1. Optical Variability of Quasars with 20-Year Photometric Light Curves
- Author
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Zachary Stone, Yue Shen, Colin J. Burke, Yu-Ching Chen, Qian Yang, Xin Liu, Robert Gruendl, Monika Adamów, Felipe Andrade-Oliveira, James Annis, David Bacon, Emmanuel Bertin, Sebastian Bocquet, David Brooks, David Burke, Aurelio Carnero Rosell, Matias Carrasco-Kind, Jorge Carretero, Luiz da Costa, Maria Elidaiana da Silva Pereira, Juan De Vicente, Shantanu Desai, H. Thomas Diehl, Peter Doel, Ismael Ferrero, Douglas Friedel, Joshua Frieman, Juan García-Bellido, Enrique Gaztanaga, Daniel Gruen, Gaston Gutierrez, Samuel Hinton, Devon L. Hollowood, Klaus Honscheid, David James, Kyler Kuehn, Nikolay Kuropatkin, Chrostopher Lidman, Marcio Maia, Felipe Menanteau, Ramon Miquel, Robert Morgan, Francisco Paz-Chinchón, Adriano Pieres, Andrés Plazas-Malagón, Martin Rodriguez-Monroy, Eusebio Sanchez, Vic Scarpine, Santiago Serrano, Ignacio Sevilla-Noarbe, Mathew Smith, Eric Suchyta, Molly Swanson, Gregory Tarlé, Chun-Hao To, National Science Foundation (US), European Commission, Agenzia Spaziale Italiana, Alfred P. Sloan Foundation, Department of Energy (US), National Aeronautics and Space Administration (US), Max Planck Society, Higher Education Funding Council for England, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), European Research Council, Instituto Nacional de Ciência e Tecnologia (Brasil), Generalitat de Catalunya, Conselho Nacional das Fundaçôes Estaduais de Amparo à Pesquisa (Brasil), and UAM. Departamento de Física Teórica
- Subjects
Astrophysics::High Energy Astrophysical Phenomena ,quasars ,supermassive black holes ,Física ,FOS: Physical sciences ,Quasars: supermassive black holes ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Surveys ,Astrophysics - Astrophysics of Galaxies ,Quasars: general ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Galaxy Astrophysics - Abstract
Z. Stone et al., We study the optical gri photometric variability of a sample of 190 quasars within the SDSS Stripe 82 region that have long-term photometric coverage during ∼1998−2020 with SDSS, PanSTARRS-1, the Dark Energy Survey, and dedicated follow-up monitoring with Blanco 4m/DECam. With on average ∼200 nightly epochs per quasar per filter band, we improve the parameter constraints from a Damped Random Walk (DRW) model fit to the light curves over previous studies with 10–15 yr baselines and ≲ 100 epochs. We find that the average damping time-scale τDRW continues to rise with increased baseline, reaching a median value of ∼750 d (g band) in the rest frame of these quasars using the 20-yr light curves. Some quasars may have gradual, long-term trends in their light curves, suggesting that either the DRW fit requires very long baselines to converge, or that the underlying variability is more complex than a single DRW process for these quasars. Using a subset of quasars with better-constrained τDRW (less than 20 per cent of the baseline), we confirm a weak wavelength dependence of τDRW∝λ0.51 ± 0.20. We further quantify optical variability of these quasars over days to decades time-scales using structure function (SF) and power spectrum density (PSD) analyses. The SF and PSD measurements qualitatively confirm the measured (hundreds of days) damping time-scales from the DRW fits. However, the ensemble PSD is steeper than that of a DRW on time-scales less than ∼ a month for these luminous quasars, and this second break point correlates with the longer DRW damping time-scale., ZS and YS acknowledge support from NSF grants AST-1715579 and AST-2009947, and NASA grant 80NSSC21K0775. 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 DES participants from Spanish institutions are partially supported by MICINN under grants ESP2017-89838, PGC2018-094773, PGC2018-102021, SEV-2016-0588, SEV-2016-0597, and MDM-2015-0509, some of which include ERDF funds from the European Union. IFAE is partially funded by the CERCA programme of the Generalitat de Catalunya. Research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Program (FP7/2007-2013) including ERC grant agreements 240672, 291329, and 306478. We acknowledge support from the Brazilian Instituto Nacional de Ciência e Tecnologia (INCT) do e-Universo (CNPq grant 465376/2014-2).
- Published
- 2023
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