TOMOGRAPHY OF THE FERMI-LAT gamma-RAY DIFFUSE EXTRAGALACTIC SIGNAL VIA CROSS CORRELATIONS WITH GALAXY CATALOGS

	TOMOGRAPHY OF THE FERMI-LAT gamma-RAY DIFFUSE EXTRAGALACTIC SIGNAL VIA CROSS CORRELATIONS WITH GALAXY CATALOGS
	Xia JQ(夏俊卿); Xia, JQ; Cuoco, A; Branchini, E; Viel, M
刊名	ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
	2015
卷号	217 期号:1 页码:15
关键词	cosmology: observations cosmology: theory gamma rays: diffuse background large-scale structure of universe
通讯作者	夏俊卿
英文摘要	Building on our previous cross-correlation analysis (Xia et al. 2011) between the isotropic.-ray background (IGRB) and different tracers of the large-scale structure of the universe, we update our results using 60 months of data from the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi). We perform a cross-correlation analysis both in configuration and spherical harmonics space between the IGRB and objects that may trace the astrophysical sources of the IGRB: QSOs in the Sloan Digital Sky Survey (SDSS) DR6, the SDSS DR8 Main Galaxy Sample, luminous red galaxies (LRGs) in the SDSS catalog, infrared-selected galaxies in the Two Micron All Sky Survey (2MASS), and radio galaxies in the NRAO VLA Sky Survey (NVSS). The benefit of correlating the Fermi-LAT signal with catalogs of objects at various redshifts is to provide tomographic information on the IGRB, which is crucial in separating the various contributions and clarifying its origin. The main result is that, unlike in our previous analysis, we now observe a significant (>3.5 sigma) cross-correlation signal on angular scales smaller than 1 degrees in the NVSS, 2MASS, and QSO cases and, at lower statistical significance (similar to 3.0 sigma), with SDSS galaxies. The signal is stronger in two energy bands, E > 0.5 GeV and E > 1 GeV, but it is also seen at E > 10 GeV. No cross-correlation signal is detected between Fermi data and the LRGs. These results are robust against the choice of the statistical estimator, estimate of errors, map cleaning procedure, and instrumental effects. Finally, we test the hypothesis that the IGRB observed by Fermi-LAT originates from the summed contributions of three types of unresolved extragalactic sources: BL Lacertae objects (BL Lacs), flat spectrum radio quasars (FSRQs), and star-forming galaxies (SFGs). We find that a model in which the IGRB is mainly produced by SFGs (72(-37)(+23) 2 sigma errors), with BL Lacs and FSRQs giving a minor contribution, provides a good fit to the data. We also consider a possible contribution from misaligned active galactic nuclei, and we find that, depending on the details of the model and its uncertainty, they can also provide a substantial contribution, partly degenerate with the SFG one.
学科主题	Astronomy & Astrophysics
类目[WOS]	Astronomy & Astrophysics
收录类别	SCI
WOS记录号	WOS:000353466600015
公开日期	2016-05-03
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/228297]
专题	中国科学院高能物理研究所
推荐引用方式 GB/T 7714	Xia JQ,Xia, JQ,Cuoco, A,et al. TOMOGRAPHY OF THE FERMI-LAT gamma-RAY DIFFUSE EXTRAGALACTIC SIGNAL VIA CROSS CORRELATIONS WITH GALAXY CATALOGS[J]. ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES,2015,217(1):15.
APA	夏俊卿,Xia, JQ,Cuoco, A,Branchini, E,&Viel, M.(2015).TOMOGRAPHY OF THE FERMI-LAT gamma-RAY DIFFUSE EXTRAGALACTIC SIGNAL VIA CROSS CORRELATIONS WITH GALAXY CATALOGS.ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES,217(1),15.
MLA	夏俊卿,et al."TOMOGRAPHY OF THE FERMI-LAT gamma-RAY DIFFUSE EXTRAGALACTIC SIGNAL VIA CROSS CORRELATIONS WITH GALAXY CATALOGS".ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES 217.1(2015):15.