High-resolution maps of 6 centimeter formaldehyde - Clumping in molecular clouds

Abstract

view Abstract Citations (30) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS High-resolution maps of 6 centimeter formaldehyde : clumping in molecular clouds. Martin-Pintado, J. ; Wilson, T. L. ; Johnston, K. J. ; Henkel, C. Abstract VLA maps of W31, W33, W49, and W51 in the 110-111 line of ortho-H2CO are presented. The maps were made with angular resolution of 10arcsec - 15arcsec and a velocity resolution of 1.8 km s-1. In all of the regions measured, the ortho-H2CO distribution breaks up into a number of condensations, or clumps. Averaged over all of the sources, the median clump size is 0.5 pc with a range from <0.2 pc to >1.4 pc. The median apparent optical depth is 0.4 with a range from <0.1 to 1.1. The median line width (FWHP) is 5.0 km s-1, with a range from <1 km s-1 to 13 km s-1. Based on line width, the clumps can be placed in two categories: those having FWHP widths ≤1 km s-1 and those having widths larger than 3 km s-1. The first group could follow the relation given by Larson in 1981 and might have masses which agree with virial estimates. For the second group, the clumps have ≡10% of the sizes predicted from the line widths, and the masses of most of these clumps toward W31 and W51 are 20% - 60% of the virial mass estimates. Publication: The Astrophysical Journal Pub Date: December 1985 DOI: 10.1086/163708 Bibcode: 1985ApJ...299..386M Keywords: Astronomical Maps; Formaldehyde; Hydrogen Clouds; Interstellar Gas; Molecular Clouds; Radio Astronomy; Carbon Monoxide; Centimeter Waves; Continuous Spectra; High Resolution; Line Spectra; Optical Thickness; Spectral Line Width; Astrophysics full text sources ADS | data products SIMBAD (9) NED (2)