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arXiv · 1903.05963

Systematic study for gas-to-dust ratio of short gamma-ray burst afterglows

Kazuki Yoshida·Daisuke Yonetoku·Makoto Arimoto·Tatsuya Sawano·Yasuaki Kagawa
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Abstract

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.

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Kazuki Yoshida, Daisuke Yonetoku, Makoto Arimoto, Tatsuya Sawano, Yasuaki Kagawa. 2019-03-14. Systematic study for gas-to-dust ratio of short gamma-ray burst afterglows. https://doi.org/10.1093/pasj%2Fpsz030

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