Galaxy evolution from strong lensing statistics: the differential evolution of the velocity dispersion function in concord with the LambdaCDM paradigm - AstrophysicsReport as inadecuate




Galaxy evolution from strong lensing statistics: the differential evolution of the velocity dispersion function in concord with the LambdaCDM paradigm - Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We study galaxy evolution from z=1 to z=0 as a function of velocitydispersion sigma for galaxies with sigma > 95 km-s based on the measured andMonte Carlo realised local velocity dispersion functions VDFs of galaxies andthe revised statistical properties of 30 strongly-lensed sources. We assumethat the total luminous plus dark mass profile of a galaxy is isothermal inthe optical region for 0 < z < 1 as suggested by mass modelling of lensinggalaxies. For the evolutionary behaviours of the VDFs we find that: 1 thenumber density of massive mostly early-type galaxies with sigma > 200 km-sevolves differentially in the way that the number density evolution is greaterat a higher velocity dispersion; 2 the number density of intermediate and lowmass early-type galaxies 95 km-s < sigma < 200 km-s is nearly constant; 3the late-type VDF transformed from the Monte Carlo realised circular velocityfunction is consistent with no evolution in its shape or integrated numberdensity consistent with galaxy survey results. These evolutionary behaviours ofthe VDFs are strikingly similar to those of the dark halo mass function DMFfrom N-body simulations and the stellar mass function SMF predicted by recentsemi-analytic models of galaxy formation under the current LambdaCDMhierarchical structure formation paradigm. Interestingly, the VDF evolutionsappear to be qualitatively different from ``stellar mass-downsizing-evolutions obtained by many galaxy surveys. The coevolution of the DMF, the VDFand the SMF is investigated in quantitative detail in a following paper. Weconsider several possible systematic errors for the lensing analysis and findthat they are not likely to alter the conclusions.abridged



Author: Kyu-Hyun Chae

Source: https://arxiv.org/







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