Browsing by Author "Munoz, Ricardo R."

Now showing 1 - 7 of 7
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    APOGEE chemical abundances of globular cluster giants in the inner Galaxy
    (2017) Schiavon, Ricardo P.; Johnson, Jennifer A.; Frinchaboy, Peter M.; Zasowski, Gail; Meszaros, Szabolcs; Garcia-Hernandez, D. A.; Cohen, Roger E.; Tang, Baitian; Villanova, Sandro; Geisler, Douglas; Beers, Timothy C.; Fernandez-Trincado, J. G.; Garcia Perez, Ana E.; Lucatello, Sara; Majewski, Steven R.; Martell, Sarah L.; O'Connell, Robert W.; Allende Prieto, Carlos; Bizyaev, Dmitry; Carrera, Ricardo; Lane, Richard R.; Malanushenko, Elena; Malanushenko, Viktor; Munoz, Ricardo R.; Nitschelm, Christian; Oravetz, Daniel; Pan, Kaike; Roman-Lopes, Alexandre; Schultheis, Matthias; Simmons, Audrey
    We report chemical abundances obtained by Sloan Digital Sky Survey (SDSS)-III/Apache Point Observatory Galactic Evolution Experiment for giant stars in five globular clusters located within 2.2 kpc of the Galactic Centre. We detect the presence of multiple stellar populations in four of those clusters (NGC 6553, NGC 6528, Terzan 5 and Palomar 6) and find strong evidence for their presence in NGC 6522. All clusters with a large enough sample present a significant spread in the abundances of N, C, Na and Al, with the usual correlations and anticorrelations between various abundances seen in other globular clusters. Our results provide important quantitative constraints on theoretical models for self-enrichment of globular clusters, by testing their predictions for the dependence of yields of elements such as Na, N, C and Al on metallicity. They also confirm that, under the assumption that field N-rich stars originate from globular cluster destruction, they can be used as tracers of their parental systems in the high-metallicity regime.
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    Final Targeting Strategy for the SDSS-IV APOGEE-2S Survey
    (2021) Santana, Felipe A.; Beaton, Rachael L.; Covey, Kevin R.; O'Connell, Julia E.; Longa-Pena, Penelope; Cohen, Roger; Fernandez-Trincado, Jose G.; Hayes, Christian R.; Zasowski, Gail; Sobeck, Jennifer S.; Majewski, Steven R.; Chojnowski, S. D.; De Lee, Nathan; Oelkers, Ryan J.; Stringfellow, Guy S.; Almeida, Andres; Anguiano, Borja; Donor, John; Frinchaboy, Peter M.; Hasselquist, Sten; Johnson, Jennifer A.; Kollmeier, Juna A.; Nidever, David L.; Price-Whelan, Adrian M.; Rojas-Arriagada, Alvaro; Schultheis, Mathias; Shetrone, Matthew; Simon, Joshua D.; Aerts, Conny; Borissova, Jura; Drout, Maria R.; Geisler, Doug; Law, C. Y.; Medina, Nicolas; Minniti, Dante; Monachesi, Antonela; Munoz, Ricardo R.; Poleski, Radoslaw; Roman-Lopes, Alexandre; Schlaufman, Kevin C.; Stutz, Amelia M.; Teske, Johanna; Tkachenko, Andrew; Van Saders, Jennifer L.; Weinberger, Alycia J.; Zoccali, Manuela
    APOGEE is a high-resolution (R similar to 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 of 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 and the Carnegie Institution for Science. This work was presented along with a companion article, Beaton et al. (2021), presenting the final target selection strategy adopted for APOGEE-2 in the Northern Hemisphere.
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    Nature of a shell of young stars in the outskirts of the Small Magellanic Cloud
    (2019) Martinez-Delgado, David; Katherina Vivas, Anna; Grebel, Eva K.; Gallart, Carme; Pieres, Adriano; Bell, Cameron P. M.; Zivick, Paul; Lemasle, Bertrand; Johnson, Lent Clifton; Carballo-Bello, Julio A.; Noel, Noelia E. D.; Cioni, Maria-Rosa L.; Choi, Yumi; Besla, Gurtina; Schmidt, Judy; Zaritsky, Dennis; Gruendl, Robert A.; Seibert, Mark; Nidever, David; Monteagudo, Laura; Monelli, Mateo; Hubl, Bernhard; van der Marel, Roeland; Ballesteros, Fernando J.; Stringfellow, Guy; Walker, Alistair; Blum, Robert; Bell, Eric F.; Conn, Blair C.; Olsen, Knut; Martin, Nicolas; Chu, You-Hua; Inno, Laura; Boer, Thomas J. L.; Kallivayalil, Nitya; De Leo, Michele; Beletsky, Yuri; Neyer, Fabian; Munoz, Ricardo R.
    Context. Understanding the evolutionary history of the Magellanic Clouds requires an in-depth exploration and characterization of the stellar content in their outer regions, which ultimately are key to tracing the epochs and nature of past interactions.
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    The age-chemical abundance structure of the Galactic disc - II. α-dichotomy and thick disc formation
    (2020) Lian, Jianhui; Thomas, Daniel; Maraston, Claudia; Beers, Timothy C.; Moni Bidin, Christian; Fernandez-Trincado, Jose G.; Garcia-Hernandez, D. A.; Lane, Richard R.; Munoz, Ricardo R.; Nitschelm, Christian; Roman-Lopes, Alexandre; Zamora, Olga
    We extend our previous work on the age-chemical abundance structure of the Galactic outer disc to the inner disc (4 < r < 8 kpc) based on the SDSS/APOGEE survey. Different from the outer disc, the inner disc stars exhibit a clear bimodal distribution in the [Mg/Fe]-[Fe/H] plane. While a number of scenarios have been proposed in the literature, it remains challenging to recover this bimodal distribution with theoretical models. To this end, we present a chemical evolution model embedding a complex multiphase inner disc formation scenario that matches the observed bimodal [Mg/Fe]-[Fe/H] distribution. In this scenario, the formation of the inner disc is dominated by two main starburst episodes 6 Gyr apart with secular, low-level star formation activity in between. In our model, the first starburst occurs at early cosmic times (t similar to 1 Gyr) and the second one 6 Gyr later at a cosmic time of t similar to 7 Gyr. Both these starburst episodes are associated with gas accretion events in our model, and are quenched rapidly. The first starburst leads to the formation of the high-a sequence, and the second starburst leads to the formation of the metal-poor low-a sequence. The metal-rich low-alpha stars, instead, form during the secular evolution phase between the two bursts. Our model shows that the alpha-dichotomy originates from the rapid suppression of star formation after the first starburst. The two starburst episodes are likely to be responsible for the formation of the geometric thick disc (z > 1 kpc), with the old inner thick disc and the young outer thick disc forming during the first and the second starbursts, respectively.
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    The Gravity Collective: A Search for the Electromagnetic Counterpart to the Neutron Star-Black Hole Merger GW190814
    (2021) Kilpatrick, Charles D.; Coulter, David A.; Arcavi, Iair; Brink, Thomas G.; Dimitriadis, Georgios; Filippenko, Alexei, V; Foley, Ryan J.; Howell, D. Andrew; Jones, David O.; Kasen, Daniel; Makler, Martin; Piro, Anthony L.; Rojas-Bravo, Cesar; Sand, David J.; Swift, Jonathan J.; Tucker, Douglas; Zheng, WeiKang; Allam, Sahar S.; Annis, James T.; Antilen, Juanita; Bachmann, Tristan G.; Bloom, Joshua S.; Bom, Clecio R.; Bostroem, K. Azalee; Brout, Dillon; Burke, Jamison; Butler, Robert E.; Butner, Melissa; Campillay, Abdo; Clever, Karoli E.; Conselice, Christopher J.; Cooke, Jeff; Dage, Kristen C.; de Carvalho, Reinaldo R.; de Jaeger, Thomas; Desai, Shantanu; Garcia, Alyssa; Garcia-Bellido, Juan; Gill, Mandeep S. S.; Girish, Nachiket; Hallakoun, Na'ama; Herner, Kenneth; Hiramatsu, Daichi; Holz, Daniel E.; Huber, Grace; Kawash, Adam M.; McCully, Curtis; Medallon, Sophia A.; Metzger, Brian D.; Modak, Shaunak; Morgan, Robert; Munoz, Ricardo R.; Munoz-Elgueta, Nahir; Murakami, Yukei S.; Felipe Olivares, E.; Palmese, Antonella; Patra, Kishore C.; Pereira, Maria E. S.; Pessi, Thallis L.; Pineda-Garcia, J.; Quirola-Vasquez, Jonathan; Ramirez-Ruiz, Enrico; Rembold, Sandro Barboza; Rest, Armin; Rodriguez, Osmar; Santana-Silva, Luidhy; Sherman, Nora F.; Siebert, Matthew R.; Smith, Carli; Smith, J. Allyn; Soares-Santos, Marcelle; Stacey, Holland; Stahl, Benjamin E.; Strader, Jay; Strasburger, Erika; Sunseri, James; Tinyanont, Samaporn; Tucker, Brad E.; Ulloa, Natalie; Valenti, Stefano; Vasylyev, Sergiy S.; Wiesner, Matthew P.; Zhang, Keto D.
    We present optical follow-up imaging obtained with the Katzman Automatic Imaging Telescope, Las Cumbres Observatory Global Telescope Network, Nickel Telescope, Swope Telescope, and Thacher Telescope of the LIGO/Virgo gravitational wave (GW) signal from the neutron star-black hole (NSBH) merger GW190814. We searched the GW190814 localization region (19 deg(2) for the 90th percentile best localization), covering a total of 51 deg(2) and 94.6% of the two-dimensional localization region. Analyzing the properties of 189 transients that we consider as candidate counterparts to the NSBH merger, including their localizations, discovery times from merger, optical spectra, likely host galaxy redshifts, and photometric evolution, we conclude that none of these objects are likely to be associated with GW190814. Based on this finding, we consider the likely optical properties of an electromagnetic counterpart to GW190814, including possible kilonovae and short gamma-ray burst afterglows. Using the joint limits from our follow-up imaging, we conclude that a counterpart with an r-band decline rate of 0.68 mag day(-1), similar to the kilonova AT 2017gfo, could peak at an absolute magnitude of at most -17.8 mag (50% confidence). Our data are not constraining for "red" kilonovae and rule out "blue" kilonovae with M > 0.5 M (circle dot) (30% confidence). We strongly rule out all known types of short gamma-ray burst afterglows with viewing angles <17 degrees assuming an initial jet opening angle of similar to 5.degrees 2 and explosion energies and circumburst densities similar to afterglows explored in the literature. Finally, we explore the possibility that GW190814 merged in the disk of an active galactic nucleus, of which we find four in the localization region, but we do not find any candidate counterparts among these sources.
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    The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar, and APOGEE-2 Data
    (2022) Abdurro'uf; Accetta, Katherine; Aerts, Conny; Aguirre, Victor Silva; Ahumada, Romina; Ajgaonkar, Nikhil; Ak, N. Filiz; Alam, Shadab; Prieto, Carlos Allende; Almeida, Andres; Anders, Friedrich; Anderson, Scott F.; Andrews, Brett H.; Anguiano, Borja; Aquino-Ortiz, Erik; Aragon-Salamanca, Alfonso; Argudo-Fernandez, Maria; Ata, Metin; Aubert, Marie; Avila-Reese, Vladimir; Badenes, Carles; Barba, Rodolfo H.; Barger, Kat; Barrera-Ballesteros, Jorge K.; Beaton, Rachael L.; Beers, Timothy C.; Belfiore, Francesco; Bender, Chad F.; Bernardi, Mariangela; Bershady, Matthew A.; Beutler, Florian; Bidin, Christian Moni; Bird, Jonathan C.; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael R.; Boardman, Nicholas Fraser; Bolton, Adam S.; Boquien, Mederic; Borissova, Jura; Bovy, Jo; Brandt, W. N.; Brown, Jordan; Brownstein, Joel R.; Brusa, Marcella; Buchner, Johannes; Bundy, Kevin; Burchett, Joseph N.; Bureau, Martin; Burgasser, Adam; Cabang, Tuesday K.; Campbell, Stephanie; Cappellari, Michele; Carlberg, Joleen K.; Wanderley, Fabio Carneiro; Carrera, Ricardo; Cash, Jennifer; Chen, Yan-Ping; Chen, Wei-Huai; Cherinka, Brian; Chiappini, Cristina; Choi, Peter Doohyun; Chojnowski, S. Drew; Chung, Haeun; Clerc, Nicolas; Cohen, Roger E.; Comerford, Julia M.; Comparat, Johan; da Costa, Luiz; Covey, Kevin; Crane, Jeffrey D.; Cruz-Gonzalez, Irene; Culhane, Connor; Cunha, Katia; Dai, Y. Sophia; Damke, Guillermo; Darling, Jeremy; Davidson, James W., Jr.; Davies, Roger; Dawson, Kyle; De Lee, Nathan; Diamond-Stanic, Aleksandar M.; Cano-Diaz, Mariana; Sanchez, Helena Dominguez; Donor, John; Duckworth, Chris; Dwelly, Tom; Eisenstein, Daniel J.; Elsworth, Yvonne P.; Emsellem, Eric; Eracleous, Mike; Escoffier, Stephanie; Fan, Xiaohui; Farr, Emily; Feng, Shuai; Fernandez-Trincado, Jose G.; Feuillet, Diane; Filipp, Andreas; Fillingham, Sean P.; Frinchaboy, Peter M.; Fromenteau, Sebastien; Galbany, Lluis; Garcia, Rafael A.; Garcia-Hernandez, D. A.; Ge, Junqiang; Geisler, Doug; Gelfand, Joseph; Geron, Tobias; Gibson, Benjamin J.; Goddy, Julian; Godoy-Rivera, Diego; Grabowski, Kathleen; Green, Paul J.; Greener, Michael; Grier, Catherine J.; Griffith, Emily; Guo, Hong; Guy, Julien; Hadjara, Massinissa; Harding, Paul; Hasselquist, Sten; Hayes, Christian R.; Hearty, Fred; Hill, Lewis; Hogg, David W.; Holtzman, Jon A.; Horta, Danny; Hsieh, Bau-Ching; Hsu, Chin-Hao; Hsu, Yun-Hsin; Huber, Daniel; Huertas-Company, Marc; Hutchinson, Brian; Hwang, Ho Seong; Ibarra-Medel, Hector J.; Chitham, Jacob Ider; Ilha, Gabriele S.; Imig, Julie; Jaekle, Will; Jayasinghe, Tharindu; Ji, Xihan; Johnson, Jennifer A.; Jones, Amy; Jonsson, Henrik; Katkov, Ivan; Khalatyan, Arman; Kinemuchi, Karen; Kisku, Shobhit; Knapen, Johan H.; Kneib, Jean-Paul; Kollmeier, Juna A.; Kong, Miranda; Kounkel, Marina; Kreckel, Kathryn; Krishnarao, Dhanesh; Lacerna, Ivan; Lane, Richard R.; Langgin, Rachel; Lavender, Ramon; Law, David R.; Lazarz, Daniel; Leung, Henry W.; Leung, Ho-Hin; Lewis, Hannah M.; Li, Cheng; Li, Ran; Lian, Jianhui; Liang, Fu-Heng; Lin, Lihwai; Lin, Yen-Ting; Lin, Sicheng; Lintott, Chris; Long, Dan; Longa-Pena, Penelope; Lopez-Coba, Carlos; Lu, Shengdong; Lundgren, Britt F.; Luo, Yuanze; Mackereth, J. Ted; de la Macorra, Axel; Mahadevan, Suvrath; Majewski, Steven R.; Manchado, Arturo; Mandeville, Travis; Maraston, Claudia; Margalef-Bentabol, Berta; Masseron, Thomas; Masters, Karen L.; Mathur, Savita; McDermid, Richard M.; Mckay, Myles; Merloni, Andrea; Merrifield, Michael; Meszaros, Szabolcs; Miglio, Andrea; Di Mille, Francesco; Minniti, Dante; Minsley, Rebecca; Monachesi, Antonela; Moon, Jeongin; Mosser, Benoit; Mulchaey, John; Muna, Demitri; Munoz, Ricardo R.; Myers, Adam D.; Myers, Natalie; Nadathur, Seshadri; Nair, Preethi; Nandra, Kirpal; Neumann, Justus; Newman, Jeffrey A.; Nidever, David L.; Nikakhtar, Farnik; Nitschelm, Christian; O'Connell, Julia E.; Garma-Oehmichen, Luis; de Oliveira, Gabriel Luan Souza; Olney, Richard; Oravetz, Daniel; Ortigoza-Urdaneta, Mario; Osorio, Yeisson; Otter, Justin; Pace, Zachary J.; Padilla, Nelson; Pan, Kaike; Pan, Hsi-An; Parikh, Taniya; Parker, James; Peirani, Sebastien; Ramirez, Karla Pena; Penny, Samantha; Percival, Will J.; Perez-Fournon, Ismael; Pinsonneault, Marc; Poidevin, Frederick; Poovelil, Vijith Jacob; Price-Whelan, Adrian M.; Queiroz, Anna Barbara de Andrade; Raddick, M. Jordan; Ray, Amy; Rembold, Sandro Barboza; Riddle, Nicole; Riffel, Rogemar A.; Riffel, Rogerio; Rix, Hans-Walter; Robin, Annie C.; Rodriguez-Puebla, Aldo; Roman-Lopes, Alexandre; Roman-Zuniga, Carlos; Rose, Benjamin; Ross, Ashley J.; Rossi, Graziano; Rubin, Kate H. R.; Salvato, Mara; Sanchez, Sebastian F.; Sanchez-Gallego, Jose R.; Sanderson, Robyn; Rojas, Felipe Antonio Santana; Sarceno, Edgar; Sarmiento, Regina; Sayres, Conor; Sazonova, Elizaveta; Schaefer, Adam L.; Schiavon, Ricardo; Schlegel, David J.; Schneider, Donald P.; Schultheis, Mathias; Schwope, Axel; Serenelli, Aldo; Serna, Javier; Shao, Zhengyi; Shapiro, Griffin; Sharma, Anubhav; Shen, Yue; Shetrone, Matthew; Shu, Yiping; Simon, Joshua D.; Skrutskie, M. F.; Smethurst, Rebecca; Smith, Verne; Sobeck, Jennifer; Spoo, Taylor; Sprague, Dani; Stark, David, V; Stassun, Keivan G.; Steinmetz, Matthias; Stello, Dennis; Stone-Martinez, Alexander; Storchi-Bergmann, Thaisa; Stringfellow, Guy S.; Stutz, Amelia; Su, Yung-Chau; Taghizadeh-Popp, Manuchehr; Talbot, Michael S.; Tayar, Jamie; Telles, Eduardo; Teske, Johanna; Thakar, Ani; Theissen, Christopher; Tkachenko, Andrew; Thomas, Daniel; Tojeiro, Rita; Toledo, Hector Hernandez; Troup, Nicholas W.; Trump, Jonathan R.; Trussler, James; Turner, Jacqueline; Tuttle, Sarah; Unda-Sanzana, Eduardo; Vazquez-Mata, Jose Antonio; Valentini, Marica; Valenzuela, Octavio; Vargas-Gonzalez, Jaime; Vargas-Magana, Mariana; Alfaro, Pablo Vera; Villanova, Sandro; Vincenzo, Fiorenzo; Wake, David; Warfield, Jack T.; Washington, Jessica Diane; Weaver, Benjamin Alan; Weijmans, Anne-Marie; Weinberg, David H.; Weiss, Achim; Westfall, Kyle B.; Wild, Vivienne; Wilde, Matthew C.; Wilson, John C.; Wilson, Robert F.; Wilson, Mikayla; Wolf, Julien; Wood-Vasey, W. M.; Yan, Renbin; Zamora, Olga; Zasowski, Gail; Zhang, Kai; Zhao, Cheng; Zheng, Zheng; Zheng, Zheng; Zhu, Kai
    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.
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    Two groups of red giants with distinct chemical abundances in the bulge globular cluster NGC 6553 through the eyes of APOGEE
    (OXFORD UNIV PRESS, 2017) Tang, Baitian; Cohen, Roger E.; Geisler, Doug; Schiavon, Ricardo P.; Majewski, Steven R.; Villanova, Sandro; Carrera, Ricardo; Zamora, Olga; Garcia Hernandez, D. A.; Shetrone, Matthew; Frinchaboy, Peter; Meza, Andres; Fernandez Trincado, J. G.; Munoz, Ricardo R.; Lin, Chien Cheng; Lane, Richard R.; Nitschelm, Christian; Pan, Kaike; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey
    Multiple populations revealed in globular clusters (GCs) are important windows to the formation and evolution of these stellar systems. The metal-rich GCs in the Galactic bulge are an indispensable part of this picture, but the high optical extinction in this region has prevented extensive research. In this work, we use the high-resolution near-infrared (NIR) spectroscopic data from Apache Point Observatory Galactic Evolution Experiment (APOGEE) to study the chemical abundances of NGC 6553, which is one of the most metal-rich bulge GCs. We identify 10 red giants as cluster members using their positions, radial velocities, iron abundances, and NIR photometry. Our sample stars show a mean radial velocity of -0.14 +/- 5.47 km s(-1), land a mean [Fe/H] of -0.15 +/- 0.05. We clearly separate two populations of stars in C and N in this GC for the first time. NGC 6553 is the most metal-rich GC where the multiple stellar population phenomenon is found until now. Substantial chemical variations are also found in Na, O, and Al. However, the two populations show similar Si, Ca, and iron-peak element abundances. Therefore, we infer that the CNO, NeNa, and MgAl cycles have been activated, but the MgAl cycle is too weak to show its effect on Mg. Type Ia and Type II supernovae do not seem to have significantly polluted the second generation stars. Comparing with other GC studies, NGC 6553 shows similar chemical variations as other relatively metal-rich GCs. We also confront current GC formation theories with our results, and suggest possible avenues for improvement in the models.