Day 884

Monday.


1505.01841
The dust mass in z>6 normal star forming galaxies
Mancini, et al

Interpret recent ALMA observations of z>6 normal star forming galaxies by means of a semi-numerical method, which couples the output of a cosmological hydrodynamical sim with a chemical evolution model which accounts for the contribution to dust enrichment from supernovae, asymptotic giant branch stars and grain growth in the interstellar medium.  Find that while stellar sources dominated the dust mass of small galaxies, the higher level of metal enrichment experienced by galaxies with M*>1e9 Msun allows efficient grain growth, which provides the dominant contribution to the dust mass.  Even assuming maximally efficient SN dust production, the observed dust mass of the z=7.5 galaxy A1689-zD1 requires very efficient grain growth.  This, in turn, implies that in this galaxy the average density of the cold and dense gas, where grain growth occurs, is comparable to that inferred from observations of QSO host galaxies at similar redshifts.  Although plausible, the upper limits on the dust continuum emission of galaxies at 6.5<z<7.5 show that these conditions must not apply to the bulk of the high z galaxy population.


1505.01871
Wide-field lensing mass maps from DES science verification data
Chang, Vikram, Jain, et al

Present a mass map reconstructed from WL shear measurements over 139 sq. deg from DES science verification data.  The mass map probes both luminous and dark matter, thus providing a tool for studying cosmology.  Find good agreement between the mass map and the distribution of massive galaxy clusters identified using a red-sequence cluster finder.  Potential candidates for super-clusters and voids are identified using these maps.  Measure the cross-correlation between the mass map and a magnitude-limited foreground galaxy sample and find a detection at the 5-7 sigma level on a large range of scales.  These measurements are consistent with simulated galaxy catalogs based on LCDM N-body sims, suggesting low systematics uncertainties in the map.  Summarize key findings in this letter; the detailed methodology and tests for systematics are presented in a companion paper.