Showing papers by "Alexie Leauthaud published in 2014"
Christopher P. Ahn1, Rachael M. Alexandroff2, Carlos Allende Prieto3, Carlos Allende Prieto4 +272 more•Institutions (69)
TL;DR: The 10th public data release (DR10) from the Sloan Digital Sky Survey (SDSS-III) was released in 2013 as mentioned in this paper, which includes the first spectroscopic data from the Apache Point Observatory Galaxy Evolution Experiment (APOGEE), along with spectroscopy data from Baryon Oscillation Spectroscopic Survey (BOSS) taken through 2012 July.
Abstract: The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April. This paper presents the Tenth Public Data Release (DR10) from its current incarnation, SDSS-III. This data release includes the first spectroscopic data from the Apache Point Observatory Galaxy Evolution Experiment (APOGEE), along with spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS) taken through 2012 July. The APOGEE instrument is a near-infrared R ~ 22,500 300 fiber spectrograph covering 1.514-1.696 μm. The APOGEE survey is studying the chemical abundances and radial velocities of roughly 100,000 red giant star candidates in the bulge, bar, disk, and halo of the Milky Way. DR10 includes 178,397 spectra of 57,454 stars, each typically observed three or more times, from APOGEE. Derived quantities from these spectra (radial velocities, effective temperatures, surface gravities, and metallicities) are also included. DR10 also roughly doubles the number of BOSS spectra over those included in the Ninth Data Release. DR10 includes a total of 1,507,954 BOSS spectra comprising 927,844 galaxy spectra, 182,009 quasar spectra, and 159,327 stellar spectra selected over 6373.2 deg2.
1,188 citations
TL;DR: RedMaPPer as discussed by the authors is a new red sequence cluster finder designed to make optimal use of ongoing and near-future large photometric surveys, which can iteratively self-train the red sequence model based on a minimal spectroscopic training sample.
Abstract: We describe redMaPPer, a new red sequence cluster finder specifically designed to make optimal use of ongoing and near-future large photometric surveys. The algorithm has multiple attractive features: (1) it can iteratively self-train the red sequence model based on a minimal spectroscopic training sample, an important feature for high-redshift surveys. (2) It can handle complex masks with varying depth. (3) It produces cluster-appropriate random points to enable large-scale structure studies. (4) All clusters are assigned a full redshift probability distribution P(z). (5) Similarly, clusters can have multiple candidate central galaxies, each with corresponding centering probabilities. (6) The algorithm is parallel and numerically efficient: it can run a Dark Energy Survey-like catalog in ~500 CPU hours. (7) The algorithm exhibits excellent photometric redshift performance, the richness estimates are tightly correlated with external mass proxies, and the completeness and purity of the corresponding catalogs are superb. We apply the redMaPPer algorithm to ~10, 000 deg2 of SDSS DR8 data and present the resulting catalog of ~25,000 clusters over the redshift range z [0.08, 0.55]. The redMaPPer photometric redshifts are nearly Gaussian, with a scatter σ z ≈ 0.006 at z ≈ 0.1, increasing to σ z ≈ 0.02 at z ≈ 0.5 due to increased photometric noise near the survey limit. The median value for |Δz|/(1 + z) for the full sample is 0.006. The incidence of projection effects is low (≤5%). Detailed performance comparisons of the redMaPPer DR8 cluster catalog to X-ray and Sunyaev-Zel'dovich catalogs are presented in a companion paper.
683 citations
TL;DR: In this paper, the authors performed the first fit to the anisotropic clustering of 10 galaxies on scales of ~0.8-32 h-1 Mpc, using a standard halo occupation distribution model evaluated near the best-fitting Planck cold dark matter (?CDM) cosmology.
Abstract: Author(s): Reid, BA; Seo, HJ; Leauthaud, A; Tinker, JL; White, M | Abstract: We perform the first fit to the anisotropic clustering of Sloan Digital Sky Survey III CMASS data release 10 galaxies on scales of ~0.8-32 h-1 Mpc.Astandard halo occupation distribution model evaluated near the best-fitting Planck ? cold dark matter (?CDM) cosmology provides a good fit to the observed anisotropic clustering, and implies a normalization for the peculiar velocity field of M~2 × 1013h-1 M haloes of fσ8(z = 0.57) = 0.450 ± 0.011. Since this constraint includes both quasi-linear and non-linear scales, it should severely constrain modified gravity models that enhance pairwise infall velocities on these scales. Though model dependent, our measurement represents a factor of 2.5 improvement in precision over the analysis of DR11 on large scales, fσ8(z = 0.57) = 0.447 ± 0.028, and is the tightest single constraint on the growth rate of cosmic structure to date. Our measurement is consistent with the Planck ?CDM prediction of 0.480 ± 0.010 at the ~1.9σ level. Assuming a halo mass function evaluated at the best-fitting Planck cosmology,we also find that 10 per cent of CMASS galaxies are satellites in haloes of mass M ~ 6 × 1013 h-1 M. While none of our tests and model generalizations indicate systematic errors due to an insufficiently detailed model of the galaxy-halo connection, the precision of these first results warrant further investigation into the modelling uncertainties and degeneracies with cosmological parameters.
215 citations