Tomographic imaging of the Fermi-LAT gamma-ray sky through cross-correlations: A wider and deeper look

Abstract

We investigate the nature of the extragalactic unresolved gamma-ray background (UGRB) by cross-correlating several galaxy catalogs with sky-maps of the UGRB built from 78 months of Pass 8 Fermi-Large Area Telescope data. This study updates and improves similar previous analyses in several aspects. Firstly, the use of a larger gamma-ray dataset allows us to investigate the energy dependence of the cross-correlation in more detail, using up to 8 energy bins over a wide energy range of [0.25-500] GeV. Secondly, we consider larger and deeper catalogs (2MASS Photometric-Redshift catalog, 2MPZ; WISE x SuperCOSMOS, WISC; and SDSS-DR12 photometric-redshift dataset) in addition to the ones employed in the previous studies (NVSS and SDSS-QSOs). Thirdly, we exploit the redshift information available for the above catalogs to divide them into redshift bins and perform the cross-correlation separately in each of them. Our results confirm, with higher statistical significance, the detection of cross-correlation signal between the UGRB maps and all the catalogs considered, on angular scales smaller than 1 degree. Significances range from 16.3 sigma for NVSS, 7 sigma for SDSS-DR12 and WISC, 5 sigma for 2MPZ and 4 sigma for SDSS-QSOs. Furthermore, including redshift tomography, the significance of the SDSS-DR12 signal strikingly rises up to 12 sigma and the one of WISC to 10.6 sigma. We offer a simple interpretation of the signal in the framework of the halo model. The precise redshift and energy information allows us to clearly detect a change over redshift in the spectral and clustering behavior of the gamma-ray sources contributing to the UGRB.

19 pages, 18 figures, 3 tables + 2 appendices; Published in ApJS

References in corpus (20)

• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV
• The Origin of the Extragalactic Gamma-Ray Background and Implications for Dark-Matter Annihilation
• WISE x SuperCOSMOS photometric redshift catalog: 20 million galaxies over 3pi steradians
• Homogeneity and isotropy in the 2MASS Photometric Redshift catalogue
• Joint anisotropy and source count constraints on the contribution of blazars to the diffuse gamma-ray background
• A Combined EIS-NVSS Survey Of Radio Sources (CENSORS) III: Spectroscopic observations
• Cross-Correlation of Cosmic Shear and Extragalactic Gamma-ray Background: Constraints on the Dark Matter Annihilation Cross-Section
• Tomography of the Fermi-LAT gamma-ray diffuse extragalactic signal via cross-correlations with galaxy catalogs
• The angular power spectrum of the diffuse gamma-ray emission as measured by the Fermi Large Area Telescope and constraints on its Dark Matter interpretation
• Particle dark matter searches outside the Local Group
• The High Redshift Integrated Sachs-Wolfe Effect
• Evidence of cross-correlation between the CMB lensing and the gamma-ray sky
• Cross-correlating the gamma-ray sky with catalogs of galaxy clusters
• Power spectrum tomography of dark matter annihilation with local galaxy distribution
• The SuperCOSMOS all-sky galaxy catalogue
• Cross-correlation of weak lensing and gamma rays: implications for the nature of dark matter
• Fermi-LAT gamma-ray anisotropy and intensity explained by unresolved Radio-Loud Active Galactic Nuclei
• Cosmological constraints on dark matter annihilation and decay: Cross-correlation analysis of the extragalactic $\gamma$-ray background and cosmic shear
• Planck Lensing and Cosmic Infrared Background Cross-Correlation with Fermi-LAT: Tracing Dark Matter Signals in the Gamma-Ray Background

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