Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Astrophysics and Astronomy
X-Ray Absorption By The Low-Redshift Intergalactic Medium: A Numerical Study Of The Lambda Cold Dark Matter Model, Xl Chen, Dh Weinberg, N Katz, R Dave
X-Ray Absorption By The Low-Redshift Intergalactic Medium: A Numerical Study Of The Lambda Cold Dark Matter Model, Xl Chen, Dh Weinberg, N Katz, R Dave
Astronomy Department Faculty Publication Series
Using a hydrodynamic simulation of a cold dark matter universe with a cosmological constant, we investigate the "X-ray forest" absorption imprinted on the spectra of background quasars by the intervening intergalactic medium (IGM), at redshift z 0. In agreement with previous studies, we find that O VII and O VIII produce the strongest absorption features. The strong oxygen absorbers that might be detectable with Chandra or XMM-Newton arise in gas with T ~ 105.5-106.5 K and overdensities δ 100 that are characteristic of galaxy groups. Future X-ray missions could detect weaker oxygen absorption produced by gas with …
The Halo Occupation Distribution And The Physics Of Galaxy Formation, Aa Berlind, Dh Weinberg, Aj Benson, Cm Baugh, S Cole, R Dave, Cs Frenk, A Jenkins, N Katz, Cg Lacey
The Halo Occupation Distribution And The Physics Of Galaxy Formation, Aa Berlind, Dh Weinberg, Aj Benson, Cm Baugh, S Cole, R Dave, Cs Frenk, A Jenkins, N Katz, Cg Lacey
Astronomy Department Faculty Publication Series
The halo occupation distribution (HOD) describes the bias between galaxies and dark matter by specifying (1) the probability P(N|M) that a halo of virial mass M contains N galaxies of a particular class and (2) the relative spatial and velocity distributions of galaxies and dark matter within halos. We calculate and compare the HODs predicted by a smoothed particle hydrodynamics (SPH) simulation of a ΛCDM cosmological model (cold dark matter with a cosmological constant) and by a semianalytic galaxy formation model applied to the same cosmology. Although the two methods predict different galaxy mass functions, …
The Influence Of Omega(B) On High-Redshift Structure, Jp Gardner, N Katz, L Hernquist, Dh Weinberg
The Influence Of Omega(B) On High-Redshift Structure, Jp Gardner, N Katz, L Hernquist, Dh Weinberg
Astronomy Department Faculty Publication Series
We analyze high-redshift structure in three hydrodynamic simulations that have identical initial conditions and cosmological parameters and differ only in the value of the baryon density parameter, Ωb = 0.02, 0.05, and 0.125. Increasing Ωb does not change the fraction of baryons in the diffuse (unshocked) phase of the intergalactic medium, but it increases cooling rates and therefore transfers some baryons from the shocked intergalactic phase to the condensed phase associated with galaxies. Predictions of Lyα forest absorption are almost unaffected by changes in Ωb at velocity scales greater than 5 km s-1 (our resolution limit), …