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University of Massachusetts Amherst

2001

Galaxies : formation

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Full-Text Articles in Physical Sciences and Mathematics

Cooling Radiation And The Ly Alpha Luminosity Of Forming Galaxies, Ma Fardal, N Katz, Jp Gardner, L Hernquist, Dh Weinberg, R Dave Jan 2001

Cooling Radiation And The Ly Alpha Luminosity Of Forming Galaxies, Ma Fardal, N Katz, Jp Gardner, L Hernquist, Dh Weinberg, R Dave

Astronomy Department Faculty Publication Series

We examine the cooling radiation from forming galaxies in hydrodynamic simulations of the LCDM model (cold dark matter with a cosmological constant), focusing on the Lyα line luminosities of high-redshift systems. Primordial composition gas condenses within dark matter potential wells, forming objects with masses and sizes comparable to the luminous regions of observed galaxies. As expected, the energy radiated in this process is comparable to the gravitational binding energy of the baryons, and the total cooling luminosity of the galaxy population peaks at z 2. However, in contrast to the classical picture of gas cooling from the ~106 K …

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Simulations Of Damped Ly Alpha And Lyman Limit Absorbers In Different Cosmologies: Implications For Structure Formation At High Redshift, Jp Gardner, N Katz, L Hernquist, Dh Weinberg Jan 2001

Simulations Of Damped Ly Alpha And Lyman Limit Absorbers In Different Cosmologies: Implications For Structure Formation At High Redshift, Jp Gardner, N Katz, L Hernquist, Dh Weinberg

Astronomy Department Faculty Publication Series

We use hydrodynamic cosmological simulations to study damped Lyα (DLA) and Lyman limit (LL) absorption at redshifts z = 2-4 in five variants of the cold dark matter scenario: COBE-normalized (CCDM), cluster-normalized (SCDM), and tilted (n = 0.8) Ωm = 1 models, as well as open (OCDM) and flat (LCDM) Ωm = 0.4 models. Our standard simulations resolve the formation of dense concentrations of neutral gas in halos with circular velocity vc ≥ vc,res 140 km s-1 for Ωm = 1 and 90 km s-1 for Ωm = 0.4, …

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