The Galaxy Hosts and Large-Scale Environments of Short-Hard Gamma-Ray Bursts

• Published in: The Astrophysical journal 2006-05, Vol.642 (2), p.989-994
• Main Authors: Prochaska, J. X, Bloom, J. S, Chen, H.-W, Foley, R. J, Perley, D. A, Ramirez-Ruiz, E, Granot, J, Lee, W. H, Pooley, D, Alatalo, K, Hurley, K, Cooper, M. C, Dupree, A. K, Gerke, B. F, Hansen, B. M. S, Kalirai, J. S, Newman, J. A, Rich, R. M, Richer, H, Stanford, S. A, Stern, D, van Breugel, W. J. M
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/501160

The rapid succession of discoveries of short-duration hard-spectrum gamma-ray bursts (GRBs) has led to unprecedented insights into the energetics of the explosion and nature of the progenitors. Yet short of the detection of a smoking gun, such as a burst of coincident gravitational radiation or a Li-Paczynski minisupernova, it is unlikely that a definitive claim can be made for the progenitors. As was the case with long-duration soft-spectrum GRBs, however, the expectation is that a systematic study of the hosts and locations of short GRBs could begin to yield fundamental clues as to their nature. We present an aggregate study of the host galaxies of short-duration hard-spectrum GRBs. In particular, we present the Gemini-North and Keck discovery spectra of the galaxies that hosted three short GRBs and a moderate-resolution (R - 6000) spectrum of a fourth host. We find that these short-hard GRBs originate in a variety of low-redshift (z < 1) environments that differ substantially from those of long-soft GRBs, both on individual galaxy scales and on galaxy-cluster scales. Specifically, three of the bursts are found to be associated with old and massive galaxies with no current (