Nordita Astrophysics Seminars

Excess light at the centre of dwarf spheroidal galaxies

by Naveen Jingade (Department of Physics, IISc, India)

132:028 ()


In this talk, I'll briefly mention about the dichotomy seen between the luminous ellipticals and dwarf elliptical galaxies, (in literature, such a dichotomy is referred as E-E dichotomy). Luminous ellipticals has a "missing-light" at the center compared to the inward-extrapolation of the outward best fit Sersic profile and dwarf galaxies has excess light. These excess light galaxies have further two subclasses, which are dwarf spheroidal galaxies (Sph) and dwarf elliptical galaxies (E). Observations mention that they have qualitatively different brightness cusp at the center. Cusp seen in E's are explained by the merger hypothesis, but cusp seen in Sph's remain outside the purview of such hypothesis. We apply an alternate model, that is the cusp formation due to the slow growth of the black hole at the center in such galaxies and show that nature of the cusp in Sph's and the cusp formed in such a model have similarities and compute the excess mass accumulated at the center which scales approximately linear with the black hole mass.