Steven J. Gibson, Ward S. Howard, Christian S. Jolly, Jonathan H. Newton, Aaron C. Bell, Mary E. Spraggs, J. Marcus Hughes, Aaron M. Tagliaboschi, Christopher M. Brunt, A. Russell Taylor, Jeroen M. Stil, Thomas M. Dame
Published 2015-10-22Version 1
We have mapped cold atomic gas in 21cm line HI self-absorption (HISA) at arcminute resolution over more than 90% of the Milky Way's disk. To probe the formation of H2 clouds, we have compared our HISA distribution with CO J=1-0 line emission. Few HISA features in the outer Galaxy have CO at the same position and velocity, while most inner-Galaxy HISA has overlapping CO. But many apparent inner-Galaxy HISA-CO associations can be explained as chance superpositions, so most inner-Galaxy HISA may also be CO-free. Since standard equilibrium cloud models cannot explain the very cold HI in many HISA features without molecules being present, these clouds may instead have significant CO-dark H2.
Comments: 2 pages, 1 figure, to appear in proceedings of IAU Symposium 315, "From Interstellar Clouds to Star-Forming Galaxies: Universal Processes?"
SHARDS: A global view of the star formation activity at z~0.84 and z~1.23
A global view on star formation: The GLOSTAR Galactic plane survey. XI. Radio source catalog IV: $2^\circ < \ell < 28^\circ$, $36^\circ < \ell < 60^\circ$ and $|b| < 1^\circ$
Dust evolution, a global view: I. Nano-particles, nascence, nitrogen and natural selection . . . joining the dots
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