| Title | The Ensemble Photometric Variability of Over 10(5) Quasars in the Dark Energy Camera Legacy Survey and the Sloan Digital Sky Survey |
| Authors | Li, Zefeng McGreer, Ian D. Wu, Xue-Bing Fan, Xiaohui Yang, Qian |
| Affiliation | Peking Univ, Sch Phys, Dept Astron, Beijing 100871, Peoples R China. Univ Arizona, Steward Observ, 933 North Cherry Ave, Tucson, AZ 85721 USA. Peking Univ, Kavli Inst Astron & Astrophys, Beijing 100871, Peoples R China. |
| Keywords | galaxies: active galaxies: nuclei quasars: general techniques: photometric ACTIVE GALACTIC NUCLEI TERM OPTICAL VARIABILITY DAMPED RANDOM-WALK BLACK-HOLE STARBURST MODEL EDDINGTON RATIO RADIO-SOURCES LIGHT CURVES QSOS FLUCTUATIONS |
| Issue Date | 2018 |
| Publisher | ASTROPHYSICAL JOURNAL |
| Citation | ASTROPHYSICAL JOURNAL. 2018, 861(1). |
| Abstract | We present the ensemble variability analysis results of quasars using the Dark Energy Camera Legacy Survey (DECaLS) and the Sloan Digital Sky Survey (SDSS) quasar catalogs. Our data set includes 119,305 quasars with redshifts up to 4.89. Combining the two data sets provides a 15 year baseline and permits the analysis of the long timescale variability. Adopting a power-law form for the variability structure function, V = A(t/1years)(gamma), we use the multidimensional parametric fitting to explore the relationships between the quasar variability amplitude and a wide variety of quasar properties, including redshift (positive), bolometric luminosity (negative), rest-frame wavelength (negative), and black hole mass (uncertain). We also find that gamma can be also expressed as a function of redshift (negative), bolometric luminosity (positive), rest-frame wavelength (positive), and black hole mass (positive). Tests of the fitting significance with the bootstrap method show that, even with such a large quasar sample, some correlations are marginally significant. The typical value of gamma for the entire data set is greater than or similar to 0.25, consistent with the results in previous studies on both the quasar ensemble variability and the structure function. A significantly negative correlation between the variability amplitude and the Eddington ratio is found, which may be explained as an effect of accretion disk instability. |
| URI | http://hdl.handle.net/20.500.11897/523488 |
| ISSN | 0004-637X |
| DOI | 10.3847/1538-4357/aac6ce |
| Indexed | SCI(E) |
| Appears in Collections: | 物理学院 科维理天文与天体物理研究所 |
