Day 909

Monday.


1506.05803
Mapping metals at high redshift with far-infrared lines
Pallottini, et al

Hard to detect metals at high z; absorption line experiments at z~6 become increasingly difficult because of instrumental limitations and the paucity of background quasars.  with ALMA, FIR emission lines provide a novel tool to study early metal enrichment.  Among these, the [CII] line at 157.74 um is the most luminous line emitted by the ISM of galaxies; it can also resonant scatter CMB photons near the peak of the CMB spectrum, thus allowing to probe the low-density IGM.  Compute both [CII] galaxy emission and metal induced CMB fluctuations at z~6 by using AMR cosmo hydro sims and produce mock observations to be directly compared with ALMA BAND6 data.  Calculated relation is in very good agreement with recent ALMA observations of M_UV<-20 galaxies.  Predict that M_UV=-19 (-18) galaxy can be detected at 4 sigma in ~40 (2000) hours.  CMB resonant scattering can produce ~±0.1 uJy/beam emission/absorptions features that are currently very challenging to be detected with current facilities.  The best strategy to detect these signals consists in the stacking of deep ALMA observations pointing fields with known M_UV~=-19 galaxies.  This would allow to simultaneously detect both [CII] emission from galactic reionization sources and CMB fluctuations produced by z~6 metals.

1506.05814
Galaxy power spectrum in redshift space: combining perturbation theory with the halo model
Okumura, Hand, Seljak, Vlah, Desjacques

Theoretical modeling of the z-space PS of galaxies is crucially important to correctly extract cosmological information from z surveys.  The task is complicated by the nonlinear biasing and z space distortion effects, which change with halo mass, and by the wide distribution of halo masses and their occupations by galaxies.  One of the main modeling challenges is the existence of satellite galaxies that have both radial distribution and large viral velocities inside haloes, a phenomenon known as the FoG effect.  Present a model for the galaxy PS of in which a given galaxy sample is decomposed into central and satellite galaxies and relate different contributions to 1- and 2-halo terms in a halo model.  The primary goal is to ensure that any parameters that are introduced have physically meaningful values, and are not just fitting parameters.  For the 2-halo terms, use the previously developed RSD modeling of haloes in the context of distribution function and perturbation theory approach.  This term needs to be multiplied by the effect of radial distances and velocities of satellites inside the halo.  To this one needs to add the 1-halo terms, which are non-perturbative.  Show that the real space 1-halo terms can be modeled as almost constant, with the finite extent of the satellites inside the halo inducing a small k^2 R^2 P(k) term, where R is related to the size of the halo.  Adopt a similar model for FoG in redshift space, ensuring that FoG velocity dispersion is related to the halo mass.  For FoG k^2 type expansions do not work and FoG resummation must be used instead.