Galactic Satellite Systems: Radial Distribution and Environment Dependence of Galaxy Morphology

TL;DR

This study analyzes how satellite galaxy morphology varies with distance from host galaxies and environmental density, revealing strong conformity effects and dependence on host type and luminosity.

Contribution

It provides the first detailed analysis of satellite morphology distribution as a function of radius and environment, highlighting the role of host influence and large-scale density.

Findings

Early-type satellite fraction depends on host luminosity and distance.

Morphology conformity is stronger between hosts and satellites.

Satellite morphology is affected by large-scale environment.

Abstract

We have studied the radial distribution of the early (E/S0) and late (S/Irr) types of satellites around bright host galaxies. We made a volume-limited sample of 4,986 satellites brighter than M_r = -18.0 associated with 2,254 hosts brighter than M_r =-19.0 from the SDSS DR5 sample. The morphology of satellites is determined by an automated morphology classifier, but the host galaxies are visually classified. We found segregation of satellite morphology as a function of the projected distance from the host galaxy. The amplitude and shape of the early-type satellite fraction profile are found to depend on the host luminosity. This is the morphology-radius/density relation at the galactic scale. There is a strong tendency for morphology conformity between the host galaxy and its satellites. The early-type fraction of satellites hosted by early-type galaxies is systematically larger than that of late-type hosts, and is a strong function of the distance from the host galaxies. Fainter satellites are more vulnerable to the morphology transformation effects of hosts. Dependence of satellite morphology on the large-scale background density was detected. The fraction of early-type satellites increases in high density regions for both early and late-type hosts. It is argued that the conformity in morphology of galactic satellite system is mainly originated by the hydrodynamical and radiative effects of hosts on satellites.