Systematic study for gas-to-dust ratio of short gamma-ray burst afterglows
Systematic study for gas-to-dust ratio of short gamma-ray burst afterglows
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DOI：
10.1093/pasj/psz030
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发表时间：
2019-03
影响因子：
2.3
通讯作者：
Kazuki Yoshida;D. Yonetoku;M. Arimoto;T. Sawano;Y. Kagawa
中科院分区：
文献类型：
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作者：
Kazuki Yoshida;D. Yonetoku;M. Arimoto;T. Sawano;Y. Kagawa
河外X射线吸收和消光现象经常出现在伽玛射线暴（GRB）的余辉中，它们可能是环暴和宿主星系环境的示踪物。通过对9个已知红移的短伽玛暴（SGRB）余辉光谱能量分布的谱分析，得到了每个SGRB静止坐标系中等效氢柱密度与尘埃消光的比值N^{rest}_{H}/A^{rest}_{V}。我们发现N^{rest}_{H}/A^{rest}_{V}的分布系统地小于长伽玛暴的分布，并且与银河系中的气尘比大致一致。这一结果意味着测量到的SGRB的气尘比将来自每个宿主星系中的星际介质。这种情况支持SGRB发生在宿主星系的非恒星形成区域的预测。
Extra-galactic X-ray absorption and optical extinction are often found in gamma-ray burst (GRB) afterglows and they could be tracers of both circumburst and host galaxy environments. By performing spectral analyses for spectral energy distribution of 9 short GRB (SGRB) afterglows with known redshift, we investigated a ratio of the equivalent hydrogen column density to the dust extinction, N^{rest}_{H}/A^{rest}_{V}, in the rest frame of each SGRB. We found that the distribution of N^{rest}_{H}/A^{rest}_{V} is systematically smaller than the one for long GRBs, and is roughly consistent with the gas-to-dust ratio in the Milky Way. This result means that the measured gas-to-dust ratio of SGRBs would originate from the interstellar medium in each host galaxy. This scenario supports the prediction that SGRBs occur in non star-forming regions in the host galaxies.