Day 792

Monday.

1411.5688
The evolution of clustering length, large-scale bias and host halo mass at 2<z<5 in the VIMOS Ultra Deep Survey (VUDS)
Durkalec, Le Févre, ... et al

Investigate the evolution of galaxy clustering for galaxies in the redshift range 2.0<z<5.0 using VUDS.  Present the projected real-space 2PCF w_p(r_p) measured by using 3022 galaxies with robust spectroscopic redshifts in two independent fields (COSMOS and VVDS-02h) covering in total 0.8 deg^2.  Quantify how the scale dependent clustering amplitude r_0 changes with z making use of mock samples to evaluate and correct the survey selection function.  Using a power-law model xi(r)=(r/r0)^-gamma, find that the correlation function for the general population is best fit by a model with a clustering length r0=3.95pm0.5 Mpc/h and slope gamma=1.8pm0.005 at z~2.25, r0=4.35pm0.06 Mpc/h and gamma=1.6pm0.12 at z~3.5.  Use this clustering parameters to derive the large-scale linear galaxy bias b_L^PL, between galaxies and DM.  Find b_L^PL=2.68pm0.22 at z~3 (assuming sigma_8=0.8), significantly higher than found at intermediate and low z.  Fit an HOD model to the data and obtain the average halo mass at z~3 is M_h=1e11.75 Msun/h.  From this fit, confirm that the large-scale linear galaxy bias is relatively high at b_L^HOD=2.82pm0.27.  Comparing these measurements with similar measurements at lower redshifts, infer that the SF population of galaxies at z~3 should evolve into the massive and bright (M_r<-21.5) galaxy population which typically occupy haloes of mass <M_h>=1e13.9Msun/h at z=0.

1411.5689
On the importance of sing appropriate spectral models to derive physical properties of galaxies at 0.7<z<2.8
Pacifici, ... Rix, ... Franx, ... van Dokkum, ... et al

Interpreting observations of distant galaxies in terms of constraints on physical parameters - such as M*, SFR and dust optical depth - requires spectral synthesis modeling.  Analyze the reliability of these physical parameters as determined under commonly adopted 'classical' assumptions: SFHs assumed to be exponentially declining functions of time, a simple dust law and no emission-line contribution.  Improved modeling techniques and data quality now allow use of a more sophisticated approach, including realistic SFHs, combined with modern prescriptions for dust attenuation and nebular emission.  Present a Bayesian analysis of the spectra and multi-wavelength photometry of 1048 galaxies from the 3D-HST survey in 0.7<z<2.8 and in the M* range 9<log(M*/Msun)<12.  Find that, using the classical spectral library, M* are systematically overestimated (~0.1 dex) and SFRs are systematically underestimated (~0.6 dex) relative to the more sophisticated approach.  Also find that the simultaneous fit of photometric fluxes and emission-line equivalent widths helps break a degeneracy between SFR and optical depth of the dust, reducing the uncertainties on these parameters.  Finally, show how the biases of classical approaches can affect the correlation between M* and SFR for SF galaxies (the 'SF MS').  Conclude that the normalization, slope and scatter of this relation strongly depends the adopted approach and demonstrate that the classical, oversimplified approach cannot recover the true distribution of M* and SFR.

1411.5691
A search for Population III galaxies in CLASH.  I.  Singly-imaged candidates at high redshift
Rydberg, ... Zitrin,.. et al

Pop III galaxies are predicted to exist at high z and may be rendered sufficiently bright for detection with current telescopes when gravitationally lensed by a FG galaxy cluster.  Pop III galaxies that exhibit strong Lya emission should furthermore be identifiable from broadband photometry because other unusual colors.  Report on a search for such objects at z>6 in the imaging data from CLASH, covering 25 galaxy clusters in 16 filters.  Select algorithm returns 5 singly-imaged candidates with Lya-like color signatures, for which ground-based spectroscopy with current 8-10m class telescopes should be able to test the predicted strength of the Lya line.  None of these 5 objects have been included in previous CLASH compilations of high-z galaxy candidates.  However, when large grids of spectral synthesis models are applied to the study of these objects, find that only two of these candidates are significantly better fitted by Pop III models than by more mundane, low-z stellar populations.