictions of radiative transfer models. We present this preliminary catalog of APOGEE-detected accreting pre-main sequence stars, and the physical properties we infer for the strongest accretion streams, and describe plans for future work to calibrate the Br11 line luminosity as a proxy for the mass accretion rate.abstract
We propose a way to select green valley galaxies based on a spectroscopic criterion, which uses solely the equivalent width of the Halpha emission line. The proposed method is “blind†in the sense that it allows to select this type of galaxies, without the need to use the Color-Magnitude Diagram. To test our method we made use of the DR15 public data release of MaNGA - SDSS IV. In this poster we describe our method and show its capabilities and limitations. Finally also we show the results of a basic characterization of the sample of galaxies selected with it.abstract
Our detailed view of the Milky Way means we now have a good understanding of the chemical evolution, star formation, and merger history of our galaxy. One clear signature of the Milky Way’s formation history is the presence of kinematically and chemically distinct substructures within its disk. Establishing the ubiquity of chemodynamic substructures similar to the Milky Way’s will help us better understand galactic evolution. Unfortunately, it can be difficult to identify these substructures in external galaxies. Even in M31, the nearest massive disk galaxy, observing individual stars in its center cannot be done spectroscopically, as the stars there are too crowded. However, we can still understand their spatial trends by using integrated light spectroscopy, as APOGEE’s high spectral resolution (R~22,500) allows us to distinguish between multiple co-spatial stellar populations. We have obtained high-resolution, near infrared, integrated light spectra of ~1100 positions in the inner ~6 kpc of M31 with APOGEE. By fitting this data with A-LIST model spectra (SSP templates with common Age, [M/H], and [ð›¼/M]), we will gain more insight into the chemodynamic substructures in the inner part of M31, and compare them to those found in the Milky Way. Our findings will help guide future galactic evolution models by identifying the typical substructures found in Milky Way-like galaxies.abstract
We used the Cannon to transfer APOGEE labels to BOSS and LAMOST spectra. We show that stellar parameters for BOSS spectra can be obtained. We investigated how the number and distribution of labeled stars affects the reliability of the transfer between APOGEE and LAMOST.abstract
Using a selection of red clump stars from APOGEE DR17 it is possible to use C/N abundances as proxy for ages to see that the age-metallicity diagram in the solar neighborhood is composed by two sequences instead of a single blurry one. I will discuss the results published in Jofre 2021, recently accepted by ApJ.abstract
The Orion Nebula Cluster (ONC) constitutes an ideal target for understanding star formation theories since it is a close (~400 pc), young and actively star forming region. We aim to resolve the 3-D velocity as well as the mass information of the stars within 4’ around the Trapezium, the heart of ONC. Observational data includes 69 targets observed by Keck II NIRSPEC+AO and 172 sources observed with SDSS APOGEE. Using a Markov Chain Monte Carlo (MCMC) method, we fit for the radial velocity as well as effective temperature of our samples. Combined with the proper motion measured in Kim et al. (2019) along with several stellar evolutionary models, we interpolate the masses assuming a 2Myr age and construct a 3-D kinematic map of our samples. The computed velocity dispersions in all three directions are (σ(vα ),σ(vδ ),σ_(vr ) )=(1.76±0.12,〖2.16〗(-0.15)^(+0.14),〖2.54〗_(-0.17)^(+0.16) ) km/s. The slightly higher radial velocity dispersion compared with virial equilibrium model of ONC suggests that the core of ONC may not be fully virialized yet. Additionally, mass and velocity do not exhibit an apparent negative correlation under either evolutionary model as the simulation conducted in Bonnel et al. (2009) predicts due to gravitational fragmentation.abstract
The star formation history and evolution of the Milky Way disk is imprinted in the ages, phase-space information, and chemical compositions of stars. The final data release of the APOGEE survey will be used to create a 3-dimensional density map of the Milky Way disk as a function of age, metallicity, and alpha-element abundances. This will result in an unprecedented global view of our Galaxy, presenting new measurements of the Milky Way’s structural parameters including scale length, scale height, and disk flaring. We can use these results to explore new constraints on the global properties of the Milky Way including integrated colors, star formation histories, mass assembly, and metallicity trends across different stellar populations.abstract
The most metal-poor stars (with [Fe/H] < -2) form from relatively pristine gas which allows us to understand the creation of the elements in our universe (nucleosynthesis) as well as early stellar formation and galaxy assembly. The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a near-infrared survey whose goal is to determine the chemical abundances and stellar parameters for a large sample of red giants which includes metal-poor stars. The APOGEE Stellar Parameters and Chemical Abundances Pipeline (ASPCAP) that is used in the automated analysis of the data has been developed for the commonly found metal-rich stars. APOGEE’s ASPCAP pipeline does not characterize metal-poor stars well since they fall at the edge of its calibration grid. There are several metal-poor stars in the APOGEE samples with flags on the data. Re-analyses of the APOGEE data for metal-poor stars can solve this problem, providing stellar parameters and detailed abundances for a wide variety of elements. In this talk, I will present an analysis of two metal-poor stars, HE 1320-1339 and CS 22877-001, both of which have been previously observed in the optical. A comparison of the near-infrared vs. optical abundances and stellar parameters will be essential for understanding the limitations of the APOGEE spectra.abstract
This is the latest of our series of investigations of the clustering properties of luminous, broad-emission line active galactic nuclei (AGN) identified in the ROSAT All-Sky Survey (RASS) and Sloan Digital Sky Survey (SDSS). In this work, we measure the cross-correlation function (CCF) between RASS/SDSS DR14 AGN with the SDSS CMASS galaxy sample at 0.44< z< 0.64. We apply HOD modeling to the CCF along with the ACF of the CMASS galaxies. We find that the X-ray and optically selected AGN clustering properties at 0.44< z< 0.64 are statistically identical, finding typical M_DMH ~ 10^{12.7} h^{-1} M_SUN. We also find weak positive correlation with the mean DMH mass with L_X and M_BH,X-ray. We compare our measurements presented in this work with our earlier works at lower redshift range, equivalent to a combined look-back time of 6 Gyr. We find (i) no significant dependence of typical M_DMH on L_Bol/L_Edd (ii) weak positive clustering dependences of typical M_DMH on L_X and M_BH, (iv) increase of M_DMH with cosmic time for a given L_X as well as for a given M_BH.Plenary 4
Aug 12 16:00-17:30
Zoom Link TBC
16:00 - Pavan Bilgi - LVM Instrument Overview and Status16:30 - Rachael Beaton - COINS: the Committee On INclusion in SDSS17:00 - Jorge Barrera-Ballesteros - ISM 101
abstract
The Local Volume Mapper (LVM) is a facility designed to provide a contiguous 2,500 deg2 integral-field survey over a 3.5 year period from Las Campanas Observatory in Chile. In this talk, an overview and status update for the LVM instrument will be presented. Each spaxel in the LVM IFU will probe linear scales that are sub-parsec (Milky Way) to ∼10 pc (Magellanic Clouds). LVM's spectral resolution is R = λ/∆λ ∼ 4, 000 which will probe velocities of 33 kms-1 (1 σ) from 365 nm to 950 nm. LVM will be using four 16-cm telescopes that feed its three three-channel spectrographs. One of the telescopes will carry the bulk of the science load with ∼1,800 fibers coupled to the field via a pair of lenslet arrays. Two telescopes will be used to measure the night sky spectra in fields that flank the science field, and a fourth telescope will contemporaneously monitor bright standard stars to determine atmospheric extinction. We expect the LVM instrument to deliver percent-level precision on important line ratios down to a few Rayleigh. The three spectrographs comprise the heart of LVM and these are being built by Winlight corporation in France. They are based on those produced for the Dark Energy Spectroscopic Instrument (DESI). This presentation will go over the high-level system design of the LVM instrument including the lenslet-coupled fiber IFUs, telescopes, guiding and acquisition system, calibration systems, enclosures, and spectrographs.abstract
abstract
AGN 2
Aug 12 18:00-20:00
Zoom Link TBC
18:00 - Caleb Lammers - AGN-Driven Quenching in SDSS-IV MaNGA Galaxy Star-Formation Histories18:15 - Wenhao Li - Multi-wavelength AGN in post-merger galaxies18:30 - James Negus - Determining if Coronal Line Emission Can Effectively Trace AGNs in MaNGA18:45 - Namrata Roy - Feeding and feedback via large scale AGN driven winds in nearby elliptical galaxies
abstract
Understanding the effects of active galactic nuclei (AGN) feedback on host galaxy star-formation is an open problem in galaxy evolution. Using DR15 of the SDSS-IV MaNGA survey, we identify 279 face-on galaxies hosting AGNs and create a control sample by selecting 2 mass- and redshift-matched galaxies for each AGN galaxy. With stellar population information from the PIPE3D pipeline (Sánchez et al. 2016) and Gaussian processes from the Dense Basis SED fitting code (Iyer et al. 2019), we reconstruct spatially resolved non-parametric star formation histories (SFHs) for each of the AGN and control galaxies. Examining these SFHs reveals notable differences in the quenching behaviour between the two samples. Specifically, we observe more prevalent inside-out quenching behaviour in the galaxies hosting AGNs than the control galaxies. The central spaxels of AGN galaxies (within R < R_eff/4) quenched a median of 1.2 Gyr before the central spaxels of control galaxies. Additionally, quenching in the center of galaxies hosting AGNs is generally less rapid (0.26 Gyr) than central quenching in the control galaxies (0.13 Gyr). However, quenching timescales in the outskirts of high stellar mass galaxies hosting AGNs are more rapid (0.16 Gyr vs. 0.24 Gyr). Our results provide evidence for inside-out AGN-driven quenching in high stellar mass MaNGA galaxies which is generally less rapid in the central regions but more rapid in the outskirts as compared to the control galaxies.abstract
It is well known that galaxy mergers can trigger both star formation and an Active Galactic Nucleus (AGN). The AGN is expected to quench star formation through “feedback†processes, by heating or expelling gas out of the galaxy, leaving behind a merger remnant. Unfortunately, confirming that mergers trigger AGN is observationally challenging, because AGN in different merger stages can have variable luminosities and lifetimes. In addition, a multi-wavelength approach is required to provide a complete census of AGN. Here I present results based on a volume limited (0.02< z< 0.06, 9.0< logM< 12.0), visually identified sample of post-merger galaxies from SDSS. I will describe the multi-wavelength AGN demographics of this sample using Chandra and XMM X-ray data, optical BPT diagnostics based on SDSS single-fiber spectra, WISE infrared color and FIRST radio data. The multi-wavelength AGN frequency in post mergers turns out to be significantly higher (> 4.5 sigma) than in non-merging galaxies, which confirms that mergers do trigger AGN.abstract
The fundamental nature and extent of the coronal line region (CLR), which may serve as a vital tracer for Active Galactic Nucleus (AGN) activity, remain unresolved. Previous studies suggest that the CLR is produced by AGN-driven outflows and occupies a distinct region between the broad line region and the narrow line region, which places it tens to hundreds of parsecs from the galactic center. Here, we investigate 10 coronal line (CL; ionization potential & 100 eV) emitting galaxies from the SDSS-IV MaNGA catalog with emission from one or more CLs detected at ≥ 5σ above the continuum in at least 10 spaxels - the largest such MaNGA catalog. We ï¬nd that the CLR is far more extended, reaching out to 1.3 - 23 kpc from the galactic center. We cross-match our sample of 10 CL galaxies with the largest existing MaNGA AGN catalog and identify 7 in it; two of the remaining three are galaxy mergers and the ï¬nal one is an AGN candidate. Further, we measure the average CLR electron temperatures to range between 12,331 K - 22,530 K, slightly above the typical threshold for pure AGN photoionization (∼ 20,000 K) and indicative of shocks (e.g., merger-induced or from supernova remnants) in the CLR. We reason that ionizing photons emitted by the central continuum source (i.e. AGN photoionization) primarily generate the CLs, and that energetic shocks are an additional ionization mechanism that likely produce the most extended CLRs we measure.abstract
We are investigating a population of relatively common early-type galaxies (ETG), named “red geysersâ€, identified in integral-field spectroscopy from the SDSS IV-MaNGA survey that show possible signature of “maintenance mode feedback†in typical ETGs. These quenched galaxies maintain a low level of star formation and are characterized by a signature bi-symmetric pattern in spatially resolved maps of strong emission lines which possibly traces large scale ionized wind. Radio continuum data from VLA FIRST reveal that they host low-luminosity radio AGNs in their center. Further evidence for the centrally driven wind has been obtained through higher resolution (R ~ 8000) followup of 2 red geysers using the Keck Echellete Spectrograph and Imager instrument. Additionally, a large fraction (~80%) of red geysers host significant amounts of cool neutral gas (M_cool ~ 10^8 Msolar) in the interstellar medium (ISM), traced by clumpy sodium (NaD) absorption. This cool gas is spatially offset from both the ionized wind and the stellar velocity gradient and shows distinct signatures of inflow into the central regions of the galaxies. This inflowing cooler gas might fuel the low luminosity radio-mode AGNs in the galaxies. More recently, we have studied the red geysers with low-frequency array (LOFAR) radio continuum data at 150 MHz to analyze the morphology of the radio emission. In this talk, I shall give a brief overview of the properties of this interesting red geyser class of objects.Milky Way 2
Aug 12 18:00-20:00
Zoom Link TBC
18:00 - Gregory Green - Deep Potential: Recovering the Gravitational Potential from a Snapshot of Phase Space18:15 - Danny Horta - Chemo-dynamically characterising halo substructure in the Milky Way with stellar surveys18:30 - Shobhit Kisku - The chemodynamical properties of the Splash according to APOGEE18:45 - James Lane - The Stellar Mass of Gaia-Enceladus with Gaia and APOGEE19:00 - Jianhui Lian - Quantifying radial migration in the Milky Way: Inefficient over short timescales but essential to the outer disc19:15 - Farnik Nikakhtar - APOGEE on FIRE: applying Gaussian Mixture models for objective classification of structures in the APOGEE-Gaia mocks and in FIRE simulations19:30 - Hans-Walter Rix - On what orbits are stars born?19:45 - Lekshmi Thulasidharan - Constraining the kinematics of Radcliffe wave
abstract
One of the major goals of the field of Milky Way dynamics is to recover the gravitational potential field. Mapping the potential would allow us to determine the combined spatial distribution of baryonic and dark matter throughout the Galaxy. I will present a novel method for determining the gravitational field from a snapshot of the phase-space positions of stars, based only on minimal physical assumptions. This method makes use of powerful techniques recently developed in the field of Deep Learning to obtain a smooth, differentiable approximation of the stellar phase-space distribution function, and then to directly solve the collisionless Boltzmann equation under the assumption of stationarity. This method is far more flexible than parametric methods, which fit narrow classes of analytic distribution functions and gravitational potentials to the data. Deep Potential offers a promising approach to determining the density structure of the Milky Way, and will be able to leverage the rich information on stellar kinematics in the disk of the Galaxy delivered by SDSS-V.abstract
The Galactic stellar halo hosts a swarm of debris resulting from cannibalised dwarf galaxies that have been accreted via the process of hierarchical mass assembly. The chemo-dynamical information recorded in the stellar populations associated with such systems helps unravel their nature, which in turn places constrains on the mass assembly history of the Milky Way. Using the latest APOGEE and Gaia data releases, I will show preliminary results from a project working towards unravelling the nature and reality of halo substructures identified in recent years.abstract
We aim to constrain the nature of the Splash population, which has recently been identified by various groups. This population is thought to result from the heating of the early disk caused by the accretion of Gaia-Enceladus/Sausage. We study the ages, chemodynamical properties and spacial distribution of Splash stars on the basis of APOGEE, Gaia and AstroNN data to better understand the effects of this merger.abstract
The halo of the Milky Way consists of a rich assortment of stellar populations, many of which are remnants of accreted dwarf galaxies. The last substantial accretion event, dubbed Gaia-Enceladus, was a disruptive episode in the history of our Galaxy, and debris from the merger comprises a large fraction of the nearby stellar halo. Despite the importance of this population, its mass has only been estimated indirectly. I present initial results of an effort to directly measure the stellar mass of the Gaia-Enceladus remnant with a Bayesian approach using Gaia and APOGEE data. A high purity sample of Gaia-Enceladus stars are selected using distribution functions representing major stellar halo populations. I outline a novel technique for correcting selection biases which arise from using such a sample of stars. This method also addresses biases arising from the APOGEE selection function, dust extinction, and metallicity dependence in the stellar population.abstract
Stellar radial migration plays an important role in reshaping a galaxy’s structure and the radial distribution of stellar population properties. In this talk I would like to introduce our recent work on radial migration, which revisited reported observational evidence for radial migration and quantify its strength using the age–[Fe/H] distribution of stars across the Milky Way with APOGEE data. We derived the strength of radial migration by decomposing the metallicity distribution function (MDF) of mono-age young populations into different components that originated from various birth radii. The decomposition results suggest limited short distance radial migration and inefficient long distance migration in the Milky Way during the last few Gyrs. We also show that the observed age–[Fe/H] distribution in the outer disc beyond 15 kpc is remarkably consistent with the prediction of pure radial migration from smaller radii, suggesting a migration origin of the very outer disc. We present an estimate of the intrinsic metallicity gradients at ages of 2 and 3 Gyr, which are −0.061 dex/kpc and−0.063 dex/kpc, respectively.abstract
The standard picture of galaxy formation motivates the decomposition of the Milky Way into 3-4 stellar populations with distinct kinematic and elemental abundance distributions. To test this idea, we construct a Gaussian mixture model (GMM) for both simulated and observed stars in the Solar neighborhood, using measured velocities and iron abundances as the distributions to be decomposed. We compare results for the APOGEE-Gaia DR16 crossmatch catalog of the Solar neighborhood with those from a suite of synthetic APOGEE-Gaia crossmatches constructed from FIRE-2 cosmological simulations of Milky Way-mass galaxies. We find that in both the synthetic and real data, the best-fit GMM uses five independent components, some of whose properties resemble the standard populations predicted by galaxy formation theory. Two components can be identified unambiguously as the thin disk and another as the halo. However, instead of a single counterpart to the thick disk, there are three intermediate components with different age and alpha abundance distributions (although these data are not used to construct the model). We use decompositions of the synthetic data to show that the classified components indeed correspond to stars with different origins.abstract
Understanding the orbit distribution of our Galaxy is a central goals of SDSS-V's Milky Way Mapper program. We have a chance to map the orbit (and orbital phase!) structure of young stars across the Galactic disk, which may tells us on which orbits the cold ISM moves that actually formed stars. To shape our thinking about what SDSS-V can deliver, I will present results from an analysis that has recently carried out (by J. Coronado and V. Fürnkranz) about the orbit--phase distribution of young stars, using Gaia and LAMOST. If one looks at orbits that contain one young cluster or association, one often finds many more distinct associations on the same orbit but at different orbital phases, like pearls on a string. With SDSS-V's dense sampling, we can map the distribution of seemingly special orbits in the Solar neighbourhood, where stars have preferentially formed of late.abstract
The Radcliffe wave is a wave-like structure formed by the young star forming regions. Our preliminary results focus on the kinematics of this structure to understand the nature of this oscillation. Taking advantage of the proper motion of young stars along the Radcliffe wave from Gaia Early Data Release 3, we constrain the kinematics of this structure, by studying the distribution of the median vertical velocity and extend it further as a function of the longitude. Using a combination of the chemical abundances and radial velocities of these stars provided by the Milky Way mapper in the SDSS-V, we aim at constraining the nature of this oscillation.Plenary 5
Aug 16 10:00-11:30
Zoom Link TBC
10:00 - Thaisa Storchi-Bergmann - The relation between Supermassive Black Holes and their host galaxies probed by the MaNGA-SDSS survey10:30 - Niall Deacon - Education and Public Outreach in SDSS11:00 - Anne-Marie Weijmans - SDSS Data 101
abstract
The evolution of galaxies is connected to that of their nuclear Supermassive Black Holes (SMBHs) via their feeding and feedback processes that can be observed in Active Galactic Nuclei (AGN). I will discuss what we have been finding from the analysis of MaNGA datacubes of AGN hosts and a control sample of non-active galaxies of the near Universe in terms of their stellar population and ionized gas properties and compare our results with those of other groups. We have applied the technique of stellar population synthesis to investigate the stellar age spatial distribution and its relation with the AGN properties, finding a significant difference relative to the control galaxies only in the most luminous AGN hosts. These AGN hosts show a larger contribution from young stars (106-108 yr) to their stellar population in the inner regions, opposite of what would be expected if the AGN would halt star formation in their hosts. The analysis of the gas excitation and derived star-formation rates (SFR) -- in the regions not ionized by the AGN, also shows a higher SFR when compared to the control galaxies in early-type AGN hosts, being similar to those of the controls for late-type hosts. On the other hand, the emission-line profiles of AGN hosts usually show larger widths than those of the control galaxies, revealing the presence of some mechanical feedback from the AGN, that nevertheless seems not to be strong enough to halt or decrease the SFR in the host galaxies during the on-going activity cycle.abstract
abstract
SDSS is really good at generating lots of data. We collect data at our telescopes at Apache Point and Las Campanas Observatories. We reduce and process all that data to generate spectra, maps, abundances and catalogs. And then we create even more data as we do our science and put together value added catalogs in the process. Where does all that data go, and what is the best way for you to access and interact with the data to do your science? In this talk we’ll go over the various data products that are available to you as SDSS members, and we will demonstrate the various platforms that you can use when downloading, viewing, visualising and analysing SDSS data. We’ll also talk about the data release process, and how your catalogs can become part of one of the next SDSS data releases!Lightning 3
Aug 16 12:00-12:30
Zoom Link TBC
- Gaoxiang Jin - An IFU View of the AGN in MaNGA Galaxy Pairs - Alicia Savelli - Analogues of the Milky Way (and local group) in Cosmological Simulations - Megan Davis - A Multi-Epoch Spectral Visualization Tool - Rachael Beaton - The Outer Disk is Still (Structurally) Weird - Jennifer Locke - Metallicity Gradients in Simulated Tidal Streams - Gabriele Ilha - Dissecting the inner region of Red Geysers with GMOS and MaNGA - Aidan Subrahimovic - Searching for Orphan in APOGEE - Gloria Fonseca Alvarez - Accretion rates of reverberation mapped quasars - Sioree Ansar - Bar Formation and Destruction in the FIRE2 Simulations - Rebecca Ceppas de Castro - Can we recognize the effects of dust attenuation on the size evolution of simulated galaxies? - Fábio Wanderley - Characterization of Hyades M dwarf stars from the APOGEE Survey - Jeongin Moon - Mock Challenges for SDSS-IV eBOSS DR16 Galaxies
abstract
The role of active galactic nuclei (AGNs) during galaxy interactions and how they influence the star formation in the system are still in debate. We use the sample of 1156 galaxies locating in galaxy pairs or mergers (hereafter `pairs') from the MaNGA survey. This pair sample was selected through their velocity offsets, projected separations, and morphological classifications, further classified into 4 cases along the merger sequence based on morphological signatures. We then identify a total of 61 (5.5%) AGNs in pairs based on the emission-lines diagnostics. No clear evolution of the AGN fraction is found either along the merger sequence or compared to isolated galaxies (5.4%). We observe a higher fraction of passive galaxies in galaxy pairs, especially in the pre-merging cases, and discuss the related environmental dependence. Compared to isolated AGNs, the global stellar mass, star formation rate (SFR), and central Σ[OIII] of AGNs in pairs have similar distributions. AGNs in pairs show radial profiles of increasing specific SFR and declining Dn4000 from center to outskirts, with no significant difference from isolated AGNs. This is clearly different from star-forming galaxy (SFG) pairs, in which enhanced central star formation have been reported and are also found in our sample. AGNs in pairs have lower Balmer decrements at outer regions, indicating possibly less dust attenuation. Our findings suggest that these AGNs are likely undergoing an inside-out quenching and the merger impact on the star formation in AGNs is less prominent than that in SFGs.abstract
The Milky Way is our most significant and detailed source of data in terms of galaxy formation and evolution on a stellar scale. If we are to ever apply what we are learning about the Milky Way in an extragalactic context, we must first determine how strongly and how accurately the Milky Way represents a “typical†spiral galaxy. Although there has been a rise in effort in recent years to make this distinction through observational studies, there has not been as much progress in the way of galaxy simulations. Our research looks at galaxies from the EAGLE suite of cosmological simulations and their properties as they form and evolve over time and space. “Milky Way Analogues†are selected from the simulations based on observed properties of the Milky Way, and are used to examine their likeness with respect both to the remaining galaxies in the simulation and to our understanding of the Milky Way from observations. Through our research, we hope to understand what makes a galaxy “typical†and to refine our definition of “Milky Way-nessâ€. In this talk, I will show how the Milky Way Analogues from EAGLE look at z=0 and the self-similarities and differences in how they evolve through the simulations.abstract
The presentation of a developing Python tool that allows for access and visualization of time-domain SDSS-V spectra, remotely. The tool can be found here: https://github.com/megcdavis/SDSS_SpecViewerabstract
I will present work on the Outer Disk by Princeton undergraduate Sydney Evans using our expanded outer disk sample. Both the orbital parameters and the chemistry suggest that structures far out of the disk plane are extremely disk like. Thus, many of the apparent halo-substructures at low-latitude are just the outer disk being (structurally) weirder than we thought.abstract
In the hierarchical paradigm of galaxy formation, massive galaxies like the Milky Way (MW) and Andromeda (M31) are built up over time partially through the accretion of smaller galaxies. By studying the remnants of these accreted galaxies, we can not only learn both about the mass assembly of the main host galaxy, but also about the properties of the accreted galaxies. Tidal streams are formed when an accreted galaxy is tidally disrupted, and one way we can constrain the mass of the tidal stream progenitor is to measure the metallicities of its stars. However, some streams have been observed to have metallicity gradients such as the Giant Stellar Stream (GSS) in M31 (Escala et al. 2021) as well as in the Sagittarius Stream (Sgr) in the MW (Hayes et al. 2020). If a stream has a metallicity gradient, the mean metallicity we measure will be dependent on what portion of the stream is observable. For example, much of the GSS is obscured by the disk of M31. We are using simulated MW-mass galaxies from the FIRE-2 suite to quantify the relationship between observed metallicity gradients in streams at present day and the metallicity gradients and total masses of their progenitors.abstract
Red Geysers are quiescent galaxies that show a bi-polar outflow, but the mechanism that produces this outflow is still unclear. For the prototype of this class of galaxies (Akira galaxy), the bipolar outflow probably is originated in a low-luminosity AGN (Active Galactic Nuclei). We have used data cubes from MaNGA (Mapping Nearby Galaxies at APO) project from SDSS-IV to select and analyze a sample of Red Geysers. The following selection criteria were used to select the Red Geyser sample: rest frame color NUV−r>5, star formation rate with log(SFR[M☉/yr]< −2), bi-symmetric pattern in Hα-EW maps aligned with the gas kinematic axis and misaligned with the stellar kinematic axis, velocity fields of Hα reaching values of ±300 km/s and being at least 1.5 times as high as the values of the stellar velocity fields. We measured the orientation of the kinematic axis of stellar and gas velocity fields and added the following criteria: difference in the orientation of the kinematic axis of stellar and gas velocity fields of 10º< ∆PA< 170º. The selected sample is composed of 92 galaxies and only 11% of them have gas ionization caused by an AGN in the nuclear region. We selected 9 of the 92 Red Geysers to observe with the GMOS (Gemini Multi-Object Spectrographs) instrument from the Gemini telescope. We will present preliminary results for 9 Red Geysers observed with GMOS.abstract
Stellar streams are long curvilinear overdensities of stars found in the halo of large galaxies like the Milky Way, and are relevant to the field of galactic archaeology for their dynamic relation to the past of their host galaxies. The Orphan stream makes up one of the longest stellar streams orbiting the Milky Way, estimated to be ~150 kpc in length and wrapping around the Milky Way in multiple spirals. Our project utilizes APOGEE DR17 data to search for potential stream members, employing selective methods in kinematic and photometric spaces to identify potential members of the stream. Once isolated, we will use data on these stream members to chemically characterize Orphan, potentially gaining insight into its dynamic past and determine the origin of one of the Milky Way halo's largest stellar structures.abstract
The Sloan Digital Sky Survey Reverberation Mapping Project (SDSS-RM) has resulted in accurate black hole masses for over 100 quasars from emission-line reverberation mapping. This sample, combined with contemporaneous, multi-wavelength SEDs will improve accretion rate measurements and bolometric corrections for a large number of quasars.abstract
One of the long standing questions about bar instabilities in galaxies is how do they form. Do they form during galaxy interactions or do they form in isolation during secular evolution of galaxies? Studies using individual galaxy formation simulations have explored both formation mechanisms in controlled simulations with fine tuned initial conditions. Once formed, the bars in these systems are seen to last for more than a few Gyrs. Do the bars in galaxies seen in observations have such stability or are they transient in nature? Cosmological simulations provide a more realistic environment for bar evolution as galaxies interact and merge with multiple satellite galaxies throughout evolution history. In this work, for the first time, we look at the 13 high resolution Milky Way mass galaxies in the FIRE2 (Feedback In Realistic Environments) suite of zoomed-in cosmological simulations to find out all the barred galaxies. We find signatures of both -bar formation due to satellite interaction and through secular evolution of a galaxy. The bars m12b and m12f oscillate with different frequencies in space and time, and some of the bars show transient nature, for example the bar in simulation m12m gains maximum strength at a lookback time of 1065 Myrs and dissolves into an x-shaped bulge at the end of evolution.abstract
Cosmological hydrodynamical simulations, such as SIMBA, provide a systematic way of analysing and tracking galaxies as they evolve through time. The truths provided by simulations can serve as a probe to study how the overall evolution of galaxies can be attributed to their different components. However, the results obtained from these simulations are not directly comparable to observational data, as they present the mass distribution of stellar, gas, and dust particles, but don’t necessarily model the resulting light distribution. In our research, we use the Powderday Radiative Transfer Package to study the effects of dust, and its spatial distribution, on how we perceive the size evolution of galaxies. Consequently, we hope to make more realistic comparisons between observations and simulation results in the future. In this talk, I will present our first results of half-light size measurements of SIMBA simulated galaxies at different redshifts, and relate them to the spatially resolved attenuation for selected galaxies.abstract
APOGEE has observed a large sample of M dwarfs in the young (600 Myr) slightly metal rich Hyades open cluster. In this study we derive effective temperatures, surface gravities, metallicities and oxygen abundances for a sample of M dwarfs covering a Teff range from 2800 - 3700 K. The methodology adopted in the analysis is independent from ASPCAP, although based on the same 1-D plane-parallel LTE MARCS atmosphere models, the radiative transfer code Turbospectrum and the APOGEE DR17 linelist. Open clusters are excellent laboratories to test chemical homogeneity and metallicities as a function of stellar parameters. We will compare our metallicities with spectroscopic results for hotter Hyades stars from the literature. The results obtained will be compared with DR17 and potentially serve as calibrators to ASPCAP results.abstract
I will briefly describe our recent eBOSS DR16 mock challenge supporting paper (MNRAS, 505, 377-407 - 2021), functional to the final analysis of the extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 16 (DR16) galaxy sample. In particular, I will highlight how we constructed high-fidelity HOD-based catalogs from the Outer Rim simulation using the NERSC supercomputer, and the pipeline we developed for testing and validating three complementary redshift space distortion (RSD) models in configuration and Fourier space, adopted for the analysis of the complete DR16 eBOSS sample of Luminous Red Galaxies (LRGs).Career Panel
Aug 16 12:30-13:30
Zoom Link TBC
Instrumentation Panel
Aug 16 14:00-15:00
Zoom Link TBC
Julia Brady
Alicia Lanz
Guillermo Blanc
Niv Drory
Tom O'Brien
Andres Almeida
Alicia Lanz
Guillermo Blanc
Niv Drory
Tom O'Brien
Andres Almeida
Data Workshop
Aug 16 15:00-17:00
Zoom Link TBC
15:00 - Miguel Aragon - A virtual Reality tour inside SDSS15:15 - Maria Argudo-Fernández - Working with MaNGA VACs using Marvin15:30 - Jordan Raddick - SciServer and SpecDash: New tools for online science15:45 - Jordan Raddick - A Brand New SkyServer16:00 - Anne-Marie Weijmans - Data Hangout Session
abstract
It has been 8 years since the Flight though the SDSS Universe animation was officially released. In this talk I will present a new multiplayer VR interactive visualization of the SDSS on the Oculus Quest system. The new dataset features improved galaxy representations created with artificial intelligence.abstract
Marvin is a complete ecosystem designed for overcoming the challenge of searching, accessing, and visualizing the MaNGA data. Marvin not only contains the official MaNGA data products but also approved SDSS/MaNGA Value Added Catalogues elaborated by the MaNGA science collaboration. VAC data, either whole catalogues or for individual targets, are accessible via Marvin Tools, a Python package designed to provide complete programmatic control over the data in a convenient way and publication-quality visualization. The tools also allow accessing individual data files locally or remotely, as well as remotely query the vast MaNGA dataset and retrieve exactly the data subsets you want. This is a hands-on Marvin session co-lead by MaNGA Value Added Catalogues (VACs) owners and the Marvin Team. We will show some tutorials on how to access and use data from different VACs for the analysis of MaNGA galaxies with Marvin.abstract
SciServer is the science platform for SDSS catalog data. The site (www.sciserver.org) offers free browser-based access to all catalog data products from all data releases from all phases of the SDSS. SciServer allows you to write create and run online Jupyter notebooks to run Python with no initial setup required – new users can perform analyses and visualize results immediately. SciServer also offers dataset management and sharing capabilities, meaning you can upload and cross-match your own and share with colleagues and students.The newest SciServer tool is SpecDash, a new application for displaying and analyzing one-dimensional spectra. SpecDash is available as an interactive or programmable Jupyter notebook widget in SciServer-Compute, as well as stand-alone website. Users can load and compare multiple spectra at the same time, overlay error bars, spectral masks and lines, and show individual exposure frames, sky background and model spectra. Spectral regions can be interactively selected for fitting the continuum or spectral lines with several predefined models, and spectral smoothing can be performed with with several kernels. All spectra and models can be downloaded, shared, and then uploaded again by other users. Learn how to use SciServer in your research and teaching, and to see examples of new research notebooks and educational activities designed and implemented by collaboration members.abstract
SkyServer (https://skyserver.sdss.org) has been the home of the catalog data for the SDSS since the Early Data Release in 2001. It is a tribute to the usefulness of SDSS data that the site is still regularly used 20 years later, but it by early 2021 it still looked and behaved like a 2001-era website. We have completely redesigned the SkyServer site, using modern web technology and usability approaches. We have also integrated SkyServer into the SciServer science platform (www.sciserver.org), making it easier than ever to connect data exploration through SkyServer with data analysis through CasJobs and SciServer Compute. Come to this talk for a demo of the completely redesigned SkyServer, and to learn how to use it to do meaningful scientific research and education.abstract
How do I get started working with SDSS data? What is the best way to make a value added catalog? What happens during a data release? And what was the password again? If you have these or any other questions related to SDSS data, then come hang out with the SDSS data team and ask us anything! (and if you don't have any questions but just want to listen in, you're very welcome too!)Poster Hour
Aug 16 17:00-18:00
Zoom Link TBC
Justus Neumann
Joshua Povick
Elisa Rita Garro
Hector Hernandez Toledo
José Luis Carrillo MartÃnez
Alejandro Miguel MunguÃa-Córdova
Bárbara Rojas-Ayala
Paulo Vasquez
Gaoxiang Jin
Hunter Campbell
Adrian Diaz-Espinoza
Jeongin Moon
Yuanhao Shi
Benjamin Roulston
Gabriel Luan Souza de Oliveira
Andres Almeida
Victoria Bonidie
Alicia Savelli
Andromeda Swissdorf
Sina Babaei Zadeh
Lucas Seaton
Sioree Ansar
Rebecca Ceppas de Castro
Ilija Medan
Bokyoung Kim
Emma Galligan
Daniella Morrone
Vivian Carvajal
Lina Pulgarin Duque
Abhijeet Anand
Joshua Povick
Elisa Rita Garro
Hector Hernandez Toledo
José Luis Carrillo MartÃnez
Alejandro Miguel MunguÃa-Córdova
Bárbara Rojas-Ayala
Paulo Vasquez
Gaoxiang Jin
Hunter Campbell
Adrian Diaz-Espinoza
Jeongin Moon
Yuanhao Shi
Benjamin Roulston
Gabriel Luan Souza de Oliveira
Andres Almeida
Victoria Bonidie
Alicia Savelli
Andromeda Swissdorf
Sina Babaei Zadeh
Lucas Seaton
Sioree Ansar
Rebecca Ceppas de Castro
Ilija Medan
Bokyoung Kim
Emma Galligan
Daniella Morrone
Vivian Carvajal
Lina Pulgarin Duque
Abhijeet Anand
Plenary 6
Aug 17 10:00-11:30
Zoom Link TBC
10:00 - Benny Trakhtenbrot - Quasars 10110:30 - Boris Gaensicke - White Dwarfs 10111:00 - Renbin Yan - MaStar Overview
abstract
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Data 2
Aug 17 12:00-14:00
Zoom Link TBC
12:00 - Jonathan Bird - The Galactic Genesis Survey - Red Giants in the era of SDSS-V 12:15 - Richard Pogge - The Robotic Focal Plane Systems for SDSS-V12:30 - Hans-Walter Rix - Selection Functions: Why we need to know them, and what to do with them.12:45 - Meszaros Szabolcs - The validation of Milky Way Mapper data13:00 - Andrew Tkachenko - The Milky Way Mapper survey calibration plan
abstract
Galactic Genesis is a previously unprecedented survey of 5 milliabstract
Update on the status of integration, testing, and deployment of the two robotic fiber positioner Focal Plane Systems (FPS) for the Sloan and Du Pont 2.5-m telescopes. The Sloan FPS unit will be shipped to Apache Point at the end of Summer 2021 and be commissioned in the August/September time frame, while the Du Pont FPS unit will be completed and shipped to Chile later in 2021. At the time of the collaboration meeting I will review the current status of both units.abstract
SDSS-V will foremost produce an unprecedented catalog of Galactic and extragalactic objects. From its, we will want to learn about the incidence or rates of astrophysical phenomena, the 'luminosity functions' of object classes, or (Galactic) dynamics. Such inferences require precise selection functions for this (or any other) catalog. It may be useful to review: What is a selection function? What should a selection function (not) depend on? How to get a selection function? How to use a selection function in modelling? I will try to do that.abstract
The Milky Way Mapper (MWM) survey will observe nearly 6 million stars to map the chemical composition of our Galaxy. Validating and calibrating the atmospheric parameters and abundances of MWM remains a significant challenge even after years of developments in the field from the APOGEE survey. In this talk, Szabocs Meszaros and Paula Jofre will present the selection of validation stars (low E(B-V), asteroseismic, solar neighborhood, cluster stars, etc) and the proposed validation plan for the first data release of MWM.abstract
The Milky Way Mapper (MWM) is a multi-object spectroscopic survey that concerns multi-epoch observations of some 4 million stars both in the optical and near-infrared parts of the spectrum. Being one of the three core ingredients of the SDSS-V survey (the other two are the Local Volume Mapper and Black Hole Mapper), the MWM’s success also largely defines the success of SDSS-V as a whole. One of the key MWM requirements to reach its scientific goals is to deliver atmospheric parameters, surface chemical compositions, and radial velocities of its targets with very high precision and accuracy. The latter in turn requires definition of a clear MWM survey calibration plan, the main topic of this contributed talk. We will touch upon the following questions/problems: 1) what is the calibration plan needed for and what are its the main ingredients? 2) what particular properties should we pay attention to when selecting a sample of calibration targets? 3) how large the calibration sample should be and what is the optimal target distribution in the parameter space? 4) how demanding the (optimal) calibration plan is in terms of the fiber hours and how does it project on the survey reality? 5) what is the relation with other large-scale spectroscopic surveys over the globe and what are the benefits from the cross-survey calibration?Galaxies 3
Aug 17 12:00-14:00
Zoom Link TBC
12:00 - Paola Alvarez-Hurtado - Exploring the impact of the Star Formation in the Mass-Metallicity relation at global scales12:15 - Nicholas Boardman - How well do local relations predict gas-phase metallicity gradients? Results from MaNGA12:30 - Artemi Camps Fariña - Chemical evolution of MaNGA galaxies12:45 - Nicholas Faucher - Untangling observed galaxy formation histories using the insights of numerical simulations13:00 - Emily Griffith - The Impact of Black Hole Formation on Population Averaged Supernova Yields13:15 - Andrew Mason - The Alpha-Fe Knee in the EAGLE Simulations and the Local Group13:30 - Justus Neumann - Drivers of stellar metallicity in galaxies
abstract
We explore the Mass-Metallicity relation (MZR) for ~1000 nearby galaxies using integrated properties from the extended version of the CALIFA integral field spectroscopy data. We focused on exploring the best mathematical form that describes the observed MZR through different functional forms as well as different statistical environments. To test the goodness of the fit of the MZR, we identify the function that yields the smallest scatter in its residuals. We use this residual to explore possible secondary relations of the MZR with other observables (e.g., SFR, Gas mass, gas fraction, and morphology). Among other results, we note a significant lack of an anti-correlation between these residuals and the SFR, in contrast to previous studies. Our results suggest that the functional form and the presence of secondary relations may depend on statistical treatment.abstract
Galaxy gas-phase metallicities are the products of numerous aspects of their galaxy’s history, and so are powerful probes of galaxy evolution. Previously, we demonstrated systematic behaviour in radial gas metallicity gradients across the galaxy mass-size plane for a sample of over 1000 MaNGA systems: at a given mass beyond approximately 10^10 solar masses, larger galaxies display steeper gradients on average. Here, we explore the ability of local trends within galaxies to predict the mass-size gradient behaviour, to better understand the behaviour's physical origins. We demonstrate that local relations — involving metallicity, mass, stellar mass density, and parameters relating to star-formation — predict similar gradient behaviour across the mass-size plane. However, we also find the most extended galaxies to display steeper gradients on average than predicted. We thus argue that gas metallicity gradients can largely be understood in terms of local processes, but that additional physical mechanisms become relevant in more extended galaxies.abstract
We present the results of applying the fossil record techinque to the MaNGA sample which allows us to trace the metallicity of its galaxies over cosmic time and see how the mass-metallicity relation (MZR) evolved. We find that the more massive galaxies became enriched first and the lower mass galaxies did so later, producing a change in the MZR which becomes shallower in time. Separating the sample into morphology and star-forming status bins we find some particularly interesting results: The mass dependency of the MZR becomes less relevant for later morphological types, to the extent that it inverts for Sd/Irr galaxies, showing how morphology is at least as important a factor as mass in chemical evolution. The MZR for the full sample shows a flattening at the high-mass end and another at the low-mass range, but the former only appears for retired galaxies while the latter only appears for star-forming galaxies. We also find an inversion in the radial metallicity gradient for low mass galaxies.abstract
The primary tool for extracting information from nearby galaxy observations is spectral energy distribution (SED) modeling, used in the inference of star formation histories (SFHs) from observations. However, the inference of these SFHs is fraught with difficulty due to our incomplete understanding of stellar populations, chemical enrichment processes, and the effects of dust on our observations. In order to quantify how these difficulties relate to our ability to infer observed galaxy formation histories, we use high resolution hydrodynamic simulations of galaxies from the NIHAO suite, coupled with state-of-the-art radiative transfer code SKIRT, to provide a critical testing ground for SED modeling techniques including the effects of dust and realistic galactic histories. We present a comparison between inferred and actual physical properties based on the simulations for a range of galaxy types, viewing angles, data selection choices, and SED modeling techniques, and describe our plans to quantify these uncertainties and biases.abstract
The landscape of black hole (BH) formation -- which massive stars explode as core-collapse supernovae (CCSN) and which implode to BHs -- profoundly affects the IMF-averaged nucleosynthetic yields of a stellar population. Building on the work of Sukhbold et al. (2016), I will discuss IMF-averaged yields at solar metallicity for a wide range of assumptions, including neutrino-driven engine models with extensive BH formation, models with a simple mass threshold for BH formation, and a model in which all stars from 8-120 solar masses explode. I will discuss the range in elemental yields achieved by varying degrees of explodability and which abundance ratios may be useful diagnostics in constraining the Galactic BH landscape. While no landscape choice achieves across-the-board agreement with observed abundance ratios, the discrepancies offer empirical clues to aspects of massive star evolution or explosion physics still missing from the models.abstract
In this talk I will present the results of an analysis of the distribution of stellar populations in the [a/Fe]-[Fe/H] plane in the Evolution and Assembly of GaLaxies and their Environments (EAGLE) simulations for galaxies comprising a mass range between 108-1011 MSun. We characterise the behaviour of the so-called 'knee' as a function of galactic parameters such as mass and star formation history (SFH) and present these results in the context of contemporary measurements of the masses and knee metallicities of Local Group Dwarfs (LGDs) derived from survey data to assess the agreement between these data and the EAGLE simulations. We find that for galaxies where the change in slope between the plateau and post-knee stars is consistent with that of the Thick Disk there is a strong correlation between total stellar mass and the metallicity of the knee. In addition we explore the variations in the SFHs of the galaxies in EAGLE that drive variations of the metallicity and slope of the knee.abstract
The distribution of stellar metallicities within and across galaxies is an excellent relic of the chemical evolution across cosmic time. Spatially resolved spectroscopic surveys offer the unique opportunity to study global and local drivers of stellar populations in galaxies. In this talk, I present results from a detailed analysis of spatially resolved stellar populations based on > 2.6 million spatial bins from 7439 nearby galaxies in the SDSS-IV MaNGA survey. Our study goes beyond the well-known global mass-metallicity relation and radial metallicity gradients by providing a statistically sound exploration of local relations between stellar metallicity, stellar surface mass density (SMD) and galactocentric distance in the global mass-morphology plane. We find a significant resolved SMD-metallicity relation for galaxies of all types and masses. The spread of the relation is mainly attributed to different radial distances. In particular, we find that at fixed SMD metallicity increases with radius. This result calls for a driver of metallicity in addition to SMD that promotes chemical enrichments in the outer parts of galaxies more strongly than in the inner parts.Milky Way 3
Aug 17 12:00-14:00
Zoom Link TBC
12:00 - James Johnson - A Hybrid Model for Stellar Migration and Chemical Enrichment in the Milky Way Disk12:15 - Jennifer Johnson - The Origin of High [alpha/Fe] Gas in Cosmological Simulations12:30 - Andrea Miglio - Improving the precision and accuracy of asteroseismic ages: a sharper view on the oldest stellar populations in the Milky Way12:45 - Sian Phillips - Detection by APOGEE of N-rich stars in the tidal tails of Palomar 513:00 - Marc Pinsonneault - Asteroseismology and Galactic Archeology13:15 - Alvaro Rojas-Arriagada - Studying the bulge stellar populations towards the midplane with APOGEE13:30 - David Weinberg - Chemical Cartography With Residual Abundances
abstract
Numerical simulations of galaxy evolution suggest stars can migrate significant distances from their birth radius, but the impact of this effect on galactic chemical evolution is poorly understood. In this talk, I will discuss the models introduced by Johnson et al. (2021, arxiv:2103.09838), which describe the Milky Way disc as a series of concentric rings combined with a prescription for stellar migration informed by a hydrodynamic simulation. The model successfully reproduces many observed features of the Galaxy's alpha and iron peak abundance structure, such as the considerable intrinsic scatter in the stellar age metallicity relation and the presence of young and intermediate-age alpha-enhanced stars in the solar neighbourhood. However, the models fail to reproduce the infamous [alpha/Fe] dichotomy, and no one variation simultaneously explains all observables. Time permitting, I will discuss follow-up investigations to these models, such as their predicted nitrogen abundances as well as alternate star formation histories.abstract
The Milky Way has an intricate pattern of high [alpha/Fe] and low [alpha/Fe] stellar populations as a function of position, kinematics, and age. These stars must have formed out of gas with similar composition. We investigate the history of gaseous [alpha/Fe] values in the evolution of Milky-Way-like galaxies, using simulations of 10 galaxies from Vincenzo & Kobayashi (2018). We identify the causes of inflection points in the mean [alpha/Fe] values and the appearance of high [alpha/Fe] gas in recent times. Overall, these galaxies show a wide range of behavior in their [alpha/Fe] chemical evolutionabstract
Our understanding of the formation and evolution of the Milky Way is often blurred and biased by the lack of precise and accurate stellar ages. In this contribution I will present the ongoing efforts and recent results of the asterochronometry project, which aims both at testing and improving our knowledge of stellar physics, and at determining precise and accurate ages of stars (to 10-15%) in the regions of the Galaxy sampled by Kepler, K2, CoRoT, and TESS. First, I will focus on the high-[alpha/Fe] sequence and discuss recent results about its intrinsic age spread and age-velocity-dispersion relation. I will then show how asteroseismic inferences based on individual-mode frequencies, as opposed to global parameters, can deliver a sufficiently high temporal resolution to study the oldest populations in the Galaxy, including stars belonging to Gaia-Enceladus.abstract
Recent results from chemical tagging studies using APOGEE data suggest a strong link between the chemical abundance patterns of stars found within globular clusters, and chemically peculiar populations in the Galactic halo field. In this talk I will describe an analysis of the chemical compositions of stars within the cluster body and tidal streams of Palomar 5, a globular cluster that is being tidally disrupted by interaction with the Galactic gravitational potential. I will report the identification of nitrogen-rich (N-rich) stars both within and beyond the tidal radius of Palomar 5, with the latter being clearly aligned with the cluster tidal streams; this acts as confirmation that N-rich stars are lost to the Galactic halo from globular clusters, and provides support to the hypothesis that field N-rich stars identified by various groups have a globular cluster origin.abstract
Asteroseismology, or the study of stellar oscillations, has proven to be a powerful tool for understanding stellar populations. When combined with spectroscopy, asteroseismology can be used to infer mass, radius and age for large numbers of evolved stars. In this talk I briefly review the major asteroseismic data sets with APOGEE data: from Kepler, K2 and TESS. By comparison with fundamental data, I demonstrate the limits of commonly used asteroseismic scaling relations, and outline the opportunities for Galactic archeology studies using these large (and available!) data sets.abstract
The APOGEE spectroscopic survey, by observing in the near-infrared H-band, has opened the opportunity to investigate with unprecedented detail the stellar content of the bulge at its most reddened regions towards the Galactic midplane. The bulge is at the center of the potential well of the Galaxy, where all Galactic components eventually meet and mix each other. As a massive and generally old structure (at least, the Galaxy's oldest stars should be located there) understanding its origin and chemo-dynamical evolution represents and important step towards the understanding of galaxy formation/evolution in general. In this talk, I aim at describing the results coming from the analysis of APOGEE survey data (DR14, and most recently from DR16) in the bulge region. We studied the bulge metallicity distribution function, its spatial variations, and the chemo-kinematic properties of the stellar populations seemingly coexisting in this region. We cast these new results in the context of those obtained with previous optical surveys sampling the complex mix of bulge stellar populations at higher Galactic latitudes. In this way, we try to assemble a global picture of the complex properties of the Galactic bulge.abstract
APOGEE and SDSS-V MWM present us the opportunity and challenge of interpreting detailed elemental fingerprints for hundreds of thousands (and soon millions) of stars. APOGEE abundances of Milky Way disk and bulge stars can be described to interestingly high accuracy by a 2-parameter model that represents contributions from core collapse supernovae and Type Ia supernovae. However, the residuals from these 2-parameter fits show significant element-to-element correlations that imply more complex structure to the origin of multi-element abundance patterns. I will discuss results from APOGEE DR17 and opportunities for MWM, including constraints on supernova physics from 2-process modeling, implications of residual correlations for additional enrichment processes and stochastic effects in chemical evolution, identification of chemically unusual stars that provide insights on stellar astrophysics, identification of stellar populations with subtle but distinctive abundance patterns, and comparison of the Milky Way disk to other populations such as the bulge, the halo, dwarf satellites, and tidal streams.Lightning 4
Aug 17 14:10-14:30
Zoom Link TBC
- Tharindu Jayasinghe - Modeling detached eclipsing binaries with ASAS-SN and APOGEE DR17 - Jennifer Cash - “Photometric Variables in the APOGEE Surveys: An introduction†- Jordan Brown - “Photometric Variables in the APOGEE Surveys: Identified Targets†- Ramon Lavender - “Photometric Variables in the APOGEE Surveys: Variability Classes†- Patricia Tissera - Metallicity gradients and the regulation of the star formation activity in galaxies - Daniella Morrone - Decoding galaxy evolution through the lens of galaxy morphology - Shawn Blackman - Identifying Red Giants From APOGEE-2 Within The Palomar 5 Stellar Stream - Samin Mahmood - Identifying Red Giants From APOGEE-2 Within The Palomar 5 Stellar Stream - janaina nascimento - Metallicity determinations in nearby AGNs with SDSS-IV MaNGA - Jeff Shen - Predicting the Ages of Stars with Machine Learning
abstract
Detached eclipsing binaries are useful astrophysical tools that can be used to derive precise measurements of the masses and radii of the component stars. Wide field photometric surveys like the All-Sky Automated Survey for SuperNovae (ASAS-SN) have discovered hundreds of thousands of eclipsing binaries. In the meantime, spectroscopic surveys like APOGEE have made sparse radial velocity (RV) measurements of hundreds of thousands of stars. In this project, we investigate detached eclipsing binaries (DEBs) with ASAS-SN light curves (Jayasinghe et al. 2021) that are also doubled-lined spectroscopic binaries in APOGEE DR17 (Kounkel et al., in prep) with multiple RV measurements. We use the binary modeling tool PHOEBE to model the light curves and APOGEE RV data for these DEBs. When available, we also use ZTF and TESS data to supplement the ASAS-SN light curves. Our goal is to produce a catalog of these double-lined DEBs with good measurements of the masses and radii for the individual stars.abstract
In this first talk on VAC 0096, we will introduce the scope and purpose of the VAC and the five main files in the VAC. We will also briefly highlight some possible science to be conducted using this VAC.abstract
In this second talk on VAC 0096, we will cover some basic statistics on the number of variable stars identified and the overlap between the variable star catalogs used in the matching process.abstract
In this third talk on VAC 0096, we will present an overview of the variability classifications found among the APOGEE targets and discuss the possibility of using the APOGEE information to help classify variables.abstract
We study the processes that regulate the star formation activity in galaxies with a variety of metallicity gradients as a function of redshifts. Our aim is to explore the link between the characteristics of the chemical abundances distributions and the properties of the galaxies at different stages of evolution. For these purpose we use hydrodynamical numerical simulation in a cosmological context.abstract
Morphology and evolution are two closely intertwined properties of galaxies. In analyzing their morphologies, vital information is revealed as a means to decode galaxy evolution. Our research analyzes the light- and mass-weighted morphologies for high redshift galaxies in order to better understand their evolution. For this purpose, images of galaxies taken from the Hubble eXtreme Deep Field (XDF) observations are compared to those from the SIMBA suite of cosmological simulations. In this analysis, the similarities in physical measurements of both the images and simulations are quantified with the goal of reaffirming the accuracy of the simulations in regard to galaxy evolution. To delve further into the understanding of galaxy evolution, this analysis can also be extended to low redshifts with SDSS observations in a manner consistent to what we are doing at higher redshifts. Through this research, we hope to determine the true stellar mass and star formation maps of galaxies from their images in order to map out their growth. In this talk, I will present our first results from performing this analysis on several galaxies in the XDF image and the next steps for decoding galaxy evolution.abstract
Palomar 5, a tidally disrupted globular cluster with stellar streams, orbits in the outer halo of the Milky Way. In the following presentation, we attempt to identify new Red Giant Branch (RGB) members within the stream using spectroscopy from the APOGEE-2 DR17 and photometry and astrometry data from Gaia. From the APOGEE-2 Palomar 5 pointings, we narrowed down 17 stars out of 997 that have a similar proper motion as the Palomar 5 stream. Looking at the chemical abundances, radial velocities, and magnitudes of these 17 candidates, we then compared them to other known RGB stars within Palomar 5. By exploring the APOGEE-2 and Gaia catalogs, we look to expand the dataset of known RGB members of the Palomar 5 tidal stream.abstract
Palomar 5, a tidally disrupted globular cluster with stellar streams, orbits in the outer halo of the Milky Way. In the following presentation, we attempt to identify new Red Giant Branch (RGB) members within the stream using spectroscopy from the APOGEE-2 DR17 and photometry and astrometry data from Gaia. From the APOGEE-2 Palomar 5 pointings, we narrowed down 17 stars out of 997 that have a similar proper motion as the Palomar 5 stream. Looking at the chemical abundances, radial velocities, and magnitudes of these 17 candidates, we then compared them to other known RGB stars within Palomar 5. By exploring the APOGEE-2 and Gaia catalogs, we look to expand the dataset of known RGB members of the Palomar 5 tidal stream.abstract
We derive the metallicity in the gas phase of the Narrow Line Regions of Seyfert~2 galaxies and the oxygen abundance gradients in the disk of 108 nearby galaxies, being 98 Seyfert~2 and 10 Seyfert~ 1 by using strong emission-line calibrations taken from the literature, and observations from SDSS-IV MaNGA survey. The metallicity of each Active Galactic Nucleus (AGN) was compared to the value obtained from the extrapolation of the oxygen gradient at central parts of the host galaxies. We find that, for most objects, the AGN metallicity is lower than the extrapolated value. In order to investigate the source of this discrepancy, we look for correlations between D and the electron density N_e, [Oiii]5007 and Halpha luminosities, extinction A_V of the AGNs as well as the stellar mass of the host galaxies.abstract
Stellar ages are important for understanding the formation and evolution of the Milky Way, but predictions of ages using stellar spectra are influenced both by stellar evolution and Galactic effects. I will describe how machine learning methods can be used to disentangle Galactic effects from stellar physics when predicting ages, while also accounting for measurement errors.COINS Townhall
Aug 17 15:00-16:00
Zoom Link TBC
Plenary 7
Aug 17 16:00-17:30
Zoom Link TBC
16:00 - Jianhui Lian - Galactic and extragalactic chemical evolution probed by SDSS data16:30 - Robyn Sanderson - Galactic Dynamics & Simulations 10117:00 - Kate Grier - Reverberation Mapping 101
abstract
Galactic chemical evolution is mainly regulated by galaxy internal star formation and external matter exchange with the environment (i.e. gas accretion and outflow winds). Therefore, understanding the chemical evolution of a galaxy is a valuable way to probe the roles played by these processes in driving galaxy formation and evolution. The SDSS-III and SDSS-IV survey have collected abundant chemistry observations in both the Milky Way and other galaxies, which impose unprecedented constraints on galactic chemical evolution. Because of dramatic differences in the observations of the Milky Way and other galaxies, studies on their chemical evolution have taken very different perspectives. In this talk, I will provide an overview of works inside the collaboration focusing on galactic chemical evolution using the chemistry observations in the Milky Way and external galaxies separately. At the end of the talk, I will share my own prospect on the future galactic chemical evolution studies in terms of linking the Galactic and extragalactic observations together.abstract
abstract
Galaxies 4
Aug 17 18:00-20:00
Zoom Link TBC
18:00 - Nikhil Ajgaonkar - Constraining quenching timescales of galaxies in the SwiM Catalog18:15 - Niel Brandt - The Nature of the X-ray Emission from Typical SDSS Radio-Loud Quasars: Jets vs. Coronae18:30 - Zhuo Cheng - Post-starburst galaxies in SDSS-IV MaNGA :abundance and global properties18:45 - Tao Jing - Origin of Gas Rich but Quenched Regions (GRQRs) in non-merger/interaction MaNGA galaxies19:00 - Justin Otter - Resolved molecular gas properties of 14 MaNGA post-starbursts with ALMA19:15 - James Trussler - A global and spatially-resolved view of galaxy quenching19:30 - Chenyu Zhao - Radial Quenching Profiles of Nearby Galaxies