The Host Galaxy of GRB 970508
The Host Galaxy of GRB 970508
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DOI：
10.1086/311682
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发表时间：
1998-07
期刊：
影响因子：
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通讯作者：
J. Bloom;J. Bloom;S. Djorgovski;S. Kulkarni;D. Frail
中科院分区：
文献类型：
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作者：
J. Bloom;J. Bloom;S. Djorgovski;S. Kulkarni;D. Frail
我们目前的后期成像和光谱观测的光学瞬变（OT）和宿主星系的GRB 970508。在爆发后大约200和300天的成像观测为光变曲线的平坦化提供了明确的证据。光谱观测揭示了两个持久的特征，我们在z=0.835的红移处识别为[O II] λ3727和[Ne III] λ3869-与瞬态明亮时看到的吸收系统相同的红移。OT与底层星系的一致性好于370质量或投影径向分离小于2.7千秒差距。[O II]线的光度意味着最小星星形成速率为1百万分之一年。在我们假设的宇宙学中，隐含的静止坐标系绝对星等为MB =-18.55，或LB=0.12 L*。这个天体可能是GRB 970508的宿主，因此可以被描述为一个活跃的恒星形成矮星系。这个矮星系和OT之间的紧密空间联系要求即使在最弱的星系势中，至少有一部分伽马射线爆发的祖先也不会被喷射出来。
We present late-time imaging and spectroscopic observations of the optical transient (OT) and host galaxy of GRB 970508. Imaging observations roughly 200 and 300 days after the burst provide unambiguous evidence for the flattening of the light curve. The spectroscopic observations reveal two persistent features that we identify with [O II] λ3727 and [Ne III] λ3869 at a redshift of z=0.835—the same redshift as the absorption system seen when the transient was bright. The OT was coincident with the underlying galaxy to better than 370 mas or a projected radial separation of less than 2.7 kpc. The luminosity of the [O II] line implies a minimum star formation rate of 1 M☉ yr-1. In our assumed cosmology, the implied rest-frame absolute magnitude isMB=-18.55, or LB=0.12 L*. This object, the likely host of GRB 970508, can thus be characterized as an actively star-forming dwarf galaxy. The close spatial connection between this dwarf galaxy and the OT requires that at least some fraction of gamma-ray burst progenitors are not ejected in even the weakest galactic potentials.