1509.08923
The metal and dust yields of the first massive stars
Marassi, et al
Quantify the role of Pop III core-collapse SNe as the first cosmic dust polluters. Starting from a homogeneous set of stellar progenitors with masses in the range [13-80] Msun, find that the mass and composition of newly formed dust depend on the mixing efficiency of the ejecta and the degree of fallback experienced during the explosion. For standard Pop III SNe, whose explosions are calibrated to reproduce the average elemental abundances of Galactic halo stars with [Fe/H]<-2.5, between 0.18 and 3.1 Msun (0.39-1.76 Msun) of dust can form in uniformly mixed (unmixed) ejecta, and the dominant grain species are silicates. Also investigate dust formation in the ejecta of faint Pop III SN, where the ejecta experience a strong fallback. By examining a set of models, tailored to minimize the scatter with the abundances of carbon-enhanced Galactic halo stars with [Fe/H]<-4, find that amorphous carbon is the only grain species that forms, with masses in the range 2.7e-3 - 0.27 Msun (7.5e-4 - 0.11 Msun) for uniformly mixed (unmixed) ejecta models. Finally for all the models, estimate the amount and composition of dust that survives the passage of the reverse shock, and find that, depending on circumstellar medium densities, between 3 and 50% (10-80%) of dust produced by standard (faint) Pop III SNe can contribute to early dust enrichment.
1509.08930
Weak-lensing mass calibration of the Atacama cosmology telescope equatorial Sunyaev-Zeldovich cluster sample with the Canada-France-Hawaii Telescope Stripe 82 survey
Battaglia, Leauthaud, Miyatake, et al
Mass calibration uncertainty is the largest systematic effect for using clusters of galaxies to constraint cosmo params. Present WL mass measurements from CFHT S82 survey for galaxy clusters selected through their high S/N tSZ signal measured with ACT. The average WL mass is (4.8±0.8)e14 Msun, consistent with the tSZ mass estimate of (4.70±1.0)e14 Msun which assumes a universal pressure profile for the cluster gas. Results are consistent with previous WL measurements of tSZ-detected clusters from the Plank satellite. When comparing the results, estimate the Eddington bias correction for the sample intersection of Planck andWL clusters which was previously neglected.
1509.08933
Unbiased methods for removing systematics from galaxy clustering measurements
Elsner, Leistedt, Peiris
Measuring the angular clustering of galaxies as a function of redshift is a powerful method for tracting information from the 3D galaxy distribution. The precision of such measurements will dramatically increase with ongoing and future wide-field galaxy surveys. However, these are also increasingly sensitive to observational and astrophysical contaminants. Study the statistical properties of 3 methods proposed for controlling such systematics - template subtraction, basic mode projection, and extended mode projection - all of which make use of externally supplied template maps, designed to characterize and capture the spatial variations of potential systematic effects. Based on a detailed mathematical analysis, and in agreement with simulations, find that the template subtraction method in its original formulation returns biased estimates of the galaxy angular clustering. Derive closed-form expressions that should be used to correct results for this shortcoming. Turning to the basic mode projections algorithm, prove it to be free of any bias, whereas it is concluded that results computed with extended mode projection are biased. Within a simplified setup, derive analytical expressions for the bias and discuss the options for correcting it in more realistic configurations. Common to all 3 methods is an increased estimator variance induced by the cleaning process, albeit at different levels. These results enable unbiased high-precision clustering measurements in the presence of spatially-varying systematics, and essential step towards realizing the full potential of current and planned galaxy surveys.
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