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Deep galex observations of the coma cluster: source catalog and galaxy counts
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Miller, N. Hornschemeier, A. E. Mobasher, B. Hammer, D. Arnouts, S. Milliard, B. Jenkins, L. Smith, R. |
| Copyright Year | 2010 |
| Description | We present a source catalog from deep 26 ks GALEX observations of the Coma cluster in the far-UV (FUV; 1530 Angstroms) and near-UV (NUV; 2310 Angstroms) wavebands. The observed field is centered 0.9 deg. (1.6 Mpc) south-west of the Coma core, and has full optical photometric coverage by SDSS and spectroscopic coverage to r-21. The catalog consists of 9700 galaxies with GALEX and SDSS photometry, including 242 spectroscopically-confirmed Coma member galaxies that range from giant spirals and elliptical galaxies to dwarf irregular and early-type galaxies. The full multi-wavelength catalog (cluster plus background galaxies) is 80% complete to NUV=23 and FUV=23.5, and has a limiting depth at NUV=24.5 and FUV=25.0 which corresponds to a star formation rate of 10(exp -3) solar mass yr(sup -1) at the distance of Coma. The GALEX images presented here are very deep and include detections of many resolved cluster members superposed on a dense field of unresolved background galaxies. This required a two-fold approach to generating a source catalog: we used a Bayesian deblending algorithm to measure faint and compact sources (using SDSS coordinates as a position prior), and used the GALEX pipeline catalog for bright and/or extended objects. We performed simulations to assess the importance of systematic effects (e.g. object blends, source confusion, Eddington Bias) that influence source detection and photometry when using both methods. The Bayesian deblending method roughly doubles the number of source detections and provides reliable photometry to a few magnitudes deeper than the GALEX pipeline catalog. This method is also free from source confusion over the UV magnitude range studied here: conversely, we estimate that the GALEX pipeline catalogs are confusion limited at NUV approximately 23 and FUV approximately 24. We have measured the total UV galaxy counts using our catalog and report a 50% excess of counts across FUV=22-23.5 and NUV=21.5-23 relative to previous GALEX measurements, which is not attributed to cluster member galaxies. Our galaxy counts are a better match to deeper UV counts measured with HST. |
| File Size | 2779457 |
| Page Count | 27 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20100020935 |
| Archival Resource Key | ark:/13960/t9x11341w |
| Language | English |
| Publisher Date | 2010-04-08 |
| Access Restriction | Open |
| Subject Keyword | Astrophysics All Sky Photography Astronomical Catalogs Elliptical Galaxies Star Formation Rate Galactic Clusters Algorithms Simulation Stellar Mass Dwarf Galaxies Far Ultraviolet Radiation Photometry Bayes Theorem Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
