A possible close supermassive black-hole binary in a quasar with optical periodicity

Article

关键词: ACTIVE GALACTIC NUCLEI;    DIGITAL SKY SURVEY;    SURVEY SPECTROSCOPIC SAMPLE;    PHOTOMETRIC STANDARD STARS;    TIME TRANSIENT SURVEY;    ACCRETION DISK;    JET PRECESSION;    VARIABILITY;    PARSEC;    MASS;   

DOI  :  10.1038/nature14143

来源: SCIE

【 摘 要 】

Quasars have long been known to be variable sources at all wavelengths. Their optical variability is stochastic and can be due to a variety of physical mechanisms; it is also well-described statistically in terms of a damped random walk model(1). The recent availability of large collections of astronomical timeseries of flux measurements (light curves(2-5)) offers new data sets for a systematic exploration of quasar variability. Here we report the detection of a strong, smooth periodic signal in the optical variability of the quasar PG 1302-102 with a mean observed period of 1,884 +/- 88 days. It was identified in a search for periodic variability in a data set of light curves for 247,000 known, spectroscopically confirmed quasars with a temporal baseline of about 9 years. Although the interpretation of this phenomenon is still uncertain, the most plausible mechanisms involve a binary system of two supermassive black holes with a subparsec separation. Such systems are an expected consequence of galaxy mergers and can provide important constraints on models of galaxy formation and evolution.

【 授权许可】

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