Evidence that gamma-ray burst sources repeat
Abstract
We investigate the angular distribution of the $\gamma$-ray bursts in the publicly available BATSE catalogue, using the measures of burst brightness $B$ and short time scale ($\simless$ 0.3 s) variability $V$ which we introduced earlier. We show that the 54 type I ($\log V \le -0.8$) bursts lying in the middle brightness range 490 counts $\le B \le$ 1250 counts (corresponding to 1/3 of all type I bursts) exhibit a Galactic dipole moment of $\langle \cos \theta \rangle = 0.204 \pm 0.079$ {\it and} a deviation of the Galactic quadrupole moment from 1/3 of $\langle \sin^2 b \rangle - 1/3 = -0.104 \pm 0.041$. Using Monte Carlo simulations which include the BATSE sky exposure map and taking into account division of the type I bursts into three equal samples, we find that the probability by chance of an isotropic distribution of 54 bursts exhibiting values of $\langle \cos \theta \rangle$ {\it and} the negative of $\langle \sin^2 b \rangle - 1/3$ which equal or exceed the observed values is $6.6 \times 10^{-5}$. We conclude that $\gamma$-ray bursts are Galactic in origin.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- December 1993
- DOI:
- 10.1093/mnras/265.1.L59
- arXiv:
- arXiv:astro-ph/9307014
- Bibcode:
- 1993MNRAS.265L..59Q
- Keywords:
-
- Gamma Ray Bursts;
- Star Distribution;
- Stellar Luminosity;
- Sky Surveys (Astronomy);
- Statistical Analysis;
- Astronomical Catalogs;
- Position (Location);
- Space Radiation;
- Astrophysics
- E-Print:
- 6 pages, 3 figures available upon request, LATEX v. 2.09, MNRAS document style mn.sty included, 1