Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Measuring the Atomic to Molecular Gas Ratio in Molecular Cloud Cores
Authors:
Krco, Marko; Goldsmith, P. F.; Brown, R. L.
Affiliation:
AA(Cornell University), AB(Jet Propulsion Laboratory), AC(Cornell University)
Publication:
American Astronomical Society, AAS Meeting #213, #485.09; Bulletin of the American Astronomical Society, Vol. 41, p.457
Publication Date:
01/2009
Origin:
AAS
Bibliographic Code:
2009AAS...21348509K

Abstract

HI Narrow Self-Absorption (HINSA) is a 21cm absorption feature which is caused by cold HI gas in the well-shielded interiors of molecular clouds and dense cloud cores. A survey using the Green Bank Telescope (GBT) of over 70 molecular cloud cores with distances of up to 700pc has found that nearly half of them exhibit HINSA features. This HI gas may be a remnant of the HI-H2 conversion process which occurs during the collapse of a diffuse atomic hydrogen cloud to form a dense molecular cloud. Comparison with 13CO emission obtained with the Five College Radio Astronomy Observatory (FCRAO) 14 m telescope yields HI/H2 ratios for over 30 molecular cloud cores. New techniques allow for more accurate determination of the HINSA content of individual velocity components within a cloud. As a result we are now able to estimate the chemical ages of molecular cloud cores and their individual components by determining their HI/H2 ratios. We find that while some clouds exhibit similar chemical ages for all their components, other clouds seem to have different ages for components along the same line of sight.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints