IMAGES: a unique view of the galaxy mass assembly since z=1

TL;DR

The IMAGES program studies galaxy evolution since z=1 by analyzing kinematics, chemistry, morphology, and photometry of 70 intermediate-mass galaxies, revealing significant kinematic anomalies 6 billion years ago that impact galaxy scaling relations.

Contribution

It provides detailed multi-wavelength data on intermediate-mass galaxies at z=0.4-0.75, uncovering the prevalence of anomalous kinematics and their role in galaxy evolution.

Findings

Over 40% of galaxies had anomalous kinematics 6 Gyr ago

Anomalous kinematics contribute to the dispersion in the Tully-Fisher relation

IMAGES enables detailed study of distant galaxies comparable to local ones

Abstract

The Large Program IMAGES is near 2/3 of its completion. It provides us with kinematics (GIRAFFE deployable IFUs), gas chemistry (FORS2), detailed morphologies (HST/ACS) and IR photometry (Spitzer) for a set of 70 galaxies representative of intermediate mass galaxies (MJ<=-20.3 or 1.5e10 Mo) at z=0.4-0.75. We discover that, 6 Gyr ago, a significant fraction of galaxies (>40%) had anomalous kinematics, i.e. kinematics significantly discrepant from those of rotational or dispersion supported galaxies. The anomalous kinematics cause the observed large dispersion of the Tully-Fisher relation at large distances. IMAGES will soon allow us to study distant galaxies at a level of detail almost comparable to that of nearby galaxies.