A Spatially Resolved Study of the GRB 020903 Host Galaxy

TL;DR

This study uses spatially-resolved spectroscopy to analyze the host galaxy of GRB 020903, revealing that the burst occurred in a typical, sub-solar metallicity region of its complex, interacting galaxy.

Contribution

It provides one of the few spatially-resolved spectroscopic analyses of a GRB host galaxy, confirming the explosion site reflects the galaxy's overall metallicity.

Findings

GRB 020903 host consists of four interacting components.

The explosion site has sub-solar metallicity similar to nearby star-forming regions.

The GRB site is representative of the host galaxy's metallicity.

Abstract

GRB 020903 is a long-duration gamma ray burst (LGRB) with a host galaxy close enough and extended enough for spatially-resolved observations, making it one of less than a dozen GRBs where such host studies are possible. GRB 020903 lies in a galaxy host complex that appears to consist of four interacting components. Here we present the results of spatially-resolved spectroscopic observations of the GRB 020903 host. By taking observations at two different position angles we were able to obtain optical spectra (3600-9000{\AA}) of multiple regions in the galaxy. We confirm redshifts for three regions of the host galaxy that match that of GRB 020903. We measure metallicity of these regions, and find that the explosion site and the nearby star-forming regions both have comparable sub-solar metallicities. We conclude that, in agreement with past spatially-resolved studies of GRBs, the GRB explosion site is representative of the host galaxy as a whole rather than localized in a metal-poor region of the galaxy.