Kinematics of molecular clouds.I. Velocity dispersion in the solar neighborhood..
Abstract
The velocity dispersions of low mass, 102M_sun; ⪉ Mc ⪉ 104M_sun;, and moderate mass, 104M_sun; ⪉Mc ⪉ 105.5M_sun;, molecular clouds in the solar neighborhood (r ⪉ 3 kpc) are determined. Velocity dispersion is defined here as the root mean square of cloud peculiar velocities. Two data sets are used: (1) a strip map of l = 180° from b = -9° to +8° observed in CO J = 1→0; (2) a subset of the Blitz, Fich, and Stark catalog of giant molecular clouds. A statistical analysis yields one-dimensional rms velocity dispersions of 9.0 km s-1 for low-mass clouds and of 6.6 km s-1 for moderate-mass clouds. The errors are about 1 km s-1. The implications of the near constancy of the velocity dispersion over many orders of magnitude in cloud mass for present theories of molecular cloud formation and dynamics and for the velocity dispersion of stars are discussed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1984
- DOI:
- 10.1086/162137
- Bibcode:
- 1984ApJ...281..624S
- Keywords:
-
- Interstellar Matter;
- Molecular Clouds;
- Solar System;
- Carbon Monoxide;
- Gas Dynamics;
- Kinematics;
- Magellanic Clouds;
- Sun;
- Velocity Distribution;
- Astrophysics