Day 734

Monday.

1408.6842
The Illustris simulation: evolving population of black holes across cosmic time
Sijacki, Voglsberger, Genel, Springel, Torrey, Snyder, Nelson, Hernquist

Study the properties of BHs and their host galaxies across cosmic time in the Illustris simulation: (106.5Mpc)^3, 12e9 resolution elements, galaxy formation physics.  Find that the BH mass density for z=0-5 and the BH MF at z=0 predicted by Illustris are in excellent agreement with the most recent observational constraints.  Show that the bolometric and hard X-ray luminosity functions of AGN at z=0 reproduce observational data very well over the full dynamic range probed.  This requires radiative efficiencies to be on average low, epsilon_r<=0.1, unless the bolometric corrections are largely underestimated.  Cosmic downsizing of the AGN population is in broad agreement with the findings from X-ray surveys, but caution that obscuration effects may introduce systematic biases in the flux-limited samples at the faint end.  Also study black hole - host galaxy scaling relations as a function of galaxy morphology, color and sSFR.  Find that BHs and galaxies co-evolve at the massive end, but for low mass, blue and SF galaxies there is no tight relation with either their central BH masses or the nuclear AGN activity.

1408.6846
GALFIT-CORSAIR: implementing the core-Sersic model into GALFIT
Bonfini

Introduce GALFIT-CORSAIR: a publicly available, fully retro-compatible modification of the 2d fitting soft are GALFIT (v.3) which adds an implementation of the core-Sersic model.  

1408.6953
A new determination of the primordial He abundance using the HeI 10830A emission line: cosmological implications
Izotov, Thuan, Guseva

Present NIR spectro-observations of HeI emission line in 45 low-metallicity HII regions, combine with optical spectra to derive primordial He abundance.  HeI line intensity is very sensitive to the density of the HII region; improves determination of the conditions in the He+ zone.  He mass fraction Y derived with accuracy better than 3%.  Derived Yp = 0.2551 pm 0.0022, higher than predicted by standard BBN model.  Combine derived Yp with D/H=(2.53pm0.25)^e-5, find that the best agreement between these light element abundances is achieved in a cosmo model with a baryon mass density Omega_b h^2=0.024pm0.0017 and an effective number of neutrino species Neff=3.58pm0.25.  A non-standard value of Neff is preferred at the 99% CL, impinge the possible existence of additional types of neutrino species.

1408.7052
3D weak gravitational lensing of the CMB and galaxies
Kitching, Heavens, Das

Present a PS formalism that combines the full 3d information from the galaxy ellipticity field, with information from the CMB.  Include in this approach galaxy cosmic shear and galaxy IA, CMB deflection, CMB T and CMB polarization data; including the inter-datm PS between all quantitates.  Apply this to forecasting cosmological parameter errors for CMB and imaging surveys and show that the additional covariance between the CMB and ellitpicity measurements can improve galaxy IA measurements by a factor of two, and DE EoS measurements by 30 %.  Present predictions for Euclid-like, KiDS, ACTPoL, and CoRE-like experience and show that the combination of cosmic shear and the CMB, from Euclid-like and CoRE-like experiments, can measure the sum of neutrino masses with an error of 0.02 eV,and the DE EoS with an error on w0 of less than 0.01.

1408.5388
The Milky Way Tomography with SDSS.  V.  Mapping the Dark Matter halo
Loebman, Ivezic, ... et al

Use the number density distribution and kinematics of SDSS halo stars, probe the DM distribution to heliocentric distances exceeding 10 kpc and galactocentric distances exceeding 20 kpc.  Analysis utilizes Jeans equations to generate 2d acceleration maps throughout the volume; this approach is thoroughly tested on N-body+SPH sim of a MW-like galaxy.  Show that the known accelerations (gradients of the gravitational potential) can be successfully recovered in such a realistic system.  Show that the gravitational potential implied by SDS observations cannot be explained, assuming Newtonian gravity, by visible matter alone: the gravitational force experienced by stars at galactocentric distances of 20 kpc is as much as 3 times stronger than what can be attributed to purely visible matter.  Show that SDSS data provide a strong constraint on the shape of the DM halo potential.  Within galactocentric distances of 20 kpc, the DM halo potential is well described as an oblate halo with axis ratio qDM=0.7pm0.1; corresponds to an axis ratio qDM=0.4pm0.1 for the DM density distribution.  Because of the precise 2d measurements of the acceleration of the halo stars, MOND models can be rejected as the explanation of the observed behavior.