Journal Article

Autocorrelations of stellar light and mass in the low-redshift Universe

Cheng Li and Simon D. M. White

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 407, issue 1, pages 515-519
Published in print September 2010 | ISSN: 0035-8711
Published online August 2010 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2010.16924.x
Autocorrelations of stellar light and mass in the low-redshift Universe

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The final data release of the Sloan Digital Sky Survey (SDSS) provides reliable photometry and spectroscopy for about half a million galaxies with median redshift 0.09. Here, we use these data to estimate projected autocorrelation functions wp(rp) for the light of galaxies in the five SDSS photometric bands. Comparison with the analogous stellar mass autocorrelation, estimated in a previous paper, shows that stellar luminosity is less strongly clustered than stellar mass in all bands and on all scales. Over the full non-linear range 10 h−1 kpc < rp < 10 h−1 Mpc our autocorrelation estimates are extremely well represented by power laws. The parameters of the corresponding spatial functions ξ(r) = (r/r0)γ vary systematically from r0= 4.5 h−1 Mpc and γ=−1.74 for the bluest band (the u band) to r0= 5.8 h−1 Mpc and γ=−1.83 for the reddest one (the z band). These may be compared with r0= 6.1 h−1 Mpc and γ=−1.84 for the stellar mass. Ratios of wp(rp) between two given wavebands are proportional to the mean colour of correlated stars at projected distance rp from a randomly chosen star. The ratio of the stellar mass to luminosity autocorrelations measures an analogous mean stellar mass-to-light ratio (). All colours get redder and all mass-to-light ratios get larger with decreasing rp, with the amplitude of the effects decreasing strongly to redder passbands. Even for the u band the effects are quite modest, with maximum shifts of about 0.1 in ug and about 25 per cent in . These trends provide a precise characterization of the well-known dependence of stellar populations on environment.

Keywords: galaxies: clusters: general; galaxies: distances and redshifts; cosmology: theory; dark matter; large-scale structure of Universe

Journal Article.  3632 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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