The HTS/ACS Coma Cluster Survey II: Data Description and Source Catalogs

Derek Hammer*, Gijs Verdoes Kleijn, Carlos Hoyos, Mark den Brok, Marc Balcells, Henry C. Ferguson, Paul Goudfrooij, David Carter, Rafael Guzman, Reynier F. Peletier, Russell J. Smith, Alister W. Graham, Neil Trentham, Eric Peng, John R. Lucey, Shardha Jogee, Alfonso L. Aguerri, Dan Batcheldor, Terry J. Bridges, Kristin ChiboucasJonathan I. Davies, Carlos del Burgo, Peter Erwin, Ann Hornschemeier, Michael J. Hudson, Avon Huxor, Leigh Jenkins, Arna Karick, Habib Khosroshahi, Ehsan Kourkchi, Yutaka Komiyama, Jennifer Lotz, Ronald O. Marzke, Irina Marinova, Ana Matkovic, David Merritt, Bryan W. Miller, Neal A. Miller, Bahram Mobasher, Mustapha Mouhcine, Sadanori Okamura, Sue Percival, Steven Phillipps, Bianca M. Poggianti, James Price, Ray M. Sharples, R. Brent Tully, Edwin Valentijn

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The Coma cluster, Abell 1656, was the target of an HST-ACS Treasury program designed for deep imaging in the F475W and F814W passbands. Although our survey was interrupted by the ACS instrument failure in early 2007, the partially completed survey still covers similar to 50% of the core high-density region in Coma. Observations were performed for 25 fields that extend over a wide range of cluster-centric radii (similar to 1.75 Mpc or 1 degrees) with a total coverage area of 274 arcmin(2). The majority of the fields are located near the core region of Coma (19/25 pointings) with six additional fields in the southwest region of the cluster. In this paper, we present reprocessed images and SEXTRACTOR source catalogs for our survey fields, including a detailed description of the methodology used for object detection and photometry, the subtraction of bright galaxies to measure faint underlying objects, and the use of simulations to assess the photometric accuracy and completeness of our catalogs. We also use simulations to perform aperture corrections for the SEXTRACTOR Kron magnitudes based only on the measured source flux and its half-light radius. We have performed photometry for similar to 73,000 unique objects; approximately one-half of our detections are brighter than the 10 sigma point-source detection limit at F814W = 25.8 mag (AB). The slight majority of objects (60%) are unresolved or only marginally resolved by ACS. We estimate that Coma members are 5%-10% of all source detections, which consist of a large population of unresolved compact sources (primarily globular clusters but also ultra-compact dwarf galaxies) and a wide variety of extended galaxies from a cD galaxy to dwarf low surface brightness galaxies. The red sequence of Coma member galaxies has a color-magnitude relation with a constant slope and dispersion over 9 mag (-21 <M-F814W <-13). The initial data release for the HST-ACS Coma Treasury program was made available to the public in 2008 August. The images and catalogs described in this study relate to our second data release.

Original languageEnglish
Pages (from-to)143-159
Number of pages17
JournalAstrophysical Journal Supplement Series
Issue number1
Publication statusPublished - Nov 2010
Externally publishedYes


  • catalogs
  • galaxies: clusters: individual (Coma)
  • galaxies: dwarf
  • galaxies: elliptical and lenticular, cD
  • galaxies: photometry


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