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The Westerbork Coma Survey begins!

Submitter: Paolo Serra
Description: On June 15 the first observation of the Westerbork Coma Survey will be taken. Coma is the largest cluster of galaxies within a distance of ~100 Mpc. It contains ~1000 galaxies packed together within a small volume of space. As all large clusters, Coma is filled with a hot gaseous medium emitting X-ray radiation. This hot gas is very hostile to galaxies' cold inter-stellar medium, so that galaxies in Coma are usually gas poor and, as a consequence, do not form new stars.

In contrast with this simplistic picture, one puzzling aspect of Coma is that many of its galaxies seem to have hosted star formation very recently. Furthermore, a fairly large number of small, blue (i.e., star forming) galaxies reside in the cluster. Direct observation of Coma galaxies' cold-gas content (traced by radio emission coming from neutral hydrogen atoms) is needed in order to understand these results and, more generally, study how galaxy evolution proceeds in such a dense environment. This is precisely the aim of the Westerbork Coma Survey.

This survey is conducted by a large international team led by ASTRON's Paolo Serra. It includes E. de Blok, G. Jozsa and T. Oosterloo, all at ASTRON, and another dozen researchers from the Netherlands, U.S., Italy, Mexico and U.K. The image above shows the survey layout. The optical colour image (taken from the Sloan Digital Sky Survey) shows the Coma cluster and the red ellipse represents the area covered by the survey. The centre of the cluster is at the location of the two, large elliptical galaxies visible in the field, and the survey will include the well known south-west infalling group. Stay tuned for the first results!!!
Copyright: SDSS and WCS team
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