A Detection of Molecular Gas Emission in the Host Galaxy of GRB 080517

TL;DR

This paper reports the detection of molecular gas in the host galaxy of a low-redshift gamma-ray burst, providing insights into the galaxy's star formation and the timing of GRB events.

Contribution

First detection of molecular gas emission in the host galaxy of a low-redshift GRB, expanding understanding of GRB environments and star formation processes.

Findings

Molecular gas mass ~6.3 x 10^8 M_sun

Gas consumption timescale ~40 Myr

GRB occurs late in star formation episode

Abstract

We have observed the host galaxy of the low redshift, low luminosity GRB 080517 at 105.8 GHz using the IRAM Plateau de Bure interferometer. We detect an emission line with integrated flux S.delta{nu} = 0.39 +/- 0.05 Jy km/s - consistent both spatially and in velocity with identification as the J=1-0 rotational transition of carbon monoxide (CO) at the host galaxy redshift. This represents only the third long GRB host galaxy with molecular gas detected in emission. The inferred molecular gas mass, M_H2 ~ 6.3 x 10^8 M_sun, implies a gas consumption timescale of ~40 Myr if star formation continues at its current rate. Similar short timescales appear characteristic of the long GRB population with CO observations to date, suggesting that the gamma-ray burst in these sources occurs towards the end of their star formation episode.