Correlated optical, X- ray, and gamma- ray flaring activity seen with INTEGRAL during the 2015 outburst of V404 Cygni

Rodriguez J, Bel MC, Alfonso-Garzon J, Siegert T, Zhang XL, Grinberg V, Savchenko V, Tomsick JA, Chenevez J, Clavel M, Corbel S, Diehl R, Domingo A, Gouiffes C, Greiner J, Krause MGH, Laurent P, Loh A, Markoff S, Mas-Hesse JM, Miller-Jones JCA, Russell DM, Wilms J (2015)

Publication Status: Published

Publication Type: Journal article

Publication year: 2015

Journal

Astronomy & Astrophysics EDP Sciences

Publisher: EDP Sciences

Book Volume: 581

DOI: 10.1051/0004-6361/201527043

Abstract

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 gamma-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 similar to 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.

Authors with CRIS profile

Jörn Wilms Professur für Astronomie und Astrophysik

Involved external institutions

Curtin University AU Australia (AU) New York University Abu Dhabi (NYU Abu Dhabi) AE United Arab Emirates (AE) University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot FR France (FR) Rechenzentrum Garching der Max-Planck-Gesellschaft (MPCDF) / Max Planck Computing & Data Facility DE Germany (DE) Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC) ES Spain (ES) Max-Planck-Institut für extraterrestrische Physik (MPE) / Max Planck Institute for Extraterrestrial Physics DE Germany (DE) Massachusetts Institute of Technology (MIT) US United States (USA) (US) University of California, Berkeley US United States (USA) (US) Technical University of Denmark / Danmarks Tekniske Universitet (DTU) DK Denmark (DK) University of Amsterdam NL Netherlands (NL)

How to cite

APA:

Rodriguez, J., Bel, M.C., Alfonso-Garzon, J., Siegert, T., Zhang, X.-L., Grinberg, V.,... Wilms, J. (2015). Correlated optical, X- ray, and gamma- ray flaring activity seen with INTEGRAL during the 2015 outburst of V404 Cygni. Astronomy & Astrophysics, 581. https://dx.doi.org/10.1051/0004-6361/201527043

MLA:

Rodriguez, J., et al. "Correlated optical, X- ray, and gamma- ray flaring activity seen with INTEGRAL during the 2015 outburst of V404 Cygni." Astronomy & Astrophysics 581 (2015).

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