1708.07349
The concentration-mass relation of clusters of galaxies from the OmegaWINGS survey
Biviano, et al
The relation between a cosmological halo concentration and its mass (cMr) is a powerful tool to constraint cosmological models of halo formation and evolution. On the scale of galaxy clusters the cMr has so far been determined mostly with X-ray and gravitational lensing data. The use of independent techniques is helpful in assessing possible systematics. Provide one of the few determinations of the cMr by the dynamical analysis of the projected-phase-space distribution of cluster members. Based on the WINGS and OmegaWINGS data sets, use the Jeans analysis with the MAMPOSSt technique to determine masses and concentrations for 49 nearby clusters, each of which has ~60 spectroscopic members or more within the viral region, after removal of substructures. The cMr is in statistical agreement with theoretical predictions based on LCDM cosmo sims. The cMr is different from most previous observational determinations because of its flatter slope and lower normalization. It is however in agreement with 2 recent cMr obtained using the lensing technique on the CLASH and LoCuSS cluster data sets. In the future, will extend the analysis to galaxy systems of lower mass and at higher redshifts.
1708.07433
The impact of the temporal distribution of communicating civilizations on their detectability
Balbi
Use a statistical model to investigate the detectability (defined by the requirement that they are in causal contact with us) of communicating civilizations within a volume of the universe surrounding the location. If the civilizations are located in the Galaxy, the detectability requirement imposes a strict constraint on their epoch of appearance and their communicating lifespan. This, in turn, implies that the fraction of civilizations of which we can find any empirical evidence strongly depends on the specific features of their temporal distribution. The approach shed light on aspects of the problem that can escape the standard treatment based on the Drake equation. Therefore, it might provide the appropriate framework for future studies dealing with the evolutionary aspects of the search for extraterrestrial intelligence (SETI).
1708.07502
Fundamental physics from future weak-lensing calibrated Sunyaev-Zel'dovich galaxy cluster counts
Madhavacheril, Battaglia, Miyatake
Future high-resolution measurements of the CMB will produce catalogs of tens of thousands of galaxy clusters through the tSZ effect. Forecast how well different configurations of a CMB Stage-4 experiment can constrain cosmological parameters, in particular the amplitude of structure as a function of redshift sigma8(z), the sum of neutrino masses Sigma m_nu, and the dark energy EoS w(z). A key element of this effort is calibrating the tSZ scaling relation by measuring the lensing signal around clusters. Examine how the mass calibration from future optical surveys like LSST compares with a purely internal calibration using lensing of the CMB itself. Find that, due to its high-redshift leverage, internal calibration gives constraints on cosmo parameters comparable to the optical calibration, and can be used as a cross-check of systematics in the optical measurement. Also show that in contrast to the constraints using the CMB lensing power spectrum, lensing-calibrated tSZ cluster counts can detect a minimal Sigma m_nu at the 3-5 sigma level even when the DE EoS is freed up.
Future high-resolution measurements of the CMB will produce catalogs of tens of thousands of galaxy clusters through the tSZ effect. Forecast how well different configurations of a CMB Stage-4 experiment can constrain cosmological parameters, in particular the amplitude of structure as a function of redshift sigma8(z), the sum of neutrino masses Sigma m_nu, and the dark energy EoS w(z). A key element of this effort is calibrating the tSZ scaling relation by measuring the lensing signal around clusters. Examine how the mass calibration from future optical surveys like LSST compares with a purely internal calibration using lensing of the CMB itself. Find that, due to its high-redshift leverage, internal calibration gives constraints on cosmo parameters comparable to the optical calibration, and can be used as a cross-check of systematics in the optical measurement. Also show that in contrast to the constraints using the CMB lensing power spectrum, lensing-calibrated tSZ cluster counts can detect a minimal Sigma m_nu at the 3-5 sigma level even when the DE EoS is freed up.
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