Radial Distribution of Near-UV Flux in Disc Galaxies in the range 0<z<1

TL;DR

This study investigates how the distribution of star formation in disc galaxies has evolved over the last 8 billion years by analyzing near-UV flux profiles and comparing them across redshifts 0 to 1.

Contribution

It provides new insights into the evolution of star formation distribution in disc galaxies using high-resolution multi-band imaging and compares near-UV and B-band profiles over cosmic time.

Findings

Effective radii of NUV flux increase by 18% from z~1 to z~0.

NUV flux distributions are more compact at higher redshift.

Star formation surface density has decreased, especially in galaxy centers.

Abstract

(Abridged) The goal of this paper is to quantify the changes on the SF distribution within the disc galaxies in the last ~8 Gyr. We use as a proxy for the SF radial profile the Near-UV surface brightness distributions, allowing suitably for extinction. We compare the effective radii (R_eff) and concentration of the flux distribution in the rest-frame Near-UV for a sample of 270 galaxies in the range 0<z<1. This radial distribution is compared to that measured in the rest-frame B-band, which traces older stellar populations. The analysis is performed using deep, high resolution, multi-band images from GALEX, SDSS, and HST/ACS - GOODS-South. The relation R_eff(NUV)- M* suffers a moderate change between z~1 and z~0: at a fixed stellar mass of 1E10 M_sun, galaxies increase their effective radii by a factor 1.18+/-0.06. Median profiles in NUV show signs of truncation at R~R_eff, and median colour profiles (NUV-B) show a minimum (a "bluest" point) also around R~1-1.5 R_eff. The distributions of NUV flux are more compact at z~1 than nowadays, in terms of the fraction of flux enclosed in a specific radius (in kpc). Our results indicate that the SF surface density has decreased dramatically in discs since z~1, and this decline has been more intense in the central parts (<~R_eff) of the galaxies. In addition, our data suggest that the bulges/pseudo-bulges have grown in surface brightness with regard to the discs since z~1.