2017年10月
Rapid optical variations correlated with X-rays in the 2015 second outburst of V404 Cygni (GS 2023+338)
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
- 巻
- 471
- 号
- 1
- 開始ページ
- 373
- 終了ページ
- 382
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1093/mnras/stx1555
- 出版者・発行元
- OXFORD UNIV PRESS
We present optical multicolour photometry of V404 Cyg during the outburst from 2015 December to 2016 January together with the simultaneous X-ray data. This outburst occurred less than sixmonths after the previous outburst in 2015 June-July. These two outbursts in 2015 were of a slow-rise and rapid-decay type and showed large-amplitude (similar to 2mag) and short-term (similar to 10 min-3 h) optical variations even at low luminosity (0.01-0.1L(Edd)). We found correlated optical and X-ray variations in two similar to 1 h time intervals and obtained a Bayesian estimate of an X-ray delay against the optical emission, which is similar to 30-50 s, during those two intervals. In addition, the relationship between the optical and X-ray luminosities was L-opt alpha L-X(0.25-0.29) at that time. These features cannot be easily explained by the conventional picture of transient black hole binaries, such as canonical disc reprocessing and synchrotron emission related to a jet. We suggest that the disc was truncated during those intervals and that the X-ray delays represent the required time for the propagation of mass accretion flow to the inner optically thin region with a speed comparable to the free-fall velocity.
- リンク情報
- ID情報
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- DOI : 10.1093/mnras/stx1555
- ISSN : 0035-8711
- eISSN : 1365-2966
- Web of Science ID : WOS:000408211700021