2010/06/30 by A. Neronov, D. Semikoz, D. V. Semikoz +4 · 55 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Fermi Gamma-ray Space Telescope #Galactic halo #Galaxy #Gamma ray #Halo #Intergalactic travel #Optics #Photon #Physics #Pulsar #Radio Astronomy Observations and Technology #Redshift #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.1051/0004-6361/201015892
published in Astronomy and Astrophysics 526, A90 (EDP Sciences) · accepted to A&A
arxiv created 2010/11/30 · openalex publication_date 2010/12/01 · arxiv updated 2015/05/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We analyze the gamma-ray halo around stacked AGNs reported by Ando & Kusenko (2010, ApJ, 722, L39). First, we show that the angular distribution of γ-rays around the stacked AGNs is consistent with the angular distribution of the γ-rays around the Crab pulsar, which is a point source for Fermi/LAT. This makes it unlikely that the halo is caused by an electromagnetic cascade of TeV photons in the intergalactic space. We then compare the angular distribution of γ-rays around the stacked AGNs with the point-spread function (PSF) of Fermi/LAT and confirm the existence of an excess above the PSF. However, we demonstrate that the magnitude and the angular size of this effect is different for photons converted in the front and back parts of the Fermi/LAT instrument, and thus is an instrumental effect.