The kinetic temperature in a damped Lyman-alpha absorption system in Q2206-199 - an example of the warm neutral medium

R. F. Carswell, G. D. Becker, R. A. Jorgenson, M. T. Murphy, A. M. Wolfe

Published 2012-02-14Version 1

By comparing the widths of absorption lines from OI, SiII and FeII in the redshift z=2.076 single-component damped Lyman alpha absorption system in the spectrum of Q2206-199 we establish that these absorption lines arise in Warm Neutral Medium gas at ~12000 +/- 3000K. This is consistent with thermal equilibrium model estimates of ~ 8000K for the Warm Neutral Medium in galaxies, but not with the presence of a significant cold component. It is also consistent with, but not required by, the absence of CII* fine structure absorption in this system. Some possible implications concerning abundance estimates in narrow-line WNM absorbers are discussed.