The Sloan Digital Sky Survey Stripe 82 Imaging Data: Depth-Optimized Co-adds Over 300 Deg^2 in Five Filters

TL;DR

This paper presents depth-optimized co-added images of SDSS Stripe 82 across five optical bands, achieving significantly deeper imaging than single-epoch data, along with object catalogs and near-IR J-band images for diverse astronomical studies.

Contribution

The authors provide the first depth-optimized co-added images of Stripe 82, with improved depth and quality, and release associated catalogs and near-IR data for the community.

Findings

Co-added images are 1.9-2.2 mag deeper than single-epoch data.

Average PSF FWHM of ~1 arcsec in key bands.

Depths reach approximately 23.9 to 25.1 AB magnitudes in optical bands.

Abstract

We present and release co-added images of the Sloan Digital Sky Survey (SDSS) Stripe 82. Stripe 82 covers an area of 300 deg^2 on the Celestial Equator, and has been repeatedly scanned 70-90 times in the ugriz bands by the SDSS imaging survey. By making use of all available data in the SDSS archive, our co-added images are optimized for depth. Input single-epoch frames were properly processed and weighted based on seeing, sky transparency, and background noise before co-addition. The resultant products are co-added science images and their associated weight images that record relative weights at individual pixels. The depths of the co-adds, measured as the 5 sigma detection limits of the aperture (3.2 arcsec diameter) magnitudes for point sources, are roughly 23.9, 25.1, 24.6, 24.1, and 22.8 AB magnitudes in the five bands, respectively. They are 1.9-2.2 mag deeper than the best SDSS single-epoch data. The co-added images have good image quality, with an average point-spread function FWHM of ~1 arcsec in the r, i, and z bands. We also release object catalogs that were made with SExtractor. These co-added products have many potential uses for studies of galaxies, quasars, and Galactic structure. We further present and release near-IR J-band images that cover ~90 deg^2 of Stripe 82. These images were obtained using the NEWFIRM camera on the NOAO 4-m Mayall telescope, and have a depth of about 20.0--20.5 Vega magnitudes (also 5 sigma detection limits for point sources).