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arXiv · 2106.15614

The MACH HI absorption survey I: Physical conditions of cold atomic gas outside of the Galactic plane

Claire E. Murray·Snežana Stanimirović·Carl Heiles·John M. Dickey·N. M. McClure-Griffiths·M. -Y. Lee·W. M. Goss·Nicholas Killerby-Smith
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Abstract

Tracing the transition between the diffuse atomic interstellar medium (ISM) and cold, dense gas is crucial for deciphering the star formation cycle in galaxies. Here we present MACH, a new survey of cold neutral hydrogen (HI) absorption at $21\rm\,cm$ by the Karl G. Jansky Very Large Array. We target 42 bright background sources with $60 0.001$ are ubiquitous ($c\sim100\%$), whereas high optical depths ($\tau>1$) are extremely rare ($c\sim0\%$).

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Claire E. Murray, Snežana Stanimirović, Carl Heiles, John M. Dickey, N. M. McClure-Griffiths, M. -Y. Lee, W. M. Goss, Nicholas Killerby-Smith. 2021-06-29. The MACH HI absorption survey I: Physical conditions of cold atomic gas outside of the Galactic plane. https://doi.org/10.3847/1538-4365%2Fac0f0b

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