Study on the Relationship between the Number Distribution of Satellite Galaxies and the Properties of Central Galaxies

Abstract

Satellite galaxies are powerful probes of galaxies formation. Recent studies have pointed out that when the central galaxy is an elliptical galaxy, there are more satellite galaxies than spiral galaxies. In order to explore this difference, we used the data constructed from TNG300-1 of the Next Generation Illustris Simulations set. We select the central galaxies within ${10}^{10}{M}_{\odot }·h^{-1}\le M_c\le {10}^{12}{M}_{\odot }·h^{-1}$ in stellar mass. At the same time, central galaxies in this range are divided into spirals and ellipticals according to the bulge-to-total mass ratio (B/T). Through the usage of statistical methods, we found that when the mass distribution of the halos is controlled (the halo mass distribution is exactly the same between spirals and ellipticals), there is still a new difference in the distribution of satellite galaxies. However, the satellites of the spirals are significantly more than ellipticals. This conclusion is contrary to observations. The main reason for this difference is that the satellite galaxies of spirals contain more cold gas, which makes the satellites of spirals more efficient in star formation.