Astron. Astrophys. Suppl. Ser. 138, 477-478

Severe new limits on the host galaxies of Gamma-Ray Bursts

B.E. Schaefer

Department of Physics, Yale University, New Haven, CT 06520-8121, U.S.A.

Received December 29, 1998; accepted June 9, 1999

Abstract:

Most burst models require bursters to reside in normal host galaxies with peak luminosities of $L = 1 \ 10^{57}$ photon s^-1 or $L = 2\ 10^{58}$ photon s^-1. These models can be directly tested by looking for host galaxies in small GRB error boxes in either of two data sets: (1) 8 optical transients detected for SAX bursts and (2) 23 of the all-time bright bursts. If the hosts are normal galaxies, then analysis of either data set shows $L\gt 6\ 10^{58}$ photon s^-1. This result strongly rejects both luminosity cases provided bursters appear in normal host galaxies, with the bright burst sample being free of problems relating to galaxy evolution. In conclusion, bursters are either more distant than allowed for in the star-formation-rate scenario or they are not in normal galaxies.

Key words: gamma-rays: bursts