Reconstructing galaxy fundamental distributions and scaling relations from photometric redshift surveys. Applications to the SDSS early-type sample |
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Authors: | Graziano Rossi Ravi K. Sheth Changbom Park |
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Affiliation: | Korea Institute for Advanced Study, Hoegiro 87, Dongdaemun-Gu, Seoul 130-722, Korea;Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd;Street, Philadelphia, PA 19104-6396, USA |
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Abstract: | Noisy distance estimates associated with photometric rather than spectroscopic redshifts lead to a biased estimate of the luminosity distribution, and produce a correlated misestimate of the sizes. We consider a sample of early-type galaxies from the Sloan Digital Sky Survey Data Release 6 for which both spectroscopic and photometric information is available, and apply the generalization of the V max method to correct for these biases. We show that our technique recovers the true redshift, magnitude and size distributions, as well as the true size–luminosity relation. We find that using only 10 per cent of the spectroscopic information randomly spaced in our catalogue is sufficient for the reconstructions to be accurate within ∼3 per cent , when the photometric redshift error is δ z ≃ 0.038 . We then address the problem of extending our method to deep redshift catalogues, where only photometric information is available. In addition to the specific applications outlined here, our technique impacts a broader range of studies, when at least one distance-dependent quantity is involved. It is particularly relevant for the next generation of surveys, some of which will only have photometric information. |
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Keywords: | methods: statistical surveys galaxies: distances and redshifts galaxies: fundamental parameters cosmology: observations distance scale |
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