1211.0007
Extragalactic number counts at 100 um, free from cosmic variance
Sibthorpe et al
DEBRIS (Disc emission via a bias-free reconnaissance in the infrared/Submillimeter) survey at 100 um on Herschel. 323 small-area mapping observations performed uniformly across the sky--- sparse sampling of the astronomical sky with an effective coverage of ~2.5 deg2. Find cosmic variance independent analyze consistent with previous count measurements made using relatively small area surveys. Find no statistically significant cosmic variance on any scale within the errors of data. Interpret results to estimate the probability of galaxy source confusion in the study of debris discs.
1210.5558
Constraints on dark matter and supersymmetry from LAT observations of dwarf galaxies
Drlica-Wagner, for Fermi-LAT collaboration
dSphs have large M/L and low astrophysical BG: good target for DM searches via gamma rays. Fermi LAT constrained DM annihilation cross section from a combined analysis of 10 dSphs. Apply constraints to experimentally valid, super-symmetric particle models derived from a phenomenological scan of the Minimal Supersymmetric Standard Model (pMSSM). Search for spatially extended, hard-spectrum gamma-ray sources lacking counterparts in other wavelengths (may be associated with DM substructures predicted from simulations).
1210.5586
Cosmology with the largest galaxy cluster survyes: Going beyond Fisher matrix forecasts
Khedekar, Majumdar
MCMC likelihood study of cosmological constraints that are expected from some of the largest, ongoing and proposed, cluster surveys in different wave-bands and compare the estimates to the prevalent Fisher matrix forecasts. Mock catalogs expected from eROSITA, WFXT, RCS2, DES and Planck, along with a mock dataset of follow-up mass calibrations are analyzed for this purpose. A fair agreement between MCMC and Fisher results is found only in the case of minimal models; in many cases, the marginalized constraints from both methods can differ by factors of 30-100%. The discrepancy can be alarmingly large for a time dependent dark energy equation of state w(a); the Fisher methods are seen to under-estimate the constraints by as much as a factor of 4-5. Fisher estimates become more and more inappropriate as we move away from LCDM to varying w DE cosmologies. [Why?] Fisher also predicts incorrect parameter degeneracies. High value of unknown scatter and its redshift dependence is largely degenerate with the cosmo parameters sigma_8 and w(a), and can degrade the cosmo constraints considerably. Addition of mass-calibrated cluster datasets can improve DE and sigma_8 constraints by factors of 2-3 from what can be obtained from CMB+SNe+BAO only. Optimal survey design must be done using MCMC rather than Fisher.
1210.5700
Stellar mass versus stellar velocity dispersion: which is better for linking galaxies to their dark matter halos?
Li, Wang, Jing
Stellar mass is a better proxy than stellar velocity dispersion for halo mass, despite previous results, when sample set is limited to central galaxies.
1210.5785
The five-hundred-meter aperture spherical radio telescope project and its early science opportunities
Li, Nan, Pan
NAOC started building the largest antenna in the world: FAST. Mega-science project funded by NDRC. Part of Chinese contribution to build the square kilometer array (SKA). Completion in 2016, sensitive in low frequence radio bands of 70 MHz and 3 GHz [few m to cm waves, FM radio to microwave oven range]. Specs, capabilities, main scientific aspirations described in Nan+ (2011); this paper review the design and key science goals of FAST. [Aracebo is 305m across]
1210.6008
CMB anisotropy science: a review
Challinor
Temperature and polarization anisotropies in the CMB play a critical role in defining the cosmological model. Review basic science, role of observations with ground-based and balloon-borne Antarctic telescopes. Most ingredients of standard cosmo model poorly understood in terms of fundamental physics. Discuss how current and future CMB observations can address some of these issues, focusing on two directly relevant for Antarctic programms: searching for gravitational waves from inflation via B-mode polarization, and mapping DM through CMB lensing.
1210.6021
Order statistics applied to the most massive and most distant galaxy clusters
Waizmann, Ettori, Bartelmann
* order statistic: equal to its kth-smallest value Most fundamental tools (along with rank statistics) in non-parametric statistics and inference.
Analytic framework for calculating the individual and joint distributions of the n-th most massive or n-th highest redshift galaxy cluster for a given survey characteristic allowing to formulate LCDM exclusion criteria. Show that the cumulative distribution functions steepen with increasing order [order of what?], giving them a higher constraining power with respect to the extreme value statistics. Find: order statistics in mass (dominated by clusters at low z) is sensitive to the matter density and the normalization of the matter fluctuations, whereas the order statistics in redshift is particularly sensitive to the geometric evolution of the universe. Both order statistics (for a fixed cosmology) are efficient probes of the functional shape of the mass function at the high mass end. To allow a quick assessment of both order statistics, provide fits as a function of the survey area that allow percentile estimation with an accuracy better than two per cent. Furthermore, we discuss the joint distributions in the 2d case for different combinations of order. With the theory, apply the order statistical analysis to SPT massive cluster sample and MCXC catalogue and find that the ten most massive clusters in the sample are consistent with LCDM and the Tinker mass function. In turn, assuming the LCDM reference cosmology, order statistics can also be utilized for consistency checks of the completeness of the observed sample and the modeling of the survey selection function.
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