H2CO and H110α observations towards NH3 sources

Abstract

We observed the H2CO(110-111) absorption lines and H110α radio recombination lines (RRL) toward 180 NH3 sources using the Nanshan 25-m radio telescope. In our observation, 138 sources were found to have H2CO lines and 36 have H110α RRLs. Among the 138 detected H2CO sources, 38 sources were first detected. The detection rates of H2CO have a better correlation with extinction than with background continuum radiation. Line center velocities of H2CO and NH3 agree well. The line width ratios of H2CO and NH3 are generally larger than 1 and are similar to that of 13CO. The correlation between column densities of H2CO and extinction is better than that between NH3 and extinction. These line width relation and column density relation indicate H2CO is distributed on a larger scale than that of NH3, being similar to the regions of 13CO. The abundance ratios between NH3 and H2CO were found to be different in local clouds and other clouds.

arXiv commentaccepted for publish in Astrophysics and Space Science, DOI:10.1007/s10509-014-1922-y

References in corpus (17)

• A computer program for fast non-LTE analysis of interstellar line spectra
• The Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• High-Mass Proto-Stellar Candidates - I : The Sample and Initial Results
• Connecting Dense Gas Tracers of Star Formation in our Galaxy to High-z Star Formation
• The COMPLETE Survey of Star-Forming Regions: Phase I Data
• Ammonia from cold high-mass clumps discovered in the inner Galactic disk by the ATLASGAL survey
• The "True" Column Density Distribution in Star-Forming Molecular Clouds
• Dynamics of Dense Cores in the Perseus Molecular Cloud
• Probing Pre-Protosellar Cores with Formaldehyde
• A Sino-German lambda6 cm polarization survey of the Galactic plane I. Survey strategy and results for the first survey region
• Formaldehyde Densitometry of Starburst Galaxies
• A Large Scale Survey of NGC1333
• Formaldehyde Densitometry of Starburst Galaxies: Density-Independent Global Star Formation
• Can We Trust the Dust? Evidence of Dust Segregation in Molecular Clouds
• The relation of H2CO, 12CO, and 13CO in molecular clouds
• Formaldehyde Silhouettes Against the Cosmic Microwave Background: A Mass-Limited, Distance-Independent, Extinction-Free Tracer of Star Formation Across the Epoch of Galaxy Evolution
• Exploring morphological correlations among H2CO, 12CO, MSX and continuum mappings

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