High-energy gamma-ray observations of the accreting black hole V404 Cygni during its 2015 June outburst
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2016-10-11
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Mcode
Degree programme
Language
en
Pages
5
L111-L115
L111-L115
Series
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS, Volume 462, issue 1
Abstract
We report on Fermi/Large Area Telescope observations of the accreting black hole low-mass X-ray binary V404 Cygni during its outburst in 2015 June-July. Detailed analyses reveal a possible excess of γ -ray emission on 2015 26 June, with a very soft spectrum above 100 MeV, at a position consistent with the direction of V404 Cyg (within the 95 per cent confidence region and a chance probability of 4 × 10-4). This emission cannot be associated with any previously known Fermi source. Its temporal coincidence with the brightest radio and hard X-ray flare in the light curve of V404 Cyg, at the end of the main active phase of its outburst, strengthens the association with V404 Cyg. If the γ -ray emission is associated with V404 Cyg, the simultaneous detection of 511 keV annihilation emission by INTEGRAL reqires that the high-energy γ -rays originate away from the corona, possibly in a Blandford-Znajek jet. The data give support to models involving a magnetically arrested disc where a bright γ -ray jet can re-form after the occurrence of a major transient ejection seen in the radio.Description
Keywords
Black hole physics, Gamma-rays: stars, Radio continuum: stars, Stars: individual: V404 Cygni, X-rays: binaries
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Citation
Loh , A , Corbel , S , Dubus , G , Rodriguez , J , Grenier , I , Hovatta , T , Pearson , T , Readhead , A , Fender , R & Mooley , K 2016 , ' High-energy gamma-ray observations of the accreting black hole V404 Cygni during its 2015 June outburst ' , MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS , vol. 462 , no. 1 , pp. L111-L115 . https://doi.org/10.1093/mnrasl/slw142