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Full-Text Articles in Physical Sciences and Mathematics
Recovery Of The Power Spectrum Of Mass Fluctuations From Observations Of The Ly Alpha Forest, Rac Croft, Dh Weinberg, N Katz, L Hernquist
Recovery Of The Power Spectrum Of Mass Fluctuations From Observations Of The Ly Alpha Forest, Rac Croft, Dh Weinberg, N Katz, L Hernquist
Astronomy Department Faculty Publication Series
We present a method to recover the shape and amplitude of the power spectrum of mass fluctuations, P(k), from observations of the high-redshift Lyα forest. The method is motivated by the physical picture that has emerged from hydrodynamic cosmological simulations and related semianalytic models, in which typical Lyα forest lines arise in a diffuse, continuous, fluctuating intergalactic medium. The thermal state of this low-density gas (δρ/ρ 10) is governed by simple physical processes, which lead to a tight correlation between the Lyα optical depth and the underlying matter density. To recover the mass power spectrum, we (1) …
The Observability Of Metal Lines Associated With The Ly Alpha Forest, U Hellsten, L Hernquist, N Katz, Dh Weinberg
The Observability Of Metal Lines Associated With The Ly Alpha Forest, U Hellsten, L Hernquist, N Katz, Dh Weinberg
Astronomy Department Faculty Publication Series
We develop a prescription for characterizing the strengths of metal lines associated with Lyα forest absorbers (LYFAs) of a given neutral hydrogen column density NH I and metallicity [O/H]. This line observability index (LOX) is line specific and translates, for weak lines, into a measure of the equivalent width. It can be evaluated quickly for thousands of transitions within the framework of a given model of the Lyα forest, providing a ranking of the absorption lines in terms of their strengths and enabling model builders to select the lines that deserve more detailed consideration, i.e., those that should be …
The Formation Of Quasars In Low-Luminosity Hosts Via Galaxy Harassment, G Lake, N Katz, B Moore
The Formation Of Quasars In Low-Luminosity Hosts Via Galaxy Harassment, G Lake, N Katz, B Moore
Astronomy Department Faculty Publication Series
We have simulated disk galaxies undergoing continual bombardment by other galaxies in a rich cluster. "Galaxy harassment" leads to dramatic evolution of smaller disk galaxies and provides an extremely effective mechanism for fueling a central quasar. Within a few billion years after a small disk galaxy enters the cluster environment, up to 90% of its gas can be driven into the inner 500 pc. Up to half of the mass can be transferred in a burst lasting just 100-200 Myr. This transport of gas to the center of galaxy is far more efficient than any mechanism proposed before. Galaxy harassment …