Rozo, E;
Rykoff, ES;
Abate, A;
Bonnett, C;
Crocce, M;
Davis, C;
Hoyle, B;
... Costa, LND; + view all
(2016)
redMaGiC: Selecting Luminous Red Galaxies from the DES Science Verification Data.
Monthly Notices of the Royal Astronomical Society
, 461
(2)
pp. 1431-1450.
10.1093/mnras/stw1281.
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Abstract
We introduce redMaGiC, an automated algorithm for selecting Luminous Red Galaxies (LRGs). The algorithm was specifically developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the color-cuts necessary to produce a luminosity-thresholded LRG sample of constant comoving density. We demonstrate that redMaGiC photozs are very nearly as accurate as the best machine-learning based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalog sampling the redshift range $z\in[0.2,0.8]$. Our fiducial sample has a comoving space density of $10^{-3}\ (h^{-1} Mpc)^{-3}$, and a median photoz bias ($z_{spec}-z_{photo}$) and scatter $(\sigma_z/(1+z))$ of 0.005 and 0.017 respectively. The corresponding $5\sigma$ outlier fraction is 1.4%. We also test our algorithm with Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8) and Stripe 82 data, and discuss how spectroscopic training can be used to control photoz biases at the 0.1% level.
| Type: | Article |
|---|---|
| Title: | redMaGiC: Selecting Luminous Red Galaxies from the DES Science Verification Data |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stw1281 |
| Publisher version: | http://doi.org/10.1093/mnras/stw1281 |
| Language: | English |
| Additional information: | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
| Keywords: | astro-ph.IM, astro-ph.IM, astro-ph.CO, astro-ph.GA |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1497959 |
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