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Full-Text Articles in Physical Sciences and Mathematics
From Galaxy-Galaxy Lensing To Cosmological Parameters, J Yoo, Jl Tinker, Dh Weinberg, Z Zheng, N Katz, R Dave
From Galaxy-Galaxy Lensing To Cosmological Parameters, J Yoo, Jl Tinker, Dh Weinberg, Z Zheng, N Katz, R Dave
Astronomy Department Faculty Publication Series
Galaxy-galaxy lensing uses the weak distortion of background sources to measure the mean excess surface density profile, ΔΣ(r), around a sample of foreground lensing galaxies. We develop a method for combining ΔΣ(r) with the galaxy-galaxy correlation function ξgg(r) to constrain the matter density parameter Ωm and the matter fluctuation amplitude σ8, going beyond the linear biasing model to reach the level of accuracy demanded by current and future measurements. We adopt the halo occupation distribution (HOD) framework and test its applicability to this problem by examining the effects of …
Probing Galaxy Formation With He Ii Cooling Lines, Yj Yang, Ai Zabludoff, R Dave, Dj Eisenstein, Pa Pinto, N Katz, Dh Weinberg, Ej Barton
Probing Galaxy Formation With He Ii Cooling Lines, Yj Yang, Ai Zabludoff, R Dave, Dj Eisenstein, Pa Pinto, N Katz, Dh Weinberg, Ej Barton
Astronomy Department Faculty Publication Series
Using high-resolution cosmological simulations, we study hydrogen and helium gravitational cooling radiation from gas accretion by young galaxies. We focus on the He II cooling lines, which arise from gas with a different temperature history (Tmax ~ 105 K) than H I line-emitting gas. We examine whether three major atomic cooling lines, H I λ1216, He II λ1640, and He II λ304, are observable, finding that Lyα and He II λ1640 cooling emission at z = 2-3 are potentially detectable with deep narrowband (R > 100) imaging and/or spectroscopy from the ground. While the expected strength of …
On The Origin Of Cold Dark Matter Halo Density Profiles, Y Lu, Hj Mo, N Katz, Md Weinberg
On The Origin Of Cold Dark Matter Halo Density Profiles, Y Lu, Hj Mo, N Katz, Md Weinberg
Astronomy Department Faculty Publication Series
N-body simulations predict that cold dark matter (CDM) halo-assembly occurs in two phases: (i) a fast-accretion phase with a rapidly deepening potential well; and (ii) a slow-accretion phase characterized by a gentle addition of mass to the outer halo with little change in the inner potential well. We demonstrate, using one-dimensional simulations, that this two-phase accretion leads to CDM haloes of the Navarro, Frenk & White (NFW) form and provides physical insight into the properties of the mass-accretion history that influence the final profile. Assuming that the velocities of CDM particles are effectively isotropized by fluctuations in the gravitational potential …