2008/12/11 by M. Galeazzi, A. Gupta, Anjali Gupta +2
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Bar (unit) #Baryon #Cosmic ray #Cosmology and Gravitation Theories #Flux (metallurgy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Intergalactic medium #Intergalactic travel #Physics #Quasar #Redshift #Universe #X-ray background #astro-ph
paper · pdf · doi:10.1088/0004-637x/695/2/1127
published as Astrophys.J.695:1127-1131,2009 · 15 pages, 3 figures, Accepted for publication on ApJ
arxiv created 2008/12/11 · openalex publication_date 2009/04/07 · arxiv updated 2014/11/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 (χ 2 >136, N = 19). The error bar in the X-ray flux is dominated, instead, by cosmic variation and model uncertainties.