Day 347

Thursday.

1212.0853
Exploiting the shift of baryonic acoustic oscillation as a dynamical probe for dark interactions
Cervantes, et al

BAO: standard ruler (jointly constrains the angular diameter distance and the Hubble expansion rate); NL effects can systematically shift the peak position.  Detect DM/DE interactions through accurate determination of BAO scale using N-body sims of interacting DE models (CoDECS).  Fit a band-filtered correlation function, destined to amplify the signal at the sound horizon.  Analyze the shifts due to NL dynamics, z-space distortions and Gaussian z errors in 0<z<2.  The coupling between DE and DM affects in a particular way the clustering properties of haloes and the location and amplitude of BAO peak; might provide a direct way to discriminate interacting DE models from LCDM framework.  Z-space correlation works better as a probe, where the NL effects are amplified.  Typical z errors of spectroscopic surveys do not significantly impact these results.

1212.0856
Simulating high-z Gamma-ray burst host galaxies
Salvaterra et al

...high-z LRGBs are found to trace the position of those faint galaxies that are thought to be the major actors in the re-ionization of the Universe.

1212.0858
PICACS: a tool for self-consistent modelling of galaxy cluster scaling relations
Maughan

A physically-motivated, internally consistent model of scaling relations between galaxy cluster masses and their observable properties.  Model can be used to constrain simultaneously the form, scatter (w/ covariance), and evolution of the scaling relations, as well as the masses of the individual clusters.  Scaling relations are modeled explicitly in terms of the fundamental mass-observable scaling relations, and so are fully constrained without being fit directly.  Apply to observational datasets; show that it performs as well as traditional regression methods for simply measuring scaling relation parameters, but presents several significant advantages.  For clusters with available X-ray hydrostatic masses, PICACS gives a modest improvement of the precision of the mass estimates, while consistently constraining the mass-observable scaling relations.  Minor improvement in precision on cluster mass estimates compared to with a single scaling relation;  also able to deconstruct the slope of the LT relation, and show that the steepening compared to self-similar expectations is due to the gas structure within that radius.  Use PICACS to illustrate the dependence of the expected self-similar evolution of the LT relation on the slopes of the mass scaling relations, and show that the self-consistent modelling predicts self-similar evolution significantly weaker than is commonly assumed.

1212.0860
The UV ontinua and inferred stellar populations of galaxies at z~7-9 revealed by the Hubble ultra deep field 2012 campaign
Dunlop, .. Ellis, ... Koekemoer, ... et al

More high-z observations.

1212.0868
Peak-backtround split, renormalization, and galaxy clustering
Schmidt, Jeong, Desjacques

Present a derivation of 2-pt correlation of general tracers in PBS framework by way of a rigorous definition of the PBS argument.  Expressions only depend on connected matter correlators and "renormalized" bias parameters with clear physical interpretation, and are independent of any coarse-graining scale; in contrast to the usual expression derived from a local bias expansion of the tracer number density with respect to the matter density perturbation coarse-grained on a scale R_L.  In the latter case, the predicted tracer correlation function receives contributions of order <delta_L^n> at each perturbative order n, where as in the other formalism, these are absorbed in the PBS bias parameters at all orders.  This approach naturally predicts both a scale-dependent bias ~k^2 such as found for peaks of the density field, and the scale-dependent bias induced by primordial non-Gaussianity in the initial conditions.  The only assumption made about the tracers is that their abundance at a given position depends solely on the matter distribution within a finite region around that position.

1212.0909
Revisiting the first galaxies: the effects of population III stars on their host galaxies
Muratov, Gnedin, Gnedin, Zemp

Hydrodynamic cosmo sims with ART code, featuring a model for H2 formation and dissociation, and a SF recipe based on molecular gas.  New recipe for the formation of metal-free Pop III stars.  Find: epoch during which Pop III stars dominated the energy and metal budget of the first galaxies short lived.  Galaxies which host Pop III stars do not retain dynamical signatures of their thermal and radiative feedback for more than 1e8 yr after the lives of the stars end in pair-instability SNe, even when the maximum reasonable efficiency feedback is considered.  Though metals ejected by the SNe can travel well beyond the virial radius of the host galaxy, they will typically begin to fall back quickly, and do not enrich a large fraction of the IGM.  Galaxies more massive than 3e6 Msun re-accrete most of their baryons and transition to metal-enriched Pop II star formation.

1212.0977
Cosmology from clustering of Lyman-alpha galaxies: breaking non-gravitational Lyman-alpha radiative transfer degeneracies using the bispectrum
Greig, Komatsu, Wyithe

LAE clustering at high-z, derive cosmological parameters.  But Ly-a radiative transfer effects may modify the observed clustering of LAE galaxies in a way that mimics gravitational effects, potentially reducing the precision of cosmological constraints.  E.g., linear z-space distortion on LAE power spectrum potentially degenerate with Ly-a radiative transfer effects owing to the dependence of observed flux on IGM velocity gradients.  Show that 3pt function (bispectrum) can distinguish between gravitational and non-gravitational effects, and breaks these degeneracies.  Constraints on the angular diameter distance and the Hubble expansion rate can also be improved by combining power spectrum and bispectrum measurements.

1212.0980
The ubiquity of supermassive black holes in the Hubble sequence
Marleau, Simard, Clancy, Bianconi

Find SMBHs in bulgeless galaxies (~10% of 16k studied), indicate that the true correlation that exists for SMBH and their host galaxies is between the BH mass and the total M* of the galaxy, and hence, conclude that the previous assumption that the BH mass is correlated with the bulge mass is only approximately correct.

1212.1063
On rates of supernovae strongly lensed by galactic haloes in Millennium simulation
Kostrzewa-Rutkowska, Wyrzykowski, Jaroszynski

For z>0.5 SNe, about 0.06% of SNe will be lensed by a factor of 2 or more.