AstroSat UV Deep Field South -- I. Far and Near-ultraviolet Source Catalog of the GOODS South region

TL;DR

The paper presents the deepest UV imaging survey of the GOODS South field using AstroSat, resulting in extensive catalogs of UV sources that enable new extragalactic studies and complement existing optical/IR data.

Contribution

This work provides the first deep far and near-UV source catalog covering the GOODS South field with unprecedented depth and area, enhancing multi-wavelength galaxy studies.

Findings

Catalog contains 13,495 and 19,374 sources in F154W and N242W filters.

Galaxy counts follow a power-law slope consistent with previous HST observations.

The data enables studies of ionizing galaxies, UV luminosity functions, and UV morphologies at redshifts 1-3.

Abstract

We present the AstroSat UV Deep Field South (AUDFs), an imaging survey using the wide-field Ultraviolet Imaging Telescope on board AstroSat. AUDFs covers $\sim 236$ arcmin$^{2}$ of the sky area, including the Great Observatories Origins Deep Survey (GOODS) South field in F154W and N242W filters. The deep and shallow parts of AUDFs have exposure time $\sim 62000$ and $\sim31000$ sec respectively, in the F154W filter, while in the N242W filter, they are $\sim 64000$ and $\sim34000$ sec. These observations reached a $3\sigma$ depth of 27.2 and 27.7 AB mag with a $50\%$ completeness limit of 27 and 27.6 AB mag in the F154W and N242W filters, respectively. With the acquired depth, AUDFs is the deepest far and near-UV imaging data covering the largest area known to date at 1.2" - 1.6" spatial resolution. Two primary catalogs were constructed for the F154W and N242W filters, each containing 13495 and 19374 sources brighter than the 3$\sigma$ detection limit, respectively. Our galaxy counts power-law slope $\sim0.43$~dex~mag$^{-1}$ in the N242W filter matches well with HST/WFC3/UVIS observations. A wide range of extra-galactic science can be achieved with this unique data, such as providing a sample of galaxies emitting ionizing photons in the redshift range $z \sim 1 - 3$ and beyond; constraining the UV luminosity function, investigating the extended-UV (XUV) emission around star-forming galaxies and UV morphologies for $z < 1$. The UV catalog will enhance the legacy value of the existing optical/IR imaging and spectroscopic observations from ground and space-based telescopes on the GOODS South field.