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Title: EVIDENCE OF CROSS-CORRELATION BETWEEN THE CMB LENSING AND THE γ-RAY SKY

We report the measurement of the angular power spectrum of cross-correlation between the unresolved component of the Fermi-LAT γ-ray sky maps and the cosmic microwave background lensing potential map reconstructed by the Planck satellite. The matter distribution in the universe determines the bending of light coming from the last scattering surface. At the same time, the matter density drives the growth history of astrophysical objects, including their capability at generating non-thermal phenomena, which in turn give rise to γ-ray emissions. The Planck lensing map provides information on the integrated distribution of matter, while the integrated history of γ-ray emitters is imprinted in the Fermi-LAT sky maps. We report here the first evidence of their correlation. We find that the multipole dependence of the cross-correlation measurement is in agreement with current models of the γ-ray luminosity function for active galactic nuclei and star-forming galaxies, with a statistical evidence of 3.0σ. Moreover, its amplitude can in general be matched only assuming that these extragalactic emitters are also the bulk contribution of the measured isotopic γ-ray background (IGRB) intensity. This leaves little room for a big contribution from galactic sources to the IGRB measured by Fermi-LAT, pointing toward direct evidence of the extragalacticmore » origin of the IGRB.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. Dipartimento di Fisica, Università di Torino, I-10125 Torino (Italy)
  2. LPSC, Université Grenoble-Alpes, CNRS/IN2P3, 53, rue des Martyrs, F-38026 Grenoble Cedex (France)
  3. Jodrell Bank Centre for Astrophysics, The University of Manchester, Manchester M13 9PL (United Kingdom)
Publication Date:
OSTI Identifier:
22518818
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 802; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; CORRELATIONS; DENSITY; EMISSION SPECTRA; GALAXIES; GALAXY NUCLEI; GAMMA RADIATION; GRAVITATIONAL LENSES; LUMINOSITY; RELICT RADIATION; SATELLITES; SCATTERING; STAR EVOLUTION; STARS; UNIVERSE; VISIBLE RADIATION