Anisotropies in the diffuse gamma-ray background measured by Fermi LAT

Details Anisotropies in the diffuse gamma-ray background measured by Fermi LAT Anisotropies in the diffuse gamma-ray background measured by Fermi LAT

2011-10-05

arxiv.org/abs/1110.1047v2

Astronomy and Astrophysics

Astrophysics

High Energy Astrophysical Phenomena

6 pages, Proceedings of the RICAP 2011 Conference, submitted to NIM A

Scientific paper

The small angular scale fluctuations of the (on large scale) isotropic gamma-ray background (IGRB) carry information about the presence of unresolved source classes. A guaranteed contribution to the IGRB is expected from the unresolved gamma-ray AGN while other extragalactic sources, Galactic gamma-ray source populations and dark matter Galactic and extragalactic structures (and sub-structures) are candidate contributors. The IGRB was measured with unprecedented precision by the Large Area Telescope (LAT) on-board of the Fermi gamma-ray observatory, and these data were used for measuring the IGRB angular power spectrum (APS). Detailed Monte Carlo simulations of Fermi-LAT all-sky observations were performed to provide a reference against which to compare the results obtained for the real data set. The Monte Carlo simulations are also a method for performing those detailed studies of the APS contributions of single source populations, which are required in order to identify the actual IGRB contributors. We present preliminary results of an anisotropy search in the IGRB. At angular scales <2deg (e.g. above multipole 155), angular power above the photon noise level is detected, at energies between 1 and 10 GeV in each energy bin, with statistical significance between 7.2 and 4.1 sigmas. The energy not dependence of the fluctuation anisotropy is pointing to the presence of one or more unclustered source populations, while the energy dependence of the intensity anisotropy is consistent with source populations having average photon index 2.40\pm0.07.

Affiliated with

Also associated with

No associations

Rating

Anisotropies in the diffuse gamma-ray background measured by Fermi LAT does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Anisotropies in the diffuse gamma-ray background measured by Fermi LAT, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Anisotropies in the diffuse gamma-ray background measured by Fermi LAT will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-325872