SKYSURF-5: Probing the Integrated Galaxy Light with a SDSS-SKYSURF Cross-matched Catalog

Abstract

Project SKYSURF aims to account for the difference between observed integrated background light levels and those expected from galaxy-count measurements using archival Hubble Space Telescope (HST) images. Due to the scarcity of bright objects in a typical HST field of view, Poisson uncertainty and Cosmic Variance can significantly hinder calculations of the total integrated background light from galaxies. Since the existing SKYSURF analysis cannot constrain bright galaxy counts well, we catalog the bright object number density by cross-matching SKYSURF pointings with objects in the Sloan Digital Sky Survey. Here, we present the cross-matched catalogs and measure the distribution of integrated galaxy light from the SDSS objects. We find a median integrated light level in the r-band of 2.45 nW m−2 sr−1, consistent with previous findings given the level of incompleteness in SDSS and suggesting that SKYSURF pointings are in general not substantially biased toward object-rich fields on the sky.