Abstract Details
| Name: Karthik A B Affiliation: Christ University Conference ID: ASI2016_751 Title : Unidentified 3.5kev line in Dwarf Galaxies,Dark Matter sources Authors and Co-Authors : Dr Firoza Sutaria, Indian Institute of Astrophysics Dr Subinoy Das, Indian Institute of Astrophysics Ms Swathi Karanth, Christ University Bangalore. Mr Karthik A B, Christ University Bangalore. Abstract Type : Poster Abstract Category : General Relativity and Cosmology Abstract : Simulations of galaxy formation based on the Lambda Cold Dark matter (ΛCDM) cosmological model predict that a large galaxy such as the Milky Way should have many (~ 200) dwarf satellite galaxies. However, only about 20 or 30 have been identified. Where are the rest? Are they really there? Warm dark matter, constituting of sterile neutrinos, is lighter, and therefore resolves this issue as it erases structures in small scale. Recently, a previously unidentified, soft X-ray excess, at (3.55−3.57) ± 0.03 keV, in the spectra of some galaxies has been associated with the decay of sterile neutrino warm dark matter [Bulbul et al. 2014ApJ...789...13B]. Here, we report on our search for this weak, previously unidentified, emission line in the stacked XMM-Newton spectra of NGC 1399 of Fornax cluster, and the Draco dwarf spheroidal galaxy. We do not find evidence for this line in the NGC 1399. If it is the case that these weak signal are absent in dwarf spheroidal but present in stacked spectra of clusters reported by Bulbul et al., once explanation could arise from the difference in dark matter density profile in dspH and galaxy clusters. Especially, if the signal originates due to annihilation rather than decay, it would be very sensitive to DM density profile towards the centre of x-ray source. |