V404 Cygni with Fermi-LAT
Abstract
We revisit the well-studied outburst of the low-mass X-ray binary (LMXB) system V404 Cygni, and claims of γ-ray excesses observed with the Fermi-LAT instrument. Upon analysing an 11.5 yr data set with the 8-yr LAT point source catalogue and 8-yr background models, we find no evidence to suggest that there is high energy γ-ray emission during the outburst period (or at any other time) from V404 Cygni. This is due to the proximity of V404 Cygni to the γ-ray emitting blazar B2023+336, a luminous source approximately 0.3○ away, which causes source confusion at the position of V404 Cygni, the luminous γ-ray background, and the use of older background models and catalogues in previous studies.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2021
- DOI:
- arXiv:
- arXiv:2107.09395
- Bibcode:
- 2021MNRAS.506.6029H
- Keywords:
-
- black hole physics;
- gamma-rays: stars;
- X-rays: binaries;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 11 pages, 6 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Society