Correlated optical, X-ray, and γ-ray flaring activity seen with INTEGRAL during the 2015 outburst of V404 Cygni
Correlated optical, X-ray, and γ-ray flaring activity seen with INTEGRAL during the 2015 outburst of V404 Cygni
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DOI：
10.1051/0004-6361/201527043
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发表时间：
2015-07
影响因子：
6.5
通讯作者：
J. Rodriguez;M. C. Bel;J. Alfonso-Garzón;T. Siegert;Xianyu Zhang;V. Grinberg;V. Savchenko;J. Tomsick;J. Chenevez;M. Clavel;S. Corbel;R. Diehl;A. Domingo;C. Gouiffès;Jochen Greiner;M. Krause;P. Laurent;A. Loh;S. Markoff;J. Mas-Hesse;J. Miller-Jones;D. Russell;J. Wilms
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作者：
J. Rodriguez;M. C. Bel;J. Alfonso-Garzón;T. Siegert;Xianyu Zhang;V. Grinberg;V. Savchenko;J. Tomsick;J. Chenevez;M. Clavel;S. Corbel;R. Diehl;A. Domingo;C. Gouiffès;Jochen Greiner;M. Krause;P. Laurent;A. Loh;S. Markoff;J. Mas-Hesse;J. Miller-Jones;D. Russell;J. Wilms
经过25年的沉寂，微类星体V404 Cyg在2015年6月进入了一个新的活动时期。已知这种X射线源在所有波长下都会发生极其明亮和可变的爆发。因此，理解吸积-喷射的联系是一个首要的兴趣。然而，这些只能通过同时观测几个波长来探测。我们利用INTEGRAL仪器从2015年6月20日15：50 UTC到6月25日4：05 UTC获得了从光学V波段到软γ射线的长时间、几乎不间断的观测。V404 Cyg在所有波段都非常多变，在三天内探测到18个通量超过6 Crab（20-40 keV）的耀斑。耀斑复发可短至约20分钟，从峰值到峰值。与模型无关的分析表明，大于6的蟹状耀斑具有硬谱。一个简单的10-400千电子伏的光谱分析的非耀斑和耀斑期间表明，强度的变化很可能只是由于一个截止的幂律分量的变化。光学耀斑似乎至少有两种不同的类型：一种与X射线耀斑同步发生，另一种延迟大于10分钟。前者可能与X射线后处理有关，无论是吸积盘还是伴星星星。我们认为，后者是与等离子体喷射，也已经看到在无线电。
After 25 years of quiescence, the microquasar V404 Cyg entered a new period of activity in June 2015. This X-ray source is known to undergo extremely bright and variable outbursts seen at all wavelengths. It is therefore an object of prime interest to understand the accretion-ejection connections. These can, however, only be probed through simultaneous observations at several wavelengths. We made use of the INTEGRAL instruments to obtain long, almost uninterrupted observations from 2015 June 20, 15:50 UTC to June 25, 4:05 UTC, from the optical V band up to the soft γ-rays. V404 Cyg was extremely variable in all bands, with the detection of 18 flares with fluxes exceeding 6 Crab (20–40 keV) within three days. The flare recurrence can be as short as ~20 min from peak to peak. A model-independent analysis shows that the >6 Crab flares have a hard spectrum. A simple 10–400 keV spectral analysis of the off-flare and flare periods shows that the variation in intensity is likely to be only due to variations of a cut-off power-law component. The optical flares seem to be at least of two different types: one occurring in simultaneity with the X-ray flares, the other showing a delay greater than 10 min. The former could be associated with X-ray reprocessing by either an accretion disk or the companion star. We suggest that the latter are associated with plasma ejections that have also been seen in radio.