Galaxy Interactions, Star Formation History, and Bulgeless Galaxies

TL;DR

This paper examines galaxy interactions over the past 7 billion years and explores the origins of bulgeless galaxies, highlighting challenges in hierarchical galaxy formation models related to baryonic evolution.

Contribution

It provides new constraints on galaxy interaction history and the formation of bulgeless galaxies within hierarchical models, addressing key challenges in baryonic evolution predictions.

Findings

Galaxy interactions influence star formation over 7 Gyr.

Bulgeless galaxies challenge hierarchical bulge formation theories.

Constraints suggest alternative bulge formation pathways.

Abstract

Hierarchical Lambda CDM models provide a successful paradigm for the growth of dark matter on large scales, but they face important challenges in predicting how the baryonic components of galaxies evolve. I present constraints on two aspects of this evolution: (1) The interaction history of galaxies over the last 7 Gyr and the impact of interactions on their star formation properties, based on Jogee et al. (2008a,b); (2) Constraints on the origin of bulges in hierarchical models and the challenge posed in accounting for galaxies with low bulge-to-total ratios, based on Weinzirl, Jogee, Khochar, Burkert, and Kormendy (2008, hereafter WJKBK08)