The AstroSat UV Deep Field South. III. Evolution of the UV Luminosity Function and Luminosity Density from z~0.8-0.4

Abstract

We characterise the rest-frame 1500 \r{A} UV luminosity Function (UVLF) from deep AstroSat/UVIT F154W and N242W imaging in the Great Observatories Origins Survey South (GOODS-S) deep field. The UVLFs are constructed and subsequently characterised with fitted Schechter function parameters from FUV observations at z$<0.13$ and NUV observations in seven redshift bins in z~0.8-0.4. The UVLF slope ($\alpha$) and characteristic magnitude ($M^*$) are consistent with previous determinations for this redshift range based on AstroSat/UVIT GOODS-North observations, as well as with those from Galaxy evolution Explorer and Hubble Space Telescope observations. However, differences in the normalisation factor ($\phi_{*}$) are present for UVLFs for some redshift bins. We compute the UV luminosity density, $\rho_{\rm UV}$, combining our determined UVLF parameters with literature determinations out to z$\sim10$. The $\rho_{\rm UV}$ trend with redshift implies the rapid increase in cosmic star formation till its peak at z$\sim3$ (cosmic noon) followed by a slow decline till present day. Both the initial increase in cosmic star formation and subsequent decline are found to be more rapid than previous determinations.