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The angular power spectra of photometric Sloan Digital Sky Survey luminous red galaxies

Authors


E-mail: sat@star.ucl.ac.uk

ABSTRACT

We construct new galaxy angular power spectra C based on the extended, updated and final Sloan Digital Sky Survey (SDSS) II luminous red galaxy (LRG) photometric redshift survey – MegaZ (DR7). Encapsulating 7746 deg2 we utilize 723 556 photometrically determined LRGs between 0.45 < z < 0.65 in a 3.3 (Gpc h−1)3 spherical harmonic analysis of the galaxy distribution. By combining four photometric redshift bins, we find preliminary parameter constraints of fb≡Ωbm= 0.173 ± 0.046 and Ωm= 0.260 ± 0.035 assuming H0= 75 km s−1 Mpc−1, ns= 1 and Ωk= 0. These limits are consistent with the cosmic microwave background and the previous data release (DR4). The C are sensitive to redshift space distortions and therefore we also recast our constraints into a measurement of β≈Ω0.55m/b in different redshift shells. The robustness of these power spectra with respect to a number of potential systematics such as extinction, photometric redshift and ANNz training set extrapolation are examined. The latter includes a cosmological comparison of available photometric redshift estimation codes where we find excellent agreement between template and empirical estimation methods. MegaZ DR7 represents a methodological prototype to next generation surveys such as the Dark Energy Survey and, furthermore, is a photometric precursor to the spectroscopic BOSS survey. Our galaxy catalogue and all power spectra data can be found at http://zuserver2.star.ucl.ac.uk/~sat/MegaZ/MegaZDR7.tar.gz.

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