An Improved Technique for Measurement of Cold HI in Molecular Cloud Cores
arXiv:0808.2975 · doi:10.1086/592553
Abstract
The presence of atomic gas mixed with molecular species in a "molecular" cloud may significantly affect its chemistry, the excitation of some species, and can serve as probe of the cloud's evolution. Cold neutral atomic hydrogen (HI) in molecular clouds is revealed by its self absorption of background galactic HI 21-cm emission. The properties of this gas can be investigated quantitatively through observation of HI Narrow Self-Absorption (HINSA). In this paper, we present a new technique for measuring atomic gas physical parameters from HINSA observations that utilizes molecular tracers to guide the HINSA extraction. This technique offers a significant improvement in the precision with which HI column densities can be determined over previous methods, and it opens several new avenues of study of relevance to the field of star formation.
Accepted for Astrophycal Journal 8/2008
Cited by in corpus (15)
- The HNC/HCN Ratio in Star-Forming Regions
- Autonomous Gaussian Decomposition
- Gamma-ray observations of the Orion Molecular Clouds with the Fermi Large Area Telescope
- Cloud formation in the atomic and molecular phase: HI self absorption (HISA) towards a Giant Molecular Filament
- Dynamical cloud formation traced by atomic and molecular gas
- On the accuracy of HI observations in molecular clouds -- More cold HI than thought?
- Atomic and molecular gas properties during cloud formation
- Kinetic tomography of the Galactic plane within 1.25 kiloparsecs from the Sun. The interstellar flows revealed by HI and CO line emission and 3D dust
- Spatially Resolved Gas-phase Metallicity in FIRE-2 Dwarfs: Late-Time Evolution of Metallicity Relations in Simulations with Feedback and Mergers
- A FAST Survey of HINSA in PGCCs Guided by HC3N
- The CO-dark molecular gas in the cold HI arc
- Tracing the Formation of Molecular Clouds in a Low-Metallicity Galaxy: A HI Narrow Self-Absorption Survey of the Large Magellanic Cloud
- The evolution of CH in Planck Galactic Cold Clumps
- HI Narrow-Line Self-Absorptions Toward the High-Mass Star-Forming Region G176.51+00.20
- Cold atomic gas identified by HI self-absorption. Cold atomic clouds toward giant molecular filaments