TY - JOUR
T1 - Observations of GRB 970228 and GRB 970508 and the neutron star merger model
AU - Sahu, Kailash C.
AU - Livio, Mario
AU - Petro, Larry
AU - Bond, Howard E.
AU - Duccio Macchetto, F.
AU - Galama, Titus J.
AU - Groot, Paul J.
AU - Van Paradijs, Jan
AU - Kouveliotou, Chryssa
N1 - Funding Information:
We are grateful to P. Madau and E. Fenimore for useful discussions. We acknowledge the help of Colin Cox with the geometric distortion correction of the HST images, and Ray Lucas and others in the scheduling division for efficiently scheduling the observations of GRB 970228. We thank F. Fron-tera and M. Garcia for communication of results in advance of publication. M. L. acknowledges support from NASA grant NAGW-2678. KPNO is operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.
PY - 1997
Y1 - 1997
N2 - We present the discovery observations for the optical counterpart of the γ-ray burster GRB 970508 and discuss its light curve in the context of the fireball model. We analyze the HST data for this object and conclude that any underlying galaxy must be fainter than R = 25.5. We also present a detailed analysis of the HST images of GRB 970228, from which a proper motion of the optical counterpart was claimed by Caraveo et al., and conclude that, within the uncertainties, there is no proper motion. We examine several aspects of the neutron star merger model for γ-ray bursts. In particular, we use this model to predict the redshift distribution of γ-ray bursters, and, adopting a recent determination of the cosmic star formation history, we show that the predicted log N- log P distribution is consistent with that observed for GRBs.
AB - We present the discovery observations for the optical counterpart of the γ-ray burster GRB 970508 and discuss its light curve in the context of the fireball model. We analyze the HST data for this object and conclude that any underlying galaxy must be fainter than R = 25.5. We also present a detailed analysis of the HST images of GRB 970228, from which a proper motion of the optical counterpart was claimed by Caraveo et al., and conclude that, within the uncertainties, there is no proper motion. We examine several aspects of the neutron star merger model for γ-ray bursts. In particular, we use this model to predict the redshift distribution of γ-ray bursters, and, adopting a recent determination of the cosmic star formation history, we show that the predicted log N- log P distribution is consistent with that observed for GRBs.
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U2 - 10.1086/316786
DO - 10.1086/316786
M3 - Article
AN - SCOPUS:21944438109
SN - 0004-637X
VL - 489
SP - L127-L131
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2 PART II
ER -