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    Chemical Abundances and Ages of the Bulge Stars in APOGEE High-velocity Peaks
    (London : Institute of Physics Publ., 2017) Zhou, Yingying; Shen, Juntai; Liu, Chao; Li, Zhao-Yu; Mao, Shude; Kunder, Andrea; Rich, R. Michael; Zasowski, G.; Fernandez-Trincado, J. G.; Majewski, Steven R.; Lin, Chien-Cheng; Geisler, Doug; Tang, Baitian; Villanova, S.; Roman-Lopes, A.; Schultheis, M.; Nidever, David L.; Meza, Andrés; Pan, Kaike; Bizyaev, D. V.
    A cold, high-velocity (HV, ∼200 km s-1) peak was first reported in several Galactic bulge fields based on the Apache Point Observatory Galaxy Evolution Experiment (APOGEE) commissioning observations. Both the existence and the nature of the HV peak are still under debate. Here we revisit this feature with the latest APOGEE DR13 data. We find that most of the low-latitude bulge fields display a skewed Gaussian distribution with an HV shoulder. However, only 3 out of 53 fields show distinct HV peaks around 200 km s-1. The velocity distribution can be well described by Gauss-Hermite polynomials, except for the three fields showing clear HV peaks. We find that the correlation between the skewness parameter (h 3) and the mean velocity (), instead of a distinctive HV peak, is a strong indicator of the bar. It was recently suggested that the HV peak is composed of preferentially young stars. We choose three fields showing clear HV peaks to test this hypothesis using the metallicity, [α/M], and [C/N] as age proxies. We find that both young and old stars show HV features. The similarity between the chemical abundances of stars in the HV peaks and the main component indicates that they are not systematically different in terms of chemical abundance or age. In contrast, there are clear differences in chemical space between stars in the Sagittarius dwarf and the bulge stars. The strong HV peaks off-plane are still to be explained properly and could be different in nature.
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    The 16th Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
    (London : Institute of Physics Publ., 2020) Ahumada, Romina; Prieto, Carlos Allende; Almeida, Andrés; Anders, Friedrich; Anderson, Scott F.; Andrews, Brett H.; Anguiano, Borja; Arcodia, Riccardo; Armengaud, Eric; Aubert, Marie; Avila, Santiago; Garcia, Rafael A.; García-Hernández, D.A.; Oehmichen, Luis Alberto Garma; Ge, Junqiang; Maia, Marcio Antonio Geimba; Geisler, Doug; Gelfand, Joseph; Goddy, Julian; Gonzalez-Perez, Violeta; Grabowski, Kathleen; Avila-Reese, Vladimir; Green, Paul; Grier, Catherine J.; Guo, Hong; Guy, Julien; Harding, Paul; Hasselquist, Sten; Hawken, Adam James; Hayes, Christian R.; Hearty, Fred; Hekker, S.; Badenes, Carles; Hogg, David W.; Holtzman, Jon A.; Horta, Danny; Hou, Jiamin; Hsieh, Bau-Ching; Huber, Daniel; Hunt, Jason A. S.; Chitham, J. Ider; Imig, Julie; Jaber, Mariana; Balland, Christophe; Angel, Camilo Eduardo Jimenez; Johnson, Jennifer A.; Jones, Amy M.; Jönsson, Henrik; Jullo, Eric; Kim, Yerim; Kinemuchi, Karen; Kirkpatrick IV, Charles C.; Kite, George W.; Klaene, Mark; Barger, Kat; Kneib, Jean-Paul; Kollmeier, Juna A.; Kong, Hui; Kounkel, Marina; Krishnarao, Dhanesh; Lacerna, Ivan; Lan, Ting-Wen; Lane, Richard R.; Law, David R.; Le Goff, Jean-Marc; Barrera-Ballesteros, Jorge K.; Leung, Henry W.; Lewis, Hannah; Li, Cheng; Lian, Jianhui; Lin, Lihwai; Long, Dan; Longa-Peña, Penélope; Lundgren, Britt; Lyke, Brad W.; Ted Mackereth, J.; Basu, Sarbani; MacLeod, Chelsea L.; Majewski, Steven R.; Manchado, Arturo; Maraston, Claudia; Martini, Paul; Masseron, Thomas; Masters, Karen L.; Mathur, Savita; McDermid, Richard M.; Merloni, Andrea; Bautista, Julian; Merrifield, Michael; Mészáros, Szabolcs; Miglio, Andrea; Minniti, Dante; Minsley, Rebecca; Miyaji, Takamitsu; Mohammad, Faizan Gohar; Mosser, Benoit; Mueller, Eva-Maria; Muna, Demitri; Beaton, Rachael L.; Muñoz-Gutiérrez, Andrea; Myers, Adam D.; Nadathur, Seshadri; Nair, Preethi; Nandra, Kirpal; do Nascimento, Janaina Correa; Nevin, Rebecca Jean; Newman, Jeffrey A.; Nidever, David L.; Nitschelm, Christian; Beers, Timothy C.; Noterdaeme, Pasquier; O’Connell, Julia E.; Olmstead, Matthew D.; Oravetz, Daniel; Oravetz, Audrey; Osorio, Yeisson; Pace, Zachary J.; Padilla, Nelson; Palanque-Delabrouille, Nathalie; Palicio, Pedro A.; Benavides, B. Izamar T.; Pan, Hsi-An; Pan, Kaike; Parker, James; Paviot, Romain; Peirani, Sebastien; Ramŕez, Karla Peña; Penny, Samantha; Percival, Will J.; Perez-Fournon, Ismael; Pérez-Ràfols, Ignasi; Bender, Chad F.; Petitjean, Patrick; Pieri, Matthew M.; Pinsonneault, Marc; Poovelil, Vijith Jacob; Povick, Joshua Tyler; Prakash, Abhishek; Price-Whelan, Adrian M.; Raddick, M. Jordan; Raichoor, Anand; Ray, Amy; Bernardi, Mariangela; Rembold, Sandro Barboza; Rezaie, Mehdi; Riffel, Rogemar A.; Riffel, Rogério; Rix, Hans-Walter; Robin, Annie C.; Roman-Lopes, A.; Román-Zúñiga, Carlos; Rose, Benjamin; Ross, Ashley J.; Bershady, Matthew; Rossi, Graziano; Rowlands, Kate; Rubin, Kate H. R.; Salvato, Mara; Sánchez, Ariel G.; Sánchez-Menguiano, Laura; Sánchez-Gallego, José R.; Sayres, Conor; Schaefer, Adam; Schiavon, Ricardo P.; Beutler, Florian; Schimoia, Jaderson S.; Schlafly, Edward; Schlegel, David; Schneider, Donald P.; Schultheis, Mathias; Schwope, Axel; Seo, Hee-Jong; Serenelli, Aldo; Shafieloo, Arman; Shamsi, Shoaib Jamal; Bidin, Christian Moni; Shao, Zhengyi; Shen, Shiyin; Shetrone, Matthew; Shirley, Raphael; Aguirre, Víctor Silva; Simon, Joshua D.; Skrutskie, M.F.; Slosar, Anže; Smethurst, Rebecca; Sobeck, Jennifer; Bird, Jonathan; Sodi, Bernardo Cervantes; Souto, Diogo; Stark, David V.; Stassun, Keivan G.; Steinmetz, Matthias; Stello, Dennis; Stermer, Julianna; Storchi-Bergmann, Thaisa; Streblyanska, Alina; Stringfellow, Guy S.; Bizyaev, Dmitry; Stutz, Amelia; Suárez, Genaro; Sun, Jing; Taghizadeh-Popp, Manuchehr; Talbot, Michael S.; Tayar, Jamie; Thakar, Aniruddha R.; Theriault, Riley; Thomas, Daniel; Thomas, Zak C.; Blanc, Guillermo A.; Tinker, Jeremy; Tojeiro, Rita; Toledo, Hector Hernandez; Tremonti, Christy A.; Troup, Nicholas W.; Tuttle, Sarah; Unda-Sanzana, Eduardo; Valentini, Marica; Vargas-González, Jaime; Vargas-Magaña, Mariana; Blanton, Michael R.; Vázquez-Mata, Jose Antonio; Vivek, M.; Wake, David; Wang, Yuting; Weaver, Benjamin Alan; Weijmans, Anne-Marie; Wild, Vivienne; Wilson, John C.; Wilson, Robert F.; Wolthuis, Nathan; Boquien, Médéric; Wood-Vasey, W. M.; Yan, Renbin; Yang, Meng; Yèche, Christophe; Zamora, Olga; Zarrouk, Pauline; Zasowski, Gail; Zhang, Kai; Zhao, Cheng; Zhao, Gongbo; Borissova, Jura; Zheng, Zheng; Zheng, Zheng; Zhu, Guangtun; Zou, Hu; Bovy, Jo; Brandt, W. N.; Brinkmann, Jonathan; Brownstein, Joel R.; Bundy, Kevin; Bureau, Martin; Burgasser, Adam; Burtin, Etienne; Cano-Díaz, Mariana; Capasso, Raffaella; Cappellari, Michele; Carrera, Ricardo; Chabanier, Solène; Chaplin, William; Chapman, Michael; Cherinka, Brian; Chiappini, Cristina; Doohyun Choi, Peter; Chojnowski, S. Drew; Chung, Haeun; Clerc, Nicolas; Coffey, Damien; Comerford, Julia M.; Comparat, Johan; da Costa, Luiz; Cousinou, Marie-Claude; Covey, Kevin; Crane, Jeffrey D.; Cunha, Katia; Ilha, Gabriele da Silva; Dai, Yu Sophia; Damsted, Sanna B.; Darling, Jeremy; Davidson, James W.; Davies, Roger; Dawson, Kyle; De, Nikhil; de la Macorra, Axel; De Lee, Nathan; Queiroz, Anna Bárbara de Andrade; Deconto Machado, Alice; de la Torre, Sylvain; Dell’Agli, Flavia; du Mas des Bourboux, Hélion; Diamond-Stanic, Aleksandar M.; Dillon, Sean; Donor, John; Drory, Niv; Duckworth, Chris; Dwelly, Tom; Ebelke, Garrett; Eftekharzadeh, Sarah; Davis Eigenbrot, Arthur; Elsworth, Yvonne P.; Eracleous, Mike; Erfanianfar, Ghazaleh; Escoffier, Stephanie; Fan, Xiaohui; Farr, Emily; Fernández-Trincado, José G.; Feuillet, Diane; Finoguenov, Alexis; Fofie, Patricia; Fraser-McKelvie, Amelia; Frinchaboy, Peter M.; Fromenteau, Sebastien; Fu, Hai; Galbany, Lluís
    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).