The HST/ACS Coma Cluster Survey: I - Survey Objectives and Design

Authors: David Carter, Paul Goudfrooij, Bahram Mobasher, Henry C. Ferguson, Thomas H. Puzia, Alfonso L. Aguerri, Marc Balcells, Dan Batcheldor, Terry J. Bridges, Jonathan I. Davies, Peter Erwin, Alister W. Graham, Rafael Guzmán, Derek Hammer, Ann Hornschemeier, Carlos Hoyos, Michael J. Hudson, Avon Huxor, Shardha Jogee, Yutaka Komiyama, Jennifer Lotz, John R. Lucey, Ronald O. Marzke, David Merritt, Bryan W. Miller, Neal A. Miller, Mustapha Mouhcine, Sadanori Okamura, Reynier F. Peletier, Steven Phillipps, Bianca M. Poggianti, Ray M. Sharples, Russell J. Smith, Neil Trentham, R. Brent Tully, Edwin Valentijn, Gijs Verdoes Kleijn

Abstract: We describe the HST ACS Coma cluster Treasury survey, a deep two-passband imaging survey of one of the nearest rich clusters of galaxies, the Coma cluster (Abell 1656).
The survey was designed to cover an area of 740 arcmin2 in regions of different density of both galaxies and intergalactic medium within the cluster. The ACS failure of January 27th 2007 leaves the survey 28% complete, with 21 ACS pointings (approximately 230 arcmin2) complete, and partial data comprising either 50% or 75% of the planned exposure time for a further 4 pointings (approximately 44 arcmin2).
The survey depth for 10 detections (0.1 mag photometric errors) predicted using the ACS exposure time calculator, is g' = 26.75 mag in the F475W filter, and IC=25.95 mag in the F814 filter, using the AB magnitude system. For extended sources, the equivalent limits for a 1 arcsecond2 constant surface brightness region are g' = 25.8 mag arcsec2 and IC = 25.0 mag arcsec2.
We highlight several of the motivating science goals of the survey, including the study of the faint end of the cluster galaxy luminosity function, structural parameters of dwarf galaxies, stellar populations and their effect on colors and color gradients, the evolution of morphological components in a dense environment, the nature of ultra compact dwarf galaxies, and the globular cluster populations of cluster galaxies of a range of luminosties and types. This survey will also provide a local rich cluster benchmark for various well known global scaling relations and explore new relations pertaining to the nuclear properties of galaxies.