Galaxy evolution by color-log(n) type since redshift unity in the Hubble Ultra Deep Field

TL;DR

This study uses the color-log(n) plane to classify high redshift galaxies in the Hubble Ultra Deep Field, revealing evolutionary trends in galaxy surface brightness and morphology since redshift one.

Contribution

It introduces the use of the color-log(n) plane as a physically-motivated classification tool for high redshift galaxies and quantifies their evolution over time.

Findings

Confirmed correlation between color-log(n) position and morphology at high redshift.

Measured decrease in B-band surface brightness for different galaxy types since redshift one.

Quantified evolution of galaxy properties with bias correction.

Abstract

We explore the use of the color-log(n) plane (where n is the global Sersic index) as a tool for subdividing the high redshift galaxy population in a physically-motivated manner. Using a series of volume-limited samples out to z=1.5 in the Hubble Ultra Deep Field (UDF) we confirm the correlation between color-log(n) plane position and visual morphology observed locally and in other high redshift studies in the color and/or structure domain. Via comparison to a low redshift sample from the Millennium Galaxy Catalogue we quantify evolution by color-log(n) type, accounting separately for the specific selection and measurement biases against each. Specifically, we measure decreases in B-band surface brightness of 1.57 +/- 0.22 mag/sq.arcsec and 1.65 +/- 0.22 mag/sq.arcsec for `blue, diffuse' and `red, compact' galaxies respectively between redshift unity and the present day.