Large-scale variations of the cosmic X-ray background and the X-ray emissivity of the local Universe

Abstract

We study the cosmic X-ray background (CXB) intensity variations on large angular scales using slew data of the RXTE observatory. We detect intensity variations up to ~2% on angular scales of 20--40deg. These variations are partly correlated with the local large-scale structure, which allowed us to estimate the emissivity of the local Universe in the energy band 2--10 keV at 9+/-4 x 10^{38} ers/sec/Mpc^{3}. The spectral energy distribution of the large-angular-scale variations is hard and is compatible with that of the CXB, which implies that normal galaxies and clusters of galaxies, whose spectra are typically much softer, do not contribute more than 15% to the total X-ray emissivity of the local Universe. Most of the observed CXB anisotropy (after exclusion of point sources with fluxes >10^{-11} erg/s/cm^2) can be attributed to low-luminosity AGNs

12 pages, 9 figures, Submitted to A&A

References in corpus (9)

• The hierarchical formation of the brightest cluster galaxies
• INTEGRAL/IBIS all-sky survey in hard X-rays
• The clustering of narrow-line AGN in the local Universe
• Hard X-ray emission from the Galactic ridge
• Cumulative hard X-ray spectrum of local AGN: a link to the cosmic X-ray background
• Resolving the Galactic X-ray background
• The X-ray luminosity function and number counts of spiral galaxies
• Hard X-ray emission of the Earth's atmosphere: Monte Carlo simulations
• The PSCz Dipole Revisited

Cited by in corpus (3)

• NuSTAR measurement of the cosmic X-ray background in the 3-20 keV energy band
• Measurements of the Cosmic X-ray Background of the Universe and the MVN Experiment
• Measuring the Cosmic X-ray Background accurately