WISE × SuperCOSMOS photometric Redshift catalog: 20 million galaxies over 3π steradians
- Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch, 7701 (South Africa)
- Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom)
- Department of Physics, University of the Western Cape, Robert Sobukwe Road, Bellville, 7530 (South Africa)
- ASTRON, The Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo (Netherlands)
- School of Physics and Astronomy, Monash University, Clayton, Victoria 3800 (Australia)
- School of Physics, University of Melbourne, VIC 3010 (Australia)
- Janusz Gil Institute of Astronomy, University of Zielona Góra, ul. Szafrana 2, 65-516, Zielona Góra (Poland)
- Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333 CA Leiden (Netherlands)
- Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool, L3 5RF (United Kingdom)
- Astronomy Centre, University of Sussex, Falmer, Brighton BN1 9QH (United Kingdom)
- ICRAR, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia)
- Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia)
- NASA Ames Research Center, N232, Moffett Field, Mountain View CA 94035 (United States)
- Sydney Institute for Astronomy, School of Physics A28, University of Sydney, NSW 2006 (Australia)
We cross-match the two currently largest all-sky photometric catalogs—mid-infrared Wide-field Infrared Survey Explorer and SuperCOSMOS scans of UKST/POSS-II photographic plates—to obtain a new galaxy sample that covers 3π steradians. In order to characterize and purify the extragalactic data set, we use external GAMA and Sloan Digital Sky Survey spectroscopic information to define quasar and star loci in multicolor space, aiding the removal of contamination from our extended source catalog. After appropriate data cleaning, we obtain a deep wide-angle galaxy sample that is approximately 95% pure and 90% complete at high Galactic latitudes. The catalog contains close to 20 million galaxies over almost 70% of the sky, outside the Zone of Avoidance and other confused regions, with a mean surface density of more than 650 sources per square degree. Using multiwavelength information from two optical and two mid-IR photometric bands, we derive photometric redshifts for all the galaxies in the catalog, using the ANNz framework trained on the final GAMA-II spectroscopic data. Our sample has a median redshift of z{sub med}=0.2, with a broad dN/dz reaching up to z > 0.4. The photometric redshifts have a mean bias of |δz|∼10{sup −3}, a normalized scatter of σ {sub z} = 0.033, and less than 3% outliers beyond 3σ {sub z}. Comparison with external data sets shows no significant variation of photo-z quality with sky position. Together with the overall statistics, we also provide a more detailed analysis of photometric redshift accuracy as a function of magnitudes and colors. The final catalog is appropriate for “all-sky” three-dimensional (3D) cosmology to unprecedented depths, in particular through cross-correlations with other large-area surveys. It should also be useful for source preselection and identification in forthcoming surveys, such as TAIPAN or WALLABY.
- OSTI ID:
- 22872488
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 225, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0067-0049
- Country of Publication:
- United States
- Language:
- English
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