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Register a new userCosmological constraints from the power spectrum of eBOSS emission line galaxies
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Mikhail M. Ivanov
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We present cosmological parameter measurements from the effective field theory-based full-shape analysis of the power spectrum of emission line galaxies (ELGs). First, we perform extensive tests on simulations and determine appropriate scale cuts for the perturbative description of the ELG power spectrum. We study in detail non-linear redshift-space distortions (fingers-of-God) for this sample and show that they are somewhat weaker than those of luminous red galaxies. This difference is not significant for current data, but may become important for future surveys like Euclid/DESI. Then we analyze recent measurements of the ELG power spectrum from the extended Baryon acoustic Oscillation Spectroscopic Survey (eBOSS) within the $ uLambda$CDM model. Combined with the BBN baryon density prior, the ELG pre- and post-reconstructed power spectra alone constrain the matter density $Omega_m=0.257_{-0.045}^{+0.031}$, the current mass fluctuation amplitude $sigma_8=0.571_{-0.076}^{+0.052}$, and the Hubble constant $H_0=84.5_{-7}^{+5.8}$ km/s/Mpc (all at 68% CL). Combining with other full-shape and BAO data we measure $Omega_m=0.321_{-0.016}^{+0.013}$, $sigma_8=0.662_{-0.042}^{+0.038}$, and $H_0=68.9_{-1.1}^{+1}$ km/s/Mpc. The total neutrino mass is constrained to be $M_{rm tot}<0.64$ eV (95% CL) from the BBN, full-shape and BAO data only.
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We present cosmological constraints based on the cosmic microwave background (CMB) lensing potential power spectrum measurement from the recent 500 deg$^2$ SPTpol survey, the most precise CMB lensing measurement from the ground to date. We fit a flat $Lambda$CDM model to the reconstructed lensing power spectrum alone and in addition with other data sets: baryon acoustic oscillations (BAO) as well as primary CMB spectra from Planck and SPTpol. The cosmological constraints based on SPTpol and Planck lensing band powers are in good agreement when analysed alone and in combination with Planck full-sky primary CMB data. With weak priors on the baryon density and other parameters, the CMB lensing data alone provide a 4% constraint on $sigma_8Omega_m^{0.25} = 0.0593 pm 0.025$.. Jointly fitting with BAO data, we find $sigma_8=0.779 pm 0.023$, $Omega_m = 0.368^{+0.032}_{-0.037}$, and $H_0 = 72.0^{+2.1}_{-2.5},text{km},text{s}^{-1},text{Mpc}^{-1} $, up to $2,sigma$ away from the central values preferred by Planck lensing + BAO. However, we recover good agreement between SPTpol and Planck when restricting the analysis to similar scales. We also consider single-parameter extensions to the flat $Lambda$CDM model. The SPTpol lensing spectrum constrains the spatial curvature to be $Omega_K = -0.0007 pm 0.0025$ and the sum of the neutrino masses to be $sum m_{ u} < 0.23$ eV at 95% C.L. (with Planck primary CMB and BAO data), in good agreement with the Planck lensing results. With the differences in the $S/N$ of the lensing modes and the angular scales covered in the lensing spectra, this analysis represents an important independent check on the full-sky Planck lensing measurement.
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We present the results of the first test plates of the extended Baryon Oscillation Spectroscopic Survey. This paper focuses on the emission line galaxies (ELG) population targetted from the Dark Energy Survey (DES) photometry. We analyse the success rate, efficiency, redshift distribution, and clustering properties of the targets. From the 9000 spectroscopic redshifts targetted, 4600 have been selected from the DES photometry. The total success rate for redshifts between 0.6 and 1.2 is 71% and 68% respectively for a bright and faint, on average more distant, samples including redshifts measured from a single strong emission line. We find a mean redshift of 0.8 and 0.87, with 15 and 13% of unknown redshifts respectively for the bright and faint samples. In the redshift range 0.6<z<1.2, for the most secure spectroscopic redshifts, the mean redshift for the bright and faint sample is 0.85 and 0.9 respectively. Star contamination is lower than 2%. We measure a galaxy bias averaged on scales of 1 and 10~Mpc/h of 1.72 pm 0.1 for the bright sample and of 1.78 pm 0.12 for the faint sample. The error on the galaxy bias have been obtained propagating the errors in the correlation function to the fitted parameters. This redshift evolution for the galaxy bias is in agreement with theoretical expectations for a galaxy population with MB-5log h < -21.0. We note that biasing is derived from the galaxy clustering relative to a model for the mass fluctuations. We investigate the quality of the DES photometric redshifts and find that the outlier fraction can be reduced using a comparison between template fitting and neural network, or using a random forest algorithm.
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