Metallicity in the GRB 100316D/SN 2010bh Host Complex

TL;DR

This study investigates the metallicity and star formation environment of the host galaxy of GRB 100316D/SN 2010bh, revealing it occurred in a low-metallicity, high star-formation region, providing insights into the explosion environment.

Contribution

It provides spatially-resolved spectrophotometric analysis of the host galaxy, linking metallicity and star formation to the GRB explosion site.

Findings

GRB 100316D/SN 2010bh occurred in a low-metallicity region.

The explosion site has the highest star formation rate.

Metallicity varies across the host galaxy.

Abstract

The recent long-duration GRB 100316D, associated with supernova SN 2010bh and detected by Swift, is one of the nearest GRB-SNe ever observed (z = 0.059). This provides us with a unique opportunity to study the explosion environment on ~kpc scale in relation to the host galaxy complex. Here we present spatially-resolved spectrophotometry of the host galaxy, focusing on both the explosion site and the brightest star-forming regions. Using these data, we extract the spatial profiles of the relevant emission features (Halpha, Hbeta, [OIII] 5007A, and [NII] 6584A), and use these profiles to examine variations in metallicity and star formation rate as a function of position in the host galaxy. We conclude that GRB 100316D/SN2010bh occurred in a low-metallicity host galaxy, and that the GRB-SN explosion site corresponds to the region with the lowest metallicity and highest star formation rate sampled by our observations.