The X-Ray Background from Groups and Clusters of Galaxies
Abstract
We present an estimate of the X-ray background (XRB) spectrum from the warm-hot intergalactic medium (IGM) associated with groups and clusters of galaxies using purely the observationally determined X-ray luminosity function and X-ray luminosity-temperature (LX-T) relations for groups and clusters. As compared with previous semianalytic models based on the Press-Schechter mass function, our approach provides a much simpler and more realistic way to evaluate the XRB from groups and clusters, in the sense that we make no assumption about the dynamical and heating properties of the IGM, and the intrinsic dispersion in the LX-T relations due to different physical mechanisms among different groups and clusters can be also included. It shows that the resulting 0.1-10 keV XRB spectrum, by summing up the X-ray emission from all groups and clusters, is consistent with current upper limits placed on the contribution from diffuse gas to the XRB. This may have profound implications for our understanding of the missing baryons in the universe.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2001
- DOI:
- 10.1086/322961
- arXiv:
- arXiv:astro-ph/0106355
- Bibcode:
- 2001ApJ...560..544W
- Keywords:
-
- Cosmology: Theory;
- Cosmology: Diffuse Radiation;
- Galaxies: Clusters: General;
- Galaxies: Intergalactic Medium;
- X-Rays: Galaxies: Clusters;
- X-Rays: General;
- Astrophysics
- E-Print:
- 6 pages, 3 figure, accepted for publication in ApJ