Formation and evolution of galactic spheroids by mergers

TL;DR

This paper investigates how galactic spheroids, especially ellipticals, form and evolve through galaxy mergers, analyzing simulated remnants to understand the roles of geometry and gas content.

Contribution

It provides detailed analysis of simulated merger remnants, highlighting the conditions under which different types of ellipticals can form from disk mergers.

Findings

Low and intermediate mass rotating ellipticals can form from disk mergers.

Massive ellipticals' properties cannot be explained by binary mergers.

Some massive non-rotating ellipticals likely formed through different processes.

Abstract

Galactic spheroids can form as a result of galaxy interactions and mergers of disks. Detailed analyses of the photometric properties, the intrinsic orbital structure, the line-of-sight velocity distributions and the kinemetry of simulated merger remnants, which depend critically on the geometry and the gas content of the interacting progenitors, indicate that low and intermediate mass rotating ellipticals can form from mergers of disks. The masses and metallicities of all massive ellipticals and the kinematics of some massive non-rotating ellipticals cannot be explained by binary mergers. Thus these galaxies might have formed in a different way.