First high-resolution details in gamma-ray burst host galaxy
Date: 27 June 2000
Satellite: Hubble Space Telescope
Depicts: ESO 184-G82, GRB 980425, SN 1998bw
Copyright: ESA, Stephen Holland (Danish Centre for Astrophysics with the HST), Jens Hjorth, Johan Fynbo (University of Copenhagen)
These images of the galaxy ESO 184-G82 are the most detailed images of a gamma-ray burst galaxy ever obtained. They were taken with the Space Telescope Imaging Spectrograph (STIS) onboard the NASA/ESA Hubble Space Telescope. The image on the left was taken with the STIS broad-band "clear" filter. A composite image created using the same broad-band image (in blue) and an image obtained with the STIS red filter (in red) is shown on the right and details from this image are shown in the upper right and in higher detail below right.
These new Hubble observations reveal that the host galaxy is actively star-forming and contains numerous clouds of hydrogen and regions teeming with activity from newly born hot stars. The galaxy is a spiral with loosely wound spiral arms and a large bar of gas and dust running through the centre.
The sharpness of the Hubble Space Telescope's vision has enabled astronomers to discover that the gamma-ray burst and the supernova occurred in an active region in one of the galaxy's spiral arms. Here an underlying hydrogen gas complex is overlaid with several bright red giant stars. At the exact position of the gamma-ray burst (marked with lines on the lower right image) a very compact source of emission is seen. Most of this emission is probably the last remnant of the fading light from the supernova itself, but the scientists suspect that a faint underlying star cluster may contribute as well.
This is a very important step forward in our understanding of gamma-ray bursts and their immediate surroundings and offers possible clues to their progenitors.
The Hubble observations were carried out 12 June 2000. The colour composite was constructed from two exposures combined in chromatic order: 1240 seconds through the clear filter (in blue), and 1185 seconds through a red filter (in red). The fields of view of the three images clockwise are 45x35 arcseconds, 13×7 arcseconds and 2x2arcseconds.
