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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 $$g\lesssim 22$$ 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.

Authors:
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Publication Date:
Research Org.:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP)
Contributing Org.:
DES Collaboration
OSTI Identifier:
1425676
Alternate Identifier(s):
OSTI ID: 1389253; OSTI ID: 1409080; OSTI ID: 1435204
Report Number(s):
BNL-114280-2017-JA; FERMILAB-PUB-17-211-AE; arXiv:1706.07875
Journal ID: ISSN 1538-4357; TRN: US1802147
Grant/Contract Number:  
AC02-76SF00515; AST-1138766; AYA2012-39559; ESP2013-48274; FPA2013-47986; 240672; 291329; 306478; SC0012704; AC02-07CH11359; AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 854; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; black hole physics; galaxies: active; line: profiles; quasars: general; surveys

Citation Formats

Rumbaugh, N., Shen, Yue, Morganson, Eric, Liu, Xin, 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., Desai, S., Doel, P., Frieman, J., García-Bellido, J., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lima, M., Maia, M. A. G., Marshall, J. L., Martini, P., Menanteau, F., Plazas, A. A., Reil, K., Roodman, A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sheldon, E., Smith, M., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Walker, A. R., and Wester, W. Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey. United States: N. p., 2018. Web. doi:10.3847/1538-4357/aaa9b6.
Rumbaugh, N., Shen, Yue, Morganson, Eric, Liu, Xin, 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., Desai, S., Doel, P., Frieman, J., García-Bellido, J., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lima, M., Maia, M. A. G., Marshall, J. L., Martini, P., Menanteau, F., Plazas, A. A., Reil, K., Roodman, A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sheldon, E., Smith, M., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Walker, A. R., & Wester, W. Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey. United States. https://doi.org/10.3847/1538-4357/aaa9b6
Rumbaugh, N., Shen, Yue, Morganson, Eric, Liu, Xin, 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., Desai, S., Doel, P., Frieman, J., García-Bellido, J., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Honscheid, K., James, D. J., Kuehn, K., Kuhlmann, S., Kuropatkin, N., Lima, M., Maia, M. A. G., Marshall, J. L., Martini, P., Menanteau, F., Plazas, A. A., Reil, K., Roodman, A., Sanchez, E., Scarpine, V., Schindler, R., Schubnell, M., Sheldon, E., Smith, M., Soares-Santos, M., Sobreira, F., Suchyta, E., Swanson, M. E. C., Walker, A. R., and Wester, W. Wed . "Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey". United States. https://doi.org/10.3847/1538-4357/aaa9b6. https://www.osti.gov/servlets/purl/1425676.
@article{osti_1425676,
title = {Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey},
author = {Rumbaugh, N. and Shen, Yue and Morganson, Eric and Liu, Xin and Banerji, M. and McMahon, R. G. and Abdalla, F. B. and Benoit-Lévy, A. and Bertin, E. and Brooks, D. and Buckley-Geer, E. and Capozzi, D. and Carnero Rosell, A. and Carrasco Kind, M. and Carretero, J. and Cunha, C. E. and D’Andrea, C. B. and da Costa, L. N. and DePoy, D. L. and Desai, S. and Doel, P. and Frieman, J. and García-Bellido, J. and Gruen, D. and Gruendl, R. A. and Gschwend, J. and Gutierrez, G. and Honscheid, K. and James, D. J. and Kuehn, K. and Kuhlmann, S. and Kuropatkin, N. and Lima, M. and Maia, M. A. G. and Marshall, J. L. and Martini, P. and Menanteau, F. and Plazas, A. A. and Reil, K. and Roodman, A. and Sanchez, E. and Scarpine, V. and Schindler, R. and Schubnell, M. and Sheldon, E. and Smith, M. and Soares-Santos, M. and Sobreira, F. and Suchyta, E. and Swanson, M. E. C. and Walker, A. R. and Wester, W.},
abstractNote = {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 $g\lesssim 22$ 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.},
doi = {10.3847/1538-4357/aaa9b6},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 854,
place = {United States},
year = {Wed Feb 21 00:00:00 EST 2018},
month = {Wed Feb 21 00:00:00 EST 2018}
}

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Figures / Tables:

Figure 1 Figure 1: The g band magnitude change between the first and second extrema is plotted versus the corresponding change in g − i, so that a positive ∆g indicates a decrease in brightness. The red points are the selected EVQs. For quasars at all levels of variability, we see amore » correlation between changes in magnitude and color. This implies that the i-band flux varies in the same direction as the g-band flux, but with a reduced amplitude.« less

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Selecting Quasars by Their Intrinsic Variability
journal, April 2010


The man Behind the Curtain: X-Rays Drive the uv Through nir Variability in the 2013 Active Galactic Nucleus Outburst in ngc 2617
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Weak Emission-Line Quasars in the Context of a Modified Baldwin Effect
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Self-Shadowing Effects of slim Accretion Disks in Active Galactic Nuclei: the Diverse Appearance of the Broad-Line Region
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A Population of X-Ray weak Quasars: phl 1811 Analogs at high Redshift
journal, July 2011


The Dark Energy Survey
conference, January 2006

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The detection and X-ray view of the changing look AGN HE 1136-2304
text, January 2016

  • Parker, Ml; Komossa, S.; Kollatschny, W.
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Slow-blue nuclear hypervariables in PanSTARRS-1
text, January 2016

  • Lawrence, A.; Bruce, A. G.; MacLeod, C.
  • Apollo - University of Cambridge Repository
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The Dark Energy Survey
conference, May 2012

  • Sevilla, Ignacio
  • Proceedings of XXIst International Europhysics Conference on High Energy Physics — PoS(EPS-HEP2011)
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The Close AGN Reference Survey (CARS): Mrk 1018 returns to the shadows after 30 years as a Seyfert 1
journal, September 2016


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
text, January 2017

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  • Apollo - University of Cambridge Repository
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Exploring the Variable Sky with the Sloan Digital Sky Survey
text, January 2007


The XMM-Newton long look of NGC 1365: uncovering of the obscured X-ray source
text, January 2008


Optically Selected BL Lacertae Candidates from the Sloan Digital Sky Survey Data Release Seven
text, January 2009


Selecting Quasars by their Intrinsic Variability
text, January 2010


The Sloan Digital Sky Survey Quasar Catalog V. Seventh Data Release
text, January 2010


The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
text, January 2010


Optimal Time-Series Selection of Quasars
text, January 2010


Unification of Luminous Type 1 Quasars through CIV Emission
text, January 2010


A Population of X-ray Weak Quasars: PHL 1811 Analogs at High Redshift
text, January 2011


A Description of Quasar Variability Measured Using Repeated SDSS and POSS Imaging
text, January 2011


The 31 Deg$^2$ Release of the Stripe 82 X-ray Survey: The Point Source Catalog
text, January 2015


The detection and X-ray view of the changing look AGN HE 1136-2304
text, January 2016


iPTF Discovery of the Rapid "Turn On" of a Luminous Quasar
text, January 2016


Mid-infrared variability of changing-look AGN
text, January 2017


A photometricity and extinction monitor at the Apache Point Observatory
text, January 2001


The Ensemble Photometric Variability of ~25000 Quasars in the Sloan Digital Sky Survey
text, January 2003


SDSS Data Management and Photometric Quality Assessment
text, January 2004


The 2.5 m Telescope of the Sloan Digital Sky Survey
text, January 2006


The Sloan Digital Sky Survey Photometric Camera
text, January 1998


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The Ensemble Photometric Variability of Over 10 5 Quasars in the Dark Energy Camera Legacy Survey and the Sloan Digital Sky Survey
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The Sloan Digital Sky Survey Reverberation Mapping Project: Accretion and Broad Emission Line Physics from a Hypervariable Quasar
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Initial Results from a Systematic Search for Changing-look Active Galactic Nuclei Selected via Mid-infrared Variability
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Discovery of an Mg ii Changing-look Active Galactic Nucleus and Its Implications for a Unification Sequence of Changing-look Active Galactic Nuclei
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NuSTAR Perspective on High-redshift MeV Blazars
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Observational Nonstationarity of AGN Variability: The Only Way to Go Is Down!
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Two New “Turn-off” Changing-look Active Galactic Nuclei and Implication on “Partially Obscured” AGNs
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An Unusual Mid-infrared Flare in a Type 2 AGN: An Obscured Turning-on AGN or Tidal Disruption Event?
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A model for AGN variability on multiple timescales
text, January 2018


A new physical interpretation of optical and infrared variability in quasars
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HST/COS observations of the newly discovered obscuring outflow in NGC 3783
text, January 2018


WISE view of Narrow-Line Seyfert 1 galaxies: mid-infrared color and variability
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A forward modelling approach to AGN variability -- Method description and early applications
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Observational nonstationarity of AGN variability: The only way to go is down!
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