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