The SKYSURF Project (Windhorst et al. 2022) analyzes the extragalactic background light (both directly using sky background measurements and indirectly using galaxy counts) using the HST Archive. While HST images probe faint galaxies unseen by ground-based imaging, its small field of view prevents it from probing the large-scale structure around its observations. To supplement SKYSURF analysis, we cross-match SKYSURF pointings with SDSS observations able to probe the surrounding large-scale environment (Bhatia et al. 2024). The tables in this database include galaxies brighter than r=22.5 AB mag photometrically identified in SDSS, within +/-5 arcmin around a SKYSURF pointing. The tables in the Object_AB directory include information on all SDSS objects, organized by the HST camera and filter of the central pointing. The tables in the IGL directory include the total galaxy counts and integrated galaxy light (down to AB mag=22.5) for all SDSS objects surrounding a given SKYSURF image.

Column Descriptions for Object_AB tables ra, dec Position of SDSS Object objid SDSS photometric object identification number u, g, r, i, z SDSS model magnitude corrected for Milky Way extinction err_u, err_g, err_r, err_i, err_z 1-sigma uncertainty in corresponding u, g, r, i, or z magnitude type_u, type_g, type_r, type_i, type_z SDSS Object Type flags_u, flags_g, flags_r, flags_i, flags_z SDSS Photometric Flag ok_u, ok_g, ok_r, ok_i, ok_z 1 if flags_* value is good; 0 if flags_* value is bad fiber2Mag_u, fiber2Mag_g, fiber2Mag_r, fiber2Mag_i, fiber2Mag_z Magnitude in central 2 arcseconds Image Names SKYSURF images for which this object is associated with (within 5 arcminutes) Datasets SKYSURF datasets for which this object is associated

Column Descriptions for IGL tables Image Name SKYSURF Image Name RA, Dec Position of the center of the SKYSURF image # of Objects Number of SDSS galaxies (ABmag<22.5) in that image # of Bright Objects Number of bright (ABmag<18) SDSS galaxies in that image Search Area Area of SDSS search (+/- 5 arcmin in RA and Dec) Object Density Number of galaxies per square arcminute (# of Occurences/ Image Area) Total u/g/r/i/z-band IGL Total IGL (down to AB mag=22.5) for the corresponding SDSS filter (u, g, r, i, or z)