The thinnest cold HI clouds in the diffuse interstellar medium?
天体物理学
2009-11-11 v2
摘要
We confirm and discuss recently discovered cold HI clouds with column densities among the lowest ever detected. The column densities of Cold Neutral Medium (CNM) towards 3C286 and 3C287 are ~10^18 cm^-2, below an observational lower limit, and also below tiny-scale-atomic clouds detected by VLBI and time-variable profiles against pulsars. These column densities are close to the minimum imposed by thermal evaporation. The fractions of the CNM to total HI towards 3C286 and 3C287 are ~4% and <2%, respectively. We discuss the CNM fraction and the CNM clouds in relation to several theoretical models.
关键词
引用
@article{arxiv.astro-ph/0505106,
title = {The thinnest cold HI clouds in the diffuse interstellar medium?},
author = {Snezana Stanimirovic and Carl Heiles},
journal= {arXiv preprint arXiv:astro-ph/0505106},
year = {2009}
}
备注
small changes, accepted by ApJ