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:
- more »
- 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 = {2018},
month = {2}
}
Web of Science
Figures / Tables:

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Understanding Broad Mg II Variability in Quasars with Photoionization: Implications for Reverberation Mapping and Changing-Look Quasars
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