Tracing the cosmic velocity field at z∼ 0.1 from galaxy luminosities in the SDSS DR7

Journal Article · Mon Sep 01 04:00:00 EDT 2014 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2014/09/019· OSTI ID:22375891

Feix, Martin; Nusser, Adi ^[1]; Branchini, Enzo ^[2]

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1. Department of Physics, Israel Institute of Technology --- Technion, Haifa 32000 (Israel)
2. Department of Physics, Università Roma Tre, Via della Vasca Navale 84, Rome 00146 (Italy)

Spatial modulations in the distribution of observed luminosities (computed using redshifts) of ∼ 5× 10{sup 5} galaxies from the SDSS Data Release 7, probe the cosmic peculiar velocity field out to z∼ 0.1. Allowing for luminosity evolution, the r-band luminosity function, determined via a spline-based estimator, is well represented by a Schechter form with M{sup *}(z)-5 log{sub 10} h = -20.52 -1.6(z-0.1)± 0.05 and α{sup *} = -1.1± 0.03. Bulk flows and higher velocity moments in two redshift bins, 0.02 < z < 0.07 and 0.07 < z < 0.22, agree with the predictions of the ΛCDM model, as obtained from mock galaxy catalogs designed to match the observations. Assuming a ΛCDM model, we estimate σ{sub 8} ≈ 1.1± 0.4 for the amplitude of the linear matter power spectrum, where the low accuracy is due to the limited number of galaxies. While the low z bin is robust against coherent photometric uncertainties, the bias of results from the second bin is consistent with the ∼1% magnitude tilt reported by the SDSS collaboration. The systematics are expected to have a significantly lower impact in future datasets with larger sky coverage and better photometric calibration.

• OSTI ID: 22375891
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 09 Vol. 2014; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCURACY
AMPLITUDES
CALIBRATION
CATALOGS
DATASETS
FORECASTING
FUNCTIONS
GALAXIES
LUMINOSITY
MATTER
MODULATION
PROBES
RED SHIFT
SKY