%0 Generic %1 murray2014excitation %A Murray, Claire E. %A Lindner, Robert R. %A Stanimirovic, Snezana %A Goss, W. M. %A Heiles, Carl %A Dickey, John %A Pingel, Nickolas M. %A Lawrence, Allen %A Jencson, Jacob %A Babler, Brian L. %A Hennebelle, Patrick %D 2014 %K medium neutral temperature %T Excitation temperature of the warm neutral medium as a new probe of the Lyman-\alpha radiation field %U http://arxiv.org/abs/1401.1215 %X We use the Karl G. Jansky Very Large Array (VLA) to conduct a high-sensitivity survey of neutral hydrogen (HI) absorption in the Milky Way. In combination with corresponding HI emission spectra obtained mostly with the Arecibo Observatory, we detect a widespread warm neutral medium (WNM) component with excitation temperature <Ts>= 7200 (+1800,-1200) K (68% confidence). This temperature lies above theoretical predictions based on collisional excitation alone, implying that Ly-\alpha scattering, the most probable additional source of excitation, is more important in the interstellar medium (ISM) than previously assumed. Our results demonstrate that HI absorption can be used to constrain the Ly-\alpha radiation field, a critical quantity for studying the energy balance in the ISM and intergalactic medium yet notoriously difficult to model because of its complicated radiative transfer, in and around galaxies nearby and at high redshift.

@misc{murray2014excitation, abstract = {We use the Karl G. Jansky Very Large Array (VLA) to conduct a high-sensitivity survey of neutral hydrogen (HI) absorption in the Milky Way. In combination with corresponding HI emission spectra obtained mostly with the Arecibo Observatory, we detect a widespread warm neutral medium (WNM) component with excitation temperature <Ts>= 7200 (+1800,-1200) K (68% confidence). This temperature lies above theoretical predictions based on collisional excitation alone, implying that Ly-{\alpha} scattering, the most probable additional source of excitation, is more important in the interstellar medium (ISM) than previously assumed. Our results demonstrate that HI absorption can be used to constrain the Ly-{\alpha} radiation field, a critical quantity for studying the energy balance in the ISM and intergalactic medium yet notoriously difficult to model because of its complicated radiative transfer, in and around galaxies nearby and at high redshift.}, added-at = {2014-01-08T10:14:28.000+0100}, author = {Murray, Claire E. and Lindner, Robert R. and Stanimirovic, Snezana and Goss, W. M. and Heiles, Carl and Dickey, John and Pingel, Nickolas M. and Lawrence, Allen and Jencson, Jacob and Babler, Brian L. and Hennebelle, Patrick}, biburl = {https://www.bibsonomy.org/bibtex/2a36b4d16d428ab3de273a40155568154/miki}, description = {[1401.1215] Excitation temperature of the warm neutral medium as a new probe of the Lyman-{\alpha} radiation field}, interhash = {072570dfebbae480f25d6cfd471d1039}, intrahash = {a36b4d16d428ab3de273a40155568154}, keywords = {medium neutral temperature}, note = {cite arxiv:1401.1215Comment: 7 pages, 3 figures, 1 table. Accepted for publication in ApJ Letters}, timestamp = {2014-01-08T10:14:28.000+0100}, title = {Excitation temperature of the warm neutral medium as a new probe of the Lyman-{\alpha} radiation field}, url = {http://arxiv.org/abs/1401.1215}, year = 2014 }