Day 1262

Tuesday.

1705.07596
Galaxy and Mass Assembly: the evolution of the cosmic spectral energy distribution from z=1 to z=0
Andrews, Driver, et al

Present the evolution of the Cosmic Spectral Energy Distribution (CSED) from z=1-0.  The CSEDs originate from stacking individual SED fits based on panchromatic photometry from GAMA and COSMOS datasets in 10 redshift intervals with completeness corrections applied.  Below z=0.45, have credible SED fits from 100nm to 1mm.  Due to the relative low sensitivity of the far-infrared data, the far-infrared CSEDs contain a mix of predicted and measured fluxes above z=0.45.  The results include appropriate errors to highlight the impact of these corrections.  Show that the bolometric energy output of the Universe has declined by a  factor of roughly four -- from 5.1±1.0 at z~1 to 1.3±0.3e35 h_70 W Mpc^-3 at the current epoch.  Show that this decrease is robust to cosmic variance, SED modeling and other various types of error.  The CSEDs are also consistent with an increase in the mean age of stellar populations.  Also show that dust attenuation has decreased over the same period, with the photon escape fraction at 150 nm increasing from 16±3 at z~1 to 24±5% at the current epoch, equivalent to a decrease in A_FUV of 0.4 mag.  The CSEDs account for 68±12 and 61±13 % of the cosmic optical and IR backgrounds respectively as defined from integrated galaxy counts and are consistent with previous estimates of the cosmic infrared background with redshift.


1705.07843
Imprints of reionization in galaxy clustering
Schmidt, Beutler

Reionization, the only phase transition in the Universe since recombination, is a key event in the cosmic history of baryonic matter.  Derive, in the context of the LS bias expansion, the imprints of the epoch of reionization in the LS distribution of galaxies, and identify two contributions of particular importance.  Fist, the Compton scattering of CMB photons off the free electrons lead to a drag force on the baryon fluid.  This drag induces a relative velocity between baryons and CDM which is of the same order of magnitude as the primordially-induced relative velocity, and enters in the evolution of the relative velocity as calculated by Boltzmann codes.  This leads to a unique contribution to galaxy bias involving the matter velocity squared.  The second important effect is a modulation of the galaxy density by the ionizing radiation field through radiative transfer effects, which is captured in the bias expansion by so-called higher-derivative terms.  Constrain both of these imprints using the power spectrum of the BOSS DR12 galaxy sample.  While they do not lead to a shift in the baryon acoustic oscillation scale, including these terms is important for unbiased cosmology constraints from the shape of the galaxy power spectrum.