RELICS obtained the first HST infrared imaging of 41 massive galaxy clusters to efficiently search for brightly lensed high-redshift galaxies in time for JWST Cycle 1. The clusters include 21 of the 34 most massive known according to Planck. Observations of each cluster were split into two epochs, enabling supernova searches in addition to high-redshift and cluster science.
For each cluster, the team observed to 5-orbit depth with ACS and WFC3/IR. The team obtained 3 orbits of ACS imaging in F435W, F606W, and F814W (minus existing archival imaging) and 2 orbits of WFC3/IR imaging in F105W, F125W, F140W, F160W. Five of the clusters required two WFC3/IR pointings. For the 18 clusters with no existing ACS archival imaging, the team also obtained 3-orbit images of blank parallel fields with WFC3/IR F105W, F125W, F140W, F160W (2 orbits) and WFC3/UVIS F350LP (1 orbit) to search for additional high-redshift candidates as in the BoRG and HIPPIES surveys.
In addition to the 188-orbit Hubble Treasury Program 14096 (PI Coe, STScI), the team also obtained 945 hours of Spitzer imaging. The team observed all RELICS clusters as needed to achieve 5-hour depth in two bands with Spitzer GO program 12005 (PI Maruša Bradač, UC Davis) and Spitzer DDT program 12123 (PI Tom Soifer, Caltech). Subsequently, the team obtained 30-hour depth Spitzer imaging for 10 RELICS clusters with DDT 13165, DDT 13210, and GO 14017 (PI Bradač).
Acknowledgments
When using RELICS HST data, please include this acknowledgment: "This work is based on observations taken by the RELICS Treasury Program (GO 14096) with the NASA/ESA HST, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555."
Each cluster contains images, catalogs, three-color images, and lens models, organized into subdirectories. For more details, see the "Images" and/or "Catalogs" README files at the top of this page. The color images were produced using Trilogy.
catalogs/
_cat.txt = Catalog of sources, using either combined ACS+WFC3/IR or just WFC3/IR images and SExtractor.
_probs.txt = Bayesian probabilities for a given redshift for each target. Each row contains the target's ID, followed by the Bayesian probabilities for redshifts between 0.01 and 13.000, in steps of δz = 0.001.
_segm.fits = SExtractor segmentation maps.
color_images/
_color.fits = Three-color image, consult the README file inside this directory for specific filters used in the three channels of the color image.
_color.png = PNG version of the three-color image.
images/30mas-resolution/
_drc.fits | _drz.fits = CTE-corrected, drizzled images (drc, for ACS) or drizzled images (drz, for WFC3), at 30 milliarcsecond resolution.
_wht.fits = Weight image, at 30 milliarcsecond resolution.
images/60mas-resolution/
_drc.fits | _drz.fits = CTE-corrected, drizzled images (drc, for ACS) or drizzled images (drz, for WFC3), at 60 milliarcsecond resolution.
_wht.fits = Weight image, at 60 milliarcsecond resolution.
_rms.fits = RMS map, at 60 milliarcsecond resolution.
models/{glafic,lenstool,zitrin-lft-gauss}/
_gamma1.fits = shear component 1.
_gamma2.fits = shear component 2.
_gamma.fits = shear.
_kappa.fits = mass surface density ("convergence").
_{x,y}-arcsec-deflect.fits = deflection (in arcseconds).
_{x,y}-pixels-deflect.fits = deflection (in pixels).
_z{01,02,04,09}-magnif.fits = magnification of lensed galaxy at z = 1, 2, 4, 9.
Links in the "Images" and "Catalogs" columns take you to the files. Interactive Displays will be available later. Links in the "Color Images" column take you to webpages with preview images, README describing which filters went into the color images, and access to the FITS files.
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