Hubble Space Telescope (HST)

Original ACS COSMOS observations

The original COSMOS Hubble Space Telescope (HST) Treasury project was allocated 640 orbits in Cycles 12 & 13 to image a 2 square degree field with the Advanced Camera for Surveys (ACS).

Per instructions from the Telescope Allocation Committee (TAC), 50 orbits were given over to an outside group to pursue high-redshift supernovae. The remaining 590 orbits have been used to observe 1.7 square degrees of the COSMOS field in F814W and 0.03 square degrees with F475W.

The ACS imaging is the central cornerstone of the COSMOS survey to study galaxy and large scale structure evolution. ACS provides morphologies of over 2 million galaxies at < 100 pc resolution. Each orbit has 4 dithered exposures in F814W for cosmic ray and bad pixel rejection and to cover the gap between the two ACS CCD arrays.

Contact: Anton Koekemoer - koekemoer [at] stsci.edu


An additional 88 orbits were allocated to the CANDELS (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey) project in Cycles 19 and 20 to obtain near infrared images with the Wide Field Camera 3 of a 0.05 square degree region in the center of the field, with ACS data in parallel.

Contact for CANDELS: Anton Koekemoer - koekemoer [at] stsci.edu ; Jeyhan Kartaltepe - jeyhan [at] noao.edu


The 3D-HST project added 88 more HST orbits to cover this same area with 2 orbit WFC-3 G141 Grism observations which include shallow F140W images as finders.

Contact for 3D-HST: Claudia Scarlatta - scarlatta [at] astro.umn.edu


Other HST observations

Additional pointed WFC3 observations have been taken in the COSMOS field. As part of a NASA grant, we are gathering all of this data and will make it available.


Summary of HST observations in the COSMOS field:
Band Depth Area (sq. Degrees) Project Notes
ACS F814W 27.2 10 σ point source 1.7 COSMOS  
ACS F475W 27.6 AB 5 σ 80% encircled light 0.03 COSMOS  
ACS F606W 27.5 AB 5 σ 80% encircled light 0.05 COSMOS  
ACS F814W   0.05 CANDELS  
WFC3 F125W 26.4 AB 5 σ 0.25” diameter aperture 0.05 CANDELS  
WFC3 F140W   0.05 3D-HST  
WFC3 F160W 26.5 AB 5 σ 0.25” diameter aperture 0.05 CANDELS  
WFPC2 F300W 27.2 10 σ point source      
WFPC2 F450W 27.2 10 σ point source      
NICMOS F160W 27.2 10 σ point source 0.135 COSMOS Separate fields