The Host Galaxies of Gamma-ray Bursts

This is a sampling of the host galaxies of long-duration gamma-ray bursts taken by NASA's Hubble Space Telescope. Gamma-ray bursts are powerful flashes of high-energy radiation that arise from some supernovae, the explosive deaths of extremely massive stars. Long-duration bursts last more than one to two seconds. The green crosshairs pinpoint the location of the gamma-ray bursts, now long faded away. The galaxies in these images were part of a study that compared the environments of long bursts with those of supernovae. Only a small fraction of a certain type of supernovae produces gamma-ray bursts. These six images show the wide variety of host galaxies of gamma-ray bursts. The distances of these bursts range from 2 billion to 10 billion light-years from Earth. Most of the galaxies in these images are misshapen, irregular galaxies. The only exception is the spiral galaxy in the middle image on the top row. In this image, the bright round objects above, below, and to the right of the cross hairs are foreground stars in the Small Magellanic Cloud, a satellite galaxy of our Milky Way Galaxy. Researchers conducting the study found that long bursts occur in the brightest regions of mostly irregular galaxies where the most massive stars are forming. Typical supernovae, on the other hand, are more uniformly distributed across their host galaxies. Supernovae also come from larger, more developed galaxies than do the gamma-ray bursts. The images were taken between 1999 and 2005 by Hubble's Wide Field Planetary Camera 2, Space Telescope Imaging Spectrograph, and Advanced Camera for Surveys.