X-ray cluster of galaxies behind the Milky way

Our project, Clusters in the Zone of Avoidance (CIZA), uses X-ray data from the RASS for the initial cluster candidate selection and subsequent optical and NIR observations to confirm or refute the cluster nature of all selected candidates. We demonstrate that an X-ray survey can find galaxy clusters at low Galactic latitude where optical searches are inefficient because of massive obscuration and extinction problems.

We discuss the rationale for such a survey in the context of large-scale structure studies and describe in detail the combined X-ray/optical/NIR approach used by CIZA to identify clusters of galaxies at |b|<20{deg}, a region of the sky that has traditionally been excluded from earlier cluster catalogs. So far, CIZA has identified and spectroscopically confirmed 137 galaxy clusters in what used to be the zone of avoidance; additional clusters have been confirmed in imaging observations and await spectroscopic observation.