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1. A Strong He ii λ1640 Emitter with an Extremely Blue UV Spectral Slope at z = 8.16: Presence of Population III Stars?

Author: Xin Wang, Cheng Cheng, Junqiang Ge, Xiao-Lei Meng, Emanuele Daddi, Haojing Yan, Zhiyuan Ji, Yifei Jin, Tucker Jones, Matthew A. Malkan, Pablo Arrabal Haro, Gabriel Brammer, Masamune Oguri, Meicun Hou, and Shiwu Zhang
Subjects: High-redshift galaxies, Reionization, Pop III stars, Metallicity, Astrophysics, QB460-466
Abstract: Cosmic hydrogen reionization and cosmic production of the first metals are major phase transitions of the Universe occurring during the first billion years after the Big Bang; however, these are still underexplored observationally. Using the JWST/NIRSpec prism spectroscopy, we report the discovery of a sub- L _* galaxy at z _spec = 8.1623 ± 0.0007, dubbed RX J2129–z8He II , via the detection of a series of strong rest-frame UV/optical nebular emission lines and the clear Lyman break. RX J2129–z8He II shows a pronounced UV continuum with an extremely steep (i.e., blue) spectral slope of $\beta =-{2.53}_{-0.07}^{+0.06}$ , the steepest among all spectroscopically confirmed galaxies at z _spec ≳ 7, in support of its very hard ionizing spectrum that could lead to a significant leakage of its ionizing flux. Therefore, RX J2129–z8He II is representative of the key galaxy population driving the cosmic reionization. More importantly, we detect a strong He II λ 1640 emission line in its spectrum, one of the highest redshifts at which such a line is robustly detected. Its high rest-frame equivalent width (EW = 21 ± 4 Å) and extreme flux ratios with respect to UV metal and Balmer lines raise the possibility that part of RX J2129–z8He II ’s stellar population could be Pop III (Pop III)-like. Through careful photoionization modeling, we show that the physically calibrated phenomenological models of the ionizing spectra of Pop III stars with strong mass loss can successfully reproduce the emission line flux ratios observed in RX J2129–z8He II . Assuming the Eddington limit, the total mass of the Pop III stars within this system is estimated to be 7.8 ± 1.4 × 10 ^5 M _⊙ . To date, this galaxy presents the most compelling case in the early Universe where trace Pop III stars might coexist with metal-enriched populations.
Published: 2024
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2. Are High-Σ1 Massive Blue Spiral Galaxies Rejuvenated Systems?

Author: Cai-Na Hao, Xiaoyang Xia, Yong Shi, Rui Guo, Yanmei Chen, Shuai Feng, Junqiang Ge, and Qiusheng Gu
Subjects: Galaxy evolution, Galaxy formation, Galaxy ages, Spiral galaxies, Galaxy spectroscopy, Astrophysics, QB460-466
Abstract: Quiescent galaxies generally possess denser cores than star-forming galaxies with similar mass. As a measurement of the core density, the central stellar mass surface density within a radius of 1 kpc (Σ _1 ) was thus suggested to be closely related to galaxy quenching. Massive star-forming galaxies with high Σ _1 do not fit into this picture. To understand the origin of such galaxies, we compare the spatially resolved stellar population and star formation properties of massive (>10 ^10.5 M _⊙ ) blue spiral galaxies with high and low Σ _1 , divided by Σ _1 = 10 ^9.4 M _⊙ kpc ^−2 , based on the final release of MaNGA integral field unit data. We find that both high-Σ _1 and low-Σ _1 blue spirals show large diversities in stellar population and star formation properties. Despite the diversities, high-Σ _1 blue spirals are statistically different from the low-Σ _1 ones. Specifically, the radial profiles of the luminosity-weighted age and Mgb/〈Fe〉 show that high-Σ _1 blue spirals consist of a larger fraction of galaxies with younger and less α -element-enhanced centers than their low-Σ _1 counterparts, ∼55% versus ∼30%. The galaxies with younger centers mostly have higher central specific star formation rates, which still follow the spaxel-based star formation main-sequence relation. Examinations of the H α velocity field and the optical structures suggest that galactic bars or galaxy interactions should be responsible for the rejuvenation of these galaxies. The remaining ∼45% of high-Σ _1 blue spirals are consistent with the inside-out growth scenario.
Published: 2024
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3. The Eighteenth Data Release of the Sloan Digital Sky Surveys: Targeting and First Spectra from SDSS-V

Author: Andrés Almeida, Scott F. Anderson, Maria Argudo-Fernández, Carles Badenes, Kat Barger, Jorge K. Barrera-Ballesteros, Chad F. Bender, Erika Benitez, Felipe Besser, Jonathan C. Bird, Dmitry Bizyaev, Michael R. Blanton, John Bochanski, Jo Bovy, William Nielsen Brandt, Joel R. Brownstein, Johannes Buchner, Esra Bulbul, Joseph N. Burchett, Mariana Cano Díaz, Joleen K. Carlberg, Andrew R. Casey, Vedant Chandra, Brian Cherinka, Cristina Chiappini, Abigail A. Coker, Johan Comparat, Charlie Conroy, Gabriella Contardo, Arlin Cortes, Kevin Covey, Jeffrey D. Crane, Katia Cunha, Collin Dabbieri, James W. Davidson Jr, Megan C. Davis, Anna Barbara de Andrade Queiroz, Nathan De Lee, José Eduardo Méndez Delgado, Sebastian Demasi, Francesco Di Mille, John Donor, Peter Dow, Tom Dwelly, Mike Eracleous, Jamey Eriksen, Xiaohui Fan, Emily Farr, Sara Frederick, Logan Fries, Peter Frinchaboy, Boris T. Gänsicke, Junqiang Ge, Consuelo González Ávila, Katie Grabowski, Catherine Grier, Guillaume Guiglion, Pramod Gupta, Patrick Hall, Keith Hawkins, Christian R. Hayes, J. J. Hermes, Lorena Hernández-García, David W. Hogg, Jon A. Holtzman, Hector Javier Ibarra-Medel, Alexander Ji, Paula Jofre, Jennifer A. Johnson, Amy M. Jones, Karen Kinemuchi, Matthias Kluge, Anton Koekemoer, Juna A. Kollmeier, Marina Kounkel, Dhanesh Krishnarao, Mirko Krumpe, Ivan Lacerna, Paulo Jakson Assuncao Lago, Chervin Laporte, Chao Liu, Ang Liu, Xin Liu, Alexandre Roman Lopes, Matin Macktoobian, Steven R. Majewski, Viktor Malanushenko, Dan Maoz, Thomas Masseron, Karen L. Masters, Gal Matijevic, Aidan McBride, Ilija Medan, Andrea Merloni, Sean Morrison, Natalie Myers, Szabolcs Mészáros, C. Alenka Negrete, David L. Nidever, Christian Nitschelm, Daniel Oravetz, Audrey Oravetz, Kaike Pan, Yingjie Peng, Marc H. Pinsonneault, Rick Pogge, Dan Qiu, Solange V. Ramirez, Hans-Walter Rix, Daniela Fernández Rosso, Jessie Runnoe, Mara Salvato, Sebastian F. Sanchez, Felipe A. Santana, Andrew Saydjari, Conor Sayres, Kevin C. Schlaufman, Donald P. Schneider, Axel Schwope, Javier Serna, Yue Shen, Jennifer Sobeck, Ying-Yi Song, Diogo Souto, Taylor Spoo, Keivan G. Stassun, Matthias Steinmetz, Ilya Straumit, Guy Stringfellow, José Sánchez-Gallego, Manuchehr Taghizadeh-Popp, Jamie Tayar, Ani Thakar, Patricia B. Tissera, Andrew Tkachenko, Hector Hernandez Toledo, Benny Trakhtenbrot, José G. Fernández-Trincado, Nicholas Troup, Jonathan R. Trump, Sarah Tuttle, Natalie Ulloa, Jose Antonio Vazquez-Mata, Pablo Vera Alfaro, Sandro Villanova, Stefanie Wachter, Anne-Marie Weijmans, Adam Wheeler, John Wilson, Leigh Wojno, Julien Wolf, Xiang-Xiang Xue, Jason E. Ybarra, Eleonora Zari, and Gail Zasowski
Subjects: Surveys, Astronomy databases, Astronomy data acquisition, Astronomy software, Astrophysics, QB460-466
Abstract: The eighteenth data release (DR18) of the Sloan Digital Sky Survey (SDSS) is the first one for SDSS-V, the fifth generation of the survey. SDSS-V comprises three primary scientific programs or “Mappers”: the Milky Way Mapper (MWM), the Black Hole Mapper (BHM), and the Local Volume Mapper. This data release contains extensive targeting information for the two multiobject spectroscopy programs (MWM and BHM), including input catalogs and selection functions for their numerous scientific objectives. We describe the production of the targeting databases and their calibration and scientifically focused components. DR18 also includes ∼25,000 new SDSS spectra and supplemental information for X-ray sources identified by eROSITA in its eFEDS field. We present updates to some of the SDSS software pipelines and preview changes anticipated for DR19. We also describe three value-added catalogs (VACs) based on SDSS-IV data that have been published since DR17, and one VAC based on the SDSS-V data in the eFEDS field.
Published: 2023
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4. A strong He II $λ$1640 emitter with extremely blue UV spectral slope at $z=8.16$: presence of Pop III stars?

Author: Xin Wang, Cheng Cheng, Junqiang Ge, Xiao-Lei Meng, Emanuele Daddi, Haojing Yan, Tucker Jones, Matthew Malkan, Pablo Arrabal Haro, Gabriel Brammer, and Masamune Oguri
Subjects: Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences
Abstract: Cosmic hydrogen reionization and cosmic production of first metals are major phase transitions of the Universe occurring during the first billion years after the Big Bang, but still poorly explored observationally. Using the JWST NIRSpec prism spectroscopy, we report the discovery of a sub-$L_{\ast}$ galaxy at $z_{\rm spec}=8.1623_{-0.0008}^{+0.0007}$, dubbed RXJ2129-z8HeII, via the detection of a series of strong rest-frame UV/optical nebular emission lines and the clear Lyman break. A strong He II $λ$1640 emission is present, the highest redshift He II line currently known. Its high rest-frame equivalent width (EW $=19.4\pm3.2$ Angstrom) and extreme flux ratios with respect to UV metal lines and Balmer lines raise the possibility that part of RXJ2129-z8HeII's stellar populations could be Pop III-like. RXJ2129-z8HeII also shows a pronounced UV continuum with an extremely steep (i.e. blue) spectral slope of $β=-2.50\pm0.08$, the steepest amongst all spectroscopically confirmed galaxies at $z\gtrsim7$, in support of its very hard ionizing spectrum that could lead to a significant leakage of its ionizing flux. Therefore, RXJ2129-z8HeII is representative of the key galaxy population driving the cosmic reionization. To date, this is also the most compelling case where trace Pop III stars might coexist with more metal-enriched stars., Submitted
Published: 2022
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5. 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
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6. SDSS-IV MaNGA: Stellar M/L gradients and the M/L-colour relation in galaxies

Author: Michele Cappellari, Shude Mao, Renbin Yan, Junqiang Ge, Youjun Lu, and Richard J. Long
Subjects: Physics, Initial mass function, Stellar mass, 010308 nuclear & particles physics, Star formation, Metallicity, Diagram, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Galaxy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Nabla symbol, 10. No inequality, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: The stellar mass-to-light ratio gradient in SDSS $r-$band $\nabla (M_*/L_r)$ of a galaxy depends on its mass assembly history, which is imprinted in its morphology and gradients of age, metallicity, and stellar initial mass function (IMF). Taking a MaNGA sample of 2051 galaxies with stellar masses ranging from $10^9$ to $10^{12}M_\odot$ released in SDSS DR15, we focus on face-on galaxies, without merger and bar signatures, and investigate the dependence of the 2D $\nabla (M_*/L_r)$ on other galaxy properties, including $M_*/L_r$-colour relationships by assuming a fixed Salpeter IMF as the mass normalization reference. The median gradient is $\nabla M_*/L_r\sim -0.1$ (i.e., the $M_*/L_r$ is larger at the centre) for massive galaxies, becomes flat around $M_*\sim 10^{10} M_{\odot}$ and change sign to $\nabla M_*/L_r\sim 0.1$ at the lowest masses. The $M_*/L_r$ inside a half light radius increases with increasing galaxy stellar mass; in each mass bin, early-type galaxies have the highest value, while pure-disk late-type galaxies have the smallest. Correlation analyses suggest that the mass-weighted stellar age is the dominant parameter influencing the $M_*/L_r$ profile, since a luminosity-weighted age is easily affected by star formation when the specific star formation rate (sSFR) inside the half light radius is higher than $10^{-3} {\rm Gyr}^{-1}$. With increased sSFR gradient, one can obtain a steeper negative $\nabla (M_*/L_r)$. The scatter in the slopes of $M_*/L$-colour relations increases with increasing sSFR, for example, the slope for post-starburst galaxies can be flattened to $0.45$ from the global value $0.87$ in the $M_*/L$ vs. $g-r$ diagram. Hence converting galaxy colours to $M_*/L$ should be done carefully, especially for those galaxies with young luminosity-weighted stellar ages, which can have quite different star formation histories., Comment: 12 pages, 10 figures. Accepted for publication in MNRAS
Published: 2021
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7. Recovering stellar population parameters via different population models and stellar libraries

Author: Youjun Lu, Michele Cappellari, Shude Mao, Renbin Yan, and Junqiang Ge
Subjects: Physics, Initial mass function, Stellar population, 010308 nuclear & particles physics, Metallicity, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Spectral line, Galaxy, Stars, Population model, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010303 astronomy & astrophysics, Stellar evolution
Abstract: Three basic ingredients are required to generate a simple stellar population (SSP) library, i.e., an initial mass function (IMF), a stellar evolution model/isochrones, and an empirical/theoretical stellar spectral library. However, there are still some uncertainties to the determination and understanding of these ingredients. We perform the spectral fitting to test the relative parameter offsets between these uncertainties using two different stellar population models, two different empirical stellar libraries, two different isochrones, and the Salpeter and Chabrier IMFs. Based on these setups, we select five SSP libraries generated with the Galaxev/STELIB and Vazdekis/MILES models, and apply them to the pPXF full-spectrum fitting of both MaNGA and mock spectra. We find that: 1) Compared to the Galaxev/STELIB model, spectral fitting qualities with the Vazdekis/MILES model have significant improvements for those metal-rich (especially over-solar) spectra, which cause better reduced $\chi^2$ distributions and more precisely fitted absorption lines. This might due to the lack of metal rich stars in the empirical STELIB library, or code improvement of the Vazdekis model. 2) When applying the Vazdekis/MILES model for spectral fitting, the IMF variation will lead to not only a systematic offset in $M_*/L_r$, but also offsets in age and metallicity, and these offsets increase with increasing stellar population ages. However, the IMF-variation caused metallicity offsets disappear in the case of Galaxev/STELIB based libraries. 3) The Padova2000 model provides a better match to the MaNGA galaxy spectra at [M/H]$_L-1.0$. Current tests suggest that spectral fitting with the Vazdekis/MILES+BaSTI combination would be a better choice for local galaxies., Comment: 19 pages, 17 figures, accepted for publication in MNRAS
Published: 2019
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8. Variation of Broad Emission Lines from QSOs with Optical/UV Periodicity to Test the Interpretation of Supermassive Binary Black Holes

Author: Zihao Song, Junqiang Ge, Chang-Shuo Yan, Xiang Ji, and Youjun Lu
Subjects: QSOS, Physics, 010504 meteorology & atmospheric sciences, Continuum (design consultancy), FOS: Physical sciences, Astronomy and Astrophysics, Quasar, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Black hole, Binary black hole, Space and Planetary Science, Position (vector), Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Emission spectrum, Circumbinary planet, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Periodic quasars have been suggested to host supermassive binary black holes (BBHs) in their centers, and their optical/UV periodicities are interpreted as caused by either the Doppler-boosting (DB) effect of continuum emission from the disk around the secondary black hole (BH) or intrinsic accretion rate variation. However, no other definitive evidence has been found to confirm such a BBH interpretation(s). In this paper, we investigate the responses of broad emission lines (BELs) to the continuum variations for these quasars under two BBH scenarios, and check whether they can be distinguished from each other and from that of a single BH system. We assume a simple circumbinary broad-line region (BLR) model, compatible with BLR size estimates, with a standard $\Gamma$ distribution of BLR clouds. We find that BELs may change significantly and periodically under the BBH scenarios due to (1) the position variation of the secondary BH and (2) the DB effect, if significant, and/or intrinsic variation, which is significantly different from the case of a single BH system. For the two BBH scenarios, the responses of BELs to (apparent) continuum variations, caused by the DB effect or intrinsic rate variation, are also significantly different from each other, mainly because the DB effect has a preferred direction along the direction of motion of the secondary BH, while that due to intrinsic variation does not. Such differences in the responses of BELs from different scenarios may offer a robust way to distinguish different interpretations of periodic quasars and to identify BBHs, if any, in these systems., Comment: 16 pages, 13 figures, accepted for publication in ApJ
Published: 2021

9. Variations of Broad Emission Lines from periodicity QSOs under the interpretation of supermassive binary black holes with misaligned circumbinary broad line regions

Author: Junqiang Ge, Youjun Lu, Xiang Ji, and Chang-Shuo Yan
Subjects: Physics, Orbital plane, Astrophysics::High Energy Astrophysical Phenomena, Continuum (design consultancy), Computer Science::Neural and Evolutionary Computation, FOS: Physical sciences, Astronomy and Astrophysics, Quasar, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Mass ratio, Light curve, Astrophysics - Astrophysics of Galaxies, Black hole, Binary black hole, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Circumbinary planet
Abstract: Quasars with periodic light curves are considered as candidates of supermassive binary black hole (BBH) systems. One way for further confirmations may be searching for other characteristic signatures, such as those in their broad emission lines (BELs), if any, which require a thorough understanding on the response of BELs to the BBH systems. In Ji et al. (2021), we have investigated the response of circumbinary broad line region (BLR) to the central active secondary black hole under the relativistic Doppler boosting (BBH-DB) and intrinsic variation (BBH-IntDB) dominant mechanisms for continuum variation by assuming the middle plane of the BLR aligned with the BBH orbital plane. In this paper, we explore how the BEL profiles vary when the BLR is misaligned from the BBH orbital plane with different offset angles under both the BBH-DB and BBH-IntDB scenarios. Given a fixed inclination angle of the BBH orbital plane viewed in edge-on and similar continuum light curves produced by the two scenarios, increasing offset angles make the initial opening angle of the circumbinary BLR enlarged due to orbital precession caused by the BBH system, especially for clouds in the inner region, which result in Lorentz-like BEL profiles for the BBH-DB model but still Gaussian-like profiles for the BBH-IntDB model at the vertical BLR case. The amplitude of profile variations decrease with increasing offset angles for the BBH-DB scenario, while keep nearly constant for the BBH-IntDB scenario, since the Doppler boosting effect is motion direction preferred but the intrinsic variation is radiated isotropically. If the circumbinary BLR is composed of a coplanar and a vertical components with their number of clouds following the mass ratio of the BBHs, then the bi-BLR features are more significant for the BBH-IntDB model that require larger mass ratio to generate similar continuum variation than the BBH-DB model., Comment: Published in RAA, 13 pages, 10 figures
Published: 2021
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10. 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
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11. SDSS-IV MaNGA: Stellar population correlates with stellar root-mean-square velocity $V_{\rm rms}$ gradients or total-density-profile slopes at fixed effective velocity dispersion $\sigma_{\rm e}$

Author: Junqiang Ge, Michele Cappellari, Ran Li, Shude Mao, and S. L. Lu
Subjects: Physics, Stellar population, Metallicity, Velocity dispersion, Sigma, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Space and Planetary Science, Bulge, Galaxy formation and evolution, Spectroscopy, Astrophysics::Galaxy Astrophysics
Abstract: Galaxy properties are known to correlate most tightly with the galaxy effective stellar velocity dispersion $\sigma_{\rm e}$. Here we look for {\em additional} trends at fixed $\sigma_{\rm e}$ using 1339 galaxies ($M_\ast \gtrsim 6\times10^9$ M$_\odot$) with different morphologies in the MaNGA (DR14) sample with integral-field spectroscopy data. We focus on the gradients ($\gamma_{\rm rms} \equiv \sigma(R_{\rm e}/4)/\sigma_{\rm e}$) of the stellar root-mean-square velocity ($V_{\rm rms} \equiv \sqrt{V^2 + \sigma^2}$), which we show traces the total mass density gradient $\gamma_{\rm tot}$ derived from dynamical models and, more weakly, the bulge fraction. We confirm that $\gamma_{\rm rms}$ increases with $\sigma_{\rm e}$, age and metallicity. We additionally find that these correlations still exist at fixed $\sigma_{\rm e}$, where galaxies with larger $\gamma_{\rm rms}$ are found to be older and more metal-rich. It means that mass density gradients contain information of the stellar population which is not fully accounted for by $\sigma_{\rm e}$. This result puts an extra constraint on our understanding of galaxy quenching. We compare our results with galaxies in the IllustrisTNG hydrodynamical simulations and find that, at fixed $\sigma_{\rm e}$, similar trends exist with age, the bulge fraction, and the total mass density slope but, unlike observations, no correlation with metallicity can be detected in the simulations., Comment: 8 pages, 6 figures; Accepted for publication in MNRAS
Published: 2020

12. Galaxy Optical Variability of Virgo Cluster: New Tracer for Environmental Influences on Galaxies

Author: Jifeng Liu, Fan Yang, Rui Guo, Jing-Hua Gao, Bo Zhang, Junqiang Ge, Su-Su Shan, Xiang Ji, and Richard J. Long
Subjects: Physics, Brightness, Mean value, Monte Carlo method, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Virgo Cluster, Standard deviation, Galaxy, Space and Planetary Science, TRACER, Astrophysics of Galaxies (astro-ph.GA), Cluster (physics), Astrophysics::Galaxy Astrophysics
Abstract: We investigate the relationship between the optical variability of galaxies and their distances from the centre of the Virgo Cluster using Palomar Transient Factory data. We define the ratio between the standard deviation of the galaxy brightness and the mean value of the standard deviation as a measure of a galaxy's optical variability. A sample of 814 Virgo galaxies with 230263 observations shows a monotonically decreasing trend of optical variability with increasing clustercentric distance. The variability level inside the cluster is 3.2$\sigma$ higher than the level outside. We fit the variability with a linear function and find that the data reject a distance-independent model. We examine 217 background galaxies for comparison and find no significant trend in galaxy variability. We assess the relation with Monte Carlo simulation by rebuilding the brightness of each galaxy. The simulation shows a monotonically decreasing relation for member galaxy variability and a distance-independent relation for background galaxies. Our result is consistent with the theory that the cold gas flowing inwards the cluster centre fuels AGN activity. This work is a new implementation of the method using optical variability to investigate the relation between galaxies evolution and their environment., Comment: 5 pages, 4 figures, in Press (accepted by MNRAS Letters)
Published: 2020
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13. Host galaxy properties of changing-look AGNs revealed in the MaNGA survey

Author: Longji Bing, Rogemar A. Riffel, Junqiang Ge, Yanmei Chen, Rogério Riffel, Yong Shi, Xiaoling Yu, Songlin Li, and Jianhang Chen
Subjects: Angular momentum, Seyfert [Galaxies], Active galactic nucleus, active [Galaxies], Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Type (model theory), 01 natural sciences, symbols.namesake, 0103 physical sciences, Evolucao galatica, Emission spectrum, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, education.field_of_study, 010308 nuclear & particles physics, Star formation, kinematics and dynamics [Galaxies], Balmer series, Astronomy and Astrophysics, evolution [Galaxies], Astrophysics - Astrophysics of Galaxies, Galaxy, Galaxias seyfert, Galáxias ativas, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), nuclei [Galaxies], symbols, Cinemática estelar, Nucleo galatico
Abstract: Changing-look Active Galactic Nuclei (CL-AGNs) are a subset of AGNs in which the broad Balmer emission lines appear or disappear within a few years. We use the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey to identify five CL-AGNs. The 2-D photometric and kinematic maps reveal common features as well as some unusual properties of CL-AGN hosts as compared to the AGN hosts in general. All MaNGA CL-AGNs reside in the star-forming main sequence, similar to MaNGA non-changing-look AGNs (NCL-AGNs). The $80\% \pm 16\%$ of our CL-AGNs do possess pseudo-bulge features, and follow the overall NCL-AGNs $M_{BH}-\sigma_{*}$ relationship. The kinematic measurements indicate that they have similar distributions in the plane of angular momentum versus galaxy ellipticity. MaNGA CL-AGNs however show a higher, but not statistically significant ($20\% \pm 16\%$) fraction of counter-rotating features compared to that ($1.84\% \pm 0.61\%$) in general star-formation population. In addition, MaNGA CL-AGNs favor more face-on (axis ratio $>$ 0.7) than that of Type I NCL-AGNs. These results suggest that host galaxies could play a role in the CL-AGN phenomenon., Comment: 11 pages, 4 tables, 4 figures. Accepted for publication in MNRAS
Published: 2020

14. Peer-Assisted Video Streaming With RTMFP Flash Player: A Measurement Study on PPTV

Author: Ye Tian, Junqiang Ge, Shan Zou, and Qiang Wang
Subjects: Multimedia, Computer science, computer.internet_protocol, Network packet, Transmission Control Protocol, business.industry, Retransmission, 020206 networking & telecommunications, 02 engineering and technology, Service-oriented architecture, computer.software_genre, Network congestion, Server, 0202 electrical engineering, electronic engineering, information engineering, Media Technology, 020201 artificial intelligence & image processing, Real Time Streaming Protocol, Electrical and Electronic Engineering, business, computer, Internet video, Computer network
Abstract: Real-time media flow protocol (RTMFP) is a protocol developed by Adobe for multimedia delivery under both client–server and peer-to-peer (P2P) paradigms. Currently, major Internet video service providers, such as PPTV and iQIYI, have already built their Web-based video streaming systems with RTMFP. In such a system, a user only needs to install a Flash Player plug-in on his Web browser, and can stream videos in a peer-assisted way. Despite its wide usage, RTMFP has received little attention from the measurement community. In this paper, we select PPTV as an example and study the RTMFP video streaming technology with a measurement approach. We reveal the architecture of PPTV’s RTMFP streaming system and show that, compared with proprietary P2P networks, the RTMFP network has a different content distribution policy, and exhibits different features on peers’ streaming behaviors, potential system bottleneck, and network dynamics. We also study RTMFP’s video transmission and find that the protocol’s selective retransmission scheme can effectively overcome packet losses and improve the video playback quality; however, the TCP-like congestion control mechanism of RTMFP does not lead to fairness between RTMFP and Transmission Control Protocol (TCP) traffics, due to the mismatch between the inherited pull-based video segment distribution model of the P2P streaming application and the protocol’s built-in congestion control mechanism. This paper provides insights into the RTMFP-based video streaming technology and is helpful for people to construct better peer-assisted video systems with RTMFP.
Published: 2018
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15. A biological cleaning agent for removing mold stains from paper artifacts

Author: Qingxia Meng, Xianchao Li, Junqiang Geng, Chenshu Liu, and Songbin Ben
Subjects: Paper artifacts, Mold stains, Bioenzymes, Biosurfactants, Cleaning agent, Fine Arts, Analytical chemistry, QD71-142
Abstract: Abstract Efficient removal of mold stains becomes an important research topic for paper conservation. In this study, a cleaning scheme based on the combination of bioenzymes and biosurfactants was explored. Morphological and molecular biology identifications were first jointly applied to identify the dominant strains sampled from five ancient books that are stored in the same environment. Cellulolytic experiments were then conducted to evaluate the cellulose degradation ability of the strains according to the cellulolytic digestive index. Finally, paper Mockups for the ancient books were constructed to investigate the most effective combination of bioenzymes and biosurfactants in removing mold stains as well as its effect on the paper’s physical properties. The result concluded that the combination of 3% papain, 7% of sophorolipid or 7% of betaine, and distilled water, achieved optimal stain removal effect with over 50% cleaning rate at 35 °C, after 30 min of infiltration. The maximum color difference of the paper material after cleaning was around 0.60, pH was between 7.45 and 7.79, and no significant changes in tensile strength were observed. At the same time, Sophorolipid and Betaine both have superior deacidification, anti-acidification, anti-aging, and reinforcement capabilities, which can provide extra support to the fibrous structure in addition to cleaning the paper materials. The microbial contamination cleaning agent proposed in this study shows promising application prospects in conserving mold-contaminated paper artifacts.
Published: 2023
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16. SDSS-IV MaNGA: pattern speeds of barred galaxies

Author: Michael R. Merrifield, Junqiang Ge, Shude Mao, Hongyu Li, E. Athanassoula, Karen L. Masters, Rui Guo, R. J. Long, Lanzhou University, 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), and Wuhan University [China]
Subjects: Stellar population, Bar (music), Metallicity, astro-ph.GA, Dark matter, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galaxies: structure, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Galaxies: kinematics and dynamics, Galaxies: evolution, Astronomy and Astrophysics, Radius, Position angle, Astrophysics - Astrophysics of Galaxies, Galaxy, Barred spiral galaxy, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA]
Abstract: The MaNGA project has obtained IFU data for several thousand nearby galaxies, including barred galaxies. With the two dimensional spectral and kinematic information provided by IFUs, we can measure the pattern speed of a barred galaxy, which determines the bar dynamics. We apply the non-parametric method proposed by Tremaine \& Weinberg to estimate the bar pattern speed for 53 barred galaxies, making this the largest sample studied so far in this way. Our sample is selected from the MaNGA first public data release as part of SDSS Data Release 13 according mainly to the axis ratio and position angle difference between the bar and disc, while kinematic data is from the later SDSS Data Release 14. We have used both the photometric position angle from the photometric image and the kinematic position angle from the stellar velocity map to derive the pattern speed. Combining three independent bar length measurements and the circular velocity from Jeans Anisotropic modelling (JAM), we also determine the dimensionless ratio $\cal{R}$ of the corotation radius to the bar length. We find that the galaxy's position angle is the main uncertainty in determining the bar pattern speed. The kinematic position angle leads to fewer ultrafast bars than the photometric position angle, and this could be due to the method of measuring the kinematic position angle. We study the dependence of $\cal{R}$ values on galaxy properties such as the dark matter fraction from JAM modelling and the stellar age and metallicity from stellar population synthesis (SPS). A positive correlation between the bar length and bar strength is found: the longer the bar, the stronger the bar. However, no other significant correlations are found. This may result from errors in deriving the $\cal{R}$ values or from the complex formation and slowdown processes of galactic bars., 27 pages, 21 figures. Accepted for publication in MNRAS
Published: 2019
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17. Redshift Evolution of the Fundamental Plane Relation in the IllustrisTNG Simulation

Author: Yunchong Wang, Shude Mao, Volker Springel, Yuan Wang, Dandan Xu, Junqiang Ge, Jill Naiman, Lars Hernquist, Mark Vogelsberger, and S. L. Lu
Subjects: Physics, Dark matter, FOS: Physical sciences, Velocity dispersion, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Redshift, Galaxy, Gravitational constant, Baryon, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Galaxy formation and evolution, Fundamental plane (elliptical galaxies)
Abstract: We investigate the fundamental plane (FP) evolution of early-type galaxies in the IllustrisTNG-100 simulation (TNG100) from redshift $z=0$ to $z=2$. We find that a tight plane relation already exists as early as $z=2$. Its scatter stays as low as $\sim 0.08$ dex across this redshift range. Both slope parameters $b$ and $c$ (where $R \propto \sigma^b I^c$ with $R$, $\sigma$, and $I$ being the typical size, velocity dispersion, and surface brightness) of the plane evolve mildly since $z=2$, roughly consistent with observations. The FP residual $\rm Res$ ($\equiv\,a\,+\,b\log \sigma\,+\,c\log I\,-\,\log R$, where $a$ is the zero point of the FP) is found to strongly correlate with stellar age, indicating that stellar age can be used as a crucial fourth parameter of the FP. However, we find that $4c+b+2=\delta$, where $\delta \sim 0.8$ for FPs in TNG, rather than zero as is typically inferred from observations. This implies that a tight power-law relation between the dynamical mass-to-light ratio $M_{\rm dyn}/L$ and the dynamical mass $M_{\rm dyn}$ (where $M_{\rm dyn}\equiv 5\sigma^2R/G$, with $G$ being the gravitational constant) is not present in the TNG100 simulation. Recovering such a relation requires proper mixing between dark matter and baryons, as well as star formation occurring with correct efficiencies at the right mass scales. This represents a powerful constraint on the numerical models, which has to be satisfied in future hydrodynamical simulations., Comment: 10 pages, 7 figures, 1 table. Accepted for publication in MNRAS
Published: 2019

18. SDSS--IV MaNGA : The Inner Density Slopes of nearby galaxies

Author: Yunchong Wang, Joel R. Brownstein, Ran Li, Hongyu Li, S. L. Lu, Liang Gao, Aaron A. Dutton, Shi Shao, Zheng Zheng, Shude Mao, Kai Zhu, Junqiang Ge, Alexie Leauthaud, Chunxiang Wang, and Kevin Bundy
Subjects: Physics, Cold dark matter, Stellar mass, 010308 nuclear & particles physics, Velocity dispersion, FOS: Physical sciences, Astronomy and Astrophysics, Radius, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Amplitude, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Satellite galaxy, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Dwarf galaxy
Abstract: We derive the mass weighted total density slopes within the effective (half-light) radius, $\gamma'$, for more than 2000 nearby galaxies from the SDSS-IV MaNGA survey using Jeans-anisotropic-models applied to IFU observations. Our galaxies span a wide range of the stellar mass ($10^9$ $M_{\rm \odot}< M_* < 10^{12}$ M$_{\odot}$) and the velocity dispersion (30 km/s $< \sigma_v 100$ km/s, the density slope has a mean value $\langle \gamma^{\prime} \rangle = 2.24$ and a dispersion $\sigma_{\gamma}=0.22$, almost independent of velocity dispersion. A clear turn over in the $\gamma'-\sigma_v$ relation is present at $\sigma\sim 100$ km/s, below which the density slope decreases rapidly with $\sigma_v$. Our analysis shows that a large fraction of dwarf galaxies (below $M_* = 10^{10}$ M$_{\odot}$) have total density slopes shallower than 1, which implies that they may reside in cold dark matter halos with shallow density slopes. We compare our results with that of galaxies in hydrodynamical simulations of EAGLE, Illustris and IllustrisTNG projects, and find all simulations predict shallower density slopes for massive galaxies with high $\sigma_v$. Finally, we explore the dependence of $\gamma'$ on the positions of galaxies in halos, namely centrals vs. satellites, and find that for the same velocity dispersion, the amplitude of $\gamma'$ is higher for satellite galaxies by about 0.1., Comment: 11 pages, 10 figures, submitted to MNRAS
Published: 2019
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19. Testing the relativistic Doppler boost hypothesis for supermassive binary black holes candidates via broad emission line profiles

Author: Zihao Song, Junqiang Ge, Youjun Lu, and Xiang Ji
Subjects: QSOS, Physics, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, symbols.namesake, Secondary component, Binary black hole, Accretion disc, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, symbols, Emission spectrum, 010303 astronomy & astrophysics, Doppler effect
Abstract: Optical periodicity QSOs found by transient surveys are suggested to be sub-parsec supermassive binary black holes (BBHs). An intriguing interpretation for the periodicity of some of those QSOs is that the continuum is radiated from the accretion disk associated with the BBH secondary component and modulated by the periodical rotation of the secondary via Doppler-boost effect. Close to edge-on orbital orientation can lead to more significant Doppler-boost effect and thus are preferred for these systems, which is distinct from those normal type-1 QSOs with more or less face-on orientations. Therefore, the profiles of broad lines emitted from these Doppler-modulated systems may be significantly different from other systems that are not Doppler-modulated. We investigate the properties of the broad emission lines of optical-periodicity QSOs, including both a sample of QSOs that can be interpreted by the Doppler-modulated effects and a sample that cannot. We find that there is no obvious difference in the profiles and other properties of various (stacked) broad emission lines of these two samples, though a simple broad line region model would suggest significant differences. Our finding raises a challenge to the Doppler boost hypothesis for some of those BBHs candidates with optical periodicity., Comment: Accepted for publication in MNRAS, 9 pages, 7 figures
Published: 2019
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20. Broad-line region configuration of the supermassive binary black hole candidate PG1302-102 in the relativistic Doppler boosting scenario

Author: Chang-Shuo Yan, Xiang Ji, Junqiang Ge, Zihao Song, and Youjun Lu
Subjects: Physics, Boosting (machine learning), Orbital plane, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Gaussian, FOS: Physical sciences, Astronomy and Astrophysics, Markov chain Monte Carlo, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, symbols.namesake, Binary black hole, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Orbital motion, symbols, Emission spectrum, 010303 astronomy & astrophysics, Doppler effect, Astrophysics::Galaxy Astrophysics
Abstract: PG1302-102 is thought to be a supermassive binary black hole (BBH) system according to the periodical variations of its optical and UV photometry, which may be interpreted as being due to the relativistic Doppler boosting of the emission mainly from the disk around the secondary black hole (BH) modulated by its orbital motion. In this paper, we investigate several broad emission lines of PG1302-102 using archived UV spectra obtained by IUE, GALEX, and Hubble, to reveal the broad-line region (BLR) emission properties of this BBH system under the Doppler boosting scenario. We find that the broad lines Ly$\alpha$, NV, CIV, and CIII] all show Gaussian profiles, and none of these lines exhibits obvious periodical variation. Adopting a simple model for the BLR, we perform Markov chain Monte Carlo fittings to these broad lines, and find that the BLR must be viewed at an orientation angle of $\sim33^{\circ}$, close to face-on. If the Doppler boosting interpretation is correct, then the BLR is misaligned with the BBH orbital plane by an angle of $\sim51^\circ$, which suggests that the Doppler boosted continuum variation has little effect on the broad-line emission and thus does not lead to periodical line variation. We further discuss the possible implications for such a BLR configuration with respect to the BBH orbital plane., Comment: 9 pages, 6 figures, matches A&A version (only minor changes)
Published: 2020
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21. SDSS-IV MaNGA:global stellar population and gradients for about 2000 early-type and spiral galaxies on the mass-size plane

Author: Zheng Zheng, David R. Law, Niv Drory, Ran Li, R. J. Long, Daniel Thomas, Michele Cappellari, Shude Mao, Houjun Mo, Kevin Bundy, Hongyu Li, Joel R. Brownstein, Alexandre Roman Lopes, Cheng Li, and Junqiang Ge
Subjects: Stellar kinematics, Stellar population, formation [galaxies], Metallicity, astro-ph.GA, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Virial theorem, Bulge, 0103 physical sciences, kinematics and dynamics [galaxies], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, evolution [galaxies], Physics, Spiral galaxy, 010308 nuclear & particles physics, Velocity dispersion, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), structure [galaxies]
Abstract: We perform full spectrum fitting stellar population analysis and Jeans Anisotropic modelling (JAM) of the stellar kinematics for about 2000 early-type galaxies (ETGs) and spiral galaxies from the MaNGA DR14 sample. Galaxies with different morphologies are found to be located on a remarkably tight mass plane which is close to the prediction of the virial theorem, extending previous results for ETGs. By examining an inclined projection (`the mass-size' plane), we find that spiral and early-type galaxies occupy different regions on the plane, and their stellar population properties (i.e. age, metallicity and stellar mass-to-light ratio) vary systematically along roughly the direction of velocity dispersion, which is a proxy for the bulge fraction. Galaxies with higher velocity dispersions have typically older ages, larger stellar mass-to-light ratios and are more metal rich, which indicates that galaxies increase their bulge fractions as their stellar populations age and become enriched chemically. The age and stellar mass-to-light ratio gradients for low-mass galaxies in our sample tend to be positive ($\rm centre, Comment: Accepted for publication in MNRAS
Published: 2018
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22. SDSS-IV MaNGA: A Distinct Mass Distribution Explored in Slow-Rotating Early-type Galaxies

Author: Liang Gao, Ran Li, José G. Fernández-Trincado, Hongyu Li, Jun Pan, Yu Rong, Jie Wang, Octavio Valenzuela, Yingjie Jing, Junqiang Ge, Erik Aquino Ortiz, 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), 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, Mass distribution, Spins, Dark matter, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxy merger, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Galaxy, Early type, Baryon, Acceleration, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Physics::Accelerator Physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010306 general physics, 10. No inequality, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics
Abstract: We study the radial acceleration relation (RAR) for early-type galaxies (ETGs) in the SDSS MaNGA MPL5 dataset. The complete ETG sample show a slightly offset RAR from the relation reported by McGaugh et al. (2016) at the low-acceleration end; we find that the deviation is due to the fact that the slow rotators show a systematically higher acceleration relation than the McGaugh's RAR, while the fast rotators show a consistent acceleration relation to McGaugh's RAR. There is a 1\sigma significant difference between the acceleration relations of the fast and slow rotators, suggesting that the acceleration relation correlates with the galactic spins, and that the slow rotators may have a different mass distribution compared with fast rotators and late-type galaxies. We suspect that the acceleration relation deviation of slow rotators may be attributed to more galaxy merger events, which would disrupt the original spins and correlated distributions of baryons and dark matter orbits in galaxies., Comment: Revised to match the publication version
Published: 2017

23. SDSS-IV MaNGA: probing the kinematic morphology–density relation of early-type galaxies with MaNGA

Author: R. Yan, A. Leauthaud, Eric Emsellem, Yen-Ting Lin, Johnny P. Greco, Brett H. Andrews, Michael R. Merrifield, David R. Law, Daniel Thomas, Jenny E. Greene, J. Brinkman, Niv Drory, Karen L. Masters, David A. Wake, Donald P. Schneider, Daniel Goddard, Junqiang Ge, Surhud More, Joel R. Brownstein, and Nobuhiro Okabe
Subjects: Physics, Angular momentum, Stellar mass, groups: general [galaxies], 010308 nuclear & particles physics, astro-ph.GA, Astronomy and Astrophysics, Kinematics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galaxy, Early type, Large sample, Space and Planetary Science, Galaxy group, kinematics and dynamics [galaxies], 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Halo, 010303 astronomy & astrophysics, elliptical and lenticular, cD [galaxies], Astrophysics::Galaxy Astrophysics
Abstract: The "kinematic" morphology-density relation for early-type galaxies posits that those galaxies with low angular momentum are preferentially found in the highest-density regions of the universe. We use a large sample of galaxy groups with halo masses 1012.5 < Mhalo < 1014.5h-1 MΘ observed with the Mapping Nearby Galaxies at APO (MaNGA) survey to examine whether there is a correlation between local environment and rotational support that is independent of stellar mass. We find no compelling evidence for a relationship between the angular momentum content of early-type galaxies and either local overdensity or radial position within the group at fixed stellar mass.
Published: 2017
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24. SDSS-IV MaNGA: variation of the stellar initial mass function in spiral and early-type galaxies

Author: R. J. Long, Ran Li, Daniel Thomas, Michele Cappellari, Alexandre Roman Lopes, Cheng Li, Aaron A. Dutton, Kevin Bundy, Hongyu Li, Eric Emsellem, Niv Drory, Junqiang Ge, Shude Mao, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Initial mass function, Stellar population, formation [galaxies], astro-ph.GA, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, dark matter, 0103 physical sciences, kinematics and dynamics [galaxies], galaxies: formation, Variation (astronomy), Anisotropy, 010303 astronomy & astrophysics, Spiral, evolution [galaxies], galaxies: kinematics and dynamics, Astrophysics::Galaxy Astrophysics, Physics, Effective radius, Spiral galaxy, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), structure [galaxies], galaxies: structure, galaxies: evolution, uploaded-in-3-months-elsewhere
Abstract: We perform Jeans anisotropic modeling (JAM) on elliptical and spiral galaxies from the MaNGA DR13 sample. By comparing the stellar mass-to-light ratios estimated from stellar population synthesis (SPS) and from JAM, we find a similar systematic variation of the initial mass function (IMF) as in the earlier $\rm ATLAS^{3D}$ results. Early type galaxies (elliptical and lenticular) with lower velocity dispersions within one effective radius are consistent with a Chabrier-like IMF while galaxies with higher velocity dispersions are consistent with a more bottom heavy IMF such as the Salpeter IMF. Spiral galaxies have similar systematic IMF variations, but with slightly different slopes and larger scatters, due to the uncertainties caused by higher gas fractions and extinctions for these galaxies. Furthermore, we examine the effects of stellar mass-to-light ratio gradients on our JAM modeling, and find that the trends from our results becomes stronger after considering the gradients., Accepted for publication in ApJ. 9 pages, 9 figures
Published: 2017
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25. SDSS-IV MaNGA:Environmental dependence of stellar age and metallicity gradients in nearby galaxies

Author: Zheng Zheng, Niv Drory, Kevin Bundy, R. J. Long, David R. Law, Cheng Li, Lihwai Lin, Ran Li, Daniel Thomas, Huiyuan Wang, Joel R. Brownstein, Kai Zhang, Karen L. Masters, Rogério Riffel, Junqiang Ge, Daniel Goddard, P. Nair, Hongyu Li, Shude Mao, Houjun Mo, Alexandre Roman Lopes, Olena Malanushenko, and Dmitry Bizyaev
Subjects: Cosmology and Gravitation, Galaxies formation, astro-ph.GA, Surface brightness fluctuation, Metallicity, structure [Galaxies], FOS: Physical sciences, abundances [Galaxies], Astrophysics, Galaxies abundances, Astrophysics::Cosmology and Extragalactic Astrophysics, Metalicidade, 01 natural sciences, Peculiar galaxy, Formacao de galaxias, Populacoes estelares, statistics [Galaxies], Galaxy group, Galaxies statistics, 0103 physical sciences, Evolucao estelar, Disc, 010303 astronomy & astrophysics, Lenticular galaxy, Galaxy cluster, Astrophysics::Galaxy Astrophysics, Physics, Mapeamentos astronômicos, 010308 nuclear & particles physics, Galaxies structure, Astronomy, Galaxies stellar content, Astronomy and Astrophysics, evolution [Galaxies], Astrophysics - Astrophysics of Galaxies, formation [Galaxies], Galaxies evolution, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Elliptical galaxy, stellar content [Galaxies]
Abstract: We present a study on the stellar age and metallicity distributions for 1105 galaxies using the STARLIGHT software on MaNGA integral field spectra. We derive age and metallicity gradients by fitting straight lines to the radial profiles, and explore their correlations with total stellar mass M*, NUV-r colour and environments, as identified by both the large scale structure (LSS) type and the local density. We find that the mean age and metallicity gradients are close to zero but slightly negative, which is consistent with the inside-out formation scenario. Within our sample, we find that both the age and metallicity gradients show weak or no correlation with either the LSS type or local density environment. In addition, we also study the environmental dependence of age and metallicity values at the effective radii. The age and metallicity values are highly correlated with M* and NUV-r and are also dependent on LSS type as well as local density. Low-mass galaxies tend to be younger and have lower metallicity in low-density environments while high-mass galaxies are less affected by environment., 18 pages, 24 figures, accepted for publication in MNRAS
Published: 2017
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26. PHL 6625: A Minor Merger-Associated QSO Behind NGC 247

Author: Lian Tao, Hua Feng, Shude Mao, Xin Liu, Yue Shen, Luis C. Ho, Philip Kaaret, and Junqiang Ge
Subjects: 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, nuclei [galaxies], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxy merger, 01 natural sciences, 0103 physical sciences, Rare case, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Very Large Telescope, interactions [galaxies], supermassive black holes [quasars], Astronomy and Astrophysics, Quasar, Astrophysics - Astrophysics of Galaxies, Galaxy, Black hole, Gravitational lens, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), active [galaxies], Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: PHL 6625 is a luminous quasi-stellar object (QSO) at z = 0.3954 located behind the nearby galaxy NGC 247 (z = 0.0005). Hubble Space Telescope (HST) observations revealed an arc structure associated with it. We report on spectroscopic observations with the Very Large Telescope (VLT) and multiwavelength observations from the radio to the X-ray band for the system, suggesting that PHL 6625 and the arc are a close pair of merging galaxies, instead of a strong gravitational lens system. The QSO host galaxy is estimated to be (4-28) x 10^10 M_sun, and the mass of the companion galaxy of is estimated to be M_* = (6.8 +/- 2.4) x 10^9 M_sun, suggesting that this is a minor merger system. The QSO displays typical broad emission lines, from which a black hole mass of about (2-5) x 10^8 M_sun and an Eddington ratio of about 0.01-0.05 can be inferred. The system represents an interesting and rare case where a QSO is associated with an ongoing minor merger, analogous to Arp 142., Comment: ApJ to appear
Published: 2017
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27. The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory

Author: Franco D. Albareti, Carlos Allende Prieto, Andres Almeida, Friedrich Anders, Scott Anderson, Brett H. Andrews, Alfonso Aragón-Salamanca, Maria Argudo-Fernández, Eric Armengaud, Eric Aubourg, Vladimir Avila-Reese, Carles Badenes, Stephen Bailey, Beatriz Barbuy, Kat Barger, Jorge Barrera-Ballesteros, Curtis Bartosz, Sarbani Basu, Dominic Bates, Giuseppina Battaglia, Falk Baumgarten, Julien Baur, Julian Bautista, Timothy C. Beers, Francesco Belfiore, Matthew Bershady, Sara Bertran de Lis, Jonathan C. Bird, Dmitry Bizyaev, Guillermo A. Blanc, Michael Blanton, Michael Blomqvist, Adam S. Bolton, J. Borissova, Jo Bovy, William Nielsen Brandt, Jonathan Brinkmann, Joel R. Brownstein, Kevin Bundy, Etienne Burtin, Nicolás G. Busca, Hugo Orlando Camacho Chavez, M. Cano Díaz, Michele Cappellari, Ricardo Carrera, Yanping Chen, Brian Cherinka, Edmond Cheung, Cristina Chiappini, Drew Chojnowski, Chia-Hsun Chuang, Haeun Chung, Rafael Fernando Cirolini, Nicolas Clerc, Roger E. Cohen, Julia M. Comerford, Johan Comparat, Janaina Correa do Nascimento, Marie-Claude Cousinou, Kevin Covey, Jeffrey D. Crane, Rupert Croft, Katia Cunha, Jeremy Darling, James W. Davidson, Kyle Dawson, Luiz Da Costa, Gabriele Da Silva Ilha, Alice Deconto Machado, Timothée Delubac, Nathan De Lee, Axel De la Macorra, Sylvain De la Torre, Aleksandar M. Diamond-Stanic, John Donor, Juan Jose Downes, Niv Drory, Cheng Du, Hélion Du Mas des Bourboux, Tom Dwelly, Garrett Ebelke, Arthur Eigenbrot, Daniel J. Eisenstein, Yvonne P. Elsworth, Eric Emsellem, Michael Eracleous, Stephanie Escoffier, Michael L. Evans, Jesús Falcón-Barroso, Xiaohui Fan, Ginevra Favole, Emma Fernandez-Alvar, J. G. Fernandez-Trincado, Diane Feuillet, Scott W. Fleming, Andreu Font-Ribera, Gordon Freischlad, Peter Frinchaboy, Hai Fu, Yang Gao, Rafael A. Garcia, R. Garcia-Dias, D. A. Garcia-Hernández, Ana E. Garcia Pérez, Patrick Gaulme, Junqiang Ge, Douglas Geisler, Bruce Gillespie, Hector Gil Marin, Léo Girardi, Daniel Goddard, Yilen Gomez Maqueo Chew, Violeta Gonzalez-Perez, Kathleen Grabowski, Paul Green, Catherine J. Grier, Thomas Grier, Hong Guo, Julien Guy, Alex Hagen, Matt Hall, Paul Harding, R. E. Harley, Sten Hasselquist, Suzanne Hawley, Christian R. Hayes, Fred Hearty, Saskia Hekker, Hector Hernandez Toledo, Shirley Ho, David W. Hogg, Kelly Holley-Bockelmann, Jon A. Holtzman, Parker H. Holzer, Jian Hu, Daniel Huber, Timothy Alan Hutchinson, Ho Seong Hwang, Héctor J. Ibarra-Medel, Inese I. Ivans, KeShawn Ivory, Kurt Jaehnig, Trey W. Jensen, Jennifer A. Johnson, Amy Jones, Eric Jullo, T. Kallinger, Karen Kinemuchi, David Kirkby, Mark Klaene, Jean-Paul Kneib, Juna A. Kollmeier, Ivan Lacerna, Richard R. Lane, Dustin Lang, Pierre Laurent, David R. Law, Alexie Leauthaud, Jean-Marc Le Goff, Chen Li, Cheng Li, Niu Li, Ran Li, Fu-Heng Liang, Yu Liang, Marcos Lima, Lihwai Lin, Lin Lin, Yen-Ting Lin, Chao Liu, Dan Long, Sara Lucatello, Nicholas MacDonald, Chelsea L. MacLeod, J. Ted Mackereth, Suvrath Mahadevan, Marcio Antonio Geimba Maia, Roberto Maiolino, Steven R. Majewski, Olena Malanushenko, Viktor Malanushenko, Nícolas Dullius Mallmann, Arturo Manchado, Claudia Maraston, Rui Marques-Chaves, Inma Martinez Valpuesta, Karen L. Masters, Savita Mathur, Ian D. McGreer, Andrea Merloni, Michael R. Merrifield, Szabolcs Meszáros, Andres Meza, Andrea Miglio, Ivan Minchev, Karan Molaverdikhani, Antonio D. Montero-Dorta, Benoit Mosser, Demitri Muna, Adam Myers, Preethi Nair, Kirpal Nandra, Melissa Ness, Jeffrey A. Newman, Robert C. Nichol, David L. Nidever, Christian Nitschelm, Julia O’Connell, Audrey Oravetz, Daniel J. Oravetz, Zachary Pace, Nelson Padilla, Nathalie Palanque-Delabrouille, Kaike Pan, John Parejko, Isabelle Paris, Changbom Park, John A. Peacock, Sebastien Peirani, Marcos Pellejero-Ibanez, Samantha Penny, Will J. Percival, Jeffrey W. Percival, Ismael Perez-Fournon, Patrick Petitjean, Matthew Pieri, Marc H. Pinsonneault, Alice Pisani, Francisco Prada, Abhishek Prakash, Natalie Price-Jones, M. Jordan Raddick, Mubdi Rahman, Anand Raichoor, Sandro Barboza Rembold, A. M. Reyna, James Rich, Hannah Richstein, Jethro Ridl, Rogemar A. Riffel, Rogério Riffel, Hans-Walter Rix, Annie C. Robin, Constance M. Rockosi, Sergio Rodríguez-Torres, Thaíse S. Rodrigues, Natalie Roe, A. Roman Lopes, Carlos Román-Zúñiga, Ashley J. Ross, Graziano Rossi, John Ruan, Rossana Ruggeri, Jessie C. Runnoe, Salvador Salazar-Albornoz, Mara Salvato, Sebastian F. Sanchez, Ariel G. Sanchez, José R. Sanchez-Gallego, Basílio Xavier Santiago, Ricardo Schiavon, Jaderson S. Schimoia, Eddie Schlafly, David J. Schlegel, Donald P. Schneider, Ralph Schönrich, Mathias Schultheis, Axel Schwope, Hee-Jong Seo, Aldo Serenelli, Branimir Sesar, Zhengyi Shao, Matthew Shetrone, Michael Shull, Victor Silva Aguirre, M. F. Skrutskie, Anže Slosar, Michael Smith, Verne V. Smith, Jennifer Sobeck, Garrett Somers, Diogo Souto, David V. Stark, Keivan G. Stassun, Matthias Steinmetz, Dennis Stello, Thaisa Storchi Bergmann, Michael A. Strauss, Alina Streblyanska, Guy S. Stringfellow, Genaro Suarez, Jing Sun, Manuchehr Taghizadeh-Popp, Baitian Tang, Charling Tao, Jamie Tayar, Mita Tembe, Daniel Thomas, Jeremy Tinker, Rita Tojeiro, Christy Tremonti, Nicholas Troup, Jonathan R. Trump, Eduardo Unda-Sanzana, O. Valenzuela, Remco Van den Bosch, Mariana Vargas-Magaña, Jose Alberto Vazquez, Sandro Villanova, M. Vivek, Nicole Vogt, David Wake, Rene Walterbos, Yuting Wang, Enci Wang, Benjamin Alan Weaver, Anne-Marie Weijmans, David H. Weinberg, Kyle B. Westfall, David G. Whelan, Eric Wilcots, Vivienne Wild, Rob A. Williams, John Wilson, W. M. Wood-Vasey, Dominika Wylezalek, Ting Xiao, Renbin Yan, Meng Yang, Jason E. Ybarra, Christophe Yeche, Fang-Ting Yuan, Nadia Zakamska, Olga Zamora, Gail Zasowski, Kai Zhang, Cheng Zhao, Gong-Bo Zhao, Zheng Zheng, Zhi-Min Zhou, Guangtun Zhu, Joel C. Zinn, Hu Zou, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire d'Astrophysique de Marseille (LAM), 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), Centre de Physique des Particules de Marseille (CPPM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Aix Marseille Université (AMU), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS 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), Laboratoire d'astrophysique de l'observatoire de Besançon (LAOB), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), 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), 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), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), SDSS, Maiolino, Roberto [0000-0002-4985-3819], Apollo - University of Cambridge Repository, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire d'astrophysique de l'observatoire de Besançon (UMR 6091) (LAOB), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-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, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), 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), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), 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), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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), 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), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), 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), Institut de Recherches sur les lois Fondamentales de l'Univers ( IRFU ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay, AstroParticule et Cosmologie ( APC - UMR 7164 ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Laboratoire d'Astrophysique de Marseille ( LAM ), Aix Marseille Université ( AMU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), Centre de Physique des Particules de Marseille ( CPPM ), Centre National de la Recherche Scientifique ( CNRS ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Aix Marseille Université ( AMU ), Centre de Recherche Astrophysique de Lyon ( CRAL ), École normale supérieure - Lyon ( ENS 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 ), Laboratoire d'astrophysique de l'observatoire de Besançon ( LAOB ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Laboratoire AIM, Université Paris Diderot - Paris 7 ( UPD7 ) -Centre d'Etudes de Saclay, Institut d'Astrophysique de Paris ( IAP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Physique Nucléaire et de Hautes Énergies ( LPNHE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), 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 Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Joseph Louis LAGRANGE ( LAGRANGE ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Observatoire de la Côte d'Azur, and Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS )
Subjects: [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], media_common.quotation_subject, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Surveys, 01 natural sciences, Set (abstract data type), surveys, Observatory, 0103 physical sciences, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, QC, Astrophysics::Galaxy Astrophysics, QB, media_common, Physics, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Atlases, DAS, Astronomy and Astrophysics, Quasar, GALÁXIAS, Galaxy, Redshift, atlases, QC Physics, Data access, Space and Planetary Science, Sky, Catalogs, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], catalogs, Data reduction
Abstract: The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in July 2014. It pursues three core programs: APOGEE-2,MaNGA, and eBOSS. In addition, eBOSS contains two major subprograms: TDSS and SPIDERS. This paper describes the first data release from SDSS-IV, Data Release 13 (DR13), which contains new data, reanalysis of existing data sets and, like all SDSS data releases, is inclusive of previously released data. DR13 makes publicly available 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA,the first data released from this survey. It includes new observations from eBOSS, completing SEQUELS. In addition to targeting galaxies and quasars, SEQUELS also targeted variability-selected objects from TDSS and X-ray selected objects from SPIDERS. DR13 includes new reductions ofthe SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification. DR13 releases new reductions of the APOGEE-1data from SDSS-III, with abundances of elements not previously included and improved stellar parameters for dwarf stars and cooler stars. For the SDSS imaging data, DR13 provides new, more robust and precise photometric calibrations. Several value-added catalogs are being released in tandem with DR13, in particular target catalogs relevant for eBOSS, TDSS, and SPIDERS, and an updated red-clump catalog for APOGEE.This paper describes the location and format of the data now publicly available, as well as providing references to the important technical papers that describe the targeting, observing, and data reduction. The SDSS website, http://www.sdss.org, provides links to the data, tutorials and examples of data access, and extensive documentation of the reduction and analysis procedures. DR13 is the first of a scheduled set that will contain new data and analyses from the planned ~6-year operations of SDSS-IV. Postprint
Published: 2017
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28. Early-stage star-forming cloud cores in Galactic Legacy Infrared Mid-Plane Survey (GLIMPSE) extended green objects (EGOs) as traced by organic species

Author: Junqiang Ge, Jinhua He, X. Chen, and Satoko Takahashi
Subjects: Physics, Astrochemistry, Infrared, Plane (geometry), business.industry, Astronomy, Astronomy and Astrophysics, Cloud computing, Astrophysics, Star (graph theory), Spectral line, Space and Planetary Science, Abundance (ecology), Stage (hydrology), business
Abstract: In order to investigate the physical and chemical properties of massive star-forming cores in the early stages, we analyse the excitation and abundance of four organic species, CH3OH, CH3OCH3, HCOOCH3 and CH3CH2CN, towards 29 extended green object (EGO) cloud cores that were observed by our previous single-dish spectral line survey. The EGO cloud cores are found to have similar methanol J(3)-J(2) rotation temperatures of similar to 44 K, a typical linear size of similar to 0.036 pc and a typical beam-averaged methanol abundance of several 10(-9) (the beam-corrected value could reach several 10(-7)). The abundances of the latter three species, normalized by that of methanol, are also found to be correlated across a large variety of clouds such as EGO cloud cores, hot corinos, massive hot cores and Galactic Centre clouds. The chemical properties of the EGO cloud cores lie between those of hot cores and hot corinos. However, the abundances and abundance ratios of the four species cannot be explained satisfactorily by recent chemical models, either among EGO cloud cores or among the various types of cloud core from literature.
Published: 2014
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29. Understanding E-Commerce Systems under Massive Flash Crowd: Measurement, Analysis, and Implications

Author: Junqiang Ge, Rongheng Lan, Xinming Zhang, Lei Liu, and Ye Tian
Subjects: 020203 distributed computing, Information Systems and Management, Computer Networks and Communications, Computer science, business.industry, 020206 networking & telecommunications, Cloud computing, 02 engineering and technology, E-commerce, Computer security, computer.software_genre, Computer Science Applications, Campus network, Hardware and Architecture, Server, 0202 electrical engineering, electronic engineering, information engineering, Performance measurement, The Internet, business, Database transaction, computer, Content management
Abstract: Leading e-commerce providers have built large and complicated systems to provide countrywide or even worldwide services. However, there have been few substantive studies on e-commerce systems in real world. In this paper, we investigate the systems of Tmall and JD, the top-two most popular e-commerce websites in China, with a measurement approach. By analyzing traffics from campus network, we present a characterization study that covers several features, including usage patterns and shopping behaviors, of the e-commerce workload; in particular, we characterize the massive flash crowd in the Double-11 Day, which is the biggest online shopping festival in the world. We also reveal Tmall and JD's e-commerce infrastructures, including content delivery networks ( CDNs ) and clouds , and evaluate their performances under the flash crowd. We find that Tmall's CDN proactively throttles bandwidths for ensuring low but guaranteed throughputs, while JD still follows the best-effort way, leading to poor and unstable performances; both providers do not have sufficient capacities in their private clouds, resulting in extraordinarily long transaction latencies. Based on the insights obtained from measurement, we discuss the design choices of e-commerce CDNs, and investigate the potential benefits brought by incorporating client-side assistances in offloading massive flash crowd of e-commerce workloads.
Published: 2019
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30. Effects of turbulent dust grain motion to interstellar chemistry

Author: Huirong Yan, Junqiang Ge, and Jinhua He
Subjects: Physics, Work (thermodynamics), Astrochemistry, Accretion (meteorology), 010308 nuclear & particles physics, Molecular cloud, Extinction (astronomy), Institut für Physik und Astronomie, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Interstellar medium, Orders of magnitude (time), Space and Planetary Science, Chemical physics, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Coulomb, ddc:520, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: Monthly notices of the Royal Astronomical Society 455(4), 3570 - 3587 (2016). doi:10.1093/mnras/stv2560, Theoretical studies have revealed that dust grains are usually moving fast through the turbulent interstellar gas, which could have significant effects upon interstellar chemistry by modifying grain accretion. This effect is investigated in this work on the basis of numerical gas–grain chemical modelling. Major features of the grain motion effect in the typical environment of dark clouds (DC) can be summarized as follows: (1) decrease of gas-phase (both neutral and ionic) abundances and increase of surface abundances by up to 2–3 orders of magnitude; (2) shifts of the existing chemical jumps to earlier evolution ages for gas-phase species and to later ages for surface species by factors of about 10; (3) a few exceptional cases in which some species turn out to be insensitive to this effect and some other species can show opposite behaviours too. These effects usually begin to emerge from a typical DC model age of about 10$^5$ yr. The grain motion in a typical cold neutral medium (CNM) can help overcome the Coulomb repulsive barrier to enable effective accretion of cations on to positively charged grains. As a result, the grain motion greatly enhances the abundances of some gas-phase and surface species by factors up to 2–6 or more orders of magnitude in the CNM model. The grain motion effect in a typical molecular cloud (MC) is intermediate between that of the DC and CNM models, but with weaker strength. The grain motion is found to be important to consider in chemical simulations of typical interstellar medium., Published by Oxford Univ. Press, Oxford
Published: 2016
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31. INTEGRAL and Swift/XRT observations of IGR J19405-3016

Author: Yu-Peng Chen, Diego F. Torres, Shu Zhang, Jian-Min Wang, Junqiang Ge, and Ti-Pei Li
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Physics, Swift, Photon, Active galactic nucleus, FOS: Physical sciences, Flux, Astronomy and Astrophysics, Astrophysics, Power law, Observational period, Error location, Space and Planetary Science, Spectral slope, Astrophysics - High Energy Astrophysical Phenomena, computer, computer.programming_language
Abstract: IGR J19405-3016 is reported in the 3rd IBIS catalog as being one of its lowest significance sources (~4.6 sigma under an exposure of about 371 ks). This leads to a caveat in multi-wavelength study although the source was identified in optical as a Seyfert 1. The currently increased INTEGRAL data stimulate us to investigate the reality of this source. We analyze all available observations carried out by INTEGRAL and Swift on IGR J19405-3016. We find that IGR J19405-3016 has a detection significance of ~ 9.4 sigma in the 20-60 keV band during the observational period between March 2003 and March 2008. Thus confirms a real source detection reported previously. The source position and error location are therefore updated. The source is found to be constant over years at the hard X-rays. Over the three XRT observations, the source flux varied by up to 39% from the average, and the spectrum is generally soft. The combined XRT/ISGRI spectrum is well fitted with a simple power law model (photon index 2.11+-0.03). Such a photon index is well consistent with the mean value 1.98 (dispersion 0.27) as obtained from Swift/BAT AGN samples at 14-195 keV. The spectral slope of IGR J19405-3016 is larger than the average spectral slope found by Molina et al. (2009). A similar discrepancy is found with the results of Beckmann et al. (2009) regarding Seyfert 1 AGNs. A possible explanation of this simple spectral description may be that the low level of the column density allows for the `true' spectrum to appear at soft X-rays as well., Astronomy and Astrophysics, in press
Published: 2009
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32. Outflows from active galactic nuclei: the BLR–NLR metallicity correlation

Author: Chen Hu, David Valls-Gabaud, Jian-Min Wang, Pu Du, Jack A. Baldwin, Junqiang Ge, Suijian Xue, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), University of Oxford [Oxford], École normale supérieure - Paris (ENS-PSL), and University of Oxford
Subjects: Active galactic nucleus, Cosmology and Nongalactic Astrophysics (astro-ph.CO), media_common.quotation_subject, Metallicity, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, 0103 physical sciences, Emission spectrum, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, media_common, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), [PHYS]Physics [physics], 010308 nuclear & particles physics, Star formation, Astronomy, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, 13. Climate action, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), H-alpha, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The metallicity of active galactic nuclei (AGNs), which can be measured by emission line ratios in their broad and narrow line regions (BLRs and NLRs), provides invaluable information about the physical connection between the different components of AGNs. From the archival databases of the International Ultraviolet Explorer, the Hubble Space Telescope and the Sloan Digital Sky Survey, we have assembled the largest sample available of AGNs which have adequate spectra in both the optical and ultraviolet bands to measure the narrow line ratio [N II]/H{\alpha} and also, in the same objects, the broad-line N V/C IV ratio. These permit the measurement of the metallicities in the NLRs and BLRs in the same objects. We find that neither the BLR nor the NLR metallicity correlate with black hole masses or Eddington ratios, but there is a strong correlation between NLR and BLR metallicities. This metallicity correlation implies that outflows from BLRs carry metal-rich gas to NLRs at characteristic radial distances of ~ 1.0 kiloparsec. This chemical connection provides evidence for a kinetic feedback of the outflows to their hosts. Metals transported into the NLR enhance the cooling of the ISM in this region, leading to local star formation after the AGNs turn to narrow line LINERs. This post-AGN star formation is predicted to be observable as an excess continuum emission from the host galaxies in the near infrared and ultraviolet, which needs to be further explored., Comment: 19 pages, 13 figures, 3 tables. Accepted for publication at MNRAS
Published: 2014
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33. Biases in physical parameter estimates through differential lensing magnification

Author: Shude Mao, Xinzhong Er, and Junqiang Ge
Subjects: Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Radio galaxy, Metallicity, Magnification, Velocity dispersion, FOS: Physical sciences, Astronomy and Astrophysics, Quasar, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxy, Stars, Space and Planetary Science, Bulge, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We study the lensing magnification effect on background galaxies. Differential magnification due to different magnifications of different source regions of a galaxy will change the lensed composite spectra. The derived properties of the background galaxies are therefore biased. For simplicity, we model galaxies as a superposition of an axis-symmetric bulge and a face-on disk in order to study the differential magnification effect on the composite spectra. We find that some properties derived from the spectra (e.g., velocity dispersion, star formation rate and metallicity) are modified. Depending on the relative positions of the source and the lens, the inferred results can be either over- or under-estimates of the true values. In general, for an extended source at strong lensing regions with high magnifications, the inferred physical parameters (e.g. metallicity) can be strongly biased. Therefore detailed lens modelling is necessary to obtain the true properties of the lensed galaxies., Comment: 5 pages, 4 figures, ApJ accepted
Published: 2013
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34. SDSS-IV MaNGA: a distinct mass distribution explored in slow-rotating early-type galaxies.

Author: Yu Rong, Hongyu Li, Jie Wang, Liang Gao, Ran Li, Junqiang Ge, Yingjie Jing, Jun Pan, Fernández-Trincado, J. G., Valenzuela, Octavio, and Ortíz, Erik Aquino
Subjects: GALAXIES, CENTRIPETAL acceleration, DARK matter, KINEMATICS, BARYONS
Abstract: We study the radial acceleration relation (RAR) for early-type galaxies (ETGs) in the SDSS MaNGA MPL5 data set. The complete ETG sample show a slightly offset RAR from the relation reported by McGaugh et al. (2016) at the low-acceleration end; we find that the deviation is due to the fact that the slow rotators show a systematically higher acceleration relation than the McGaugh's RAR, while the fast rotators show a consistent acceleration relation to McGaugh's RAR. There is a 1σ significant difference between the acceleration relations of the fast and slow rotators, suggesting that the acceleration relation correlates with the galactic spins, and that the slow rotators may have a different mass distribution compared with fast rotators and late-type galaxies. We suspect that the acceleration relation deviation of slow rotators may be attributed to more galaxy merger events, which would disrupt the original spins and correlated distributions of baryons and dark matter orbits in galaxies. [ABSTRACT FROM AUTHOR]
Published: 2018
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35. SDSS-IV MaNGA: global stellar population and gradients for about 2000 early-type and spiral galaxies on the mass-size plane.

Author: Hongyu Li, Shude Mao, Cappellari, Michele, Junqiang Ge, Long, R. J., Ran Li, Mo, H. J., Cheng Li, Zheng Zheng, Bundy, Kevin, Thomas, Daniel, Brownstein, Joel R., Roman Lopes, Alexandre, Law, David R., and Drory, Niv
Subjects: STELLAR populations, SPIRAL galaxies, ANISOTROPY, KINEMATICS, STELLAR mass
Abstract: We perform full spectrum fitting stellar population analysis and Jeans Anisotropic modelling of the stellar kinematics for about 2000 early-type galaxies (ETGs) and spiral galaxies from the MaNGA DR14 sample. Galaxies with different morphologies are found to be located on a remarkably tight mass plane which is close to the prediction of the virial theorem, extending previous results for ETGs. By examining an inclined projection ('the mass-size' plane), we find that spiral and early-type galaxies occupy different regions on the plane, and their stellar population properties (i.e. age, metallicity, and stellar mass-to-light ratio) vary systematically along roughly the direction of velocity dispersion, which is a proxy for the bulge fraction. Galaxies with higher velocity dispersions have typically older ages, larger stellar mass-to-light ratios and are more metal rich, which indicates that galaxies increase their bulge fractions as their stellar populations age and become enriched chemically. The age and stellar mass-to-light ratio gradients for low-mass galaxies in our sample tend to be positive (centre < outer), while the gradients for most massive galaxies are negative. The metallicity gradients show a clear peak around velocity dispersion log10 σe ≈ 2.0, which corresponds to the critical mass ~3 x 1010 M⊙ of the break in the mass-size relation. Spiral galaxies with large mass and size have the steepest gradients, while the most massive ETGs, especially above the critical mass Mcrit ≳ 2 x 1011 M⊙, where slow rotator ETGs start dominating, have much flatter gradients. This may be due to differences in their evolution histories, e.g. mergers. [ABSTRACT FROM AUTHOR]
Published: 2018
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36. Double-peaked narrow emission-line galaxies from Sloan Digital Sky Survey. I. Sample and basic properties

Author: Junqiang Ge, Jian-Min Wang, Shu Zhang, Jin-Ming Bai, and Chen Hu
Subjects: Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Balmer series, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Double star, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxy merger, Galaxy, Black hole, symbols.namesake, Space and Planetary Science, Sky, symbols, Emission spectrum, Astrophysics::Galaxy Astrophysics, media_common, Line (formation), Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: Recently, much attention has been given to double-peaked narrow emission-line galaxies, some of which are suggested to be related with merging galaxies. We make a systematic search to build the largest sample of these sources from Data Release 7 of Sloan Digital Sky Survey (SDSS DR7). With reasonable criteria of fluxes, full-width-half-maximum of emission lines and separations of the peaks, we select 3,030 double-peaked narrow emission-lines galaxies. In light of the existence of broad Balmer lines and the locations of the two components of double-peaked narrow emission lines distinguished by the Kauffmann et al. (2003) criteria in the Baldwin-Phillips-Terlevich (BPT) diagram, we find that there are 81 type I AGN, 837 double-type II AGN (2-type II), 708 galaxies with double star forming components (2-SF), 400 with mixed star forming and type II AGN components (type II + SF) and 1,004 unknown-type objects. As a by-product, a sample of galaxies (12,582) with asymmetric or top-flat profiles of emission lines is established. After inspecting the SDSS images of the two samples visually, we find 54 galaxies with dual cores. The present samples can be used to study the dynamics of merging galaxies, the triggering mechanism of black hole activity, the hierarchical growth of galaxies and dynamics of narrow line regions driven by outflows and rotating disk., Comment: 36 pages, 12 figures
Published: 2012
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37. Star formation in self-gravitating disks in active galactic nuclei. II. Episodic formation of broad line regions

Author: Jack A. Baldwin, Junqiang Ge, Pu Du, Chen Hu, Jian-Min Wang, and Gary J. Ferland
Subjects: Active galactic nucleus, Cosmology and Nongalactic Astrophysics (astro-ph.CO), 010504 meteorology & atmospheric sciences, Metallicity, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Line (formation), Physics, Star formation, Astronomy and Astrophysics, Quasar, Astrophysics - Astrophysics of Galaxies, Galaxy, Radiation pressure, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Equivalent width, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: (abridged) We study the consequence of star formation (SF) in an self-gravity dominated accretion disk in quasars. The warm skins of the SF disk are governed by the radiation from the inner part of the accretion disk to form Compton atmosphere (CAS). The CAS are undergoing four phases to form broad line regions. Phase I is the duration of pure accumulation supplied by the SF disk. During phase II clouds begin to form due to line cooling and sink to the SF disk. Phase III is a period of preventing clouds from sinking to the SF disk through dynamic interaction between clouds and the CAS. Finally, phase IV is an inevitable collapse of the entire CAS through line cooling. This CAS evolution drives the episodic appearance of BLRs. Geometry and dynamics of BLRs can be self-consistently derived from the thermal instability of the CAS during phases II and III by linear analysis. The metallicity gradient of SF disk gives rise to different properties of clouds from outer to inner part of BLRs. We find that clouds have column density N_H < 10^22cm^{-2} in the metal-rich regions whereas they have N_H > 10^22 cm^{-2} in the metal-poor regions. The metal-rich clouds compose the high ionization line (HIL) regions whereas the metal-poor clouds are in low ionization line (LIL) regions. Metal-rich clouds in HIL regions will be blown away by radiation pressure, forming the observed outflows. The LIL regions are episodic due to the mass cycle of clouds with the CAS in response to continuous injection by the SF disk, giving rise to different types of AGNs. Based on SDSS quasar spectra, we identify a spectral sequence in light of emission line equivalent width from Phase I to IV. A key phase in the episodic appearance of the BLRs is bright type II AGNs with no or only weak BLRs. We discuss observational implications and tests of the theoretical predictions of this model., 27 pages in emulateapj style, 10 figures, Accepted by ApJ 2012
Published: 2012
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38. INTEGRAL and Swift/XRT observations of IGR~J16460+0849

Author: Yu-Peng Chen, Ti-Pei Li, Shu Zhang, Jian-Min Wang, and Junqiang Ge
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Swift, Physics, Ibis, biology, FOS: Physical sciences, Flux, Astronomy and Astrophysics, Astrophysics, biology.organism_classification, Observational period, Space and Planetary Science, Spectral analysis, Astrophysics - High Energy Astrophysical Phenomena, computer, computer.programming_language
Abstract: IGR J16460+0849 is reported in the 3rd IBIS catalog with the shortest exposure of about 10 ks among all the detected sources, which makes it the most interesting target to be investigated with a deeper exposure. We analyze all available observations carried out by the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) on the unidentified source IGR J16460+0849. The data were processed by using the latest version OSA 7.0. In addition we analyze also all the available Swift/XRT data on this source. We find that IGR J16460+0849 has a detection significance of ~ 4.4 sigma in the 20-100 keV band during the observational period between March 2003 and September 2004, when it was exposed by ~ 19 ks. Thereafter the source was not detected anymore, despite an additional exposure of ~ 271 ks. This suggests a flux variability on a timescale of years. The spectral analysis shows that the IBIS/ISGRI data are well presented by a power-law shape, with a photon index obtained as 1.45+-0.86. So far, the source has been detected consistently by IBIS/ISGRI in the subsequent observations and in the adjacent energy bands. We have analyzed the Swift/XRT observations on IGR J16460+0849 as well, and found no source inside the IBIS/ISGRI error circle. The non-detection during the Swift/XRT observation is consistent with the source having a variable nature., published in A&A
Published: 2009

39. Evolution of gaseous disk viscosity driven by supernova explosion in star-forming galaxies at high redshift

Author: Jian-Min Wang, Chang-Shuo Yan, Chen Hu, Yan-Rong Li, Fei Xiang, Yanmei Chen, Shu Zhang, and Junqiang Ge
Subjects: Physics, Angular momentum, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Turbulence, Star formation, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Supernova, Viscosity, Stars, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: Motivated by Genzel et al.'s observations of high-redshift star-forming galaxies, containing clumpy and turbulent rings or disks, we build a set of equations describing the dynamical evolution of gaseous disks with inclusion of star formation and its feedback. Transport of angular momentum is due to "turbulent" viscosity induced by supernova explosions in the star formation region. Analytical solutions of the equations are found for the initial cases of a gaseous ring and the integrated form for a gaseous disk, respectively. For a ring with enough low viscosity, it evolves in a slow processes of gaseous diffusion and star formation near the initial radius. For a high viscosity, the ring rapidly diffuses in the early phase. The diffusion drives the ring into a region with a low viscosity and start the second phase undergoing pile-up of gas at a radius following the decreased viscosity torque. The third is a sharply deceasing phase because of star formation consumption of gas and efficient transportation of gas inward forming a stellar disk. We apply the model to two $z\sim 2$ galaxies BX 482 and BzK 6004, and find that they are undergoing a decline in their star formation activity., Comment: To appear in ApJ, 5 figures
Published: 2009
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40. SDSS-IV MaNGA: environmental dependence of stellar age and metallicity gradients in nearby galaxies.

Author: Zheng Zheng, Huiyuan Wang, Junqiang Ge, Shude Mao, Cheng Li, Ran Li, Houjun Mo, Goddard, Daniel, Bundy, Kevin, Hongyu Li, Nair, Preethi, Lihwai Lin, Long, R. J., Riffel, Rogério, Thomas, Daniel, Masters, Karen, Bizyaev, Dmitry, Brownstein, Joel R., Kai Zhang, and Law, David R.
Subjects: AGE of stars, STELLAR mass, GALACTIC evolution, GALAXY formation
Abstract: We present a study on the stellar age and metallicity distributions for 1105 galaxies using the starlight software on MaNGA (Mapping Nearby Galaxies at APO) integral field spectra. We derive age and metallicity gradients by fitting straight lines to the radial profiles, and explore their correlations with total stellar mass M*, NUV - r colour and environments, as identified by both the large-scale structure (LSS) type and the local density. We find that the mean age and metallicity gradients are close to zero but slightly negative, which is consistent with the inside-out formation scenario. Within our sample, we find that both the age and metallicity gradients show weak or no correlation with either the LSS type or local density environment. In addition, we also study the environmental dependence of age and metallicity values at the effective radii. The age and metallicity values are highly correlated with M* and NUV - r and are also dependent on LSS type as well as local density. Low-mass galaxies tend to be younger and have lower metallicity in low-density environments while high-mass galaxies are less affected by environment. [ABSTRACT FROM AUTHOR]
Published: 2017
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41. STAR FORMATION IN SELF-GRAVITATING DISKS IN ACTIVE GALACTIC NUCLEI. I. METALLICITY GRADIENTS IN BROAD-LINE REGIONS

Author: Shu Zhang, Chang-Shuo Yan, Jack A. Baldwin, Yan-Rong Li, Chen Hu, Fei Xiang, Gary J. Ferland, Jian-Min Wang, and Junqiang Ge
Subjects: Physics, Supermassive black hole, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Active galactic nucleus, Star formation, Astrophysics::High Energy Astrophysical Phenomena, Metallicity, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Quasar, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Supernova, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics, Line (formation)
Abstract: It has been suggested that the high metallicity generally observed in active galactic nuclei (AGNs) and quasars originates from ongoing star formation in the self-gravitating part of accretion disks around the supermassive black holes. We designate this region as the star forming (SF) disk, in which metals are produced from supernova explosions (SNexp) while at the same time inflows are driven by SNexp-excited turbulent viscosity to accrete onto the SMBHs. In this paper, an equation of metallicity governed by SNexp and radial advection is established to describe the metal distribution and evolution in the SF disk. We find that the metal abundance is enriched at different rates at different positions in the disk, and that a metallicity gradient is set up that evolves for steady-state AGNs. Metallicity as an integrated physical parameter can be used as a probe of the SF disk age during one episode of SMBH activity. In the SF disk, evaporation of molecular clouds heated by SNexp blast waves unavoidably forms hot gas. This heating is eventually balanced by the cooling of the hot gas, but we show that the hot gas will escape from the SF disk before being cooled, and diffuse into the BLRs forming with a typical rate of $\sim 1\sunmyr$. The diffusion of hot gas from a SF disk depends on ongoing star formation, leading to the metallicity gradients in BLR observed in AGNs. We discuss this and other observable consequences of this scenario., 11 pages, 5 Figures, ApJ, Vol. 737, in press
Published: 2011
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42. BIASES IN PHYSICAL PARAMETER ESTIMATES THROUGH DIFFERENTIAL LENSING MAGNIFICATION.

Author: XINZHONG ER, JUNQIANG GE, and SHUDE MAO
Subjects: *GALACTIC magnetic fields, *STAR formation, *GRAVITATIONAL lenses, *GALACTIC redshift, *GRAVITATIONAL redshift
Abstract: We study the lensing magnification effect on background galaxies. Differential magnification due to different magnifications of different source regions of a galaxy will change the lensed composite spectra. The derived properties of the background galaxies are therefore biased. For simplicity, we model galaxies as a superposition of an axis-symmetric bulge and a face-on disk in order to study the differential magnification effect on the composite spectra. We find that some properties derived from the spectra (e.g., velocity dispersion, star formation rate, and metallicity) are modified. Depending on the relative positions of the source and the lens, the inferred results can be either over- or underestimates of the true values. In general, for an extended source at strong lensing regions with high magnifications, the inferred physical parameters (e.g., metallicity) can be strongly biased. Therefore, detailed lens modeling is necessary to obtain the true properties of the lensed galaxies. [ABSTRACT FROM AUTHOR]
Published: 2013
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43. SDSS-IV MaNGA: Variation of the Stellar Initial Mass Function in Spiral and Early-type Galaxies.

Author: Hongyu Li, Junqiang Ge, Shude Mao, Michele Cappellari, R. J. Long, Ran Li, Eric Emsellem, Aaron A. Dutton, Cheng Li, Kevin Bundy, Daniel Thomas, Niv Drory, and Alexandre Roman Lopes
Subjects: *STELLAR mass, *STELLAR initial mass function, *SPIRAL galaxies, *STELLAR populations, *ASTROPHYSICS
Abstract: We perform Jeans anisotropic modeling (JAM) on elliptical and spiral galaxies from the MaNGA DR13 sample. By comparing the stellar mass-to-light ratios estimated from stellar population synthesis and from JAM, we find a systematic variation of the initial mass function (IMF) similar to that in the earlier results. Early-type galaxies (elliptical and lenticular) with lower velocity dispersions within one effective radius are consistent with a Chabrier-like IMF, while galaxies with higher velocity dispersions are consistent with a more bottom-heavy IMF such as the Salpeter IMF. Spiral galaxies have similar systematic IMF variations, but with slightly different slopes and larger scatters, due to the uncertainties caused by the higher gas fractions and extinctions for these galaxies. Furthermore, we examine the effects of stellar mass-to-light ratio gradients on our JAM modeling, and we find that the trends become stronger after considering the gradients. [ABSTRACT FROM AUTHOR]
Published: 2017
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