Publication Date:
2015-01-07
Description:
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. The recent availability of large collections of astronomical time series of flux measurements (light curves) 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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Graham, Matthew J -- Djorgovski, S G -- Stern, Daniel -- Glikman, Eilat -- Drake, Andrew J -- Mahabal, Ashish A -- Donalek, Ciro -- Larson, Steve -- Christensen, Eric -- England -- Nature. 2015 Feb 5;518(7537):74-6. doi: 10.1038/nature14143. Epub 2015 Jan 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA. ; Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, USA. ; Department of Physics, Middlebury College, Middlebury, Vermont 05753, USA. ; Lunar and Planetary Laboratory, Department of Planetary Sciences, University of Arizona, 1629 East University Boulevard, Tucson, Arizona 85721, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25561176" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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