Astro Data Lab

The Legacy Surveys cover 14,000 square degrees of the extragalactic sky, and yield high-quality optical, near-infrared, and infrared photometric catalogs. The sky coverage is approximately bounded by -18° < δ < +84° in celestial coordinates and |b| > 18° in Galactic coordinates. Resulting images, models, and catalogs will enhance current and future wide area surveys such as SDSS/BOSS/eBOSS and DESI.

The Legacy Surveys data products and database are accessible via the Astro Data Lab as described here. See the Legacy Surveys team page for a complete description of the surveys and data files.

The Legacy Surveys are a combination of the DECam Legacy Survey (DECaLS) using the Dark Energy Camera on the Blanco 4m telescope, the Mayall z-band Legacy Survey (MzLS) using the MOSAIC instrument on the Mayall 4m telescope, and the Beijing-Arizona Sky Survey (BASS) using the 90Prime instrument at the Steward Observatory Bok telescope.

Tenth Data Release (DR10)

The latest release from the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys team, the tenth data release (DR10) of the Legacy Surveys significantly expands its photometric observations to >20,000 square degrees, and includes entirely new imaging in the i-band, in addition to grz imaging and four infrared bands from WISE and NEOWISE. The imaging includes DECaLS g, r, z-band observations taken with the Dark Energy Camera (DECam), as well as imaging in the g, r, i, z-bands associated with other observing programs using DECam such as the DeROSITAS survey, the BLISS+ survey, and the Dark Energy Survey (DES).

However, imaging data of the Northern sky from BASS and MzLS were not reprocessed for DR10. For convenience, we serve both the DR10-South main photometry table (ls_dr10.tractor_s) and a combined table comprising that table and its DR9-North counterpart (ls_dr9.tractor_n), called simply ls_dr10.tractor, along with corresponding combined table of aperture flux values from the DR10-South (ls_dr10.apflux_s) with its DR9-North counterpart (ls_dr9.apflux_n) called ls_dr10.apflux, and also a combined WISE light curves photometry table from DR10-South (ls_dr10.wise_s) with its counterpart from DR9-North (ls_dr9.wise_n), called ls_dr10.wise. Note that the additional columns in DR10 (almost all of them related to the i-band) are not in DR9-North. Values for Northern sources in those columns of the combined tables have the value -9999.

The ls_dr10.tractor table has been crossmatched against our default reference datasets within a 1.5 arcsec radius, nearest neighbor only. These tables will appear with x1p5 in their name in our table browser (not listed in the table below).
Example: ls_dr10.x1p5__tractor__gaia_dr3__gaia_source.

A sky map of the full imaging survey coverage (DR10-South and DR9-North) is included below, color-coded by the depth in the z-band filter, and shown in an equatorial projection. The solid grey line traces the Galactic plane. (Figure credit: Dustin Lang).

Ninth Data Release (DR9)

The ninth data release (DR9) is the official release used to select DESI targets. It contains data over the entire footprint of the DESI survey, including data from MzLS (z-band) and BASS (g & r bands) surveys (DR9-North), and data from DECaLS (g, r, & z bands; DR9-South). The footprint of DR9 covers approximately 14,800 deg² with 3 passes in all three optical filters (g, r, z), and over 19,000 deg² with at least one pass in all three filters. The main changes between DR8 and DR9 consist in improvements of the data processing and catalog creation. Additionally, the unWISE images used to extract WISE forced photometry for DR9 include up to year 6 of NEOWISE Reactivation. An overview of the Legacy Surveys is available in Dey et al. (2019).

The ls_dr9.tractor table has been crossmatched against our default reference datasets within a 1.5 arcsec radius, nearest neighbor only. These tables will appear with x1p5 in their name in our table browser (not listed in the table below). Example: ls_dr9.x1p5__tractor__gaia_dr3__gaia_source.

A sky map of the full imaging survey coverage is included below, color-coded by the depth in the z-band filter, and shown in an equatorial projection. The solid grey line traces the Galactic plane. (Figure credit: Dustin Lang).

Visit the Data Access page for instructions to access the database, retrieve Legacy Surveys images, and catalogs.

Eighth Data Release (DR8)

Data release 8 (DR8) is the eighth public data release of the Legacy Surveys. It is the sixth public data release of images and catalogs from DECaLS (DR7) comprised the fifth release of data from DECaLS) and the third release of data from BASS and MzLS (DR6 comprised the second release of data from BASS and MzLS). DR8 is the first release to include images and catalogs from all three of the Legacy Surveys in a single release. Imaging from the Legacy Surveys is first reduced through the NOIRLab Community Pipeline before being processed using the Tractor processing tool. DR8 also includes WISE fluxes from all imaging through year 4 of NEOWISE-Reactivation force-photometered in the unWISE maps at the locations of Legacy Surveys optical sources.

The ls_dr8.tractor table has been crossmatched against our default reference datasets within a 1.5 arcsec radius, nearest neighbor only. These tables will appear with x1p5 in their name in our table browser (not listed in the table below).
Example: ls_dr8.x1p5__tractor__gaia_dr3__gaia_source.

Initially, they were also crossmatched with several tables of the SDSS survey. These table start with dr8_<north|south> followed by the SDSS table they are crossmatched against (not listed in the table below).
Example: ls_dr8.dr8_north_specobj_dr14.