Evidence for the Missing Baryons in the Angular Correlation of the Diffuse X-Ray Background
Abstract
The amount of detected baryons in the local universe is at least a factor of 2 smaller than that measured at high redshift. It is believed that a significant fraction of the baryons in the current universe is "hiding" in a hot filamentary structure filling the intergalactic space, the warm-hot intergalactic medium (WHIM). We found evidence of the missing baryons in the WHIM by detecting their signature on the angular correlation of diffuse X-ray emission with the XMM-Newton satellite. Our result indicates that 12% ± 5% of the total diffuse X-ray emission in the energy range 0.4-0.6 keV is due to intergalactic filaments. The statistical significance of our detection is several sigmas (χ2>136, N = 19). The error bar in the X-ray flux is dominated, instead, by cosmic variation and model uncertainties.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2009
- DOI:
- 10.1088/0004-637X/695/2/1127
- arXiv:
- arXiv:0812.2219
- Bibcode:
- 2009ApJ...695.1127G
- Keywords:
-
- large-scale structure of universe;
- X-rays: diffuse background;
- Astrophysics
- E-Print:
- 15 pages, 3 figures, Accepted for publication on ApJ