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1. The Hobby–Eberly Telescope VIRUS Parallel Survey (HETVIPS)

Author: Gregory R. Zeimann, Maya H. Debski, Donald P. Schneider, William P. Bowman, Niv Drory, Gary J. Hill, Hanshin Lee, Phillip MacQueen, and Matthew Shetrone
Subjects: Surveys, Redshift surveys, Stellar classification, Sky surveys, Catalogs, Astrophysics, QB460-466
Abstract: The Hobby–Eberly Telescope (HET) VIRUS Parallel Survey (HETVIPS) is a blind spectroscopic program that sparsely covers approximately two-thirds of the celestial sphere and consists of roughly 252 million fiber spectra. The spectra were taken in parallel mode with the Visible Integral-field Replicable Unit Spectrograph (VIRUS) instrument when the HET was observing a primary target with other HET facility instruments. VIRUS can simultaneously obtain approximately 35,000 spectra covering 3470–5540 Å at a spectral resolution of ≈800. Although the vast majority of these spectra cover blank sky, we used the Pan-STARRS1 Data Release 2 Stacked Catalog to identify objects encompassed in the HETVIPS pointings and extract their spectra. This paper presents the first HETVIPS data release, containing 493,012 flux-calibrated spectra obtained through 2023 March 31, as well as a description of the data processing technique. Each of the object spectra were classified, resulting in a catalog of 74,196 galaxies, 4,087 quasars, 259,396 stars, and 154,543 unknown sources.
Published: 2024
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2. GHOST Commissioning Science Results: Identifying a New Chemically Peculiar Star in Reticulum II

Author: Christian R. Hayes, Kim A. Venn, Fletcher Waller, Jaclyn Jensen, Alan W. McConnachie, John Pazder, Federico Sestito, André Anthony, Gabriella Baker, John Bassett, Joao Bento, Trystyn Berg, Gregory Burley, Jurek Brzeski, Scott Case, Edward Chapin, Timothy Chin, Eric Chisholm, Vladimir Churilov, Adam Densmore, Ruben Diaz, Jennifer Dunn, Michael Edgar, Tony Farrell, Veronica Firpo, Joeleff Fitzsimmons, Juan Font-Serra, Javier Fuentes, Colin Ganton, Manuel Gomez-Jimenez, Tim Hardy, David Henderson, Alexis Hill, Brian Hoff, Michael Ireland, Venu Kalari, Neal Kelly, Urs Klauser, Yuriy Kondrat, Kathleen Labrie, Sam Lambert, Lance Luvaul, Jon Lawrence, Jordan Lothrop, G. Scott Macdonald, Slavko Mali, Steve Margheim, Richard McDermid, Helen McGregor, Bryan Miller, Felipe Miranda, Rolf Muller, Jon Nielsen, Ryan Norbury, Oliver Oberdorf, Naveen Pai, Gabriel Perez, Pablo Prado, Ian Price, Carlos Quiroz, Vladimir Reshetov, Gordon Robertson, Roque Ruiz-Carmona, Ricardo Salinas, Kim M. Sebo, Andrew Sheinis, Matthew Shetrone, Keith Shortridge, Katherine Silversides, Karleyne Silva, Chris Simpson, Greg Smith, Kei Szeto, Julia Tims, Eduardo Toro, Cristian Urrutia, Sudharshan Venkatesan, Lewis Waller, Ivan Wevers, Ramunas Wierzbicki, Marc White, Peter Young, and Ross Zhelem
Subjects: Dwarf galaxies, Chemically peculiar stars, Chemical abundances, High resolution spectroscopy, Observational astronomy, Astrophysics, QB460-466
Abstract: The Gemini High-resolution Optical SpecTrograph (GHOST) is the newest high-resolution spectrograph to be developed for a large-aperture telescope, recently deployed and commissioned at the Gemini-South telescope. In this paper, we present the first science results from the GHOST spectrograph taking during its commissioning runs. We have observed the bright metal-poor benchmark star HD 122563, along with two stars in the ultrafaint dwarf galaxy Reticulum II (Ret ii ), one of which was previously identified as a candidate member, but did not have a previous detailed chemical abundance analysis. We find that this candidate (GDR3 0928) to be a bona fide member of Ret ii , and from a spectral synthesis analysis it is also revealed to be a CEMP- r star, with significant enhancements in several light elements (C, N, O, Na, Mg, and Si), in addition to featuring an r -process enhancement like many other Ret ii stars. The light-element enhancements in this star resemble the abundance patterns seen in the CEMP-no stars of other ultrafaint dwarf galaxies, and are thought to have been produced by an independent source from the r -process. These unusual abundance patterns are thought to be produced by faint supernovae, which may be produced by some of the earliest generations of stars.
Published: 2023
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3. A Tale of Two Disks: Mapping the Milky Way with the Final Data Release of APOGEE

Author: Julie Imig, Cathryn Price, Jon A. Holtzman, Alexander Stone-Martinez, Steven R. Majewski, David H. Weinberg, Jennifer A. Johnson, Carlos Allende Prieto, Rachael L. Beaton, Timothy C. Beers, Dmitry Bizyaev, Michael R. Blanton, Joel R. Brownstein, Katia Cunha, José G. Fernández-Trincado, Diane K. Feuillet, Sten Hasselquist, Christian R. Hayes, Henrik Jönsson, Richard R. Lane, Jianhui Lian, Szabolcs Mészáros, David L. Nidever, Annie C. Robin, Matthew Shetrone, Verne Smith, and John C. Wilson
Subjects: Milky Way Galaxy, Milky Way disk, Galactic abundances, Stellar ages, Galaxy stellar content, Galactic archaeology, Astrophysics, QB460-466
Abstract: We present new maps of the Milky Way disk showing the distribution of metallicity ([Fe/H]), α -element abundances ([Mg/Fe]), and stellar age, using a sample of 66,496 red giant stars from the final data release (DR17) of the Apache Point Observatory Galactic Evolution Experiment survey. We measure radial and vertical gradients, quantify the distribution functions for age and metallicity, and explore chemical clock relations across the Milky Way for the low- α disk, high- α disk, and total population independently. The low- α disk exhibits a negative radial metallicity gradient of −0.06 ± 0.001 dex kpc ^−1 , which flattens with distance from the midplane. The high- α disk shows a flat radial gradient in metallicity and age across nearly all locations of the disk. The age and metallicity distribution functions shift from negatively skewed in the inner Galaxy to positively skewed at large radius. Significant bimodality in the [Mg/Fe]–[Fe/H] plane and in the [Mg/Fe]–age relation persist across the entire disk. The age estimates have typical uncertainties of ∼0.15 in log(age) and may be subject to additional systematic errors, which impose limitations on conclusions drawn from this sample. Nevertheless, these results act as critical constraints on galactic evolution models, constraining which physical processes played a dominant role in the formation of the Milky Way disk. We discuss how radial migration predicts many of the observed trends near the solar neighborhood and in the outer disk, but an additional more dramatic evolution history, such as the multi-infall model or a merger event, is needed to explain the chemical and age bimodality elsewhere in the Galaxy.
Published: 2023
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4. The LIGO HET Response (LIGHETR) Project to Discover and Spectroscopically Follow Optical Transients Associated with Neutron Star Mergers

Author: M. J. Bustamante-Rosell, Greg Zeimann, J. Craig Wheeler, Karl Gebhardt, Aaron Zimmerman, Chris Fryer, Oleg Korobkin, Richard Matzner, V. Ashley Villar, S. Karthik Yadavalli, Kaylee M. de Soto, Matthew Shetrone, Steven Janowiecki, Pawan Kumar, David Pooley, Benjamin P. Thomas, Hsin-Yu Chen, Lifan Wang, Jozsef Vinkó, David J. Sand, Ryan Wollaeger, Frederic V. Hessman, and Kristen B. McQuinn
Subjects: Gravitational wave astronomy, Astrophysics, QB460-466
Abstract: The LIGO HET Response (LIGHETR) project is an enterprise to follow up optical transients (OTs) discovered as gravitational-wave merger sources by the LIGO/Virgo collaboration (LVC). Early spectroscopy has the potential to constrain crucial parameters such as the aspect angle. The LIGHETR collaboration also includes the capacity to model the spectroscopic evolution of mergers to facilitate a real-time direct comparison of models with our data. The principal facility is the Hobby–Eberly Telescope. LIGHETR uses the massively replicated VIRUS array of spectrographs to search for associated OTs and obtain early blue spectra, and in a complementary role, the low-resolution LRS2 spectrograph is used to obtain spectra of viable candidates as well as a densely sampled series of spectra of true counterparts. Once an OT is identified, the anticipated cadence of spectra would match or considerably exceed anything achieved for GW170817 = AT2017gfo for which there were no spectra in the first 12 hr and thereafter only roughly once daily. We describe special HET-specific software written to facilitate the program and attempts to determine the flux limits to undetected sources. We also describe our campaign to follow up OT candidates during the third observational campaign of the LIGO and Virgo Scientific Collaborations. We obtained VIRUS spectroscopy of candidate galaxy hosts for five LVC gravitational-wave events and LRS2 spectra of one candidate for the OT associated with S190901ap. We identified that candidate, ZTF19abvionh = AT2019pip, as a possible Wolf–Rayet star in an otherwise unrecognized nearby dwarf galaxy.
Published: 2023
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5. The chemical characterization of halo substructure in the Milky Way based on APOGEE

Author: Danny Horta, Ricardo P Schiavon, J Ted Mackereth, David H Weinberg, Sten Hasselquist, Diane Feuillet, Robert W O’Connell, Borja Anguiano, Carlos Allende-Prieto, Rachael L Beaton, Dmitry Bizyaev, Katia Cunha, Doug Geisler, D A García-Hernández, Jon Holtzman, Henrik Jönsson, Richard R Lane, Steve R Majewski, Szabolcs Mészáros, Dante Minniti, Christian Nitschelm, Matthew Shetrone, Verne V Smith, and Gail Zasowski
Subjects: Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: Galactic haloes in a $\Lambda$-CDM universe are predicted to host today a swarm of debris resulting from cannibalised dwarf galaxies. The chemo-dynamical information recorded in their stellar populations helps elucidate their nature, constraining the assembly history of the Galaxy. Using data from APOGEE and \textit{Gaia}, we examine the chemical properties of various halo substructures, considering elements that sample various nucleosynthetic pathways. The systems studied are Heracles, \textit{Gaia}-Enceladus/Sausage (GES), the Helmi stream, Sequoia, Thamnos, Aleph, LMS-1, Arjuna, I'itoi, Nyx, Icarus, and Pontus. Abundance patterns of all substructures are cross-compared in a statistically robust fashion. Our main findings include: {\it i)} the chemical properties of most substructures studied match qualitatively those of dwarf Milky Way satellites, such as the Sagittarius dSph. Exceptions are Nyx and Aleph, which are chemically similar to disc stars, implying that these substructures were likely formed \textit{in situ}; {\it ii)} Heracles differs chemically from {\it in situ} populations such as Aurora and its inner halo counterparts in a statistically significant way. The differences suggest that the star formation rate was lower in Heracles than in the early Milky Way; {\it iii)} the chemistry of Arjuna, LMS-1, and I'itoi is indistinguishable from that of GES, suggesting a possible common origin; {\it iv)} all three Sequoia samples studied are qualitatively similar. However, only two of those samples present chemistry that is consistent with GES in a statistically significant fashion; {\it v)} the abundance patterns of the Helmi stream and Thamnos are different from all other halo substructures., Comment: Accepted for publication in MNRAS. The revised version contains a detailed comparison of the chemical composition of Heracles against Aurora and its inner halo in situ counterparts as well as a revised discussion of the chemistry of various Sequoia samples in contrast with Gaia-Enceladus/Sausage
Published: 2022

6. Chemical Evolution in the Milky Way: Rotation-based Ages for APOGEE-Kepler Cool Dwarf Stars

Author: Zachary R. Claytor, Jennifer L. van Saders, Ângela R. G. Santos, Rafael A. García, Savita Mathur, Jamie Tayar, Marc H. Pinsonneault, and Matthew Shetrone
Published: 2020
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7. The massive M31 cluster G1: detailed chemical abundances from integrated light spectroscopy★

Author: Matthew Shetrone, Charli M. Sakari, George Wallerstein, and Andrew McWilliam
Subjects: Physics, 010308 nuclear & particles physics, Metallicity, FOS: Physical sciences, Velocity dispersion, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Star cluster, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Cluster (physics), Halo, Spectroscopy, 010303 astronomy & astrophysics, Dwarf galaxy
Abstract: G1, also known as Mayall II, is one of the most massive star clusters in M31. Its mass, ellipticity, and location in the outer halo make it a compelling candidate for a former nuclear star cluster. This paper presents an integrated light abundance analysis of G1, based on a moderately high-resolution (R=15,000) spectrum obtained with the High Resolution Spectrograph on the Hobby-Eberly Telescope in 2007 and 2008. To independently determine the metallicity, a moderate resolution (R~4,000) spectrum of the calcium-II triplet lines in the near-infrared was also obtained with the Astrophysical Research Consortium's 3.5-m telescope at Apache Point Observatory. From the high-resolution spectrum, G1 is found to be a moderately metal-poor cluster, with [Fe/H]=-0.98+/-0.05. G1 also shows signs of alpha-enhancement (based on Mg, Ca, and Ti) and lacks the s-process enhancements seen in dwarf galaxies (based on comparisons of Y, Ba, and Eu), indicating that it originated in a fairly massive galaxy. Intriguingly, G1 also exhibits signs of Na and Al enhancement, a unique signature of GCs -- this suggests that G1's formation is intimately connected with GC formation. G1's high [Na/Fe] also extends previous trends with cluster velocity dispersion to an even higher mass regime, implying that higher mass clusters are more able to retain Na-enhanced ejecta. The effects of intracluster abundance spreads are discussed in a subsequent paper. Ultimately, G1's chemical properties are found to resemble other M31 GCs, though it also shares some similarities with extragalactic nuclear star clusters., Accepted for publication in MNRAS
Published: 2021

8. BACCHUS Analysis of Weak Lines in APOGEE Spectra (BAWLAS)

Author: Christian R. Hayes, Thomas Masseron, Jennifer Sobeck, D. A. García-Hernández, Carlos Allende Prieto, Rachael L. Beaton, Katia Cunha, Sten Hasselquist, Jon A. Holtzman, Henrik Jönsson, Steven R. Majewski, Matthew Shetrone, Verne V. Smith, and Andrés Almeida
Subjects: Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: Elements with weak and blended spectral features in stellar spectra are challenging to measure and require specialized analysis methods to precisely measure their chemical abundances. In this work, we have created a catalog of approximately 120,000 giants with high signal-to-noise APOGEE DR17 spectra, for which we explore weak and blended species to measure Na, P, S, V, Cu, Ce, and Nd abundances and $^{12}$C/$^{13}$C isotopic ratios. We employ an updated version of the BACCHUS (Brussels Automatic Code for Characterizing High accUracy Spectra) code to derive these abundances using the stellar parameters measured by APOGEE's DR17 ASPCAP pipeline, quality flagging to identify suspect spectral lines, and a prescription for upper limits. Combined these allow us to provide our BACCHUS Analysis of Weak Lines in APOGEE Spectra (BAWLAS) catalog of precise chemical abundances for these weak and blended species that agrees well with literature and improves upon APOGEE abundances for these elements, some of which are unable to be measured with APOGEE's current, grid-based approach without computationally expensive expansions. This new catalog can be used alongside APOGEE and provide measurements for many scientific applications ranging from nuclear physics to Galactic chemical evolution and Milky Way population studies. To illustrate this we show some examples of uses for this catalog, such as, showing that we observe stars with enhanced s-process abundances or that we can use the our $^{12}$C/$^{13}$C ratios to explore extra mixing along the red giant branch., Comment: 49 Pages, 30 figures, 7 Tables. Accepted for publishing in The Astrophysical Journal Supplement Series. The BAWLAS chemical abundance catalog to be made publicly available as an SDSS DR17 value-added catalog: https://www.sdss.org/dr17/data_access/value-added-catalogs/
Published: 2022
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9. Detailed Chemical Abundances for a Benchmark Sample of M Dwarfs from the APOGEE Survey

Author: Diogo Souto, Katia Cunha, Verne V. Smith, C. Allende Prieto, Kevin Covey, D. A. García-Hernández, Jon A. Holtzman, Henrik Jönsson, Suvrath Mahadevan, Steven R. Majewski, Thomas Masseron, Marc Pinsonneault, Donald P. Schneider, Matthew Shetrone, Keivan G. Stassun, Ryan Terrien, Olga Zamora, Guy S. Stringfellow, Richard R. Lane, Christian Nitschelm, and Bárbara Rojas-Ayala
Subjects: Astronomi, astrofysik och kosmologi, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astronomy, Astrophysics and Cosmology, Astrophysics::Solar and Stellar Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: Individual chemical abundances for fourteen elements (C, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Ni) are derived for a sample of M-dwarfs using high-resolution near-infrared $H$-band spectra from the SDSS-IV/APOGEE survey. The quantitative analysis included synthetic spectra computed with 1-D LTE plane-parallel MARCS models using the APOGEE DR17 line list to determine chemical abundances. The sample consists of eleven M-dwarfs in binary systems with warmer FGK-dwarf primaries and ten measured interferometric angular diameters. To minimize atomic diffusion effects, [X/Fe] ratios are used to compare M-dwarfs in binary systems and literature results for their warmer primary stars, indicating good agreement ($, Comment: 19 pages. Accepted to ApJ
Published: 2022
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10. Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey

Author: Rachael L. Beaton, Ryan J. Oelkers, Christian R. Hayes, Kevin R. Covey, S. D. Chojnowski, Nathan De Lee, Jennifer S. Sobeck, Steven R. Majewski, Roger E. Cohen, José Fernández-Trincado, Penélope Longa-Peña, Julia E. O’Connell, Felipe A. Santana, Guy S. Stringfellow, Gail Zasowski, Conny Aerts, Borja Anguiano, Chad Bender, Caleb I. Cañas, Katia Cunha, John Donor, Scott W. Fleming, Peter M. Frinchaboy, Diane Feuillet, Paul Harding, Sten Hasselquist, Jon A. Holtzman, Jennifer A. Johnson, Juna A. Kollmeier, Marina Kounkel, Suvrath Mahadevan, Adrian. M. Price-Whelan, Alvaro Rojas-Arriagada, Carlos Román-Zúñiga, Edward F. Schlafly, Mathias Schultheis, Matthew Shetrone, Joshua D. Simon, Keivan G. Stassun, Amelia M. Stutz, Jamie Tayar, Johanna Teske, Andrew Tkachenko, Nicholas Troup, Franco D. Albareti, Dmitry Bizyaev, Jo Bovy, Adam J. Burgasser, Johan Comparat, Juan José Downes, Doug Geisler, Laura Inno, Arturo Manchado, Melissa K. Ness, Marc H. Pinsonneault, Francisco Prada, Alexandre Roman-Lopes, Gregory V. A. Simonian, Verne V. Smith, Renbin Yan, and Olga Zamora
Subjects: Science & Technology, GLOBULAR-CLUSTER, CLOUD FORMATION, EXPLORING HALO SUBSTRUCTURE, DATA RELEASE, Astronomy and Astrophysics, Astronomy & Astrophysics, GIANT STARS, STAR-FORMATION, Space and Planetary Science, 1ST SPECTROSCOPIC DATA, Physical Sciences, MILKY-WAY, NEARBY GALAXIES, MASSIVE STARS, Astronomical and Space Sciences
Abstract: The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is a dual-hemisphere, near-infrared (NIR), spectroscopic survey with the goal of producing a chemodynamical mapping of the Milky Way. The targeting for APOGEE-2 is complex and has evolved with time. In this paper, we present the updates and additions to the initial targeting strategy for APOGEE-2N presented in Zasowski et al. (2017). These modifications come in two implementation modes: (i) “Ancillary Science Programs” competitively awarded to Sloan Digital Sky Survey IV PIs through proposal calls in 2015 and 2017 for the pursuit of new scientific avenues outside the main survey, and (ii) an effective 1.5 yr expansion of the survey, known as the Bright Time Extension (BTX), made possible through accrued efficiency gains over the first years of the APOGEE-2N project. For the 23 distinct ancillary programs, we provide descriptions of the scientific aims, target selection, and how to identify these targets within the APOGEE-2 sample. The BTX permitted changes to the main survey strategy, the inclusion of new programs in response to scientific discoveries or to exploit major new data sets not available at the outset of the survey design, and expansions of existing programs to enhance their scientific success and reach. After describing the motivations, implementation, and assessment of these programs, we also leave a summary of lessons learned from nearly a decade of APOGEE-1 and APOGEE-2 survey operations. A companion paper, F. Santana et al. (submitted; AAS29036), provides a complementary presentation of targeting modifications relevant to APOGEE-2 operations in the Southern Hemisphere.
Published: 2021

11. The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar, and APOGEE-2 Data

Author: null Abdurro’uf, Katherine Accetta, Conny Aerts, Víctor Silva Aguirre, Romina Ahumada, Nikhil Ajgaonkar, N. Filiz Ak, Shadab Alam, Carlos Allende Prieto, Andrés Almeida, Friedrich Anders, Scott F. Anderson, Brett H. Andrews, Borja Anguiano, Erik Aquino-Ortíz, Alfonso Aragón-Salamanca, Maria Argudo-Fernández, Metin Ata, Marie Aubert, Vladimir Avila-Reese, Carles Badenes, Rodolfo H. Barbá, Kat Barger, Jorge K. Barrera-Ballesteros, Rachael L. Beaton, Timothy C. Beers, Francesco Belfiore, Chad F. Bender, Mariangela Bernardi, Matthew A. Bershady, Florian Beutler, Christian Moni Bidin, Jonathan C. Bird, Dmitry Bizyaev, Guillermo A. Blanc, Michael R. Blanton, Nicholas Fraser Boardman, Adam S. Bolton, Médéric Boquien, Jura Borissova, Jo Bovy, W. N. Brandt, Jordan Brown, Joel R. Brownstein, Marcella Brusa, Johannes Buchner, Kevin Bundy, Joseph N. Burchett, Martin Bureau, Adam Burgasser, Tuesday K. Cabang, Stephanie Campbell, Michele Cappellari, Joleen K. Carlberg, Fábio Carneiro Wanderley, Ricardo Carrera, Jennifer Cash, Yan-Ping Chen, Wei-Huai Chen, Brian Cherinka, Cristina Chiappini, Peter Doohyun Choi, S. Drew Chojnowski, Haeun Chung, Nicolas Clerc, Roger E. Cohen, Julia M. Comerford, Johan Comparat, Luiz da Costa, Kevin Covey, Jeffrey D. Crane, Irene Cruz-Gonzalez, Connor Culhane, Katia Cunha, Y. Sophia Dai, Guillermo Damke, Jeremy Darling, James W. Davidson Jr., Roger Davies, Kyle Dawson, Nathan De Lee, Aleksandar M. Diamond-Stanic, Mariana Cano-Díaz, Helena Domínguez Sánchez, John Donor, Chris Duckworth, Tom Dwelly, Daniel J. Eisenstein, Yvonne P. Elsworth, Eric Emsellem, Mike Eracleous, Stephanie Escoffier, Xiaohui Fan, Emily Farr, Shuai Feng, José G. Fernández-Trincado, Diane Feuillet, Andreas Filipp, Sean P Fillingham, Peter M. Frinchaboy, Sebastien Fromenteau, Lluís Galbany, Rafael A. García, D. A. García-Hernández, Junqiang Ge, Doug Geisler, Joseph Gelfand, Tobias Géron, Benjamin J. Gibson, Julian Goddy, Diego Godoy-Rivera, Kathleen Grabowski, Paul J. Green, Michael Greener, Catherine J. Grier, Emily Griffith, Hong Guo, Julien Guy, Massinissa Hadjara, Paul Harding, Sten Hasselquist, Christian R. Hayes, Fred Hearty, Jesús Hernández, Lewis Hill, David W. Hogg, Jon A. Holtzman, Danny Horta, Bau-Ching Hsieh, Chin-Hao Hsu, Yun-Hsin Hsu, Daniel Huber, Marc Huertas-Company, Brian Hutchinson, Ho Seong Hwang, Héctor J. Ibarra-Medel, Jacob Ider Chitham, Gabriele S. Ilha, Julie Imig, Will Jaekle, Tharindu Jayasinghe, Xihan Ji, Jennifer A. Johnson, Amy Jones, Henrik Jönsson, Ivan Katkov, Dr. Arman Khalatyan, Karen Kinemuchi, Shobhit Kisku, Johan H. Knapen, Jean-Paul Kneib, Juna A. Kollmeier, Miranda Kong, Marina Kounkel, Kathryn Kreckel, Dhanesh Krishnarao, Ivan Lacerna, Richard R. Lane, Rachel Langgin, Ramon Lavender, David R. Law, Daniel Lazarz, Henry W. Leung, Ho-Hin Leung, Hannah M. Lewis, Cheng Li, Ran Li, Jianhui Lian, Fu-Heng Liang, Lihwai Lin, Yen-Ting Lin, Sicheng Lin, Chris Lintott, Dan Long, Penélope Longa-Peña, Carlos López-Cobá, Shengdong Lu, Britt F. Lundgren, Yuanze Luo, J. Ted Mackereth, Axel de la Macorra, Suvrath Mahadevan, Steven R. Majewski, Arturo Manchado, Travis Mandeville, Claudia Maraston, Berta Margalef-Bentabol, Thomas Masseron, Karen L. Masters, Savita Mathur, Richard M. McDermid, Myles Mckay, Andrea Merloni, Michael Merrifield, Szabolcs Meszaros, Andrea Miglio, Francesco Di Mille, Dante Minniti, Rebecca Minsley, Antonela Monachesi, Jeongin Moon, Benoit Mosser, John Mulchaey, Demitri Muna, Ricardo R. Muñoz, Adam D. Myers, Natalie Myers, Seshadri Nadathur, Preethi Nair, Kirpal Nandra, Justus Neumann, Jeffrey A. Newman, David L. Nidever, Farnik Nikakhtar, Christian Nitschelm, Julia E. O’Connell, Luis Garma-Oehmichen, Gabriel Luan Souza de Oliveira, Richard Olney, Daniel Oravetz, Mario Ortigoza-Urdaneta, Yeisson Osorio, Justin Otter, Zachary J. Pace, Nelson Padilla, Kaike Pan, Hsi-An Pan, Taniya Parikh, James Parker, Sebastien Peirani, Karla Peña Ramírez, Samantha Penny, Will J. Percival, Ismael Perez-Fournon, Marc Pinsonneault, Frédérick Poidevin, Vijith Jacob Poovelil, Adrian M. Price-Whelan, Anna Bárbara de Andrade Queiroz, M. Jordan Raddick, Amy Ray, Sandro Barboza Rembold, Nicole Riddle, Rogemar A. Riffel, Rogério Riffel, Hans-Walter Rix, Annie C. Robin, Aldo Rodríguez-Puebla, Alexandre Roman-Lopes, Carlos Román-Zúñiga, Benjamin Rose, Ashley J. Ross, Graziano Rossi, Kate H. R. Rubin, Mara Salvato, Sebástian F. Sánchez, José R. Sánchez-Gallego, Robyn Sanderson, Felipe Antonio Santana Rojas, Edgar Sarceno, Regina Sarmiento, Conor Sayres, Elizaveta Sazonova, Adam L. Schaefer, Ricardo Schiavon, David J Schlegel, Donald P. Schneider, Mathias Schultheis, Axel Schwope, Aldo Serenelli, Javier Serna, Zhengyi Shao, Griffin Shapiro, Anubhav Sharma, Yue Shen, Matthew Shetrone, Yiping Shu, Joshua D. Simon, M. F. Skrutskie, Rebecca Smethurst, Verne Smith, Jennifer Sobeck, Taylor Spoo, Dani Sprague, David V. Stark, Keivan G. Stassun, Matthias Steinmetz, Dennis Stello, Alexander Stone-Martinez, Thaisa Storchi-Bergmann, Guy S. Stringfellow, Amelia Stutz, Yung-Chau Su, Manuchehr Taghizadeh-Popp, Michael S. Talbot, Jamie Tayar, Eduardo Telles, Johanna Teske, Ani Thakar, Christopher Theissen, Andrew Tkachenko, Daniel Thomas, Rita Tojeiro, Hector Hernandez Toledo, Nicholas W. Troup, Jonathan R. Trump, James Trussler, Jacqueline Turner, Sarah Tuttle, Eduardo Unda-Sanzana, José Antonio Vázquez-Mata, Marica Valentini, Octavio Valenzuela, Jaime Vargas-González, Mariana Vargas-Magaña, Pablo Vera Alfaro, Sandro Villanova, Fiorenzo Vincenzo, David Wake, Jack T. Warfield, Jessica Diane Washington, Benjamin Alan Weaver, Anne-Marie Weijmans, David H. Weinberg, Achim Weiss, Kyle B. Westfall, Vivienne Wild, Matthew C. Wilde, John C. Wilson, Robert F. Wilson, Mikayla Wilson, Julien Wolf, W. M. Wood-Vasey, Renbin Yan, Olga Zamora, Gail Zasowski, Kai Zhang, Cheng Zhao, Zheng Zheng, Kai Zhu, Institute of Astronomy [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Radboud University [Nijmegen], Department of Physics and Astronomy [Aarhus], Aarhus University [Aarhus], Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Instituto de Astrofisica de Canarias (IAC), Universidad de Antofagasta, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of St Andrews. School of Physics and Astronomy, University of St Andrews. Centre for Contemporary Art, European Space Agency, National Aeronautics and Space Administration (US), Alfred P. Sloan Foundation, and Abdurro'uf, Katherine Accetta, Conny Aerts, Victor Silva Aguirre, Romina Ahumada, Nikhil Ajgaonkar, N. Filiz Ak, Shadab Alam, Carlos Allende Prieto, Andres Almeida, Friedrich Anders, Scott F. Anderson, Brett H. Andrews, Borja Anguiano, Erik Aquino-Ortiz, Alfonso Aragon-Salamanca, Maria Argudo-Fernandez, Metin Ata, Marie Aubert, Vladimir Avila-Reese, Carles Badenes, Rodolfo H. Barba, Kat Barger, Jorge K. Barrera-Ballesteros, Rachael L. Beaton, Timothy C. Beers, Francesco Belfiore, Chad F. Bender, Mariangela Bernardi, Matthew A. Bershady, Florian Beutler, Christian Moni Bidin, Jonathan C. Bird, Dmitry Bizyaev, Guillermo A. Blanc, Michael R. Blanton, Nicholas Fraser Boardman, Adam S. Bolton, Mederic Boquien, Jura Borissova, Jo Bovy, W.N. Brandt, Jordan Brown, Joel R. Brownstein, Marcella Brusa, Johannes Buchner, Kevin Bundy, Joseph N. Burchett, Martin Bureau, Adam Burgasser, Tuesday K. Cabang, Stephanie Campbell, Michele Cappellari, Joleen K. Carlberg, Fabio Carneiro Wanderley, Ricardo Carrera, Jennifer Cash, Yan-Ping Chen, Wei-Huai Chen, Brian Cherinka, Cristina Chiappini, Peter Doohyun Choi, S. Drew Chojnowski, Haeun Chung, Nicolas Clerc, Roger E. Cohen, Julia M. Comerford, Johan Comparat, Luiz da Costa, Kevin Covey, Jeffrey D. Crane, Irene Cruz-Gonzalez, Connor Culhane, Katia Cunha, Y. Sophia Dai, Guillermo Damke, Jeremy Darling, James W. Davidson Jr., Roger Davies, Kyle Dawson, Nathan De Lee, Aleksandar M. Diamond-Stanic, Mariana Cano-Diaz, Helena Dominguez Sanchez, John Donor, Chris Duckworth, Tom Dwelly, Daniel J. Eisenstein, Yvonne P. Elsworth, Eric Emsellem, Mike Eracleous, Stephanie Escoffier, Xiaohui Fan, Emily Farr, Shuai Feng, Jose G. Fernandez-Trincado, Diane Feuillet, Andreas Filipp, Sean P Fillingham, Peter M. Frinchaboy , Sebastien Fromenteau, Lluis Galbany, Rafael A. Garcia, D. A. Garcia-Hernandez, Junqiang Ge, Doug Geisler, Joseph Gelfand, Tobias Geron, Benjamin J. Gibson, Julian Goddy, Diego Godoy-Rivera, Kathleen Grabowski, Paul J. Green, Michael Greener, Catherine J. Grier, Emily Griffith, Hong Guo, Julien Guy, Massinissa Hadjara, Paul Harding, Sten Hasselquist, Christian R. Hayes, Fred Hearty, Jesus Hernandez, Lewis Hill, David W. Hogg, Jon A. Holtzman, Danny Horta, Bau-Ching Hsieh, Chin-Hao Hsu, Yun-Hsin Hsu, Daniel Huber, Marc Huertas-Company, Brian Hutchinson, Ho Seong Hwang, Hector J. Ibarra-Medel, Jacob Ider Chitham, Gabriele S. Ilha, Julie Imig, Will Jaekle, Tharindu Jayasinghe, Xihan Ji, Jennifer A. Johnson, Amy Jones, Henrik Jonsson, Ivan Katkov, Dr. Arman Khalatyan, Karen Kinemuchi, Shobhit Kisku, Johan H. Knapen, Jean-Paul Kneib, Juna A. Kollmeier, Miranda Kong, Marina Kounkel, Kathryn Kreckel, Dhanesh Krishnarao, Ivan Lacerna, Richard R. Lane, Rachel Langgin, Ramon Lavender, David R. Law, Daniel Lazarz, Henry W. Leung, Ho-Hin Leung, Hannah M. Lewis, Cheng Li, Ran Li, Jianhui Lian, Fu-Heng Liang, Lihwai Lin, Yen-Ting Lin, Sicheng Lin, Chris Lintott, Dan Long, Penelope Longa-Pena, Carlos Lopez-Coba, Shengdong Lu, Britt F. Lundgren, Yuanze Luo, J. Ted Mackereth, Axel de la Macorra, Suvrath Mahadevan, Steven R. Majewski, Arturo Manchado, Travis Mandeville, Claudia Maraston, Berta Margalef-Bentabol, Thomas Masseron, Karen L. Masters, Savita Mathur, Richard M. McDermid, Myles Mckay, Andrea Merloni, Michael Merrifield, Szabolcs Meszaros, Andrea Miglio, Francesco Di Mille, Dante Minniti, Rebecca Minsley, Antonela Monachesi, Jeongin Moon, Benoit Mosser, John Mulchaey, Demitri Muna, Ricardo R. Munoz, Adam D. Myers, Natalie Myers, Seshadri Nadathur, Preethi Nair, Kirpal Nandra, Justus Neumann, Jeffrey A. Newman, David L. Nidever, Farnik Nikakhtar, Christian Nitschelm, Julia E. O'Connell, Luis Garma-Oehmichen, Gabriel Luan Souza de Oliveira, Richard Olney, Daniel Oravetz, Mario Ortigoza-Urdaneta, Yeisson Osorio, Justin Otter, Zachary J. Pace, Nelson Padilla, Kaike Pan, Hsi-An Pan, Taniya Parikh, James Parker, Sebastien Peirani, Karla Pena Ramirez, Samantha Penny, Will J. Percival, Ismael Perez-Fournon, Marc Pinsonneault, Frederick Poidevin, Vijith Jacob Poovelil, Adrian M. Price-Whelan, Anna Barbara de Andrade Queiroz, M. Jordan Raddick, Amy Ray, Sandro Barboza Rembold, Nicole Riddle, Rogemar A. Riffel, Rogerio Riffel, Hans-Walter Rix, Annie C. Robin, Aldo Rodriguez-Puebla, Alexandre Roman-Lopes, Carlos Roman-Zuniga, Benjamin Rose, Ashley J. Ross, Graziano Rossi, Kate H. R. Rubin, Mara Salvato, Sebastian F. Sanchez, Jose R. Sanchez-Gallego, Robyn Sanderson, Felipe Antonio Santana Rojas, Edgar Sarceno, Regina Sarmiento, Conor Sayres, Elizaveta Sazonova, Adam L. Schaefer, Ricardo Schiavon, David J Schlegel, Donald P. Schneider, Mathias Schultheis, Axel Schwope, Aldo Serenelli, Javier Serna, Zhengyi Shao, Griffin Shapiro, Anubhav Sharma, Yue Shen, Matthew Shetrone, Yiping Shu, Joshua D. Simon, M. F. Skrutskie, Rebecca Smethurst, Verne Smith, Jennifer Sobeck, Taylor Spoo, Dani Sprague, David V. Stark, Keivan G. Stassun, Matthias Steinmetz, Dennis Stello, Alexander Stone-Martinez, Thaisa Storchi-Bergmann, Guy S. Stringfellow, Amelia Stutz, Yung-Chau Su, Manuchehr Taghizadeh-Popp, Michael S. Talbot, Jamie Tayar, Eduardo Telles, Johanna Teske, Ani Thakar, Christopher Theissen, Daniel Thomas, Andrew Tkachenko, Rita Tojeiro, Hector Hernandez Toledo, Nicholas W. Troup, Jonathan R. Trump, James Trussler, Jacqueline Turner, Sarah Tuttle, Eduardo Unda-Sanzana, Jose Antonio Vazquez-Mata, Marica Valentini, Octavio Valenzuela, Jaime Vargas-Gonzalez, Mariana Vargas-Magana, Pablo Vera Alfaro, Sandro Villanova, Fiorenzo Vincenzo, David Wake, Jack T. Warfield, Jessica Diane Washington, Benjamin Alan Weaver, Anne-Marie Weijmans, David H. Weinberg, Achim Weiss, Kyle B. Westfall, Vivienne Wild, Matthew C. Wilde, John C. Wilson, Robert F. Wilson, Mikayla Wilson, Julien Wolf, W. M. Wood-Vasey, Renbin Yan, Olga Zamora, Gail Zasowski, Kai Zhang, Cheng Zhao, Zheng Zheng, Zheng Zheng, Kai Zhu
Subjects: ABSORPTION-LINE SPECTRA, ACTIVE GALACTIC NUCLEI, anisotropic power spectrum, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astrophysics - astrophysics of galaxies, absorption-line spectra, FOS: Physical sciences, Astronomy & Astrophysics, large-scale structure, OSCILLATION SPECTROSCOPIC SURVEY, cluster chemical abundances, reverberation mapping project, Astronomi, astrofysik och kosmologi, LARGE-SCALE STRUCTURE, Astronomy, Astrophysics and Cosmology, QB Astronomy, OLD STELLAR POPULATIONS, CLUSTER CHEMICAL ABUNDANCES, Instrumentation and Methods for Astrophysics (astro-ph.IM), QC, QB, MCC, FINAL TARGETING STRATEGY, Science & Technology, REVERBERATION MAPPING PROJECT, DAS, Astronomy and Astrophysics, ANISOTROPIC POWER SPECTRUM, oscillation spectroscopic survey, Astrophysics - Astrophysics of Galaxies, final targeting strategy, sdss-iv manga, QC Physics, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), active galactic nuclei, Physical Sciences, old stellar populations, Astrophysics - Instrumentation and Methods for Astrophysics, SDSS-IV MANGA, Astrophysics - instrumentation and methods for Astrophysics
Abstract: Abdurro’uf et al., This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys., This publication uses data generated via the Zooniverse.org platform, development of which is funded by generous support, including a Global Impact Award from Google, and by a grant from the Alfred P. Sloan Foundation. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC; https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.
Published: 2022

12. APOGEE Chemical Abundance Patterns of the Massive Milky Way Satellites

Author: Sten Hasselquist, Christian R. Hayes, Jianhui Lian, David H. Weinberg, Gail Zasowski, Danny Horta, Rachael Beaton, Diane K. Feuillet, Elisa R. Garro, Carme Gallart, Verne V. Smith, Jon A. Holtzman, Dante Minniti, Ivan Lacerna, Matthew Shetrone, Henrik Jönsson, Maria-Rosa L. Cioni, Sean P. Fillingham, Katia Cunha, Robert O’Connell, José G. Fernández-Trincado, Ricardo R. Muñoz, Ricardo Schiavon, Andres Almeida, Borja Anguiano, Timothy C. Beers, Dmitry Bizyaev, Joel R. Brownstein, Roger E. Cohen, Peter Frinchaboy, D. A. García-Hernández, Doug Geisler, Richard R. Lane, Steven R. Majewski, David L. Nidever, Christian Nitschelm, Joshua Povick, Adrian Price-Whelan, Alexandre Roman-Lopes, Margarita Rosado, Jennifer Sobeck, Guy Stringfellow, Octavio Valenzuela, Sandro Villanova, and Fiorenzo Vincenzo
Subjects: Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astronomy and Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics::Galaxy Astrophysics
Abstract: The SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey has obtained high-resolution spectra for thousands of red giant stars distributed among the massive satellite galaxies of the Milky Way (MW): the Large and Small Magellanic Clouds (LMC/SMC), the Sagittarius Dwarf (Sgr), Fornax (Fnx), and the now fully disrupted \emph{Gaia} Sausage/Enceladus (GSE) system. We present and analyze the APOGEE chemical abundance patterns of each galaxy to draw robust conclusions about their star formation histories, by quantifying the relative abundance trends of multiple elements (C, N, O, Mg, Al, Si, Ca, Fe, Ni, and Ce), as well as by fitting chemical evolution models to the [$\alpha$/Fe]-[Fe/H] abundance plane for each galaxy. Results show that the chemical signatures of the starburst in the MCs observed by Nidever et al. in the $\alpha$-element abundances extend to C+N, Al, and Ni, with the major burst in the SMC occurring some 3-4 Gyr before the burst in the LMC. We find that Sgr and Fnx also exhibit chemical abundance patterns suggestive of secondary star formation epochs, but these events were weaker and earlier ($\sim$~5-7 Gyr ago) than those observed in the MCs. There is no chemical evidence of a second starburst in GSE, but this galaxy shows the strongest initial star formation as compared to the other four galaxies. All dwarf galaxies had greater relative contributions of AGB stars to their enrichment than the MW. Comparing and contrasting these chemical patterns highlight the importance of galaxy environment on its chemical evolution., Comment: 37 pages, 21 figures, accepted for publication in ApJ
Published: 2021

13. Final Targeting Strategy for the SDSS-IV APOGEE-2S Survey

Author: Felipe A. Santana, Rachael L. Beaton, Kevin R. Covey, Julia E. O’Connell, Penélope Longa-Peña, Roger Cohen, José G. Fernández-Trincado, Christian R. Hayes, Gail Zasowski, Jennifer S. Sobeck, Steven R. Majewski, S. D. Chojnowski, Nathan De Lee, Ryan J. Oelkers, Guy S. Stringfellow, Andrés Almeida, Borja Anguiano, John Donor, Peter M. Frinchaboy, Sten Hasselquist, Jennifer A. Johnson, Juna A. Kollmeier, David L. Nidever, Adrian M. Price-Whelan, Alvaro Rojas-Arriagada, Mathias Schultheis, Matthew Shetrone, Joshua D. Simon, Conny Aerts, Jura Borissova, Maria R. Drout, Doug Geisler, C. Y. Law, Nicolas Medina, Dante Minniti, Antonela Monachesi, Ricardo R. Muñoz, Radosław Poleski, Alexandre Roman-Lopes, Kevin C. Schlaufman, Amelia M. Stutz, Johanna Teske, Andrew Tkachenko, Jennifer L. Van Saders, Alycia J. Weinberger, and Manuela Zoccali
Subjects: Science & Technology, STELLAR HALO, EXPLORING HALO SUBSTRUCTURE, HOMOGENEOUS ANALYSIS, DATA RELEASE, FOS: Physical sciences, Astronomy and Astrophysics, MILKY-WAY BULGE, Astronomy & Astrophysics, GALACTIC ARCHAEOLOGY, Astrophysics - Astrophysics of Galaxies, VELOCITY DISPERSION PROFILES, GLOBULAR-CLUSTER CANDIDATES, Space and Planetary Science, FORNAX DWARF GALAXY, Astrophysics of Galaxies (astro-ph.GA), Physical Sciences, LARGE-MAGELLANIC-CLOUD
Abstract: APOGEE is a high-resolution (R sim 22,000), near-infrared, multi-epoch, spectroscopic survey of the Milky Way. The second generation of the APOGEE project, APOGEE-2, includes an expansion of the survey to the Southern Hemisphere called APOGEE-2S. This expansion enabled APOGEE to perform a fully panoramic mapping of all the main regions of the Milky Way; in particular, by operating in the H-band, APOGEE is uniquely able to probe the dust-hidden inner regions of the Milky Way that are best accessed from the Southern Hemisphere. In this paper we present the targeting strategy of APOGEE-2S, with special attention to documenting modifications to the original, previously published plan. The motivation for these changes is explained as well as an assessment of their effectiveness in achieving their intended scientific objective. In anticipation of this being the last paper detailing APOGEE targeting, we present an accounting of all such information complete through the end of the APOGEE-2S project; this includes several main survey programs dedicated to exploration of major stellar populations and regions of the Milky Way, as well as a full list of programs contributing to the APOGEE database through allocations of observing time by the Chilean National Time Allocation Committee (CNTAC) and the Carnegie Institution for Science (CIS). This work was presented along with a companion article, R. Beaton et al. (submitted; AAS29028), presenting the final target selection strategy adopted for APOGEE-2 in the Northern Hemisphere., 43 pages; 5 figures; 6 Tables; 1 Appendix; Submitted to Journal and Under Review; Posting to accompany papers using the SDSS-IV/APOGEE-2 Data Release 17 scheduled for December 2021
Published: 2021

14. Chemical Cartography with APOGEE: Mapping Disk Populations with a 2-process Model and Residual Abundances

Author: David H. Weinberg, Jon A. Holtzman, Jennifer A. Johnson, Christian Hayes, Sten Hasselquist, Matthew Shetrone, Yuan-Sen Ting, Rachael L. Beaton, Timothy C. Beers, Jonathan C. Bird, Dmitry Bizyaev, Michael R. Blanton, Katia Cunha, José G. Fernández-Trincado, Peter M. Frinchaboy, D. A. García-Hernández, Emily Griffith, James W. Johnson, Henrik Jönsson, Richard R. Lane, Henry W. Leung, J. Ted Mackereth, Steven R. Majewski, Szabolcs Mészáros, Christian Nitschelm, Kaike Pan, Ricardo P. Schiavon, Donald P. Schneider, Mathias Schultheis, Verne Smith, Jennifer S. Sobeck, Keivan G. Stassun, Guy S. Stringfellow, Fiorenzo Vincenzo, John C. Wilson, and Gail Zasowski
Subjects: Space and Planetary Science, Astronomy and Astrophysics
Abstract: We apply a novel statistical analysis to measurements of 16 elemental abundances in 34,410 Milky Way disk stars from the final data release (DR17) of APOGEE-2. Building on recent work, we fit median abundance ratio trends [X/Mg] versus [Mg/H] with a 2-process model, which decomposes abundance patterns into a “prompt” component tracing core-collapse supernovae and a “delayed” component tracing Type Ia supernovae. For each sample star, we fit the amplitudes of these two components, then compute the residuals Δ[X/H] from this two-parameter fit. The rms residuals range from ∼0.01–0.03 dex for the most precisely measured APOGEE abundances to ∼0.1 dex for Na, V, and Ce. The correlations of residuals reveal a complex underlying structure, including a correlated element group comprised of Ca, Na, Al, K, Cr, and Ce and a separate group comprised of Ni, V, Mn, and Co. Selecting stars poorly fit by the 2-process model reveals a rich variety of physical outliers and sometimes subtle measurement errors. Residual abundances allow for the comparison of populations controlled for differences in metallicity and [α/Fe]. Relative to the main disk (R = 3–13 kpc), we find nearly identical abundance patterns in the outer disk (R = 15–17 kpc), 0.05–0.2 dex depressions of multiple elements in LMC and Gaia Sausage/Enceladus stars, and wild deviations (0.4–1 dex) of multiple elements in ω Cen. The residual abundance analysis opens new opportunities for discovering chemically distinctive stars and stellar populations, for empirically constraining nucleosynthetic yields, and for testing chemical evolution models that include stochasticity in the production and redistribution of elements.
Published: 2022

15. The Stars of the HETDEX Survey. I. Radial Velocities and Metal-Poor Stars from Low-Resolution Stellar Spectra

Author: Karl Gebhardt, Keith Hawkins, Christopher Sneden, Dustin Davis, Barbara G. Castanheira, Donald P. Schneider, Caitlin M. Casey, Andreas Kelz, J. Craig Wheeler, Steven L. Finkelstein, Daniel J. Farrow, Gary J. Hill, Erin Mentuch Cooper, Andreia Carrillo, Howard E. Bond, Robin Ciardullo, Greg Zeimann, Matthias Steinmetz, Matthew Shetrone, Chenxu Liu, Else Starkenburg, and Astronomy
Subjects: Physics, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Segue, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Galaxy, Astronomical spectroscopy, Spectral line, law.invention, LAMOST, Telescope, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, law, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Dark energy, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is an unbiased, massively multiplexed spectroscopic survey, designed to measure the expansion history of the universe through low-resolution ($R\sim750$) spectra of Lyman-Alpha Emitters. In its search for these galaxies, HETDEX will also observe a few 10$^{5}$ stars. In this paper, we present the first stellar value-added catalog within the internal second data release of the HETDEX Survey (HDR2). The new catalog contains 120,571 low-resolution spectra for 98,736 unique stars between $10 < G < 22$ spread across the HETDEX footprint at relatively high ($b\sim60^\circ$) Galactic latitudes. With these spectra, we measure radial velocities (RVs) for $\sim$42,000 unique FGK-type stars in the catalog and show that the HETDEX spectra are sufficient to constrain these RVs with a 1$��$ precision of 28.0 km/s and bias of 3.5 km/s with respect to the LAMOST surveys and 1$��$ precision of 27.5 km/s and bias of 14.0 km/s compared to the SEGUE survey. Since these RVs are for faint ($G\geq16$) stars, they will be complementary to Gaia. Using t-Distributed Stochastic Neighbor Embedding (t-SNE), we also demonstrate that the HETDEX spectra can be used to determine a star's T${\rm{eff}}$, and log g and its [Fe/H]. With the t-SNE projection of the FGK-type stars with HETDEX spectra we also identify 416 new candidate metal-poor ([Fe/H] $< -1$~dex) stars for future study. These encouraging results illustrate the utility of future low-resolution stellar spectroscopic surveys., 18 Pages, 11 Figures, 2 Tables. Accepted to ApJ
Published: 2021

16. Homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code - III. omega Cen

Author: Henrik Jönsson, Dante Minniti, Christian R. Hayes, Thomas Masseron, Rebecca Lane, Doug Geisler, D. A. García-Hernández, Matthew Shetrone, Timothy C. Beers, Steven R. Majewski, José G. Fernández-Trincado, Verne V. Smith, László Szigeti, Rachael L. Beaton, Szabolcs Mészáros, Olga Zamora, Joel R. Brownstein, Alexandre Roman-Lopes, Christian Nitschelm, Ricardo R. Munoz, and Katia Cunha
Subjects: Physics, 010308 nuclear & particles physics, Red giant, Metallicity, Milky Way, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Galaxy, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Globular cluster, 0103 physical sciences, Thick disk, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Dwarf galaxy
Abstract: We study the multiple populations of $\omega$ Cen by using the abundances of Fe, C, N, O, Mg, Al, Si, K, Ca, and Ce from the high-resolution, high signal-to-noise (S/N$>$70) spectra of 982 red giant stars observed by the SDSS-IV/APOGEE-2 survey. We find that the shape of the Al-Mg and N-C anticorrelations changes as a function of metallicity, continuous for the metal-poor groups, but bimodal (or unimodal) at high metallicities. There are four Fe populations, similar to what has been found in previously published investigations, but we find seven populations based on Fe, Al, and Mg abundances. The evolution of Al in $\omega$ Cen is compared to its evolution in the Milky Way and in five representative globular clusters. We find that the distribution of Al in metal-rich stars of $\omega$ Cen closely follows what is observed in the Galaxy. Other $\alpha-$elements and C, N, O, and Ce are also compared to the Milky Way, and significantly elevated abundances are observed over what is found in the thick disk for almost all elements. However, we also find some stars with high metallicity and low [Al/Fe], suggesting that $\omega$ Cen could be the remnant core of a dwarf galaxy, but the existence of these peculiar stars needs an independent confirmation. We also confirm the increase in the sum of CNO as a function of metallicity previously reported in the literature and find that the [C/N] ratio appears to show opposite correlations between Al-poor and Al-rich stars as a function of metallicity., Comment: Accepted for publication in MNRAS, 17 pages, 16 figures, 3 tables
Published: 2021

17. Homogeneity in the early chemical evolution of the Sextans dwarf Spheroidal galaxy

Author: Francesca Primas, Matthew Shetrone, Pascale Jablonka, Carmela Lardo, Pierre North, Mike Irwin, R. Lucchesi, Vanessa Hill, Else Starkenburg, Giuseppina Battaglia, Kim Venn, P. François, Eline Tolstoy, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lucchesi R., Lardo C., Primas F., Jablonka P., North P., Battaglia G., Starkenburg E., Hill V., Irwin M., Francois P., Shetrone M., Tolstoy E., Venn K., and Astronomy
Subjects: enrichment, Stellar population, stars: abundances, neutron-capture elements, Metallicity, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, high-resolution, 01 natural sciences, Spectral line, local group, nlte analysis, 0103 physical sciences, Homogeneity (physics), galaxies: formation, Astrophysics::Solar and Stellar Astrophysics, metal-poor stars, 010306 general physics, 10. No inequality, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, abundance, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], formation history, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], r-process, Local Group, Astronomy and Astrophysics, galaxies: dwarf, effective temperature scale, Astrophysics - Astrophysics of Galaxies, Galaxy, Dwarf spheroidal galaxy, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], s-process
Abstract: We present the high-resolution spectroscopic analysis of two new extremely metal-poor stars (EMPS) candidates in the dwarf spheroidal galaxy Sextans. These targets were pre-selected from medium resolution spectra centered around the Ca II triplet in the near-infrared and followed-up at higher resolution with VLT/UVES. We confirm their low metallicities with [Fe/H]=-2.95 and [Fe/H]=-3.01, placing them among the most metal-poor stars known in Sextans. The abundances of 18 elements, including C, Na, the alpha-elements, Fe-peak, and neutron capture elements, are determined. In particular, we present the first measurements of Zn in a classical dwarf at extremely low metallicity. There has been previous hints of a large scatter in the abundance ratios of the Sextans stellar population around [Fe/H] -3 when compared to other galaxies. We took the opportunity of this work to re-analyse the full sample of EMPS and find a Milky-Way -like plateau and a normal dispersion at fixed metallicity., Accepted for publication in A&A. 14 pages, 10 figures
Published: 2020

18. The 16th Data Release of the Sloan Digital Sky Surveys : First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra

Author: Romina Ahumada, Carlos Allende Prieto, Andrés Almeida, Friedrich Anders, Scott F. Anderson, Brett H. Andrews, Borja Anguiano, Riccardo Arcodia, Eric Armengaud, Marie Aubert, Santiago Avila, Vladimir Avila-Reese, Carles Badenes, Christophe Balland, Kat Barger, Jorge K. Barrera-Ballesteros, Sarbani Basu, Julian Bautista, Rachael L. Beaton, Timothy C. Beers, B. Izamar T. Benavides, Chad F. Bender, Mariangela Bernardi, Matthew Bershady, Florian Beutler, Christian Moni Bidin, Jonathan Bird, Dmitry Bizyaev, Guillermo A. Blanc, Michael R. Blanton, Médéric Boquien, Jura Borissova, Jo Bovy, W. N. Brandt, Jonathan Brinkmann, Joel R. Brownstein, Kevin Bundy, Martin Bureau, Adam Burgasser, Etienne Burtin, Mariana Cano-Díaz, Raffaella Capasso, Michele Cappellari, Ricardo Carrera, Solène Chabanier, William Chaplin, Michael Chapman, Brian Cherinka, Cristina Chiappini, Peter Doohyun Choi, S. Drew Chojnowski, Haeun Chung, Nicolas Clerc, Damien Coffey, Julia M. Comerford, Johan Comparat, Luiz da Costa, Marie-Claude Cousinou, Kevin Covey, Jeffrey D. Crane, Katia Cunha, Gabriele da Silva Ilha, Yu Sophia Dai, Sanna B. Damsted, Jeremy Darling, James W. Davidson, Roger Davies, Kyle Dawson, Nikhil De, Axel de la Macorra, Nathan De Lee, Anna Bárbara de Andrade Queiroz, Alice Deconto Machado, Sylvain de la Torre, Flavia Dell’Agli, Hélion du Mas des Bourboux, Aleksandar M. Diamond-Stanic, Sean Dillon, John Donor, Niv Drory, Chris Duckworth, Tom Dwelly, Garrett Ebelke, Sarah Eftekharzadeh, Arthur Davis Eigenbrot, Yvonne P. Elsworth, Mike Eracleous, Ghazaleh Erfanianfar, Stephanie Escoffier, Xiaohui Fan, Emily Farr, José G. Fernández-Trincado, Diane Feuillet, Alexis Finoguenov, Patricia Fofie, Amelia Fraser-McKelvie, Peter M. Frinchaboy, Sebastien Fromenteau, Hai Fu, Lluís Galbany, Rafael A. Garcia, D. A. García-Hernández, Luis Alberto Garma Oehmichen, Junqiang Ge, Marcio Antonio Geimba Maia, Doug Geisler, Joseph Gelfand, Julian Goddy, Violeta Gonzalez-Perez, Kathleen Grabowski, Paul Green, Catherine J. Grier, Hong Guo, Julien Guy, Paul Harding, Sten Hasselquist, Adam James Hawken, Christian R. Hayes, Fred Hearty, S. Hekker, David W. Hogg, Jon A. Holtzman, Danny Horta, Jiamin Hou, Bau-Ching Hsieh, Daniel Huber, Jason A. S. Hunt, J. Ider Chitham, Julie Imig, Mariana Jaber, Camilo Eduardo Jimenez Angel, Jennifer A. Johnson, Amy M. Jones, Henrik Jönsson, Eric Jullo, Yerim Kim, Karen Kinemuchi, Charles C. Kirkpatrick IV, George W. Kite, Mark Klaene, Jean-Paul Kneib, Juna A. Kollmeier, Hui Kong, Marina Kounkel, Dhanesh Krishnarao, Ivan Lacerna, Ting-Wen Lan, Richard R. Lane, David R. Law, Jean-Marc Le Goff, Henry W. Leung, Hannah Lewis, Cheng Li, Jianhui Lian, Lihwai Lin, Dan Long, Penélope Longa-Peña, Britt Lundgren, Brad W. Lyke, J. Ted Mackereth, Chelsea L. MacLeod, Steven R. Majewski, Arturo Manchado, Claudia Maraston, Paul Martini, Thomas Masseron, Karen L. Masters, Savita Mathur, Richard M. McDermid, Andrea Merloni, Michael Merrifield, Szabolcs Mészáros, Andrea Miglio, Dante Minniti, Rebecca Minsley, Takamitsu Miyaji, Faizan Gohar Mohammad, Benoit Mosser, Eva-Maria Mueller, Demitri Muna, Andrea Muñoz-Gutiérrez, Adam D. Myers, Seshadri Nadathur, Preethi Nair, Kirpal Nandra, Janaina Correa do Nascimento, Rebecca Jean Nevin, Jeffrey A. Newman, David L. Nidever, Christian Nitschelm, Pasquier Noterdaeme, Julia E. O’Connell, Matthew D. Olmstead, Daniel Oravetz, Audrey Oravetz, Yeisson Osorio, Zachary J. Pace, Nelson Padilla, Nathalie Palanque-Delabrouille, Pedro A. Palicio, Hsi-An Pan, Kaike Pan, James Parker, Romain Paviot, Sebastien Peirani, Karla Peña Ramŕez, Samantha Penny, Will J. Percival, Ismael Perez-Fournon, Ignasi Pérez-Ràfols, Patrick Petitjean, Matthew M. Pieri, Marc Pinsonneault, Vijith Jacob Poovelil, Joshua Tyler Povick, Abhishek Prakash, Adrian M. Price-Whelan, M. Jordan Raddick, Anand Raichoor, Amy Ray, Sandro Barboza Rembold, Mehdi Rezaie, Rogemar A. Riffel, Rogério Riffel, Hans-Walter Rix, Annie C. Robin, A. Roman-Lopes, Carlos Román-Zúñiga, Benjamin Rose, Ashley J. Ross, Graziano Rossi, Kate Rowlands, Kate H. R. Rubin, Mara Salvato, Ariel G. Sánchez, Laura Sánchez-Menguiano, José R. Sánchez-Gallego, Conor Sayres, Adam Schaefer, Ricardo P. Schiavon, Jaderson S. Schimoia, Edward Schlafly, David Schlegel, Donald P. Schneider, Mathias Schultheis, Axel Schwope, Hee-Jong Seo, Aldo Serenelli, Arman Shafieloo, Shoaib Jamal Shamsi, Zhengyi Shao, Shiyin Shen, Matthew Shetrone, Raphael Shirley, Víctor Silva Aguirre, Joshua D. Simon, M. F. Skrutskie, Anže Slosar, Rebecca Smethurst, Jennifer Sobeck, Bernardo Cervantes Sodi, Diogo Souto, David V. Stark, Keivan G. Stassun, Matthias Steinmetz, Dennis Stello, Julianna Stermer, Thaisa Storchi-Bergmann, Alina Streblyanska, Guy S. Stringfellow, Amelia Stutz, Genaro Suárez, Jing Sun, Manuchehr Taghizadeh-Popp, Michael S. Talbot, Jamie Tayar, Aniruddha R. Thakar, Riley Theriault, Daniel Thomas, Zak C. Thomas, Jeremy Tinker, Rita Tojeiro, Hector Hernandez Toledo, Christy A. Tremonti, Nicholas W. Troup, Sarah Tuttle, Eduardo Unda-Sanzana, Marica Valentini, Jaime Vargas-González, Mariana Vargas-Magaña, Jose Antonio Vázquez-Mata, M. Vivek, David Wake, Yuting Wang, Benjamin Alan Weaver, Anne-Marie Weijmans, Vivienne Wild, John C. Wilson, Robert F. Wilson, Nathan Wolthuis, W. M. Wood-Vasey, Renbin Yan, Meng Yang, Christophe Yèche, Olga Zamora, Pauline Zarrouk, Gail Zasowski, Kai Zhang, Cheng Zhao, Gongbo Zhao, Zheng Zheng, Guangtun Zhu, Hu Zou, Department of Physics, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Canarias (IAC), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional Autónoma de México (UNAM), Department of Astrophysical Sciences [Princeton], Princeton University, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Department of Astronomy, Yale University [New Haven], University of Notre Dame [Indiana] (UND), Department of Physics and Astronomy [Philadelphia], University of Pennsylvania [Philadelphia], University of Wisconsin-Madison, Texas Tech University Health Sciences Center, Texas Tech University [Lubbock] (TTU), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), California Institute of Technology (CALTECH), Sub-department of Astrophysics [Oxford], Department of Physics [Oxford], University of Oxford [Oxford]-University of Oxford [Oxford], Center for Astrophysics and Space Sciences [La Jolla] (CASS), University of California [San Diego] (UC San Diego), University of California-University of California, Department of Psychology, St John's University, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Departamento de FisicaTeorica e IFT-UAM/CSIC, Universidad Autonoma de Madrid (UAM), Lowell Observatory [Flagstaff], Observatorio Nacional [Rio de Janeiro], Vernalis (R&D) Ltd, Special Care Dentistry, UCLH Eastman Dental Hospital, University of Utah, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Universidad de La Laguna [Tenerife - SP] (ULL), University of Virginia [Charlottesville], University of Wyoming (UW), School of Physics and Astronomy, University of Birmingham [Birmingham], Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Arizona State University [Tempe] (ASU), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Max-Planck-Institut für Astronomie (MPIA), Texas Christian University (TCU), Department of Physics and Astronomy [Irvine], University of California [Irvine] (UCI), Department of Physics and Astronomy [Pittsburgh], University of Pittsburgh (PITT), Pennsylvania Commonwealth System of Higher Education (PCSHE)-Pennsylvania Commonwealth System of Higher Education (PCSHE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), New York University [New York] (NYU), NYU System (NYU), Research Institute of Forest Resource Information Techniques, Chinese Academy of Forestry, New Mexico State University, Pennsylvania State University (Penn State), Penn State System, Princess Margaret Hospital, University of Toronto, Cognition, Langues, Langage, Ergonomie (CLLE-ERSS), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Toulouse - Jean Jaurès (UT2J)-Université Bordeaux Montaigne-Centre National de la Recherche Scientifique (CNRS), J. A. Baker Institute, Cornell University [New York], Institute of Infection, Immunity & Inflammation, University of Glasgow, Sainsbury Laboratory Cambridge University (SLCU), University of Cambridge [UK] (CAM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Carnegie Observatories, Carnegie Institution for Science [Washington], Institute of Science and Technology [Austria] (IST Austria), Universidad de Atacama, Department of Chemical and Biomolecular Engineering, Universidad de Antofagasta, Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Institute of cosmology and gravitation, University of Portsmouth, Institut d'Astronomie et d'Astrophysique [Bruxelles] (IAA), Université libre de Bruxelles (ULB), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Max-Planck-Institut für Astrophysik (MPA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Département des Sciences et Gestion de l'Environnement/Océanologie [Liège], Université de Liège, Universidad Andrés Bello [Santiago] (UNAB), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Montana State University (MSU), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy (Ohio State University), Ohio State University [Columbus] (OSU), Institut Lagrange de Paris, Sorbonne Université (SU), The Wellcome Trust Centre for Human Genetics [Oxford], University of Oxford [Oxford], Liverpool John Moores University (LJMU), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Space Sciences [Barcelona] (ICE-CSIC), Spanish National Research Council [Madrid] (CSIC), Chinese Academy of Sciences [Beijing] (CAS), McDonald Observatory, University of Texas at Austin [Austin], Astronomy Centre, University of Sussex, Department of Physics and Astronomy [Aarhus], Aarhus University [Aarhus], University of Washington [Seattle], Vanderbilt University [Nashville], Stellar Astrophysics Centre [Aarhus] (SAC), University of Colorado [Boulder], Laboratoire de Biochimie Médicale (LBM), CHU Rouen, Normandie Université (NU)-Normandie Université (NU), University of St Andrews [Scotland], Instituto de Astronomıa, universidad catolica del Norte, Institut d'Astrophysique et de Géophysique [Liège], Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Department of Computer Science and Engineering [Minneapolis], University of Minnesota [Twin Cities] (UMN), University of Minnesota System-University of Minnesota System, Dunlap Institute for Astronomy and Astrophysics [Toronto], World Bank, State Key Laboratory in Computer Science [Beijing] (SKLCS), Institute of Software Chinese Academy of Sciences [Beijing], Nanjing University of Information Science and Technology (NUIST), Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), Johns Hopkins University (JHU), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Pennsylvania, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Oxford-University of Oxford, University of California (UC)-University of California (UC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Universidad Autónoma de Madrid (UAM), University of Virginia, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), University of California [Irvine] (UC Irvine), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Bordeaux Montaigne (UBM)-Centre National de la Recherche Scientifique (CNRS), Carnegie Institution for Science, Institute of Science and Technology [Klosterneuburg, Austria] (IST Austria), Harvard University-Smithsonian Institution, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of Oxford, Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Ahumada R., Prieto C.A., Almeida A., Anders F., Anderson S.F., Andrews B.H., Anguiano B., Arcodia R., Armengaud E., Aubert M., Avila S., Avila-Reese V., Badenes C., Balland C., Barger K., Barrera-Ballesteros J.K., Basu S., Bautista J., Beaton R.L., Beers T.C., Benavides B.I.T., Bender C.F., Bernardi M., Bershady M., Beutler F., Bidin C.M., Bird J., Bizyaev D., Blanc G.A., Blanton M.R., Boquien M., Borissova J., Bovy J., Brandt W.N., Brinkmann J., Brownstein J.R., Bundy K., Bureau M., Burgasser A., Burtin E., Cano-Diaz M., Capasso R., Cappellari M., Carrera R., Chabanier S., Chaplin W., Chapman M., Cherinka B., Chiappini C., Doohyun Choi P., Chojnowski S.D., Chung H., Clerc N., Coffey D., Comerford J.M., Comparat J., Da Costa L., Cousinou M.-C., Covey K., Crane J.D., Cunha K., Ilha G.D.S., Dai Y.S., Damsted S.B., Darling J., Davidson J.W., Davies R., Dawson K., De N., De La Macorra A., De Lee N., Queiroz A.B.D.A., Deconto Machado A., De La Torre S., Dell'Agli F., Du Mas Des Bourboux H., Diamond-Stanic A.M., Dillon S., Donor J., Drory N., Duckworth C., Dwelly T., Ebelke G., Eftekharzadeh S., Davis Eigenbrot A., Elsworth Y.P., Eracleous M., Erfanianfar G., Escoffier S., Fan X., Farr E., Fernandez-Trincado J.G., Feuillet D., Finoguenov A., Fofie P., Fraser-Mckelvie A., Frinchaboy P.M., Fromenteau S., Fu H., Galbany L., Garcia R.A., Garcia-Hernandez D.A., Oehmichen L.A.G., Ge J., Maia M.A.G., Geisler D., Gelfand J., Goddy J., Gonzalez-Perez V., Grabowski K., Green P., Grier C.J., Guo H., Guy J., Harding P., Hasselquist S., Hawken A.J., Hayes C.R., Hearty F., Hekker S., Hogg D.W., Holtzman J.A., Horta D., Hou J., Hsieh B.-C., Huber D., Hunt J.A.S., Chitham J.I., Imig J., Jaber M., Angel C.E.J., Johnson J.A., Jones A.M., Jonsson H., Jullo E., Kim Y., Kinemuchi K., Kirkpatrick Iv C.C., Kite G.W., Klaene M., Kneib J.-P., Kollmeier J.A., Kong H., Kounkel M., Krishnarao D., Lacerna I., Lan T.-W., Lane R.R., Law D.R., Le Goff J.-M., Leung H.W., Lewis H., Li C., Lian J., Lin L., Long D., Longa-Peña P., Lundgren B., Lyke B.W., Ted Mackereth J., Macleod C.L., Majewski S.R., Manchado A., Maraston C., Martini P., Masseron T., Masters K.L., Mathur S., McDermid R.M., Merloni A., Merrifield M., Meszaros S., Miglio A., Minniti D., Minsley R., Miyaji T., Mohammad F.G., Mosser B., Mueller E.-M., Muna D., Muñoz-Gutierrez A., Myers A.D., Nadathur S., Nair P., Nandra K., Do Nascimento J.C., Nevin R.J., Newman J.A., Nidever D.L., Nitschelm C., Noterdaeme P., O'Connell J.E., Olmstead M.D., Oravetz D., Oravetz A., Osorio Y., Pace Z.J., Padilla N., Palanque-Delabrouille N., Palicio P.A., Pan H.-A., Pan K., Parker J., Paviot R., Peirani S., Ramrez K.P., Penny S., Percival W.J., Perez-Fournon I., Perez-Rafols I., Petitjean P., Pieri M.M., Pinsonneault M., Poovelil V.J., Povick J.T., Prakash A., Price-Whelan A.M., Raddick M.J., Raichoor A., Ray A., Rembold S.B., Rezaie M., Riffel R.A., Riffel R., Rix H.-W., Robin A.C., Roman-Lopes A., Roman-Zuñiga C., Rose B., Ross A.J., Rossi G., Rowlands K., Rubin K.H.R., Salvato M., Sanchez A.G., Sanchez-Menguiano L., Sanchez-Gallego J.R., Sayres C., Schaefer A., Schiavon R.P., Schimoia J.S., Schlafly E., Schlegel D., Schneider D.P., Schultheis M., Schwope A., Seo H.-J., Serenelli A., Shafieloo A., Shamsi S.J., Shao Z., Shen S., Shetrone M., Shirley R., Aguirre V.S., Simon J.D., Skrutskie M.F., Slosar A., Smethurst R., Sobeck J., Sodi B.C., Souto D., Stark D.V., Stassun K.G., Steinmetz M., Stello D., Stermer J., Storchi-Bergmann T., Streblyanska A., Stringfellow G.S., Stutz A., Suarez G., Sun J., Taghizadeh-Popp M., Talbot M.S., Tayar J., Thakar A.R., Theriault R., Thomas D., Thomas Z.C., Tinker J., Tojeiro R., Toledo H.H., Tremonti C.A., Troup N.W., Tuttle S., Unda-Sanzana E., Valentini M., Vargas-Gonzalez J., Vargas-Magaña M., Vazquez-Mata J.A., Vivek M., Wake D., Wang Y., Weaver B.A., Weijmans A.-M., Wild V., Wilson J.C., Wilson R.F., Wolthuis N., Wood-Vasey W.M., Yan R., Yang M., Yeche C., Zamora O., Zarrouk P., Zasowski G., Zhang K., Zhao C., Zhao G., Zheng Z., Zhu G., Zou H., Alfred P. Sloan Foundation, and Department of Energy (US)
Subjects: Optical telescopes, SAMPLE, Astrophysics, 01 natural sciences, Astronomi, astrofysik och kosmologi, Infrared astronomy, Observatory, Astronomy, Astrophysics and Cosmology, Astrophysics::Solar and Stellar Astrophysics, REDSHIFT 0.8, redshift surveys, stellar spectral lines, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, media_common, Astronomy databases, Redshift surveys, Physics, Astrophysics::Instrumentation and Methods for Astrophysics, stellar properties, CATALOG, astro-ph.CO, astronomy databases, Data release, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], infrared astonomy, TELESCOPE, astro-ph.GA, media_common.quotation_subject, Astrophysics::Cosmology and Extragalactic Astrophysics, MASS, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Galactic abundances, Stellar properties, 0103 physical sciences, Astrophysics::Galaxy Astrophysics, DISTANCES, Stellar spectral lines, 010308 nuclear & particles physics, Astronomy and Astrophysics, optical telescopes, 115 Astronomy, Space science, Galaxy, GALAXY, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], STELLAR, 13. Climate action, Space and Planetary Science, Sky, [SDU]Sciences of the Universe [physics], galactic abundances, MILKY, astro-ph.IM, SDSS-IV MANGA
Abstract: This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17)., Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS website is www.sdss.org.
Published: 2020

19. NLTE for APOGEE: Simultaneous Multi-Element NLTE Radiative Transfer

Author: Ivan Hubeny, Matthew Shetrone, C. Allende Prieto, Sz. Meszaros, and Yeisson Osorio
Subjects: Physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Multi element, Computational physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Radiative transfer, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: Context.Relaxing the assumption of local thermodynamic equilibrium (LTE) in modelling stellar spectra is a necessary step to determine chemical abundances to better than about 10% in late-type stars.Aims.We describe our multi-element (Na, Mg, K, and Ca) non-LTE (NLTE) calculations, which can be applied to the APOGEE survey.Methods.The new version ofTLUSTYallows for the calculation of restricted NLTE in cool stars using pre-calculated opacity tables. We demonstrate thatTLUSTYgives consistent results withMULTI, a well-tested code for NLTE in cool stars. We usedTLUSTYto perform LTE and a series of NLTE calculations that simultaneously used all combinations of one, two, three and four of the elements in NLTE.Results.We take into account that departures from LTE in one element can affect others through changes in the opacities of Na, Mg, K, and Ca. We find that atomic Mg, which provides strong UV opacity and exhibits significant departures from LTE in the low-energy states, can affect the NLTE populations of Ca, leading to abundance corrections as large as 0.07 dex. The differences in the derived abundances between the single-element and the multi-element cases can exceed those between the single-element NLTE determinations and an LTE analysis. We therefore caution that this is not always a second-order effect. Based on detailed tests for three stars with reliable atmospheric parameters (Arcturus, Procyon, and the Sun), we conclude that our NLTE calculations provide abundance corrections that can in the optical amount to 0.1, 0.2, and 0.7 dex for Ca, Na and K, but LTE is a good approximation for Mg. In theH-band, NLTE corrections are much smaller and always lower than 0.1 dex. The derived NLTE abundances in the optical and in the IR are consistent. In all three stars, NLTE line profiles fit the observations better than the LTE counterparts for all four elements.Conclusions.The atomic elements in ionisation stages where over-ionisation is an important NLTE mechanism are likely affected by departures from LTE in Mg. Particular care must be taken with the collisions that are adopted for high-lying levels when NLTE profiles of lines in theH-band are calculated. The derived NLTE corrections in the optical and in theH-band differ, but the derived NLTE abundances are consistent between the two spectral regions.
Published: 2020

20. Orbital Torus Imaging: Using Element Abundances to Map Orbits and Mass in the Milky Way

Author: Adrian M. Price-Whelan, D. A. García-Hernández, Hans-Walter Rix, Rebecca Lane, Sten Hasselquist, Rachael L. Beaton, Melissa Ness, Matthew Shetrone, David W. Hogg, Kathryn V. Johnston, Jennifer Sobeck, Gail Zasowski, Joel R. Brownstein, and Christian R. Hayes
Subjects: Physics, Stellar kinematics, 010504 meteorology & atmospheric sciences, Milky Way, FOS: Physical sciences, Astronomy and Astrophysics, Torus, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Mass ratio, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Gravitational potential, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Orbit (dynamics), Astrophysics::Earth and Planetary Astrophysics, Invariant (mathematics), 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract: Many approaches to galaxy dynamics assume that the gravitational potential is simple and the distribution function is time-invariant. Under these assumptions there are traditional tools for inferring potential parameters given observations of stellar kinematics (e.g., Jeans models). However, spectroscopic surveys measure many stellar properties beyond kinematics. Here we present a new approach for dynamical inference, Orbital Torus Imaging, which makes use of kinematic measurements and element abundances (or other invariant labels). We exploit the fact that, in steady state, stellar labels vary systematically with orbit characteristics (actions), yet must be invariant with respect to orbital phases (conjugate angles). The orbital foliation of phase space must therefore coincide with surfaces along which all moments of all stellar label distributions are constant. Both classical-statistics and Bayesian methods can be built on this; these methods will be more robust and require fewer assumptions than traditional tools because they require no knowledge of the (spatial) survey selection function and they do not involve second moments of velocity distributions. We perform a classical-statistics demonstration with red giant branch stars from the APOGEE surveys: We model the vertical orbit structure in the Milky Way disk to constrain the local disk mass, scale height, and the disk--halo mass ratio (at fixed local circular velocity). We find that the disk mass can be constrained (na\"ively) at the few-percent level with Orbital Torus Imaging using only eight element-abundance ratios, demonstrating the promise of combining stellar labels with dynamical invariants., Comment: 34 pages, 8 figures. Published in ApJ
Published: 2020
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21. The S2 Stream: the shreds of a primitive dwarf galaxy

Author: Sergey E. Koposov, Camila Navarrete, Carlos Allende Prieto, Luca Sbordone, Zhen Yuan, Luis Peralta de Arriba, David Aguado, Jonay I. González Hernández, Vasily Belokurov, Gustavo A. Lanfranchi, Matthew Shetrone, Francesca Matteucci, N. Wyn Evans, Julio Chanamé, G. C. Myeong, Belokurov, Vasily [0000-0002-0038-9584], Evans, Wyn [0000-0002-5981-7360], and Apollo - University of Cambridge Repository
Subjects: Physics, Galaxy: evolution, stars: abundances, 010308 nuclear & particles physics, astro-ph.GA, Metallicity, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy: halo, Chemical evolution, Galactic halo, Stars, Space and Planetary Science, Galaxy: formation, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Galaxy formation and evolution, Spectroscopy, 010303 astronomy & astrophysics, Galaxy: kinematics and dynamics, Dwarf galaxy
Abstract: The S2 stream is a kinematically cold stream that is plunging downwards through the Galactic disc. It may be part of a hotter and more diffuse structure called the Helmi stream. We present a multi-instrument chemical analysis of the stars in the metal-poor S2 stream using both high- and low-resolution spectroscopy, complemented with a re-analysis of the archival data to give a total sample of 62 S2 members. Our high-resolution program provides alpha-elements (C, Mg, Si, Ca and Ti), iron-peak elements (V, Cr, Mn, Fe, Ni), n-capture process elements (Sr, Ba) and other elements such as Li, Na, Al, and Sc for a subsample of S2 objects. We report coherent abundance patterns over a large metallicity spread (~1 dex) confirming that the S2 stream was produced by a disrupted dwarf galaxy. The combination of S2's $\alpha$-elements displays a mildly decreasing trend with increasing metallicity which can be tentatively interpreted as a ``knee'' at [Fe/H], Comment: Accepted for publitacion in MNRAS. 20 pages and 12 figures
Published: 2020
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22. APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South

Author: Henrik Jönsson, Verne V. Smith, Marc H. Pinsonneault, Olga Zamora, Matthew Shetrone, Vijith Jacob Poovelil, Dmitry Bizyaev, Jo Bovy, John Donor, Sten Hasselquist, Bengt Edvardsson, Diogo Souto, Jennifer Sobeck, D. A. García-Hernández, Carlos Allende Prieto, Thomas Masseron, Szabolcs Mészáros, Jon A. Holtzman, Rachael L. Beaton, Katia Cunha, Yeisson Osorio, Steven R. Majewski, and Guy S. Stringfellow
Subjects: Normalization (statistics), 010504 meteorology & atmospheric sciences, media_common.quotation_subject, Continuum (design consultancy), FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Spectral line, Astronomical spectroscopy, law.invention, Telescope, law, Observatory, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, media_common, Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Stars, 13. Climate action, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics
Abstract: The spectral analysis and data products in Data Release 16 (DR16; 2019 December) from the high-resolution near-infrared Apache Point Observatory Galactic Evolution Experiment (APOGEE)-2/Sloan Digital Sky Survey (SDSS)-IV survey are described. Compared to the previous APOGEE data release (DR14; 2017 July), APOGEE DR16 includes about 200,000 new stellar spectra, of which 100,000 are from a new southern APOGEE instrument mounted on the 2.5 m du Pont telescope at Las Campanas Observatory in Chile. DR16 includes all data taken up to 2018 August, including data released in previous data releases. All of the data have been re-reduced and re-analyzed using the latest pipelines, resulting in a total of 473,307 spectra of 437,445 stars. Changes to the analysis methods for this release include, but are not limited to, the use of MARCS model atmospheres for calculation of the entire main grid of synthetic spectra used in the analysis, a new method for filling "holes"in the grids due to unconverged model atmospheres, and a new scheme for continuum normalization. Abundances of the neutron-capture element Ce are included for the first time. A new scheme for estimating uncertainties of the derived quantities using stars with multiple observations has been applied, and calibrated values of surface gravities for dwarf stars are now supplied. Compared to DR14, the radial velocities derived for this release more closely match those in the Gaia DR2 database, and a clear improvement in the spectral analysis of the coolest giants can be seen. The reduced spectra as well as the result of the analysis can be downloaded using links provided on the SDSS DR16 web page. (Less)
Published: 2020
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23. Metallicity and $\alpha$-element Abundance Gradients along the Sagittarius Stream as Seen by APOGEE

Author: Szabolcs Mészáros, Richard R. Lane, Audrey Oravetz, Adrian M. Price-Whelan, David R. Law, David L. Nidever, Ivan Lacerna, Matthew Shetrone, Christian Moni Bidin, Daniel Oravetz, Joel R. Brownstein, Borja Anguiano, Guy S. Stringfellow, Roger E. Cohen, Ricardo P. Schiavon, Alexandre Roman-Lopes, Steven R. Majewski, Sten Hasselquist, Kaike Pan, Rachael L. Beaton, Peter M. Frinchaboy, Christian R. Hayes, Ricardo R. Mũnoz, Giuseppina Battaglia, Katia Cunha, Jennifer Sobeck, D. A. García-Hernández, Carlos Allende Prieto, Verne V. Smith, and Dmitry Bizyaev
Subjects: 010504 meteorology & atmospheric sciences, Smithsonian institution, Library science, Astronomy and Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, 13. Climate action, Space and Planetary Science, 0103 physical sciences, media_common.cataloged_instance, Christian ministry, 14. Life underwater, European union, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, media_common, Mathematics
Abstract: Using 3D positions and kinematics of stars relative to the Sagittarius (Sgr) orbital plane and angular momentum, we identify 166 Sgr stream members observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) that also have Gaia DR2 astrometry. This sample of 63/103 stars in the Sgr trailing/leading arm are combined with an APOGEE sample of 710 members of the Sgr dwarf spheroidal core (385 of them newly presented here) to establish differences of 0.6 dex in median metallicity and 0.1 dex in [$\alpha$/Fe] between our Sgr core and dynamically older stream samples. Mild chemical gradients are found internally along each arm, but these steepen when anchored by core stars. With a model of Sgr tidal disruption providing estimated dynamical ages (i.e., stripping times) for each stream star, we find a mean metallicity gradient of 0.12 +/- 0.03 dex/Gyr for stars stripped from Sgr over time. For the first time, an [$\alpha$/Fe] gradient is also measured within the stream, at 0.02 +/- 0.01 dex/Gyr using magnesium abundances and 0.04 +/- 0.01 dex/Gyr using silicon, which imply that the Sgr progenitor had significant radial abundance gradients. We discuss the magnitude of those inferred gradients and their implication for the nature of the Sgr progenitor within the context of the current family of Milky Way satellite galaxies, and suggest that more sophisticated Sgr models are needed to properly interpret the growing chemodynamical detail we have on the Sgr system., Comment: 27 pages, 11 figures, 2 tables. Accepted for publishing in The Astrophysical Journal
Published: 2019

24. Homogeneous Analysis of Globular Clusters from the APOGEE Survey with the BACCHUS Code. II. The Southern Clusters and Overview

Author: Verne V. Smith, Matthew Shetrone, Thomas Masseron, Garrett Ebelke, Steven R. Majewski, Jennifer Sobeck, Rebecca Lane, Guy S. Stringfellow, Dante Minniti, Kaike Pan, Ivan Lacerna, Doug Geisler, F. Dell'Agli, D. A. García-Hernández, Roger E. Cohen, Carlos Allende Prieto, Jennifer A. Johnson, Szabolcs Mészáros, Sarah L. Martell, David M. Nataf, José G. Fernández-Trincado, Peter M. Frinchaboy, László Szigeti, Jon A. Holtzman, Dmitry Bizyaev, Baitian Tang, Penélope Longa-Peña, Olga Zamora, Drew Chojnowski, Timothy C. Beers, Fred Hearty, Ricardo P. Schiavon, Katia Cunha, John C. Wilson, David L. Nidever, Sten Hasselquist, Eötvös Loránd University (ELTE), Universidad de La Laguna [Tenerife - SP] (ULL), Instituto de Astrofisica de Canarias (IAC), University of Notre Dame [Indiana] (UND), New Mexico State University, Space Telescope Science Institute (STSci), Steward Observatory, University of Arizona, Observatorio Nacional [Rio de Janeiro], University of Virginia [Charlottesville], Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Universidad de Atacama, Texas Christian University (TCU), University of Utah, Pennsylvania State University (Penn State), Penn State System, Department of Astronomy, The Ohio State University, Ohio State University [Columbus] (OSU), Pontificia Universidad Católica de Chile (UC), Universidad de Antofagasta, University of New South Wales [Sydney] (UNSW), Universidad Andrés Bello [Santiago] (UNAB), Millennium Institute of Astrophysics, Specola Vaticana/Vatican Observatory, Johns Hopkins University (JHU), Montana State University (MSU), National Optical Astronomy Observatory (NOAO), Liverpool John Moores University (LJMU), McDonald Observatory, University of Texas at Austin [Austin], University of Colorado [Boulder], National Sun Yat-Sen University (NSYSU), Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Red giant, Metallicity, Milky Way, FOS: Physical sciences, Astrophysics, 01 natural sciences, Spectral line, Luminosity, 0103 physical sciences, Cluster (physics), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QC, ComputingMilieux_MISCELLANEOUS, QB, Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Globular cluster, Astrophysics of Galaxies (astro-ph.GA), miscellaneous – surveys – stars, galaxies: abundances – stars: late-type – globular clusters: general – galaxies: fundamental parameters. [astronomical data bases], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We investigate 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 unprecedented homogeneous dataset, largest to date, allows 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. We find that the Fe spread does not depend on these parameters within our uncertainties including cluster metallicity, contradicting earlier observations. We do not confirm the metallicity variations previously observed in M22 and NGC 1851. Some clusters show a bimodal Al distribution, while others exhibit a continuous distribution as has been previously reported in the literature. We confirm more than 2 populations in $\omega$ Cen and NGC 6752, and find new ones in M79. We discuss the scatter of Al by implementing a correction to the standard chemical evolution of Al in the Milky Way. After correction, its dependence on cluster mass is increased suggesting that the extent of Al enrichment as a function of mass was suppressed before the correction. We observe a turnover in the Mg-Al anticorrelation at very low Mg in $\omega$ Cen, similar to the pattern previously reported in M15 and M92. $\omega$ Cen may also have a weak K-Mg anticorrelation, and if confirmed, it would be only the third cluster known to show such a pattern., Comment: Published in MNRAS, 31 pages, 24 figures, 7 tables. Further typos are corrected, now identical in text, figures and tables to the published paper
Published: 2019

25. Chemical Evolution in the Milky Way: Rotation-based ages for APOGEE-Kepler cool dwarf stars

Author: Savita Mathur, Matthew Shetrone, Ângela R. G. Santos, Zachary R. Claytor, Rafael A. García, Marc H. Pinsonneault, Jamie Tayar, and Jennifer L. van Saders
Subjects: Angular momentum, endocrine system, 010504 meteorology & atmospheric sciences, Milky Way, Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Rotation, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Gyrochronology, education, 010303 astronomy & astrophysics, Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, education.field_of_study, Stellar rotation, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics
Abstract: We use models of stellar angular momentum evolution to determine ages for $\sim500$ stars in the APOGEE-\textit{Kepler} Cool Dwarfs sample. We focus on lower main-sequence stars, where other age-dating tools become ineffective. Our age distributions are compared to those derived from asteroseismic and giant samples and solar analogs. We are able to recover gyrochronological ages for old, lower-main-sequence stars, a remarkable improvement over prior work in hotter stars. Under our model assumptions, our ages have a median relative uncertainty of $14\%$, comparable to the age precision inferred for more massive stars using traditional methods. We investigate trends of galactic $\alpha$-enhancement with age, finding evidence of a detection threshold between the age of the oldest $\alpha$-poor stars and that of the bulk $\alpha$-rich population. We argue that gyrochronology is an effective tool reaching ages of 10--12 Gyr in K- and early M-dwarfs. Finally, we present the first effort to quantify the impact of detailed abundance patterns on rotational evolution. We estimate a $\sim15\%$ bias in age for cool, $\alpha$-enhanced (+ 0.4 dex) stars when standard solar-abundance-pattern rotational models are used for age inference, rather than models that appropriately account for $\alpha$-enrichment., Comment: 22 pages, 11 figures, 3 tables. Submitted to AAS Journals. Electronic version of Table 3 is available as ancillary file (sidebar on the right). For a brief video explaining this paper, see https://youtu.be/z5qQLUZzFDc. The code developed to interact with, interpolate, and sample the stellar models is publicly available at https://github.com/zclaytor/kiauhoku/
Published: 2019

26. The Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) Survey Design, Reductions, and Detections*

Author: Karl Gebhardt, Erin Mentuch Cooper, Robin Ciardullo, Viviana Acquaviva, Ralf Bender, William P. Bowman, Barbara G. Castanheira, Gavin Dalton, Dustin Davis, Roelof S. de Jong, D. L. DePoy, Yaswant Devarakonda, Sun Dongsheng, Niv Drory, Maximilian Fabricius, Daniel J. Farrow, John Feldmeier, Steven L. Finkelstein, Cynthia S. Froning, Eric Gawiser, Caryl Gronwall, Laura Herold, Gary J. Hill, Ulrich Hopp, Lindsay R. House, Steven Janowiecki, Matthew Jarvis, Donghui Jeong, Shardha Jogee, Ryota Kakuma, Andreas Kelz, W. Kollatschny, Eiichiro Komatsu, Mirko Krumpe, Martin Landriau, Chenxu Liu, Maja Lujan Niemeyer, Phillip MacQueen, Jennifer Marshall, Ken Mawatari, Emily M. McLinden, Shiro Mukae, Gautam Nagaraj, Yoshiaki Ono, Masami Ouchi, Casey Papovich, Nao Sakai, Shun Saito, Donald P. Schneider, Andreas Schulze, Khavvia Shanmugasundararaj, Matthew Shetrone, Chris Sneden, Jan Snigula, Matthias Steinmetz, Benjamin P. Thomas, Brianna Thomas, Sarah Tuttle, Tanya Urrutia, Lutz Wisotzki, Isak Wold, Gregory Zeimann, and Yechi Zhang
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We describe the survey design, calibration, commissioning, and emission-line detection algorithms for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). The goal of HETDEX is to measure the redshifts of over a million Ly$\alpha$ emitting galaxies between 1.88, Comment: 51 pages, accepted for publication in the Astrophysical Journal
Published: 2021

27. The APOGEE Data Release 16 Spectral Line List

Author: D. A. García-Hernández, Carlos Allende Prieto, Szabolcs Mészáros, Guy S. Stringfellow, Rachael L. Beaton, Henrik Jönsson, Matthew Shetrone, Steven R. Majewski, Jennifer Sobeck, Yeisson Osorio, Diogo Souto, Dmitry Bizyaev, Jon Holtzman, Bertrand Plez, Katia Cunha, Thomas Masseron, Verne V. Smith, Sten Hasselquist, Laboratoire Univers et Particules de Montpellier (LUPM), and Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, FOS: Physical sciences, chemistry.chemical_element, Astrophysics, Atomic spectroscopy, 01 natural sciences, 7. Clean energy, Neodymium, Spectral line, 0103 physical sciences, Arcturus, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Spectroscopy, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Hyperfine structure, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Line (formation), Physics, Astronomy and Astrophysics, Stars, Astrophysics - Solar and Stellar Astrophysics, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The updated H-band spectral line list (from \lambda 15,000 - 17,000\AA) adopted by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) for the SDSS IV Data Release 16 (DR16) is presented here. The APOGEE line list is a combination of atomic and molecular lines with data from laboratory, theoretical, and astrophysical sources. Oscillator strengths and damping constants are adjusted using high signal-to-noise, high-resolution spectra of the Sun and alpha Boo (Arcturus) as "standard stars". Updates to the DR16 line list, when compared to the previous DR14 version, are the inclusion of molecular H_2O and FeH lines, as well as a much larger (by a factor of ~4) atomic line list, which includes significantly more transitions with hyperfine splitting. More recent references and line lists for the crucial molecules CO and OH were used, as well as for C_2 and SiH. In contrast to DR14, DR16 contains measurable lines from the heavy neutron-capture elements cerium (as Ce II), neodymium (as Nd II), and ytterbium (as Yb II), as well as one line from rubidium (as Rb I), that may be detectable in a small fraction of APOGEE red giants., Comment: 29 pages, 11 figures, accepted by AJ
Published: 2021

28. The peculiar globular cluster Palomar 1 and persistence in the SDSS-APOGEE data base

Author: Charli M. Sakari, Peter M. Frinchaboy, Ruth A. R. Digby, Mike Irwin, Matthew Shetrone, Kim A. Venn, Farbod Jahandar, Jo Bovy, and Collin Kielty
Subjects: Physics, 010308 nuclear & particles physics, Metallicity, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Spectral line, Radial velocity, Galactic halo, Stars, Star cluster, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Globular cluster, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Tidal tail, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: The SDSS-III APOGEE DR12 is a unique resource to search for stars beyond the tidal radii of star clusters. We have examined the APOGEE DR12 database for new candidates of the young star cluster Palomar 1, a system with previously reported tidal tails (Niederste-Ostholt et al. 2010). The APOGEE ASPCAP database includes spectra and stellar parameters for two known members of Pal 1 (Stars I and II), however these do not agree with the stellar parameters determined from optical spectra by Sakari et al. (2011). We find that the APOGEE analysis of these two stars is strongly affected by the known persistence problem (Majewski et al. 2015; Nidever et al. 2015). By re-examining the individual visits, and removing the blue (and sometimes green) APOGEE detector spectra affected by persistence, then we find excellent agreement in a re-analysis of the combined spectra. These methods are applied to another five stars in the APOGEE field with similar radial velocities and metallicities as those of Pal 1. Only one of these new candidates, Star F, may be a member located in the tidal tail based on its heliocentric radial velocity, metallicity, and chemistry. The other four candidates are not well aligned with the tidal tails, and comparison to the Besancon model (Robin et al. 2003) suggests that they are more likely to be non-members, i.e. part of the Galactic halo. This APOGEE field could be re-examined for other new candidates if the persistence problem can be removed from the APOGEE spectral database., 15 pages, 7 tables, 8 figures: Accepted for publication in MNRAS, 2017 June 23
Published: 2017

29. VLT/FLAMES high-resolution chemical abundances in Sculptor: a textbook dwarf spheroidal galaxy

Author: M. Spite, Eline Tolstoy, Matthew Shetrone, P. Francois, Vanessa Hill, Á. Skúladóttir, Andreas Kaufer, F. Primas, Giuseppina Battaglia, Amina Helmi, Else Starkenburg, K. A. Venn, Pascale Jablonka, B. Letarte, T. J. L. de Boer, Astronomy, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Netherlands Institute of Ecology (NIOO-KNAW), Departament Llenguatges i Sistemes Informatics, and Universitat Politècnica de Catalunya [Barcelona] (UPC)
Subjects: Initial mass function, neutron-capture elements, stars: abundances, Astrophysics::High Energy Astrophysical Phenomena, Milky Way, Metallicity, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Galactic halo, galaxies: individual: Sculptor, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, metal-poor stars, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, r-process, metallicity distribution, Astronomy and Astrophysics, effective temperature scale, galaxies: dwarf, model atmospheres, Astrophysics - Astrophysics of Galaxies, Galaxy, Dwarf spheroidal galaxy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Local Group, ursa-minor, galaxies: abundances, giant branch stars, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], s-process, galaxies: evolution
Abstract: We present detailed chemical abundances for 99 red-giant branch stars in the centre of the Sculptor dwarf spheroidal galaxy, obtained from high-resolution VLT/FLAMES spectroscopy. This includes abundances of Li (detected in 1 out of 99 stars), Na, $\alpha$-elements (O, Mg, Si, Ca Ti), iron-peak elements (Sc, Cr, Fe, Co, Ni, Zn), r- and s-process elements (Ba, La, Nd, Eu). The sample, covering -2.3< [Fe/H], Comment: Accepted for publication in A&A, 21 pages, 16 figures, +Appendix (in total 34 pages)
Published: 2019

30. Identifying Sagittarius Stream Stars by Their APOGEE Chemical Abundance Signatures

Author: Christian R. Hayes, Borja Anguiano, David L. Nidever, Dmitry Bizyaev, Steven R. Majewski, D. A. García-Hernández, Jeffrey L. Carlin, Carlos Allende Prieto, Kaike Pan, José G. Fernández-Trincado, Sten Hasselquist, Jennifer Sobeck, Matthew Shetrone, Richard R. Lane, Jon A. Holtzman, Katia Cunha, John C. Wilson, Rachael L. Beaton, Verne V. Smith, Olga Zamora, University of Utah, New Mexico State University, McDonald Observatory, University of Texas at Austin [Austin], National Optical Astronomy Observatory (NOAO), University of Washington [Seattle], Montana State University (MSU), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Instituto de Astronomia y ciencias Planetarias de Atacama (INCT), Universidad de Atacama, Universidad de Concepción [Chile], University of Virginia [Charlottesville], and Universidad de La Laguna [Tenerife - SP] (ULL)
Subjects: 010504 meteorology & atmospheric sciences, Red giant, Astrophysics::High Energy Astrophysical Phenomena, Milky Way, Population, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Sagittarius Stream, Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, education.field_of_study, Star formation, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Dwarf spheroidal galaxy, Stars, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey provides precise chemical abundances of 18 chemical elements for $\sim$ 176,000 red giant stars distributed over much of the Milky Way Galaxy (MW), and includes observations of the core of the Sagittarius dwarf spheroidal galaxy (Sgr). The APOGEE chemical abundance patterns of Sgr have revealed that it is chemically distinct from the MW in most chemical elements. We employ a \emph{k}-means clustering algorithm to 6-dimensional chemical space defined by [(C+N)/Fe], [O/Fe], [Mg/Fe], [Al/Fe], [Mn/Fe], and [Ni/Fe] to identify 62 MW stars in the APOGEE sample that have Sgr-like chemical abundances. Of the 62 stars, 35 have \emph{Gaia} kinematics and positions consistent with those predicted by \emph{N}-body simulations of the Sgr stream, and are likely stars that have been stripped from Sgr during the last two pericenter passages ($, Comment: 15 pages, 10 figures, accepted for publication in ApJ
Published: 2019

31. The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs

Author: W. Richardson, Paul Harding, Paul Maseman, Bo Zhao, Ben Breslauer, A. Uomoto, D. C. Nguyen, Suvrath Mahadevan, Stephen A. Smee, Al Harding, Stephen A. Shectman, Larry N. Carey, R. Stoll, Daniel J. Eisenstein, Joseph Huehnerhoff, J. P. Colque, Michael L. Evans, James W. Davidson, D. Skinner, J. D. Trujillo, Matthew J. Nelson, G. J. Damke, Jon A. Holtzman, Thomas P. O'Brien, J. Karakla, Nicholas MacDonald, Basil Blank, Steve Majewski, Russell Owen, John C. Wilson, B. Anthony-Brumfield, James A. Arns, Matthew Shetrone, T. Mitcheltree, Dmitry Bizyaev, Robert H. Barkhouser, David L. Nidever, José R. Sánchez-Gallego, Conor Sayres, Janice D. R. Dean, Elena Malanushenko, Calen B. Henderson, Samuel Halverson, M. Vernieri, Jeff Crane, Sophia Brunner, E. Walker, Alexandre Roman-Lopes, Mita Tembe, Ricardo P. Schiavon, Stephane Beland, T. Stolberg, Frederick R. Hearty, James E. Gunn, J. Barr, E. Leon, N. De Lee, Michael R. Blanton, S. Melton, Dan Long, Charles R. Lam, Mark A. Klaene, Bruce Gillespie, Erick T. Young, N. Shane, D. Hancock, Rosemarie W. Hammond, J. Matsunari, Alim Y. Patten, Mike Skrutskie, Matthew A. Bershady, David H. Weinberg, George H. Rieke, Marcia J. Rieke, Matthew Hall, K. W. Don, Greg Fitzgerald, Fritz Stauffer, T. Horne, F. Di Mille, Michael A. Carr, Stephen C. Hope, C. Harrison, J. Downey, F. Leger, Andrew J. Burton, Garrett Ebelke, Jennifer Sobeck, and Robert W. O'Connell
Subjects: 010504 meteorology & atmospheric sciences, Red giant, Milky Way, media_common.quotation_subject, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, law.invention, Telescope, law, Observatory, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Spectrograph, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, media_common, Physics, Instrument control, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, Galaxy, Space and Planetary Science, Sky, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: We describe the design and performance of the near-infrared (1.51--1.70 micron), fiber-fed, multi-object (300 fibers), high resolution (R = lambda/delta lambda ~ 22,500) spectrograph built for the Apache Point Observatory Galactic Evolution Experiment (APOGEE). APOGEE is a survey of ~ 10^5 red giant stars that systematically sampled all Milky Way populations (bulge, disk, and halo) to study the Galaxy's chemical and kinematical history. It was part of the Sloan Digital Sky Survey III (SDSS-III) from 2011 -- 2014 using the 2.5 m Sloan Foundation Telescope at Apache Point Observatory, New Mexico. The APOGEE-2 survey is now using the spectrograph as part of SDSS-IV, as well as a second spectrograph, a close copy of the first, operating at the 2.5 m du Pont Telescope at Las Campanas Observatory in Chile. Although several fiber-fed, multi-object, high resolution spectrographs have been built for visual wavelength spectroscopy, the APOGEE spectrograph is one of the first such instruments built for observations in the near-infrared. The instrument's successful development was enabled by several key innovations, including a "gang connector" to allow simultaneous connections of 300 fibers; hermetically sealed feedthroughs to allow fibers to pass through the cryostat wall continuously; the first cryogenically deployed mosaic volume phase holographic grating; and a large refractive camera that includes mono-crystalline silicon and fused silica elements with diameters as large as ~ 400 mm. This paper contains a comprehensive description of all aspects of the instrument including the fiber system, optics and opto-mechanics, detector arrays, mechanics and cryogenics, instrument control, calibration system, optical performance and stability, lessons learned, and design changes for the second instrument., 81 pages, 67 figures, PASP, accepted
Published: 2019

32. The origin of accreted stellar halo populations in the Milky Way using APOGEE, Gaia , and the EAGLE simulations

Author: Robert W. O'Connell, Carlos Allende Prieto, Sten Hasselquist, Jennifer A. Johnson, José G. Fernández-Trincado, Borja Anguiano, Steven R. Majewski, Joel Pfeffer, Jo Bovy, Matthew Shetrone, Christian R. Hayes, J. Ted Mackereth, Ricardo P. Schiavon, Jon A. Holtzman, Patricia B. Tissera, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)
Subjects: Milky Way, Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galactic halo, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Dwarf galaxy, Physics, education.field_of_study, 010308 nuclear & particles physics, Star formation, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Accretion (astrophysics), Stars, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Recent work indicates that the nearby Galactic halo is dominated by the debris from a major accretion event. We confirm that result from an analysis of APOGEE-DR14 element abundances and $\textit{Gaia}$-DR2 kinematics of halo stars. We show that $\sim$2/3 of nearby halo stars have high orbital eccentricities ($e \gtrsim 0.8$), and abundance patterns typical of massive Milky Way dwarf galaxy satellites today, characterised by relatively low [Fe/H], [Mg/Fe], [Al/Fe], and [Ni/Fe]. The trend followed by high $e$ stars in the [Mg/Fe]-[Fe/H] plane shows a change of slope at [Fe/H]$\sim-1.3$, which is also typical of stellar populations from relatively massive dwarf galaxies. Low $e$ stars exhibit no such change of slope within the observed [Fe/H] range and show slightly higher abundances of Mg, Al and Ni. Unlike their low $e$ counterparts, high $e$ stars show slightly retrograde motion, make higher vertical excursions and reach larger apocentre radii. By comparing the position in [Mg/Fe]-[Fe/H] space of high $e$ stars with those of accreted galaxies from the EAGLE suite of cosmological simulations we constrain the mass of the accreted satellite to be in the range $10^{8.5}\lesssim M_*\lesssim 10^{9}\mathrm{M_\odot}$. We show that the median orbital eccentricities of debris are largely unchanged since merger time, implying that this accretion event likely happened at $z\lesssim1.5$. The exact nature of the low $e$ population is unclear, but we hypothesise that it is a combination of $\textit{in situ}$ star formation, high $|z|$ disc stars, lower mass accretion events, and contamination by the low $e$ tail of the high $e$ population. Finally, our results imply that the accretion history of the Milky Way was quite unusual., 19 Pages, 11 Figures (+4 in abstracts), Accepted for publication in MNRAS. ** Important new additions include an appendix showing numerical convergence tests, and a new figure and accompanying text demonstrating the consistency in element abundances between accreted satellites in EAGLE and the high eccentricity stars from APOGEE **
Published: 2019

33. H-band discovery of additional second-generation stars in the Galactic bulge globular cluster NGC 6522 as observed by APOGEE and Gaia

Author: Dante Minniti, Mathias Schultheis, J. Schiappacasse Ulloa, Ryan J. Oelkers, Andres Almeida, D. A. García-Hernández, Adam J. Burgasser, Arturo Manchado, Olga Zamora, Matthew Shetrone, Katia Cunha, Penélope Longa-Peña, Inese I. Ivans, Sandro Villanova, Gail Zasowski, Thomas Masseron, Baitian Tang, Ricardo Carrera, Frederick R. Hearty, Roger Cohen, Diogo Souto, Sz. Meszaros, Felipe A. Santana, Ricardo P. Schiavon, Steven R. Majewski, Sten Hasselquist, Doug Geisler, F. Dell'Agli, A. Rojas-Arriagada, Alexandre Roman-Lopes, Richard R. Lane, Timothy C. Beers, José G. Fernández-Trincado, Ronald E. Mennickent, Dominik R. G. Schleicher, Jennifer Sobeck, Javier Alonso-García, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto de Astronomia y ciencias Planetarias de Atacama (INCT), Universidad de Atacama, Universidad de Concepción [Chile], Instituto de Astrofisica de Canarias (IAC), Universidad de La Laguna [Tenerife - SP] (ULL), Universidad Andrés Bello [Santiago] (UNAB), Vatican Observatory, Instituto de Astrofísica de Canarias and Consejo Superior de Investigaciones Científicas, Center for the Study of Cosmic Evolution (CSCE), Michigan State University [East Lansing], Michigan State University System-Michigan State University System, University of Notre Dame [Indiana] (UND), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica de Chile (UC), Facultad de Ciencias, Universidad de La Serena, Universidad de La Serena (USERENA), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: stars: abundances, Metallicity, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, Bulge, 0103 physical sciences, Galaxy formation and evolution, Cluster (physics), Astrophysics::Solar and Stellar Astrophysics, globular clusters: individual: NGC 6522, ABUNDÂNCIA ESTELAR, 010303 astronomy & astrophysics, Galaxy: structure, QC, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, stars: Population II, Giant star, Astrophysics - Astrophysics of Galaxies, Stars, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Galaxy: formation, Globular cluster, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We present elemental abundance analysis of high-resolution spectra for five giant stars, deriving Fe, Mg, Al, C, N, O, Si and Ce abundances, and spatially located within the innermost regions of the bulge globular cluster NGC 6522, based on H-band spectra taken with the multi-object APOGEE-north spectrograph from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. Of the five cluster candidates, two previously unremarked stars are confirmed to have second-generation (SG) abundance patterns, with the basic pattern of depletion in C and Mg simultaneous with enrichment in N and Al as seen in other SG globular cluster populations at similar metallicity. } In agreement with the most recent optical studies, the NGC 6522 stars analyzed exhibit (when available) only mild overabundances of the s-process element Ce, contradicting the idea of the NGC 6522 stars being formed from gas enriched by spinstars and indicating that other stellar sources such as massive AGB stars could be the primary intra-cluster medium polluters. The peculiar abundance signature of SG stars have been observed in our data, confirming the presence of multiple generations of stars in NGC 6522., Comment: 13 pages, 8 figures, 4 tables, matches the accepted version in A&A
Published: 2019

34. The chemical evolution of the dwarf Spheroidal galaxy Sextans

Author: Matthew Shetrone, Giuseppina Battaglia, R. Theler, Pascale Jablonka, Eline Tolstoy, Kim Venn, Pierre North, Vanessa Hill, Andreas Kaufer, Amina Helmi, Mike Irwin, Francesca Primas, R. Lucchesi, Carmela Lardo, Ecole Polytechnique Fédérale de Lausanne (EPFL), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astronomy, Theler R., Jablonka P., Lucchesi R., Lardo C., North P., Irwin M., Battaglia G., Hill V., Tolstoy E., Venn K., Helmi A., Kaufer A., Primas F., and Shetrone M.
Subjects: metallicity, spectroscopy, stars: abundances, Metallicity, 1st stars, FOS: Physical sciences, Astrophysics, 01 natural sciences, 0103 physical sciences, Asymptotic giant branch, metal-poor stars, 10. No inequality, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Dwarf galaxy, parameters, Physics, high-dispersion-spectrograph, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], carbon, abundance patterns, White dwarf, Astronomy and Astrophysics, effective temperature scale, galaxies: dwarf, Horizontal branch, Astrophysics - Astrophysics of Galaxies, Galaxy, Dwarf spheroidal galaxy, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Red-giant branch, elements, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], galaxies: evolution
Abstract: We present the analysis of the FLAMES dataset targeting the central 25 arcmin region of the Sextans dSph. This dataset is the third major part of the high resolution spectroscopic section of the ESO large program 171.B-0588(A) obtained by the Dwarf galaxy Abundances and Radial-velocities Team (DART). Our sample is composed of red giant branch stars down to the level of the horizontal branch in Sextans. It allows to address questions related to both stellar nucleosynthesis and galaxy evolution. We provide metallicities for 81 stars, which cover the wide [Fe/H]=$-$3.2 to $-$1.5 dex range. The abundances of 10 other elements are derived: Mg, Ca, Ti, Sc, Cr, Mn, Co, Ni, Ba, and Eu. Despite its small mass, Sextans is a chemically evolved system, with evidence for the contribution of core-collapse and Type Ia supernovae as well as low metallicity AGBs. This new FLAMES sample offers a sufficiently large number of stars with chemical abundances derived at high accuracy to firmly establish the existence of a plateau in [$\alpha$/Fe] at $\sim 0.4$ dex, followed by a decrease above [Fe/H]$\sim-2$ dex. This is in stark similarity with the Fornax and Sculptor dSphs despite their very different masses and star formation histories. This suggests that these three galaxies had very similar star formation efficiencies in their early formation phases, probably driven by the early accretion of smaller galactic fragments, until the UV-background heating impacted them in different ways. The parallel between the Sculptor and Sextans dSph is also striking when considering Ba and Eu. Finally, as to the iron-peak elements, the decline of [Co/Fe] and [Ni/Fe] above [Fe/H]$\sim -2$ implies that the production yields of Ni and Co in SNeIa is lower than that of Fe. The decrease in [Ni/Fe] favours models of SNeIa based on the explosion of double degenerate sub-Chandrasekhar mass white dwarfs., Comment: Accepted for publication in A&A. All tables included
Published: 2019
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35. Chemical Abundances of Main-Sequence, Turnoff, Subgiant and red giant Stars from APOGEE spectra II: Atomic Diffusion in M67 Stars

Author: Henrik Jönsson, Diogo Souto, Rafael Garcia-Dias, Kaike Pan, Christian Nitschelm, Katia Cunha, Matthew Shetrone, Verne V. Smith, Olga Zamora, Steve Majewski, Jo Bovy, C. Allende Prieto, Marc H. Pinsonneault, Jennifer Sobeck, D. A. García-Hernández, Jennifer A. Johnson, and Jon A. Holtzman
Subjects: Physics, 010504 meteorology & atmospheric sciences, Stellar mass, Red giant, Subgiant, Hertzsprung–Russell diagram, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Spectral line, symbols.namesake, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, symbols, 010303 astronomy & astrophysics, Red clump, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Open cluster
Abstract: Chemical abundances for 15 elements (C, N, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Ni) are presented for 83 stellar members of the 4 Gyr old solar-metallicity open cluster M67. The sample contains stars spanning a wide range of evolutionary phases, from G dwarfs to red clump stars. The abundances were derived from near-IR ($\lambda$1.5 -- 1.7$\mu$m) high-resolution spectra ($R$ = 22,500) from the SDSS-IV/APOGEE survey. A 1-D LTE abundance analysis was carried out using the APOGEE synthetic spectral libraries, via chi-square minimization of the synthetic and observed spectra with the qASPCAP code. We found significant abundance differences ($\sim$0.05 -- 0.30 dex) between the M67 member stars as a function of the stellar mass (or position on the HR diagram), where the abundance patterns exhibit a general depletion (in [X/H]) in stars at the main-sequence turnoff. The amount of the depletion is different for different elements. We find that atomic diffusion models provide, in general, good agreement with the abundance trends for most chemical species, supporting recent studies indicating that measurable atomic diffusion operates in M67 stars., Comment: Accepted to ApJ
Published: 2019
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36. APOGEE [C/N] Abundances across the Galaxy: Migration and Infall from Red Giant Ages

Author: Jonathan C. Bird, Ivan Minchev, Jon A. Holtzman, Marc H. Pinsonneault, Matthew Shetrone, Katia Cunha, Jennifer Johnson, Christian Nitschelm, Olga Zamora, Sten Hasselquist, Timothy C. Beers, Ricardo P. Schiavon, David H. Weinberg, D. A. García-Hernández, José G. Fernández-Trincado, D. Feuillet, Jamie Tayar, New Mexico State University, McDonald Observatory, University of Texas at Austin [Austin], Department of Astronomy (Ohio State University), Ohio State University [Columbus] (OSU), Ohio State Univ, Dept Phys, Columbus, OH 43210 USA, Observatorio Nacional [Rio de Janeiro], University of Notre Dame [Indiana] (UND), Liverpool John Moores University (LJMU), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Universidad de Concepción [Chile], Instituto de Astronomia y ciencias Planetarias de Atacama (INCT), Universidad de Atacama, and Universidad de La Laguna [Tenerife - SP] (ULL)
Subjects: 010504 meteorology & atmospheric sciences, Red giant, Metallicity, Milky Way, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Galaxy formation and evolution, Astrophysics::Solar and Stellar Astrophysics, Disc, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Red-giant branch, Stars, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We present [C/N]-[Fe/H] abundance trends from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey, Data Release 14 (DR14), for red giant branch stars across the Milky Way Galaxy (MW, 3 kpc $$ 1 kpc) exhibit a radial gradient in [C/N] ($\sim$ $-$0.04 dex/kpc). The [C/N] dispersion increases toward the plane ($\sigma_{[C/N]}$ = 0.13 at $|$Z$|$ $>$ 1 kpc to $\sigma_{[C/N]}$ = 0.18 dex at $|$Z$|$ $, Comment: 15 pages, 13 figures, accepted for publication in ApJ
Published: 2019

37. A homogeneous analysis of globular clusters from the APOGEE survey with the BACCHUS code. I. The Northern clusters

Author: Matthew Shetrone, Thomas Masseron, Sz. Meszaros, Roger E. Cohen, Bengt Edvardsson, Doug Geisler, K. M. Cunha, H. Jönsson, Olga Zamora, F. Dell'Agli, C. Allende Prieto, Timothy C. Beers, D. A. García-Hernández, José G. Fernández-Trincado, and B. Plez
Subjects: Physics, 010504 meteorology & atmospheric sciences, Metallicity, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Surface gravity, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Luminosity, Red-giant branch, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Globular cluster, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Asymptotic giant branch, Microturbulence, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences
Abstract: We analyze a large sample of 885 GCs giants from the APOGEE survey. We used the Cannon results to separate the red giant branch and the asymptotic giant branch stars, not only allowing for a refinement of surface gravity from isochrones, but also providing an independent H-band spectroscopic method to distinguish stellar evolutionary status in clusters. We then use the BACCHUS code to derive metallicity, microturbulence, acroturbulence and many light-element abundances as well as the neutron-capture elements Nd and Ce for the first time from the APOGEE GCs data. Our independent analysis helped us to diagnose issues regarding the standard analysis of the APOGEE DR14 for low-metallicity GC stars. Furthermore, while we confirm most of the known correlations and anti-correlation trends (Na-O, Mg-Al,C-N), we discover that some stars within our most metal-poor clusters show an extreme Mg depletion and some Si enhancement but at the same time show some relative Al depletion, displaying a turnover in the Mg-Al diagram. These stars suggest that Al has been partially depleted in their progenitors by very hot proton-capture nucleosynthetic processes. Furthermore, we attempted to quantitatively correlate the spread of Al abundances with the global properties of GCs. We find an anti-correlation of the Al spread against clusters metallicity and luminosity, but the data do not allow to find clear evidence of a dependence of N against metallicity in the more metal-poor clusters. Large and homogeneously analyzed samples from on-going spectroscopic surveys unveil unseen chemical details for many clusters, including a turnover in the Mg-Al anti-correlation, thus yielding new constrains for GCs formation evolution models., 17 pages, 23 figures, accepted in A&A
Published: 2018

38. Research Output Between 1965 and 2019 from the Use of Telescopes at Lick Observatory

Author: Matthew Shetrone and Graeme H. Smith
Subjects: Physics, History of astronomy, Space and Planetary Science, Observatory, Astronomy, Astronomy and Astrophysics
Published: 2020

39. Stellar Characterization of M Dwarfs from the APOGEE Survey: A Calibrator Sample for M-dwarf Metallicities

Author: Verne V. Smith, Johanna Teske, Henrik Jönsson, Thomas Masseron, Jennifer Sobeck, Matthew Shetrone, Keivan G. Stassun, D. A. García-Hernández, Jennifer A. Johnson, Jon A. Holtzman, Steven R. Majewski, Suvrath Mahadevan, Fabio Wanderley, C. Allende Prieto, Olga Zamora, Katia Cunha, Bárbara Rojas-Ayala, Diogo Souto, Adam J. Burgasser, Kevin R. Covey, and Ryan Terrien
Subjects: 010504 meteorology & atmospheric sciences, Metallicity, FOS: Physical sciences, Binary number, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Spectral line, Mean difference, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Plane parallel, Molecular line, Astronomy and Astrophysics, Radius, Astrophysics - Astrophysics of Galaxies, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: We present spectroscopic determinations of the effective temperatures, surface gravities and metallicities for 21 M-dwarfs observed at high-resolution (R $\sim$ 22,500) in the \textit{H}-band as part of the SDSS-IV APOGEE survey. The atmospheric parameters and metallicities are derived from spectral syntheses with 1-D LTE plane parallel MARCS models and the APOGEE atomic/molecular line list, together with up-to-date H$_{2}$O and FeH molecular line lists. Our sample range in $T_{\rm eff}$ from $\sim$ 3200 to 3800K, where eleven stars are in binary systems with a warmer (FGK) primary, while the other 10 M-dwarfs have interferometric radii in the literature. We define an $M_{K_{S}}$--Radius calibration based on our M-dwarf radii derived from the detailed analysis of APOGEE spectra and Gaia DR2 distances, as well as a mass-radius relation using the spectroscopically-derived surface gravities. A comparison of the derived radii with interferometric values from the literature finds that the spectroscopic radii are slightly offset towards smaller values, with $\Delta$ = -0.01 $\pm$ 0.02 $R{\star}$/$R_{\odot}$. In addition, the derived M-dwarf masses based upon the radii and surface gravities tend to be slightly smaller (by $\sim$5-10\%) than masses derived for M-dwarf members of eclipsing binary systems for a given stellar radius. The metallicities derived for the 11 M-dwarfs in binary systems, compared to metallicities obtained for their hotter FGK main-sequence primary stars from the literature, shows excellent agreement, with a mean difference of [Fe/H](M-dwarf - FGK primary) = +0.04 $\pm$ 0.18 dex, confirming the APOGEE metallicity scale derived here for M-dwarfs., Comment: Accepted to ApJ, 2 tables and 11 figures
Published: 2020

40. Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era

Author: Verne V. Smith, Matthew Shetrone, Corinne Charbonnel, J. Krugler Hollek, G. Ottoni, Pierre North, Rodolfo Smiljanic, Nadège Lagarde, A. Palacios, Gérard Jasniewicz, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Ecole Polytechnique Fédérale de Lausanne (EPFL), University of North Texas (UNT), Twitter Inc, National Optical Astronomy Observatory (NOAO), University of Geneva [Switzerland], Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), and Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: stars: abundances, 010504 meteorology & atmospheric sciences, open cluster, Red giant, FOS: Physical sciences, k-giant, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Asteroseismology, Spectral line, Photometry (optics), surveys, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, stars: evolution, 010303 astronomy & astrophysics, Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, stellar evolution, stars: late-type, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, mu-gradients, Giant star, low-mass stars, Stars, Astrophysics - Solar and Stellar Astrophysics, subgiant branch, 13. Climate action, Space and Planetary Science, Thermohaline circulation, Astrophysics::Earth and Planetary Astrophysics, chemical-composition, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], main-sequence stars, internal gravity-waves, s-process
Abstract: Lithium is extensively known to be a good tracer of non-standard mixing processes occurring in stellar interiors. We present the results of a new large Lithium survey in red giant stars and combine it with surveys from the literature to probe the impact of rotation-induced mixing and thermohaline double-diffusive instability along stellar evolution. We determined the surface Li abundance for a sample of 829 giant stars with accurate Gaia parallaxes for a large sub-sample (810 stars) complemented with accurate Hipparcos parallaxes (19 stars). The spectra of our sample of northern and southern giant stars were obtained in three ground-based observatories (OHP, ESO-La Silla, Mc Donald). We determined the atmospheric parameters (Teff, log(g), [Fe/H]), and the Li abundance. We used Gaia parallaxes and photometry to determine the luminosity of our objects and we estimated the mass and evolution status of each sample star with a maximum-likelihood technique using stellar evolution models computed with the STAREVOL code. We compared the observed Li behaviour with predictions from stellar models, including rotation and thermohaline mixing. The same approach was used for stars from selected Li surveys from the literature. Rotation-induced mixing accounts nicely for the lithium behaviour in stars warmer than about 4200K, independently of the mass domain. For stars with masses lower than 2Msun thermohaline mixing leads to further Li depletion below the Teff of the RGB bump (about 4000K), and on the early AGB, as observed. Depending on the definition we adopt, we find between 0.8 and 2.2% of Li-rich giants in our new sample. Gaia puts a new spin on the understanding of mixing processes in stars, and our study confirms the importance of rotation-induced processes and of thermohaline mixing. However asteroseismology is required to definitively pinpoint the actual evolution status of Li-rich giants., Comment: 16 pages, 18 figures, A&A, accepted for publication (new version with an additional reference)
Published: 2020

41. The Origin of the 300 km s −1 Stream near Segue 1

Author: Alexandre Roman-Lopes, D. A. García-Hernández, Carlos Allende Prieto, Paul Harding, Joshua D. Simon, Matthew Shetrone, José G. Fernández-Trincado, Olga Zamora, Jennifer Sobeck, Jo Bovy, Christian Nitschelm, Vinicius M. Placco, Richard R. Lane, Timothy C. Beers, Sal Wanying Fu, Inese I. Ivans, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Physics, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Segue, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galactic halo, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: We present a search for new members of the 300 km s$^{-1}$ stream (300S) near the dwarf galaxy Segue 1 using wide-field survey data. We identify 11 previously unknown bright stream members in the APOGEE-2 and SEGUE-1 and 2 spectroscopic surveys. Based on the spatial distribution of the high-velocity stars, we confirm for the first time that this kinematic structure is associated with a 24$^{\circ}$-long stream seen in SDSS and Pan-STARRS imaging data. The 300S stars display a metallicity range of $-2.17 < {\rm [Fe/H]} < -1.24$, with an intrinsic dispersion of 0.21$_{-0.09}^{+0.12}$ dex. They also have chemical abundance patterns similar to those of Local Group dwarf galaxies, as well as that of the Milky Way halo. Using the open-source code galpy to model the orbit of the stream, we find that the progenitor of the stream passed perigalacticon about 70 Myr ago, with a closest approach to the Galactic Center of about 4.1 kpc. Using Pan-STARRS DR1 data, we obtain an integrated stream luminosity of $4 \times 10^3$ L$_{\odot}$. We conclude that the progenitor of the stream was a dwarf galaxy that is probably similar to the satellites that were accreted to build the present-day Milky Way halo., 20 pages, 13 figures, accepted to ApJ. Updated with discussion on possible association of 300S with the Virgo Overdensity. Corrected RA range in Fig 2
Published: 2018

42. APOGEE Data Releases 13 and 14: Stellar Parameter and Abundance Comparisons with Independent Analyses

Author: Diogo Souto, Guy S. Stringfellow, Steven R. Majewski, D. Feuillet, Marc H. Pinsonneault, Verne V. Smith, Katia Cunha, Olga Zamora, Johanna Teske, Matthew Shetrone, Dmitry Bizyaev, Henrik Jönsson, Jennifer Sobeck, Keith Hawkins, D. A. García-Hernández, Carlos Allende Prieto, Szabolcs Mészáros, José G. Fernández-Trincado, Sten Hasselquist, Jon A. Holtzman, Ricardo Carrera, Sainsbury Laboratory Cambridge University (SLCU), University of Cambridge [UK] (CAM), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Department of Astronomy (Ohio State University), and Ohio State University [Columbus] (OSU)
Subjects: Physics, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Standard deviation, Spectral line, Optical spectra, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Observatory, Abundance (ecology), Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Thick disk, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS
Abstract: Data from the SDSS-IV / Apache Point Observatory Galactic Evolution Experiment (APOGEE-2) have been released as part of SDSS Data Releases 13 (DR13) and 14 (DR14). These include high resolution H-band spectra, radial velocities, and derived stellar parameters and abundances. DR13, released in August 2016, contained APOGEE data for roughly 150,000 stars, and DR14, released in August 2017, added about 110,000 more. Stellar parameters and abundances have been derived with an automated pipeline, the APOGEE Stellar Parameter and Chemical Abundance Pipeline (ASPCAP). We evaluate the performance of this pipeline by comparing the derived stellar parameters and abundances to those inferred from optical spectra and analysis for several hundred stars. For most elements -- C, Na, Mg, Al, Si, S, Ca, Cr, Mn, Ni -- the DR14 ASPCAP analysis have systematic differences with the comparisons samples of less than 0.05 dex (median), and random differences of less than 0.15 dex (standard deviation). These differences are a combination of the uncertainties in both the comparison samples as well as the ASPCAP-analysis. Compared to the references, magnesium is the most accurate alpha-element derived by ASPCAP, and shows a very clear thin/thick disk separation, while nickel is the most accurate iron-peak element (besides iron)., Accepted for publication in AJ
Published: 2018

43. VIRUS: the instrument infrastructure to support the deployment and upkeep of 156 spectrographs at the Hobby-Eberly Telescope

Author: James R. Fowler, G. Smith, John M. Good, Renny Spencer, Darren L. DePoy, Matthew Shetrone, Dave M. Perry, M. Sauseda, Hermanus Kriel, Phillip J. MacQueen, Trent Peterson, George Damm, Emily Mrozinski, Jennifer L. Marshall, Richard Savage, Edmundo Balderrama, Erika Cook, Travis Prochaska, and Gary J. Hill
Subjects: Air cooling, Telescope, Engineering, business.industry, Software deployment, law, Hobby–Eberly Telescope, Support system, Cryogenics, Aerospace engineering, business, Spectrograph, law.invention
Abstract: The Visible Integral-field Replicable Unit Spectrograph (VIRUS) consists of 156 identical spectrographs fed by 35,000 fibers from the upgraded 10-meter Hobby-Eberly Telescope (HET). VIRUS is in a phased deployment. At the submission of this paper, over half of the units are installed and the full support infrastructure is operational. This paper will describe the VIRUS infrastructure which includes the physical support system, the air cooling, the cryogenic cooling, and the temperature control of VIRUS. The paper will also discuss the various installation, maintenance, and operational procedures based on growing experience with the VIRUS array.
Published: 2018

44. Wavefront sensing for active alignment control of a telescope with dynamically varying pupil geometry: theory, implementation, on-sky performance

Author: Jason Ramsey, Hanshin Lee, Matthew Shetrone, Niv Drory, Randy Bryant, and Gary J. Hill
Subjects: Telescope, Wavefront, Optics, law, Sky, business.industry, media_common.quotation_subject, business, Pupil, law.invention, media_common, Mathematics
Published: 2018

45. The habitable-zone planet finder: engineering and commissioning on the Hobby Eberly telescope (Conference Presentation)

Author: John Darling, Jeff Jennings, Connor Fredrick, Emily Lubar, Renny Spencer, Andrew J. Monson, Adam Dykhouse, Fred Hearty, Arpita Roy, Shubham Kanodia, Samuel Halverson, Emily Bevins, Chad F. Bender, Scott A. Diddams, Gudmundur Stefansson, Matthew Shetrone, Tyler Anderson, Ryan Terrien, Jason T. Wright, Kyle Kaplan, David Conran, Eric Levi, Scott Blakeslee, Paul Robertson, Christian Schwab, Edmundo Balderrama, Suvrath Mahadevan, Colin Nitroy, Andrew J. Metcalf, Lawrence W. Ramsey, Amanda Cole, and Joe P. Ninan
Subjects: Physics, Spectrometer, business.industry, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, law.invention, Telescope, Radial velocity, Optics, law, Hobby–Eberly Telescope, Astrophysics::Earth and Planetary Astrophysics, Spectral resolution, business, Spectrograph, Astrophysics::Galaxy Astrophysics, Echelle grating
Abstract: The Habitable-Zone Planet Finder (HPF) is a stabilized, fiber-fed, NIR spectrometer recently commissioned at the 10m Hobby-Eberly telescope (HET). HPF has been designed and built from the ground up to be capable of discovering low mass planets around mid-late M dwarfs using the Doppler radial velocity technique. Novel apects of the instrument design include mili-kelvin temperature control, careful attending to fiber scrambling, and optics, mounting and detector readout schemes designed to minimize drifts and maximize the radial velocity precision. The optical design of the HPF is an asymmetric white pupil spectrograph layout in a vacuum cryostat cooled to 180 K. The spectrograph uses gold-coated mirrors, a mosaic echelle grating, and a single Teledyne Hawaii-2RG (H2RG) NIR detector with a 1.7-micron cutoff covering parts of the information-rich z, Y and J NIR bands at a spectral resolution of R~55,000. The use of 1.7 micron H2RG enables HPF to operate warmer than most other cryogenic instruments- with the instrument operating at 180K (allowing normal glasses to be used in the camera) and the detector at 120K. We summarize the engineering and commissioning tests on the telescope and the current radial velocity performance of HPF. With data in hand we revisit some of the design trades that went into the instrument design to explore the remaining tall poles in precision RV measurements in the near-infrared. HPF seeks to extend the precision radial velocity technique from the optical to the near-infrared, and in this presentation, we seek to share with the community our experience in this relatively new regime.
Published: 2018

46. VIRUS: status and performance of the massively replicated fiber integral field spectrograph for the upgraded Hobby-Eberly Telescope

Author: Thomas Jahn, Maximilian Fabricius, Edmundo Balderrama, Taft Armandroff, Darren L. DePoy, Andreas Kelz, Stephen C. Odewahn, Harald Nicklas, Greg C. Smith, Renny Spencer, Jan Snigula, Gavin Dalton, Gary J. Hill, Cynthia S. Froning, Daniel J. Farrow, Jennifer L. Marshall, John M. Good, Ralf Bender, James R. Fowler, Karl Gebhardt, Andrew M. Peterson, Travis Prochaska, Matthias Steinmetz, Matthew Shetrone, Taylor S. Chonis, Greg Zeimann, George Damm, S. I. Rostopchin, Niv Drory, Sarah Tuttle, Dionne M. Haynes, Herman Kriel, Phillip J. MacQueen, Francesco Montesano, Hanshin Lee, Jerry Martin, Trent Peterson, Jason Ramsey, Eva Noyola, Emily Mrozinski, Amy Westfall, Brian L. Vattiat, Brent Buetow, Randy Bryant, and Briana L. Indahl
Subjects: Physics, media_common.quotation_subject, Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Galaxy, law.invention, 010309 optics, Telescope, Integral field spectrograph, law, Sky, 0103 physical sciences, Hobby–Eberly Telescope, Dark energy, Emission spectrum, 0210 nano-technology, Spectrograph, media_common
Abstract: The Visible Integral-field Replicable Unit Spectrograph (VIRUS) consists of 156 identical spectrographs (arrayed as 78 pairs, each with a pair of spectrographs) fed by 35,000 fibers, each 1.5 arcsec diameter, at the focus of the upgraded 10 m Hobby-Eberly Telescope (HET). VIRUS has a fixed bandpass of 350-550 nm and resolving power R~750. The fibers are grouped into 78 integral field units, each with 448 fibers and 20 m average length. VIRUS is the first example of large-scale replication applied to optical astronomy and is capable of surveying large areas of sky, spectrally. The VIRUS concept offers significant savings of engineering effort and cost when compared to traditional instruments. The main motivator for VIRUS is to map the evolution of dark energy for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX‡), using 0.8M Lyman-alpha emitting galaxies as tracers. The VIRUS array has been undergoing staged deployment starting in late 2015. Currently, more than half of the array has been populated and the HETDEX survey started in 2017 December. It will provide a powerful new facility instrument for the HET, well suited to the survey niche of the telescope, and will open up large spectroscopic surveys of the emission line universe for the first time. We will review the current state of production, lessons learned in sustaining volume production, characterization, deployment, and commissioning of this massive instrument.
Published: 2018

47. Completion and performance of the Hobby-Eberly Telescope wide field upgrade

Author: Taft Armandroff, Katie Smither, Matthew Shetrone, Edmundo Balderrama, Jason Ramsey, Amy Westfall, Niv Drory, Lawrence W. Ramsey, Brian L. Vattiat, Hanshin Lee, John M. Good, Stephen C. Odewahn, Ron Leck, S. I. Rostopchin, Brent Buetow, Karl Gebhardt, James E. Fowler, Herman Kriel, Gary J. Hill, Phillip J. MacQueen, Amanda Martin, Martin Landriau, Renny Spencer, Greg Smith, Jerry Martin, Eusebio Terrazas, Emily Mrozinski, John Caldwell, Justin Pautzke, Emily Bevins, Randy Bryant, and George Damm
Subjects: Engineering, business.industry, Astronomy, Field of view, 01 natural sciences, Star tracker, law.invention, 010309 optics, Telescope, Primary mirror, Upgrade, law, Observatory, 0103 physical sciences, Hobby–Eberly Telescope, business, 010303 astronomy & astrophysics, Spectrograph
Abstract: The Hobby-Eberly Telescope (HET) is an innovative large telescope with 10 meter aperture, located in West Texas at the McDonald Observatory. The HET operates with a fixed segmented primary and has a tracker, which moves the fourmirror corrector and prime focus instrument package to track the sidereal and non-sidereal motions of objects. We have completed a major multi-year upgrade of the HET that has substantially increased the field of view to 22 arcminutes by replacing the optical corrector, tracker, and prime focus instrument package and by developing a new telescope control system. The upgrade has replaced all hardware and systems except for the structure, enclosure, and primary mirror. The new, reinvented wide-field HET feeds the revolutionary Visible Integral-field Replicable Unit Spectrograph (VIRUS‡), fed by 35,000 fibers, in support of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX§), a new low resolution spectrograph (LRS2), the Habitable Zone Planet Finder (HPF), and the upgraded high resolution spectrograph (HRS2). The HET Wide Field Upgrade has now been commissioned and has been in science operations since mid 2016 and in full science operations from mid 2018. This paper reviews and summarizes the upgrade, lessons learned, and the operational performance of the new HET.
Published: 2018

48. New Hobby Eberly telescope metrology systems: design, implementation, and on-sky performance

Author: S. C. Odewahn, Herman Kriel, Randy Bryant, Brian L. Vattiat, Hanshin Lee, George Damm, Matthew Shetrone, Niv Drory, Ron Leck, Gary J. Hill, S. I. Rostopchin, James R. Fowler, Martin Landriau, and Jason Ramsey
Subjects: Computer science, business.industry, Field of view, Wavefront sensor, Metrology, law.invention, Telescope, Upgrade, Observatory, law, Hobby–Eberly Telescope, Systems design, Aerospace engineering, business
Abstract: The Hobby-Eberly Telescope is an innovative 10-meter telescope, located at the McDonald Observatory. We have completed a major multi-year upgrade of the HET that has substantially increased the field of view to 22 arcminutes by replacing the optical corrector, tracker, and prime focus instrument package and by developing a new telescope control and metrology systems. The metrology systems include four independent optical sensors to provide fully redundant alignment and pointing information to keep the telescope aligned to within a few microns and a few arc seconds. We detail the design, implementation, on-sky performance, and lessons learned.
Published: 2018

49. 12C/13C isotopic ratios in red-giant stars of the open cluster NGC 6791

Author: Corinne Charbonnel, Matthew Shetrone, Szabolcs Mészáros, Katia Cunha, Marc H. Pinsonneault, Sandro Villanova, Verne V. Smith, Nadège Lagarde, D. A. García-Hernández, Carlos Allende Prieto, José G. Fernández-Trincado, László Szigeti, József Kovács, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Université de Genève = University of Geneva (UNIGE)
Subjects: 010504 meteorology & atmospheric sciences, Library science, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Christian ministry, National laboratory, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Mathematics
Abstract: Carbon isotope ratios, along with carbon and nitrogen abundances, are derived in a sample of 11 red-giant members of one of the most metal-rich clusters in the Milky Way, NGC 6791. The selected red-giants have a mean metallicity and standard deviation of [Fe/H]=+0.39+-0.06 (Cunha et al. 2015). We used high resolution H-band spectra obtained by the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE). The advantage of using high-resolution spectra in the H-band is that lines of CO are well represented and their line profiles are sensitive to the variation of 12C/13C. Values of the 12C/13C ratio were obtained from a spectrum synthesis analysis. The derived 12C/13C ratios varied between 6.3 and 10.6 in NGC 6791, in agreement with the final isotopic ratios from thermohaline-induced mixing models. The ratios derived here are combined with those obtained for more metal poor red-giants from the literature to examine the correlation between 12C/13C, mass, metallicity and evolutionary status., Accepted for publication in MNRAS, 9 pages, 4 figures, 2 tables
Published: 2018

50. The Metal-poor non-Sagittarius (?) Globular Cluster NGC 5053: Orbit and Mg, Al, and Si Abundances

Author: Baitian Tang, Dante Minnti, Annie C. Robin, Steven R. Majewski, D. A. García-Hernández, Richard R. Lane, Timothy C. Beers, Szabolcs Mészáros, Olga Zamora, Sangmo Tony Sohn, Sten Hasselquist, Thomas Masseron, José G. Fernández-Trincado, F. Dell'Agli, Alexandre Roman-Lopes, Doug Geisler, E. Moreno, Sandro Villanova, Matthew Shetrone, Ricardo P. Schiavon, Jose Schiappacasse Ulloa, Andres Almeida, Roger Cohen, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Instituto de Astrofisica de Canarias (IAC), Departamento de Astrofísica [La laguna], Universidad de La Laguna [Tenerife - SP] (ULL), Pontifícia Universidade Católica do Rio Grande do Sul [Porto Alegre] (PUCRS), Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Physics, 010308 nuclear & particles physics, media_common.quotation_subject, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Universe, Spectral line, Radial velocity, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Globular cluster, 0103 physical sciences, Cluster (physics), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Sagittarius, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Dwarf galaxy, media_common
Abstract: Metal-poor globular clusters (GCs) exhibit intriguing Al-Mg anti-correlations and possible Si-Al correlations, which are important clues to decipher the multiple-population phenomenon. NGC 5053 is one of the most metal-poor GCs in the nearby Universe, and has been suggested to be associated with the Sagittarius (Sgr) dwarf galaxy, due to its similarity in location and radial velocity with one of the Sgr arms. In this work, we simulate the orbit of NGC 5053, and argue against a physical connection between Sgr and NGC 5053. On the other hand, the Mg, Al, and Si spectral lines, which are difficult to detect in the optical spectra of NGC 5053 stars, have been detected in the near-infrared APOGEE spectra. We use three different sets of stellar parameters and codes to derive the Mg, Al, and Si abundances. Regardless of which method is adopted, we see a large Al variation, and a substantial Si spread. Along with NGC 5053, metal-poor GCs exhibit different Mg, Al, and Si variations. Moreover, NGC 5053 has the lowest cluster mass among the GCs that have been identified to exhibit an observable Si spread until now., Comment: ApJ accepted. 14 pages, 12 figures
Published: 2018

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