Day 1097

Wednesday.

1605.04910
Doubling strong lensing as a cosmological probe
Linder

SL provides a geometric probe of cosmology in a unique manner through distance ratios involving the source and lens.  This is well known for the time delay distance derived from measured delays between light curves of the images of variable sources such as quasars.  Recently, double source plane lens systems involving two constant sources lensed by the same foreground lens have been proposed as another probe, involving a different ratio of distances measured from the image positions and fairly insensitive to the lens modeling.  Here, demonstrate that these two different sets of SL distance ratios have strong complementarity in cosmo leverage.  Unlike other probes, the double source distance ratio is actually more sensitive to the DE EoS parameters w_0 and w_a than to the matter density Omega_m, for low redshift lenses.  Adding double source distance ratio measurements can improve the DE FoM by 40% for a sample of fewer than 100 low z systems, or even better for the optimal z distribution derived.


1605.05088
An empirical model to form an evolve galaxies in dark matter haloes
Li et al

Based on SFH of galaxies in haloes of different masses, develop an empirical model to grow galaxies in DM haloes.  This model has very few ingredients, any of which can be associated to observational data and thus be efficiently assessed.  By applying this model to a very high resolution cosmo N-body sim, predict a number of galaxy properties that are a very good match to relevant observational data.  Namely, for both centrals and satellites, the galaxy stellar mass function (SMF) up to z~4 and the conditional stellar mass functions (CSMF) in the local universe are in good agreement with observations.  In addition, the 2pt correlation is well predicted in the different stellar mass ranges explored by the model.  Furthermore, after applying stellar population synthesis models to the stellar composition as a function of z, find that the luminosity functions in 0.1u, 0.1g, 0.1r, 0.1i and 0.1z bands agree quite well wit the SDSS observational results down to an absolute magnitude at about -17.0.  The SDSS conditional luminosity functions (CLF) itself is predicted well.  Finally, the cold gas is derived from the SFR to predict the HI gas mass within each mock galaxy.  Find a remarkable good match to observed HI-to-stellar mass ratios.  These features ensure that such galaxy/gas catalogs can be used to generate reliable mock redshift surveys.


1605.05286
Testing the spherical evolution of cosmic voids
Demochenko, Kai, Heymans, Peacock

Study the spherical evolution model for voids in LCDM, where the evolution of voids is governed by DE at an earlier time than that for the whole universe or in overdensities.  Show that the presence of DE suppresses the growth of peculiar velocities, causing void shell-crossing to occur at progressively later epochs as Omega_Lambda increases.  Apply the spherical model to evolve the initial conditions of N-body simulated voids and compare the resulting final void profiles.  Find that the model is successful in tracking the evolution of voids with radii greater than 30 Mpc/h, implying that void profiles could be used to constrain DE.  Find the the initial peculiar velocities of voids play a significant role in shaping their evolution.  Excluding the peculiar velocity in the evolution model delays the time of shell crossing.