Stefano Andreon (INAF-OA Brera)

Gas-poor clusters: what kind of beasts are they?

The known variety of galaxy clusters is constantly increasing with our  progress in understanding the severity of selection effects on observational samples and with obvious implications on cosmology and cluster physics. In the talk, after a general introduction on galaxy clusters and a reminder on  selection effects, I present perhaps the first X-ray unbiased sample of clusters with known masses and X-ray follow-up, its more variegate nature compared to clusters selected by the intracluster medium (X-ray or SZ), and first results based on a deeper X-ray follow-up of a few of them.