# Cosmology with X-ray Galaxy Clusters

The massive dark matter halos that host galaxy clusters can be well traced by X-ray satellite observatories. The intracluster gas trapped in the deep potential wells gets heated to 10s of millions of Kelvin, emitting thermal bremsstrahlung at X-ray wavelengths. The latest cosmological constraints from X-ray selected galaxy clusters will be discussed. A new test to constrain the cosmological luminosity distance anisotropy using galaxy clusters is introduced and results indicating a violation of isotropy are shown. New X-ray selected very extended nearby galaxy groups and clusters have been discovered in ROSAT All-Sky Survey images at positions where no X-ray source was found previously; the properties of the cluster candidate sample (>1,000 in total) and implications for cosmological constraints from clusters are discussed. The current status of and prospects for the eROSITA telescope to be launched aboard the SRG mission early next year are outlined. The expectations for the ESA L-class mission Athena to discover and characterize early galaxy groups, massive and evolved enough to contain $>$10 million Kelvin gas, above redshift 2 are quantified.

Speaker:
Thomas H. Reiprich (Argelander-Institut für Astronomie, Bonn University)
Location:
KIAA, 1st meeting room
Time:
Tue, 2018-11-13 12:00 to 13:00