Updates since DR9

DR10 only contains updates for the south part of the Legacy Surveys from new imaging with DECam. Northern areas can be obtained from DR9 (see, e.g., the status page).

The sweep files are now partitioned into 5° x 5° areas rather than 10° x 5° areas.

Multiple \(i\hbox{-}\mathrm{band}\) quantities have been added to the Tractor catalogs and the sweep files.

Gaia quantities included in files and catalogs are now drawn from Gaia EDR3.

• Note, though, that the astrometric solution for DR10 was still calculated using positions and proper motions from Gaia DR2.

The MASKBITS bitmask is now 32-bit rather than 16-bit, as a new bit called SUB_BLOB was added. This bit is described on the DR10 bitmasks page under MASKBITS.

The CCD_CUTS bitmask is now 64-bit rather than 32-bit, as two new bits called PHRMS_S7 and DEPTH_CUT_2 were added. These bits are described on the DR10 bitmasks page under CCD_CUTS.

The Tractor catalogs contain a new per-band quantity called ngood_x where x is one of \(g\), \(r\), \(i\) or \(z\). These quantities record the number of good (unmasked) images that contribute to a source in a particular band at a particular pixel-location. Prior to DR9, only nobs_x (the total number of images that contributed to a source in each band) were recorded in the Tractor catalogs, which created an inconsistency with the "nexp" pixel-maps in the image stacks (which only record the number of good images). So, ngood_x is recorded to allow a direct mapping between the number of good images in the Tractor catalogs and image stacks.

• As an example of the difference, for saturated sources one would expect ngood_x and the "nexp" pixel maps to be zero, but nobs_x to correspond to the total number of exposures that contributed to the source.

• The addition of ngood_x fixes a known issue from DR9.

The WISE imaging has been updated to include observations through the 7th year of the NEOWISE W1/W2 data.

The potential number of unWISE epochs has been expanded for the WISE light curves (e.g. columns such as lc_flux_w1 in the Tractor catalogs can now have up to 17 entries).