2015/11/30 by Li Shang, Shang Li, Yun-Feng Liang +8 · 1 citation
Physics and Astronomy · #Annihilation #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark matter #Dwarf galaxy #Dwarf spheroidal galaxy #Fermi Gamma-ray Space Telescope #Galaxy #Gamma ray #Interacting galaxy #Particle physics #Physics #astro-ph.CO #astro-ph.HE #hep-ph
paper · pdf · doi:10.1103/physrevd.93.043518
published as Physical Review D 93, 043518 (2016) · To appear in Phys. Rev. D, Fig.4 has been updated and main conclusions are unchanged
arxiv created 2016/01/28 · openalex publication_date 2016/02/10 · arxiv updated 2016/03/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Very recently the Dark Energy Survey (DES) Collaboration has released their second group of dwarf spheroidal (dSph) galaxy candidates. With the publicly available Pass 8 data of Fermi-LAT we search for \ensuremathγ-ray emissions from the directions of these eight newly discovered dSph galaxy candidates. No statistically significant \ensuremathγ-ray signal has been found in the combined analysis of these sources. With the empirically estimated J-factors of these sources, the constraint on the annihilation channel of \ensuremathχ\ensuremathχ\ensuremath→\ensuremathτ+\ensuremathτ^\ensuremath- is comparable to the bound set by the joint analysis of fifteen previously known dSphs with kinematically constrained J-factors for the dark matter mass m_\ensuremathχ>250 GeV. In the direction of Tucana III (DES J2356-5935), one of the nearest dSph galaxy candidates that is \ensuremath∼25 kpc away, there is a weak \ensuremathγ-ray signal and its peak test statistic (TS) value for the dark matter annihilation channel \ensuremathχ\ensuremathχ\ensuremath→\ensuremathτ+\ensuremathτ^\ensuremath-1 is \ensuremath≈6.7 at m_\ensuremathχ\ensuremath∼15 GeV. The significance of the possible signal likely increases with time. More data is highly needed to pin down the physical origin of such a GeV excess.