About the Survey

The Cosmic Dawn Survey is a 50 square degree multi-wavelength survey of the Euclid Deep and Calibration fields.  The scientific aim is to understand the co-evolution of galaxies, black holes, and the dark matter haloes that host them from Re-Ionization (z~12, about 500 million years after the big-bang) to the present (z~0).   The fields are some of the darkest and most observable fields on the sky and have existing multi-wavelength data that will enable immediate science. The survey parameters are designed to enable stellar mass measurement at 3 < z < 12 (2 billion years of Cosmic time, starting 500 million years after the Big Bang), to probe the large scale structure of reionization in the early Universe, and find luminous quasars to the highest redshifts where they exist.


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The survey aims to obtain uniform ultra-deep multiwavelength imaging data for all the Euclid Deep and Calibration fields through a number of new observational programs:

The Hawaii-2-O Hyper-Suprimecam and Keck survey (H20)  (ongoing, https://project.ifa.hawaii.edu/h20/)

H20 comprises 30 nights on the Subaru 8.3m telescope and 10 nights on Keck to carry out deep imaging and complementary spectroscopic followup. By its completion, H20 will cover a total of 20 deg2 split evenly over the Euclid Deep Fields: the North Ecliptic Pole and Chandra Deep Field South.

The Euclid/WFIRST Spitzer Legacy Survey (SLS) (complete)

SLS is a the largest observational program carried our with the Spitzer Space telescope to date, with 5286 hours of survey time at 3-5 micro-meters in the infrared. Now complete, the observations provide coverage over the 20 deg2 of two of the Euclid Deep Fields (NEP and CDFS).

The Euclid Deep Field South Survey (complete)

DFSS is an ultra-deep survey complenetary to SLS consisting of 687h on the Spitzer Space Telescope to cover the 20 square degrees Euclid Deep Field South.

The 3CR2 Sample (ongoing)

3CR2 is a fully representative spectroscopic sample of galaxies in the Euclid Calibration FIelds (CDFS, VVDS-2h, SXDS, COSMOS, HDF-N, and EGS).

The Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH) (complete)

SPLASH contains existing coverage of the Euclid Calibration fields COSMOS and SXDS with 2,600h of Spitzer Space telescope at 3-5 micro-meters and ~7h per pixel with the Hyper-Suprime-Cam on the Subaru telescope.

Toltech Large Scale Structure Survey (TLSS) (planned)

TLSS will cover 20 deg2 over the Euclid deep fields with the Large Millimeter Telescope, providing imaging at 1.2, 1.44 and 2.0 mmm. 

The Texas - Euclid Survey for Lyman Alpha (TESLA) (ongoing)

TESLA will cover 10 deg2 in NEP with a fully blind IFU survey with the VIRUS instrument on the Hobby-Eberly telecope . It is expected to confirm 100.000 redshifts in the range 1.9<z<3.5 via detection of Lya.