A population of short-period variable quasars from PTF as supermassive black hole binary candidates
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- 28 July 2016
- journal article
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 463 (2), 2145-2171
- https://doi.org/10.1093/mnras/stw1838
Abstract
Supermassive black hole binaries (SMBHBs) at sub-parsec separations should be common in galactic nuclei, as a result of frequent galaxy mergers. Hydrodynamical simulations of circum-binary discs predict strong periodic modulation of the mass accretion rate on time-scales comparable to the orbital period of the binary. As a result, SMBHBs may be recognized by the periodic modulation of their brightness. We conducted a statistical search for periodic variability in a sample of 35 383 spectroscopically confirmed quasars in the photometric data base of the Palomar Transient Factory (PTF). We analysed Lomb–Scargle periodograms and assessed the significance of our findings by modelling each individual quasar's variability as a damped random walk (DRW). We identified 50 quasars with significant periodicity beyond the DRW model, typically with short periods of a few hundred days. We find 33 of these to remain significant after a re-analysis of their periodograms including additional optical data from the intermediate-PTF and the Catalina Real-Time Transient Survey. Assuming that the observed periods correspond to the redshifted orbital periods of SMBHBs, we conclude that our findings are consistent with a population of unequal-mass SMBHBs, with a typical mass ratio as low as q ≡ M2/M1 ≈ 0.01.Other Versions
This publication has 95 references indexed in Scilit:
- STRUCTURE AND EVOLUTION OF CIRCUMBINARY DISKS AROUND SUPERMASSIVE BLACK HOLE BINARIESThe Astrophysical Journal, 2013
- Coevolution (Or Not) of Supermassive Black Holes and Host GalaxiesAnnual Review of Astronomy and Astrophysics, 2013
- IS QUASAR OPTICAL VARIABILITY A DAMPED RANDOM WALK?The Astrophysical Journal, 2013
- Super-massive binary black holes and emission lines in active galactic nucleiNew Astronomy Reviews, 2012
- KEPLER OBSERVATIONS OF RAPID OPTICAL VARIABILITY IN ACTIVE GALACTIC NUCLEIThe Astrophysical Journal Letters, 2011
- A close nuclear black-hole pair in the spiral galaxy NGC 3393Nature, 2011
- CHANDRA OBSERVATIONS OF A 1.9 kpc SEPARATION DOUBLE X-RAY SOURCE IN A CANDIDATE DUAL ACTIVE GALACTIC NUCLEUS GALAXY AT z = 0.16The Astrophysical Journal Letters, 2011
- An Eccentric Circumbinary Accretion Disk and the Detection of Binary Massive Black HolesThe Astrophysical Journal, 2008
- Time Series Analysis with Clean - Part One - Derivation of a SpectrumThe Astronomical Journal, 1987
- Studies in astronomical time series analysis. II - Statistical aspects of spectral analysis of unevenly spaced dataThe Astrophysical Journal, 1982