Science with the unresolved cosmic background - An example from X-rays

The cosmic background carries unique information about diffuse emission and unresolved source populations. They are inaccessible by studies of the surface brightness of resolved source populations, but can be accessed via angular correlation studies of the surface brightness fluctuations. Since the discovery of the cosmic X-ray background (CXB) more than half a century ago, analyzing its surface brightness fluctuations has been a powerful tool in understanding its origin. Such analyses have suggested very early on that the CXB is dominated by extragalactic discrete sources, with Active Galactic Nuclei (AGN) leading the way. I will present you the currently most accurate measurement of CXB fluctuations on small angular scales (<3deg), where we find that they have also a great potential for studying X-ray unresolved and resolved clusters and groups of galaxies.

Speaker: 
Alexander Kolodzig
Location: 
KIAA first floor meeting room
Time: 
Fri, 2017-03-03 12:00 to 13:00