Provenance
Coverage
1003 DES DR2 coadd tiles, about 530 deg² after de-overlapping, spanning RA −57° to +98° and Dec −64° to +2°.
What the catalog is
Three draws from a posterior over catalogs of 1003 Dark Energy Survey DR2 coadd tiles, produced by AstroMatch — a transdimensional flow-matching model that samples the number of sources and their marks jointly from the pixels. Detection samples first; the marks (star/galaxy type, five-band flux, position) then integrate together in lockstep, each conditioned on the others' in-progress state. Sources are canonically ordered brightest-first, so no permutation matching is needed.
Each draw is a complete, internally consistent catalog. They are not three measurements of the same list, and a source present in one but not another is not an error in either.
Columns
- ra, dec
- ICRS degrees, from each tile's WCS.
- mag_g, mag_r, mag_i, mag_z, mag_Y
- AB magnitudes on the DES zeropoint of 30.0. Blank where the sampled flux is non-positive — a real posterior draw for a very faint source, not a failure.
- is_galaxy
- 1 if this draw calls the source a galaxy, 0 if a star. It can differ between draws.
What is not published
Morphology and redshift are model outputs but were not exercised in this run, so they are absent rather than published as zeros. Per-source uncertainties are likewise absent by design: the samples are the uncertainty, and collapsing them to error bars would undo the point.
Overlaps
Adjacent DES tiles share a border, so every source is assigned to exactly one owning tile — the nearest tile centre that actually holds data at that position. After merging, sources within 0.2″ of each other are genuine close pairs, not tile duplicates.
Reuse
Catalog and site are CC BY 4.0. Imagery is DES DR2, served by CDS, not by us. Source code.