Excess light at the centre of dwarf spheroidal galaxies
Nordita Astrophysics seminars
Wednesday 07 September 2016
to 14:30 at
Naveen Jingade (Department of Physics, IISc, India)
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.