Abstract Details

Name: Pooja Bhattacharjee
Affiliation: Bose Institute, Kolkata
Conference ID: ASI2017_540
Title : Searching for signatures of dark matter annihilation from Triangulum II using FERMI gamma ray data
Authors and Co-Authors : Sayan Biswas (Bose Institute, Kolkata, India), Pratik Majumdar (Saha Institute of Nuclear Physics,HBNI, Kolkata, India), Mousumi Das (Indian Institute of Astrophysics, Bengaluru, India), Partha S. Joarder (Bose Institute, Kolkata, India), Pijushpani Bhattacharjee (Saha Institute of Nuclear Physics,HBNI, Kolkata, India)
Abstract Type : Oral
Abstract Category : Extragalactic astronomy
Abstract : Triangulum II (Tri II) is a recently discovered satellite of Milky Way by Pan-STARRS Survey and it appears to be a small ultra-faint and dark matter (DM) dominated dwarf spheroidal galaxy (dSphs) or globular Cluster on the edge of our galaxy. Its apparent low metallicity, high velocity dispersion and high mass to light ratio of 3600+3500 -2100 makes it a strong candidate for dark matter search. Current high precision data on cosmic microwave background (CMB) has established that non-baryonic form of matter i.e. DM, constitutes around 80% mass density of matter in the Universe. Experimental evidences and theoretical arguments favour the existence of some non-baryonic cold dark matter (CDM) to explain the formation of observed large-scale structures in the Universe. From this CDM scenario, dSphs are possibly the largest galactic substructures and they are ideal sites for indirect search of DM. Weakly interacting massive particles (WIMPs), predicted in several theories beyond the Standard Model (of particle physics), are the most probable candidates for CDM. It is assumed that pair-annihilation (or decay) would also occur in present days that would yield high energy gamma rays. Detection of such high energy gamma rays will provide indirect signature of DM. We here report on the observations of Tri-II with Fermi Gamma-Ray Space Telescope taken during its first (almost) seven years of all sky survey operation mode in the energy range 100 MeV to 50 GeV. No excess γ-ray emission has been detected above 100 MeV from Tri-II. Following this, we calculate the upper limit of gamma-ray flux due to the annihilation of WIMPs in Tri-II and put limits on the pair-annihilation cross section of WIMPs related to various theoretical models which are widely used to explain the nature of DM.