Severe New Limits on the Host Galaxies of Gamma-Ray Bursts

The nature of Gamma Ray Bursts (GRBs) remains a complete mystery, despite therecent breakthrough discovery of low energy counterparts, although it is nowgenerally believed that at least most GRBs are at cosmological distances.Virtually all proposed cosmological models require bursters to reside inordinary galaxies. This can be tested by looking inside the smallest GRB errorboxes to see if ordinary galaxies appear at the expected brightness levels.This letter reports on an analysis of the contents of 26 of the smallestregions, many from the brightest bursts. These events will have $z < 0.4$ andsmall uncertainties about luminosity functions, K corrections and galaxyevolutions; whereas the recent events with optical transients are much fainterand hence have high redshifts and grave difficulties in interpretation. Thisanalysis strongly rejects the many models with peak luminosities of $10^{57}photons \cdot s^{-1}$ as deduced from the $LogN-LogP$ curve with no evolution.Indeed, the lower limit on acceptable luminosities is $6 \times 10^{58} photons\cdot s^{-1}$. The only possible solution is to either place GRBs atunexpectedly large distances (with $z > 5.9$ for the faint BATSE bursts) or torequire bursters to be far outside any normal host galaxy.Comment: 17 pages, to be published by ApJ