An updated gamma-ray analysis of the Be-BH binary HD~215227
| Title: | An updated gamma-ray analysis of the Be-BH binary HD~215227 |
|---|---|
| Authors: | Alexander, Michael J., McSwain, M. Virginia |
| Publication Year: | 2015 |
| Collection: | Astrophysics |
| Subject Terms: | Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena |
| More Details: | We report an updated analysis of the gamma-ray source AGL J2241+4454 that was detected as a brief two-day flare in 2010 by the AGILE satellite. The high-energy emission of AGL J2241+4454 has been attributed to the binary system HD 215227, which consists of a Be star being orbited by a black hole making it the first known Be-black hole binary system. We have analyzed the AGILE data and find a gamma-ray flux of $(1.8\pm0.7)\times10^{-6}$ ph cm$^{-2}$ s$^{-1}$, in agreement with the initial report. Additionally, we examined data from the Fermi LAT over several time intervals including the two day flare, the folded orbital phase, and the entire mission ($\sim$6-years). We do not detect AGL J2241+4454 over any of these time periods with Fermi and find upper limits of $1.1\times10^{-7}$ ph cm$^{-2}$ s$^{-1}$ and $5.2\times10^{-10}$ ph cm$^{-2}$ s$^{-1}$ for the flare and the full mission, respectively. We conclude that the HD 215227 Be-black hole binary is not a true gamma-ray binary as previous speculated. While analyzing the Fermi data of the AGL J2241+4454 region, we discovered a previously unknown gamma-ray source with average flux of $(13.56\pm0.02)\times10^{-8}$ ph cm$^{-2}$ s$^{-1}$ that is highly variable on monthly timescales. We associate this emission with the known quasar 87GB 215950.2+503417. Comment: Accepted for publication in MNRAS, 10 pages, 5 figures |
| Document Type: | Working Paper |
| DOI: | 10.1093/mnras/stv400 |
| Access URL: | http://arxiv.org/abs/1502.07385 |
| Accession Number: | edsarx.1502.07385 |
| Database: | arXiv |
Be the first to leave a comment!