Chen 2007 NGC1705-1的环境观测

主要内容:
可能能发生伽玛暴。

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文章信息:
arXiv:0706.2364 [ps, pdf, other] : Title: Super Star Cluster NGC1705-1: A Local Analogue to the Birthsite of Long-duration Gamma-ray Bursts
Authors: Hsiao-Wen Chen (University of Chicago), J. X. Prochaska (UCO/Lick Observatory), Joshua S. Bloom (UC Berkeley)
Comments: 20 pages, including 3 figurs. ApJ in press

Recent observations suggest that global properties of the host galaxies for long-duration gamma-ray bursts (GRBs) are particularly well-suited for creating the massive star progenitors of these GRBs. Motivated by the hypothesis that massive young star clusters located in metal-poor, low-metallicity galaxies are a natural birthsite for GRB progenitors, we present a comparison study of the ISM properties along the sightline toward the super star cluster, NGC1705-1, and those in distant GRB hosts. Using the same set of metal transitions in the UV and applying known ISM structures in NGC1705, we find that NGC1705-1 resembles distant GRB host galaxies in its high neutral gas column, low molecular gas fraction, low metallicity, alpha-element enhancement,and low dust depletion. The lack of molecular gas is due to the enhanced UV radiation field in the starburst environment, consistent with the expectations for GRB progenitors. In addition, the known presence of dense neutral gas clouds at r<500>