Spectral variability of a sample of extreme variability quasars and implications for the Mg ii broad-line region-Reference-Cited by-同舟云学术

Spectral variability of a sample of extreme variability quasars and implications for the Mg ii broad-line region

Published:2020-03-13 Issue:4 Volume:493 Page:5773-5787
ISSN:0035-8711
Container-title:Monthly Notices of the Royal Astronomical Society
language:en
Short-container-title:

Author:

Yang Qian¹^ORCID,Shen Yue¹²,Chen Yu-Ching¹²,Liu Xin¹,Annis James³,Avila Santiago⁴^ORCID,Bertin Emmanuel⁵⁶,Brooks David⁷,Buckley-Geer Elizabeth³,Carnero Rosell Aurelio⁸⁹^ORCID,Carrasco Kind Matias¹²^ORCID,Carretero Jorge¹⁰,da Costa Luiz⁸¹¹,Desai Shantanu¹²,Thomas Diehl H³,Doel Peter⁷,Frieman Josh³¹³,Garcia-Bellido Juan⁴,Gaztanaga Enrique¹⁴¹⁵^ORCID,Gerdes David¹⁶¹⁷,Gruen Daniel¹⁸¹⁹^ORCID,Gruendl Robert¹²,Gschwend Julia⁸¹¹,Gutierrez Gaston³,Hollowood Devon L²⁰,Honscheid Klaus²¹²²,Hoyle Ben²³²⁴^ORCID,James David²⁵,Krause Elisabeth²⁶,Kuehn Kyler²⁷,Lidman Christopher²⁸^ORCID,Lima Marcos⁸²⁹,Maia Marcio⁸¹¹,Marshall Jennifer³⁰,Martini Paul²²³¹,Menanteau Felipe¹²,Miquel Ramon¹⁰³²,Plazas Malagón Andrés³³^ORCID,Sanchez Eusebio⁹,Scarpine Vic³,Schindler Rafe¹⁸,Schubnell Michael¹⁷,Serrano Santiago¹⁴¹⁵,Sevilla Ignacio⁹,Smith Mathew³⁴^ORCID,Soares-Santos Marcelle³⁵^ORCID,Sobreira Flavia⁸³⁶,Suchyta Eric³⁷^ORCID,Swanson Molly²,Tarle Gregory¹⁷,Vikram Vinu³⁸,Walker Alistair³⁹

Affiliation:

1. Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA

2. National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA

3. Fermi National Accelerator Laboratory, PO Box 500, Batavia, IL 60510, USA

4. Instituto de Fisica Teorica UAM/CSIC, Universidad Autonoma de Madrid, E-28049 Madrid, Spain

5. CNRS, Institut d’Astrophysique de Paris, UMR 7095, F-75014, Paris, France

6. Institut d’Astrophysique de Paris, Sorbonne Universités, UPMC Univ Paris 06, UMR 7095, F-75014, Paris, France

7. Department of Physics & Astronomy, University College London, Gower Street, London, WC1E 6BT, UK

8. Laboratório Interinstitucional de e-Astronomia - LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil

9. Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), 28040 Madrid, Spain

10. Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, E-08193 Bellaterra, Spain

11. Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400, Brazil

12. Department of Physics, IIT Hyderabad, Kandi, Telangana 502285, India

13. Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637, USA

14. Institut d’Estudis Espacials de Catalunya (IEEC), 08193 Barcelona, Spain

15. Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, E008193 Barcelona, Spain

16. Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA

17. Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA

18. SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA

19. Kavli Institute for Particle Astrophysics & Cosmology, Stanford University, PO Box 2450, Stanford, CA 94305, USA

20. Santa Cruz Institute for Particle Physics, Santa Cruz, CA 95064, USA

21. Department of Physics, The Ohio State University, Columbus, OH 43210, USA

22. Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210, USA

23. Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, D-85748 Garching, Germany

24. Fakultät für Physik, Ludwig-Maximilians Universität MünchenUniversitäts-Sternwarte, Scheinerstr. 1, D-81679 München, Germany

25. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA

26. Department of Astronomy/Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721-0065, USA

27. Australian Astronomical Observatory, North Ryde, NSW 2113, Australia

28. The Research School of Astronomy and Astrophysics, Australian National University, ACT 2601, Australia

29. Departamento de Física Matemática, Instituto de Física, Universidade de São Paulo, CP 66318, São Paulo, SP, 05314-970, Brazil

30. George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA

31. Department of Astronomy, The Ohio State University, Columbus, OH 43210, USA

32. Institució Catalana de Recerca i Estudis Avançats, E-08010 Barcelona, Spain

33. Department of Astrophysical Sciences, Princeton University, Peyton Hall, Princeton, NJ 08544, US

34. School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK

35. Department of Physics, Brandeis University, Waltham, MA 02453, USA

36. Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas, SP, Brazil

37. Computer Science and Mathematics Division, Oak Ridge National Laboratory, US, Oak Ridge, TN 37831

38. Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439, USA

39. Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena, Chile

Abstract

ABSTRACT We present new Gemini/GMOS optical spectroscopy of 16 extreme variability quasars (EVQs) that dimmed by more than 1.5 mag in the g band between the Sloan Digital Sky Survey (SDSS) and the Dark Energy Survey epochs (separated by a few years in the quasar rest frame). These EVQs are selected from quasars in the SDSS Stripe 82 region, covering a redshift range of 0.5 < z < 2.1. Nearly half of these EVQs brightened significantly (by more than 0.5 mag in the g band) in a few years after reaching their previous faintest state, and some EVQs showed rapid (non-blazar) variations of greater than 1–2 mag on time-scales of only months. To increase sample statistics, we use a supplemental sample of 33 EVQs with multi-epoch spectra from SDSS that cover the broad Mg ii λ2798 line. Leveraging on the large dynamic range in continuum variability between the multi-epoch spectra, we explore the associated variations in the broad Mg ii line, whose variability properties have not been well studied before. The broad Mg ii flux varies in the same direction as the continuum flux, albeit with a smaller amplitude, which indicates at least some portion of Mg ii is reverberating to continuum changes. However, the full width at half-maximum (FWHM) of Mg ii does not vary accordingly as continuum changes for most objects in the sample, in contrast to the case of the broad Balmer lines. Using the width of broad Mg ii to estimate the black hole mass with single epoch spectra therefore introduces a luminosity-dependent bias.

Funder

National Sleep Foundation

National Science Foundation

Ministerio de Economía y Competitividad

European Research Council

Seventh Framework Programme

Conselho Nacional de Desenvolvimento Científico e Tecnológico

University of Hawaii

Durham University

University of Edinburgh

Queen's University Belfast

Smithsonian Astrophysical Observatory