Description
The Dark Energy Survey (DES) is a 5000 square degree survey of the Southern sky in grizY aimed at understanding the accelerating expansion of the Universe and the nature of dark energy. DES uses four complementary measurements to probe the evolution of the Universe: weak gravitational lensing, galaxy cluster counts, the large-scale clustering of galaxies (including baryon acoustic oscillations), and the distances to type Ia supernovae. DES uses the Dark Energy Camera (DECam), a 570 Megapixel CCD imaging camera with a 3 square degree field of view installed at the prime focus of on the Blanco 4m telescope at the Cerro Tololo Interamerican Observatory in northern Chile. DES observed for a period of six years (2013-2019), and has collected information from roughly 550 million distant galaxies and 150 million Milky Way stars. DES has also performed a 27 square degree time domain survey aimed at discovering thousands of supernova and other transients. The DES webpage contains a full description of the survey.
DES survey footprint from DES Collaboration (2021).
Goals
- Supernovae. DES observes a 27 square degree area, distributed over several fields, with a weekly cadence aimed at discovering thousands of supernovae for use for cosmology.
- Weak gravitational lensing. DES measures the total matter content and structure of the Universe via the weak gravitational lensing of distant galaxies.
- Galaxy clusters. DES detects tens of thousands of galaxy clusters, the most massive gravitationally bound systems in the Universe.
- Galaxy clustering. DES measures the spatial distribuiton of galaxies which is a sensitive probe of large-scale structure and the primordial distribution of matter.
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Data Releases
DES DR2
Documentation for DES DR2 can be found in DES Collaboration (2021).
| DES DR2 Summary | |
|---|---|
| Area covered | ~5000 deg2 |
| Bands | grizY |
| Median catalog depth for 1.95 arcsec diameter aperture at S/N~10 in grizY | 24.7, 24.4, 23.8, 23.1, 21.7 mag |
| Median PSF FWHM in grizY | 1.11, 0.95, 0.88, 0.83, 0.90 arcsec |
| Median astrometric internal precision | ~27 mas |
| Number of co-added image tiles / exposures | 10,169 / 96,263 |
| Number of objects / galaxies / stellar sources | 691,483,608 / 543 million / 145 million |
| DES DR2 Tables | |
| Table Name | Description |
| main | Main photometry; summary table |
| magnitude | Magnitudes |
| flux | Fluxes |
| coverage | Coverage table; fraction of the Healpix 4096 (Nest) pixel covered by a certain band (values between 0 and 1) |
| des_dr2.x1p5__main__gaia_edr3__gaia_source | Crossmatch of DES DR2 main table with Gaia EDR3 gaia_source table; 1.5 arcsec matching radius, single-nearest match only |
| des_dr2.x1p5__main__nsc_dr2__object | Crossmatch of DES DR2 main table with NSC DR2 object table; 1.5 arcsec matching radius, single-nearest match only |
| des_dr2.x1p5__main__allwise__source | Crossmatch of DES DR2 main table with AllWISE source table; 1.5 arcsec matching radius, single-nearest match only |
| des_dr2.x1p5__main__unwise_dr1__object | Crossmatch of DES DR2 main table with unWISE DR1 object table; 1.5 arcsec matching radius, single-nearest match only |
| des_dr2.x1p5__main__sdss_dr16__specobj | Crossmatch of DES DR2 main table with SDSS DR16 specobj table; 1.5 arcsec matching radius, single-nearest match only |
DES DR1
Documentation on DES DR1 can be found in DES Collaboration (2018).
| DES DR1 Summary | |
|---|---|
| Area covered | ~5000 deg2 |
| Bands | grizY |
| Median catalog depth for 1.95 arcsec diameter aperture at S/N~10 in grizY | 24.45, 24.3, 23.5, 22.90, 21.70 mag |
| Median PSF FWHM in grizY | 1.12, 0.96, 0.88, 0.84, 0.90 arcsec |
| Median astrometric internal precision | ~30 mas |
| Number of co-added image tiles | 10,338 |
| Number of objects / galaxies / stellar sources | 399,263,026 / 310 million / 80 million |
| DES DR1 Tables | |
| Table Name | Description |
| main | Main object summary table |
| complement | Secondary metadata |
| exposure | Exposure information |
| hpix | HEALPIX tile table |
| neighbors | Objects within 30 arcsec |
| tile_info | Tile information table |
| galex_des | GALEX crossmatch |
| vhs_des | VISTA Hemisphere Survey crossmatch |
| wise_des | WISE crossmatch |
| band_g | Single-band SExtractor table |
| band_i | Single-band SExtractor table |
| band_r | Single-band SExtractor table |
| band_y | Single-band SExtractor table |
| band_z | Single-band SExtractor table |
| vac_sextractor | SExtractor summary table |
To view the schema of any of these tables, use the Query Tool.
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Data Reduction
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