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Angular power spectrum of gamma-ray sources for GLAST: blazars and clusters of galaxies

Ando, Shin'ichiro and Komatsu, Eiichiro and Narumoto, Takuro and Totani, Tomonori (2007) Angular power spectrum of gamma-ray sources for GLAST: blazars and clusters of galaxies. Monthly Notices of the Royal Astronomical Society, 376 (4). pp. 1635-1647. ISSN 0035-8711. doi:10.1111/j.1365-2966.2007.11421.x.

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Blazars, a beamed population of active galactic nuclei, radiate high-energy γ-rays, and thus are a good target for the Gamma Ray Large Area Space Telescope (GLAST). As the blazars trace the large-scale structure of the Universe, one may observe spatial clustering of blazars. We calculate the angular power spectrum of blazars that would be detected by GLAST. We show that we have the best chance of detecting their clustering at large angular scales, θ ≳ 10°, where shot noise is less important, and the dominant contribution to the correlation comes from relatively low redshift, z ≲ 0.1. The GLAST can detect the correlation signal, if the blazars detected by GLAST trace the distribution of low-z quasars observed by optical galaxy surveys, which have the bias of unity. If the bias of blazars is greater than 1.5, GLAST will detect the correlation signal unambiguously. We also find that GLAST may detect spatial clustering of clusters of galaxies in γ-rays. The shape of the angular power spectrum is different for blazars and clusters of galaxies; thus, we can separate these two contributions on the basis of the shape of the power spectrum.

Item Type:Article
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Komatsu, Eiichiro0000-0002-0136-2404
Additional Information:© 2007 Royal Astronomical Society. Accepted 2006 December 18. Received 2006 October 5. SA and EK would like to thank Jennifer Carson for useful discussion; SA is also grateful to Andrew Benson and Marc Kamionkowski for comments. SA was supported by Sherman Fairchild Fellowship at Caltech. EK acknowledges support from an Alfred P. Sloan Foundation. TN and TT were supported by a Grant-in-Aid for the 21st Century COE ‘Centre for Diversity and Universality in Physics’ from the Ministry of Education, Culture, Sports, Science and Technology of Japan.
Funding AgencyGrant Number
Sherman Fairchild FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Ministry of Education, Culture, Sports, Science and Technology (MEXT)UNSPECIFIED
Subject Keywords:galaxies: active; BL Lacertae objects: general; galaxies: clusters: general; cosmology: theory; large-scale structure of Universe; gamma-rays: theory
Issue or Number:4
Record Number:CaltechAUTHORS:20090408-112326455
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13893
Deposited On:16 Jul 2009 19:56
Last Modified:08 Nov 2021 22:41

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