Astron. Astrophys. Suppl. Ser. 138, 413-414

Twelve hundred non-triggered gamma ray bursts

B. Stern^1,4 - Ya. Tikhomirova² - M. Stepanov³ - D. Kompaneets² - A. Berezhnoy³ - R. Svensson⁴

1 - Institute for Nuclear Research, Russian Academy of Sciences, Moscow 117312, Russia
e-mail: stern@al20.inr.troitsk.ru
2 - Astro Space Center of Lebedev Physical Institute, Moscow, Profsoyuznaya 84/32, 117810, Russia
3 - Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119899, Russia
4 - Stockholm Observatory, S-133 36 Saltsjöbaden, Sweden

Received January 21; accepted June 25, 1999

Abstract:

We present preliminary results of an off-line search for non-triggered gamma-ray bursts (GRBs) in the BATSE daily records for about 5.7 years of observations. We found more GRB-like events than the yield of the similar search of Kommers et al. (1998) and extended the $\log\, N - \log\, P$ distribution down to $\rm \sim 0.1\, ph\, cm^{-2}\, s^{-1}$. The indication of a turnover of the $\log\, N - \log\, P$ at a small P is not confirmed: the distribution is straight at 1.5 decades with the power law index -.6 and cannot be fitted with a standard candle cosmological model.

Key words: gamma-ray bursts -- methods: data analysis