Systematic study for gas-to-dust ratio of short gamma-ray burst afterglows
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.
Keywords
Cite
@article{arxiv.1903.05963,
title = {Systematic study for gas-to-dust ratio of short gamma-ray burst afterglows},
author = {Kazuki Yoshida and Daisuke Yonetoku and Makoto Arimoto and Tatsuya Sawano and Yasuaki Kagawa},
journal= {arXiv preprint arXiv:1903.05963},
year = {2019}
}
Comments
15 pages, 4 figures