Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey

N. Rumbaugh; Yue Shen; Eric Morganson; Xin Liu; M. Banerji; R. G. McMahon; F. B. Abdalla; A. Benoit-Lévy; E. Bertin; D. Brooks; E. Buckley-Geer; D. Capozzi; A. Carnero Rosell; M. Carrasco Kind; J. Carretero; C. E. Cunha; C. B. D'Andrea; L. N. Da Costa; D. L. Depoy; S. Desai; P. Doel; J. Frieman; J. García-Bellido; D. Gruen; R. A. Gruendl; J. Gschwend; G. Gutierrez; K. Honscheid; D. J. James; K. Kuehn; S. Kuhlmann; N. Kuropatkin; M. Lima; M. A.G. Maia; J. L. Marshall; P. Martini; F. Menanteau; A. A. Plazas; K. Reil; A. Roodman; E. Sanchez; V. Scarpine; R. Schindler; M. Schubnell; E. Sheldon; M. Smith; M. Soares-Santos; F. Sobreira; E. Suchyta; M. E.C. Swanson; A. R. Walker; W. Wester

doi:10.3847/1538-4357/aaa9b6

Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey

N. Rumbaugh, Yue Shen, Eric Morganson, Xin Liu, M. Banerji, R. G. McMahon, F. B. Abdalla, A. Benoit-Lévy, E. Bertin, D. Brooks, E. Buckley-Geer, D. Capozzi, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, C. E. Cunha, C. B. D'Andrea, L. N. Da Costa, D. L. Depoy, S. DesaiP. Doel, J. Frieman, J. García-Bellido, D. Gruen, R. A. Gruendl, J. Gschwend, G. Gutierrez, K. Honscheid, D. J. James, K. Kuehn, S. Kuhlmann, N. Kuropatkin, M. Lima, M. A.G. Maia, J. L. Marshall, P. Martini, F. Menanteau, A. A. Plazas, K. Reil, A. Roodman, E. Sanchez, V. Scarpine, R. Schindler, M. Schubnell, E. Sheldon, M. Smith, M. Soares-Santos, F. Sobreira, E. Suchyta, M. E.C. Swanson, A. R. Walker, W. Wester

Workflow Systems

Research output: Contribution to journal › Review article › peer-review

92 Scopus citations

Abstract

We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey and 3 Year Dark Energy Survey imaging, which provide light curves spanning more than 15 years. We identified ∼1000 EVQs with a maximum change in g-band magnitude of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L _bol ∼ 10⁴⁵-10⁴⁷ erg s^-1 and L/L _Edd ∼ 0.01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ∼30%-50% among all quasars over a baseline of ∼15 yr. We performed detailed multi-wavelength, spectral, and variability analyses for the EVQs and compared them to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggests that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low rates, where the accretion flow is more likely to experience instabilities that drive the changes in flux by a factor of a few on multi-year timescales.

Original language	English
Article number	160
Journal	Astrophysical Journal
Volume	854
Issue number	2
DOIs	https://doi.org/10.3847/1538-4357/aaa9b6
State	Published - Feb 20 2018

Funding

We thank the referee, Andy Lawrence, for a constructive report that greatly improved this work, and Yan-Fei Jiang, Charles Gammie, Stephanie LaMassa, Chelsea MacLeod, Suvi Gezari, and Aaron Barth for useful comments on the manuscript. Y.S. acknowledges support from an Alfred P. Sloan Research Fellowship and NSF grant AST-1715579. The DES data management system is supported by the National Science Foundation under Grant Number AST-1138766. The DES participants from Spanish institutions are partially supported by MINECO under grants AYA2012-39559, ESP2013-48274, FPA2013-47986, and Centro de Excelencia Severo Ochoa SEV-2012-0234. Research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme FP7/2007-2013) including ERC grant agreements 240672, 291329, and 306478. Funding for the DES Projects has been provided by the U.S. Department of Energy, the U.S. National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, the Center for Cosmology and Astro-Particle Physics at the Ohio State University, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência, Tecnologia e Inovação, the Deutsche Forschungs-gemeinschaft and the Collaborating Institutions in the DES. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web site ishttp://www.sdss.org/. Y.S. acknowledges support from an Alfred P. Sloan Research Fellowship and NSF grant AST-1715579. Funding for the DES Projects has been provided by the U.S. Department of Energy, the U.S. National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, the Center for Cosmology and Astro-Particle Physics at the Ohio State University.

Funders	Funder number
Centro de Excelencia Severo Ochoa	SEV-2012-0234
Deutsche Forschungs-gemeinschaft
Kavli Institute of Cosmological Physics at the University of Chicago
Ministry of Science and Education of Spain
Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University
National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign
U.S. National Science Foundation
National Science Foundation	AST-1715579, AST-1138766
U.S. Department of Energy
National Aeronautics and Space Administration
Alfred P. Sloan Foundation
University of Illinois at Urbana-Champaign
Ohio State University
Seventh Framework Programme	1138766, 240672, 306478, 1715579, 291329
Higher Education Funding Council for England
Center for Cosmology and Astroparticle Physics, Ohio State University
Engineering Research Centers
Science and Technology Facilities Council
Higher Education Funding Council for England
European Research Council
Ministerio de Economía y Competitividad	FPA2013-47986, AYA2012-39559, ESP2013-48274
Ministério da Ciência, Tecnologia e Inovação
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Max-Planck-Gesellschaft
Norsk Sykepleierforbund
Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro
Financiadora de Estudos e Projetos
Seventh Framework Programme

Keywords

black hole physics
galaxies: active
line: profiles
quasars: general
surveys

Access to Document

10.3847/1538-4357/aaa9b6

Cite this

Rumbaugh, N., Shen, Y., Morganson, E., Liu, X., Banerji, M., McMahon, R. G., Abdalla, F. B., Benoit-Lévy, A., Bertin, E., Brooks, D., Buckley-Geer, E., Capozzi, D., Carnero Rosell, A., Carrasco Kind, M., Carretero, J., Cunha, C. E., D'Andrea, C. B., Da Costa, L. N., Depoy, D. L., ... Wester, W. (2018). Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey. Astrophysical Journal, 854(2), Article 160. https://doi.org/10.3847/1538-4357/aaa9b6

@article{9c7bf6f659d34acd9fa21a51da4b05e4,

title = "Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey",

abstract = "We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey and 3 Year Dark Energy Survey imaging, which provide light curves spanning more than 15 years. We identified ∼1000 EVQs with a maximum change in g-band magnitude of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L bol ∼ 1045-1047 erg s-1 and L/L Edd ∼ 0.01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ∼30%-50% among all quasars over a baseline of ∼15 yr. We performed detailed multi-wavelength, spectral, and variability analyses for the EVQs and compared them to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggests that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low rates, where the accretion flow is more likely to experience instabilities that drive the changes in flux by a factor of a few on multi-year timescales.",

keywords = "black hole physics, galaxies: active, line: profiles, quasars: general, surveys",

author = "N. Rumbaugh and Yue Shen and Eric Morganson and Xin Liu and M. Banerji and McMahon, {R. G.} and Abdalla, {F. B.} and A. Benoit-L{\'e}vy and E. Bertin and D. Brooks and E. Buckley-Geer and D. Capozzi and {Carnero Rosell}, A. and {Carrasco Kind}, M. and J. Carretero and Cunha, {C. E.} and D'Andrea, {C. B.} and {Da Costa}, {L. N.} and Depoy, {D. L.} and S. Desai and P. Doel and J. Frieman and J. Garc{\'i}a-Bellido and D. Gruen and Gruendl, {R. A.} and J. Gschwend and G. Gutierrez and K. Honscheid and James, {D. J.} and K. Kuehn and S. Kuhlmann and N. Kuropatkin and M. Lima and Maia, {M. A.G.} and Marshall, {J. L.} and P. Martini and F. Menanteau and Plazas, {A. A.} and K. Reil and A. Roodman and E. Sanchez and V. Scarpine and R. Schindler and M. Schubnell and E. Sheldon and M. Smith and M. Soares-Santos and F. Sobreira and E. Suchyta and Swanson, {M. E.C.} and Walker, {A. R.} and W. Wester",

year = "2018",

month = feb,

day = "20",

doi = "10.3847/1538-4357/aaa9b6",

language = "English",

volume = "854",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2",

}

Rumbaugh, N, Shen, Y, Morganson, E, Liu, X, Banerji, M, McMahon, RG, Abdalla, FB, Benoit-Lévy, A, Bertin, E, Brooks, D, Buckley-Geer, E, Capozzi, D, Carnero Rosell, A, Carrasco Kind, M, Carretero, J, Cunha, CE, D'Andrea, CB, Da Costa, LN, Depoy, DL, Desai, S, Doel, P, Frieman, J, García-Bellido, J, Gruen, D, Gruendl, RA, Gschwend, J, Gutierrez, G, Honscheid, K, James, DJ, Kuehn, K, Kuhlmann, S, Kuropatkin, N, Lima, M, Maia, MAG, Marshall, JL, Martini, P, Menanteau, F, Plazas, AA, Reil, K, Roodman, A, Sanchez, E, Scarpine, V, Schindler, R, Schubnell, M, Sheldon, E, Smith, M, Soares-Santos, M, Sobreira, F, Suchyta, E, Swanson, MEC, Walker, AR & Wester, W 2018, 'Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey', Astrophysical Journal, vol. 854, no. 2, 160. https://doi.org/10.3847/1538-4357/aaa9b6

TY - JOUR

T1 - Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey

AU - Rumbaugh, N.

AU - Shen, Yue

AU - Morganson, Eric

AU - Liu, Xin

AU - Banerji, M.

AU - McMahon, R. G.

AU - Abdalla, F. B.

AU - Benoit-Lévy, A.

AU - Bertin, E.

AU - Brooks, D.

AU - Buckley-Geer, E.

AU - Capozzi, D.

AU - Carnero Rosell, A.

AU - Carrasco Kind, M.

AU - Carretero, J.

AU - Cunha, C. E.

AU - D'Andrea, C. B.

AU - Da Costa, L. N.

AU - Depoy, D. L.

AU - Desai, S.

AU - Doel, P.

AU - Frieman, J.

AU - García-Bellido, J.

AU - Gruen, D.

AU - Gruendl, R. A.

AU - Gschwend, J.

AU - Gutierrez, G.

AU - Honscheid, K.

AU - James, D. J.

AU - Kuehn, K.

AU - Kuhlmann, S.

AU - Kuropatkin, N.

AU - Lima, M.

AU - Maia, M. A.G.

AU - Marshall, J. L.

AU - Martini, P.

AU - Menanteau, F.

AU - Plazas, A. A.

AU - Reil, K.

AU - Roodman, A.

AU - Sanchez, E.

AU - Scarpine, V.

AU - Schindler, R.

AU - Schubnell, M.

AU - Sheldon, E.

AU - Smith, M.

AU - Soares-Santos, M.

AU - Sobreira, F.

AU - Suchyta, E.

AU - Swanson, M. E.C.

AU - Walker, A. R.

AU - Wester, W.

PY - 2018/2/20

Y1 - 2018/2/20

N2 - We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey and 3 Year Dark Energy Survey imaging, which provide light curves spanning more than 15 years. We identified ∼1000 EVQs with a maximum change in g-band magnitude of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L bol ∼ 1045-1047 erg s-1 and L/L Edd ∼ 0.01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ∼30%-50% among all quasars over a baseline of ∼15 yr. We performed detailed multi-wavelength, spectral, and variability analyses for the EVQs and compared them to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggests that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low rates, where the accretion flow is more likely to experience instabilities that drive the changes in flux by a factor of a few on multi-year timescales.

AB - We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey and 3 Year Dark Energy Survey imaging, which provide light curves spanning more than 15 years. We identified ∼1000 EVQs with a maximum change in g-band magnitude of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L bol ∼ 1045-1047 erg s-1 and L/L Edd ∼ 0.01-1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ∼30%-50% among all quasars over a baseline of ∼15 yr. We performed detailed multi-wavelength, spectral, and variability analyses for the EVQs and compared them to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggests that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low rates, where the accretion flow is more likely to experience instabilities that drive the changes in flux by a factor of a few on multi-year timescales.

KW - black hole physics

KW - galaxies: active

KW - line: profiles

KW - quasars: general

KW - surveys

UR - http://www.scopus.com/inward/record.url?scp=85042690696&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/aaa9b6

DO - 10.3847/1538-4357/aaa9b6

M3 - Review article

AN - SCOPUS:85042690696

SN - 0004-637X

VL - 854

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 160

ER -

Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Cite this