Multi-color observations of short GRB afterglows: 20 events observed between 2007 and 2010

TL;DR

This paper presents comprehensive multi-color optical and near-infrared observations of 20 short gamma-ray burst afterglows, providing valuable data on their light curves, host galaxies, and afterglow properties.

Contribution

It offers one of the most extensive datasets on short GRB afterglows, including early observations and host galaxy identifications, enhancing understanding of their nature.

Findings

Early observations led to the discovery of afterglows and host galaxies.

Light-curve evolution was tracked in multiple cases.

Upper limits were established for other bursts.

Abstract

We report on follow-up observations of 20 short-duration gamma-ray bursts performed in g'r'i'z'JHKs with the seven-channel imager GROND between mid-2007 and the end of 2010. This is one of the most comprehensive data sets on GRB afterglow observations of short bursts published so far. In three cases GROND was on target within less than 10 min after the trigger, leading to the discovery of the afterglow of GRB 081226A and its faint underlying host galaxy. In addition, GROND was able to image the optical afterglow and follow the light-curve evolution in further five cases, GRBs 090305, 090426, 090510, 090927, and 100117A. In all other cases optical/NIR upper limits can be provided on the afterglow magnitudes.