School of Astronomy

Abstract:

There are two populations of early-type galaxies generally known as Core and Power-law, when classified according to their central radial surface brightness profiles. Their luminosity distribution is fairly bimodal with core profile galaxies show a peak at M_v~ -23 and the power-law profile galaxies are peaked at M_v~-20. There is also a significant overlap around the dividing luminosity between the two populations as well as the existence of small number of galaxies known as `intermediate' population. We use the information on the environment of galaxies in the overlapping region to investigate whether the two populations are predominantly driven by the local galaxy density.

In order to disentangle the intrinsic luminosity from the environment richness, I compare the local environment of luminous power-law galaxies with that of faint core galaxies. I find power-law galaxies more isolated than the core galaxies suggesting a strong correlation between the two populations and the local density of galaxies.