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The Physical Conditions of Intermediate Redshift MgII Absorbing Clouds from Voigt Profile Analysis

Chris Churchill·Steven Vogt·Jane Charlton
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Abstract

[Slightly Abridged] We present a detailed statistical analysis of the column densities, N, and Doppler parameters, b, of MgII absorbing clouds at redshifts 0.4 ~5 km/s for MgII and FeII and ~7 km/s for MgI. The clouds are consistent with being thermally broadened, with temperatures in the 30-40,000K range. (4) A two-component Gaussian model to the velocity two-point correlation function yielded velocity dispersions of 54 km/s and 166 km/s. The narrow component has roughly twice the amplitude of the broader component. The width and amplitude of the broader component decreases as equivalent width increases. (5) From photoionization models we find that the column density ratios are most consistent with photoionization by the extragalactic background, as opposed to stars. Based upon N(MgI)/N(MgII), it appears that at least two-phase ionization models are required to explain the data.

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Chris Churchill, Steven Vogt, Jane Charlton. 2002-10-09. The Physical Conditions of Intermediate Redshift MgII Absorbing Clouds from Voigt Profile Analysis. https://doi.org/10.1086/345513

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