The Millennium Galaxy Catalogue: The Photometric accuracy, completeness and contamination of the 2dFGRS and SDSS-EDR & DR1 datasets
Dec, 2003
23 pages
Published in:
- Mon.Not.Roy.Astron.Soc. 349 (2004) 576
e-Print:
- astro-ph/0312317 [astro-ph]
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Abstract: (arXiv)
The Millennium Galaxy Catalogue (MGC) is a deep ( mag arcsec), wide field CCD imaging survey, covering 37.5deg and is completely contained within the 2dFGRS and SDSS-EDR. We compare the photometry and completeness of the 2dFGRS and the SDSS-EDR with the MGC. We have also undertaken a photometric comparison to SCOS and SDSS-DR1 data. We find that mag with an uncertainty of 0.142 mag per galaxy, mag with an uncertainty of 0.108 mag, mag with an uncertainty of 0.094 mag, and mag with an uncertainty of 0.086 mag. We find that high surface brightness 2dFGRS galaxies are systematically too faint. In the SDSS there is a weak non-linear scale error, which is negligible for faint galaxies. LSBGs in the SDSS are systematically fainter. We find that the 2dFGRS catalogue has 5.2% stellar contamination, 7.0% of objects are resolved into 2 or more by the MGC and is 8.7% incomplete compared to the MGC. From our all object spectroscopic survey we find that the MGC is itself misclassifying 5.6% of galaxies as stars, hence the 2dFGRS misses 14.3% of the galaxies. The SDSS-EDR galaxy catalogue has 1.3% stellar contamination and 5.3% of galaxies misclassified as stars, and is 1.8% incomplete compared to the MGC. Altogether 7.1% of the total galaxy population are missing from the SDSS-EDR catalogue from incompleteness or misclassification.Note:
- 23 pages, 18 figures, accepted in MNRAS
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