A search for pair haloes around active galactic nuclei through a temporal analysis of Fermi-Large Area Telescope data
Abstract
We develop a method to search for pair haloes around active galactic nuclei (AGN) through a temporal analysis of γ-ray data. The basis of our method is an analysis of the spatial distributions of photons coming from AGN flares and from AGN quiescent states and a further comparison of these two spatial distributions. This method can also be used for a reconstruction of a point spread function (PSF). We found no evidence for a pair halo component through this method by applying it to the Fermi-Large Area Telescope (LAT) data in the energy bands of 4.5-6, 6-10, and >10 GeV and set upper limits on the fraction of photons attributable to a pair halo component. An illustration of how to reconstruct the PSF of Fermi-LAT is given. We demonstrate that the PSF reconstructed by using this method is in good agreement with that which was obtained by using the γ-ray data taken by LAT in the direction of the Crab pulsar and nebula.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 2016
- DOI:
- 10.1093/mnras/stw056
- arXiv:
- arXiv:1506.00593
- Bibcode:
- 2016MNRAS.457.2433P
- Keywords:
-
- methods: data analysis;
- galaxies: active;
- intergalactic medium;
- gamma-rays: general;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 14 pages, 1 figure, a typo corrected. The version published in MNRAS