We have developed an analytical method based on forward-modeling techniques to characterize the high-mass end of the red sequence (RS) galaxy population at redshift $zsim0.55$, from the DR10 BOSS CMASS spectroscopic sample, which comprises $sim600,00
0$ galaxies. The method, which follows an unbinned maximum likelihood approach, allows the deconvolution of the intrinsic CMASS colour-colour-magnitude distributions from photometric errors and selection effects. This procedure requires modeling the covariance matrix for the i-band magnitude, g-r colour and r-i colour using Stripe 82 multi-epoch data. Our results indicate that the error-deconvolved intrinsic RS distribution is consistent, within the photometric uncertainties, with a single point ($<0.05~{rm{mag}}$) in the colour-colour plane at fixed magnitude, for a narrow redshift slice. We have computed the high-mass end ($^{0.55}M_i lesssim -22$) of the $^{0.55}i$-band RS Luminosity Function (RS LF) in several redshift slices within the redshift range $0.52<z<0.63$. In this narrow redshift range, the evolution of the RS LF is consistent, within the uncertainties in the modeling, with a passively-evolving model with $Phi_* = (7.248 pm 0.204) times10^{-4}$ Mpc$^{-3}$ mag$^{-1}$, fading at a rate of $1.5pm0.4$ mag per unit redshift. We report RS completeness as a function of magnitude and redshift in the CMASS sample, which will facilitate a variety of galaxy-evolution and clustering studies using BOSS. Our forward-modeling method lays the foundations for future studies using other dark-energy surveys like eBOSS or DESI, which are affected by the same type of photometric blurring/selection effects.
We investigate the cosmological implications of the latest growth of structure measurement from the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS Data Release 11 with particular focus on the sum of the neutrino masses, $sum m_{ u}$. We examine
the robustness of the cosmological constraints from the Baryon Acoustic Oscillation (BAO) scale, the Alcock-Paczynski effect and redshift-space distortions ($D_V/r_s$, $F_{rm AP}$, $fsigma_8$) of citet{Beutler:2013b}, when introducing a neutrino mass in the power spectrum template. We then discuss how the neutrino mass relaxes discrepancies between the Cosmic Microwave Background (CMB) and other low-redshift measurements within $Lambda$CDM. Combining our cosmological constraints with WMAP9 yields $sum m_{ u} = 0.36pm0.14,$eV ($68%$ c.l.), which represents a $2.6sigma$ preference for non-zero neutrino mass. The significance can be increased to $3.3sigma$ when including weak lensing results and other BAO constraints, yielding $sum m_{ u} = 0.35pm0.10,$eV ($68%$ c.l.). However, combining CMASS with Planck data reduces the preference for neutrino mass to $sim 2sigma$. When removing the CMB lensing effect in the Planck temperature power spectrum (by marginalising over $A_{rm L}$), we see shifts of $sim 1sigma$ in $sigma_8$ and $Omega_m$, which have a significant effect on the neutrino mass constraints. In case of CMASS plus Planck without the $A_{rm L}$-lensing signal, we find a preference for a neutrino mass of $sum m_{ u} = 0.34pm 0.14,$eV ($68%$ c.l.), in excellent agreement with the WMAP9+CMASS value. The constraint can be tightened to $3.4sigma$ yielding $sum m_{ u} = 0.36pm 0.10,$eV ($68%$ c.l.) when weak lensing data and other BAO constraints are included.
We present an analysis of the evolution of the central mass-density profile of massive elliptical galaxies from the SLACS and BELLS strong gravitational lens samples over the redshift interval z ~ 0.1-0.6, based on the combination of strong-lensing a
perture mass and stellar velocity-dispersion constraints. We find a significant trend towards steeper mass profiles (parameterized by the power-law density model with rho ~ r^[-gamma]) at later cosmic times, with magnitude d<gamma>/dz = -0.60 +/- 0.15. We show that the combined lens-galaxy sample is consistent with a non-evolving distribution of stellar velocity dispersions. Considering possible additional dependence of <gamma> on lens-galaxy stellar mass, effective radius, and Sersic index, we find marginal evidence for shallower mass profiles at higher masses and larger sizes, but with a significance that is sub-dominant to the redshift dependence. Using the results of published Monte Carlo simulations of spectroscopic lens surveys, we verify that our mass-profile evolution result cannot be explained by lensing selection biases as a function of redshift. Interpreted as a true evolutionary signal, our result suggests that major dry mergers involving off-axis trajectories play a significant role in the evolution of the average mass-density structure of massive early-type galaxies over the past 6 Gyr. We also consider an alternative non-evolutionary hypothesis based on variations in the strong-lensing measurement aperture with redshift, which would imply the detection of an inflection zone marking the transition between the baryon-dominated and dark-matter halo-dominated regions of the lens galaxies. Further observations of the combined SLACS+BELLS sample can constrain this picture more precisely, and enable a more detailed investigation of the multivariate dependences of galaxy mass structure across cosmic time.
