SKYSURF Source Counts

SDSS Source Counts

While HST images allow for a robust assessment of the number density of faint objects, their small fields of view limit SKYSURF's ability to constrain the abundance of bright objects. In addition to Poisson uncertainty (each ACS or WFC3 field of view has approximately 0.3 objects brighter than 20 magnitude per FOV; Driver et al. 2016), the number counts of bright and faint objects will be affected by cosmic variance (each FOV has a cosmic variance error of ~30% out to z = 1; Driver & Robotham 2010). Thus, to provide context for the measurement of the faint galaxy number density resulting from SKYSURF, we here provide a measurement of the bright object number density in the subset of SKYSURF fields within the SDSS footprint. Please refer to Bhatia et al. 2024 for more details.

We provide SDSS-SKYSURF catalogs for 27 filters, both in units of jankys and in units of AB-mag. The column names for each table is as follows. The "ra" and "dec" columns provide the RA and Dec coordinates for each object. The "u", "g", "r", "i", and "z" columns provide the SDSS flux for the corresponding SDSS filter. The "objid" column is the SDSS object ID. The "Image Names" column is the corresponding HST image where the object appears. The "Datasets" column is the corresponding datatset where the SDSS object appears. The "Object Type" is what type of object it is, where 3 is a galaxy and 6 is a star.