Rotation of Two Micron All Sky Survey Clumps in Molecular Clouds
Abstract
We have analyzed the rotational properties of 12 clumps using 13CO (1-0) and C18O (1-0) maps of the Five College Radio Astronomy Observatory 13.7 m radio telescope. The clumps, located within molecular clouds, have radii (R) in the range of 0.06-0.27 pc. The direction of clump elongation is not correlated with the direction of the velocity gradient. We measured the specific angular momentum (J/M) to be between 0.0022-0.025 pc km s-1 based on 13CO images, and between 0.0025-0.021 pc km s-1 based on C18O images. The consistency of J/M based on different tracers indicates the 13CO and C18O in dense clumps trace essentially the same material despite significantly different opacities. We also found that J/M increases monotonically as a function of R in power-law form, $J/M\,\propto \,{R}^{1.58\pm 0.11}$ . The ratio between rotation energy and gravitational energy, β, ranges from 0.0012 to 0.018. The small values of β imply that rotation alone is not sufficient to support the clump against gravitational collapse.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2020
- DOI:
- 10.3847/1538-4357/ab9a45
- arXiv:
- arXiv:2006.04309
- Bibcode:
- 2020ApJ...898..122X
- Keywords:
-
- Interstellar medium;
- Interstellar dynamics;
- Interstellar molecules;
- Intercloud medium;
- Interstellar emissions;
- 847;
- 839;
- 849;
- 803;
- 840;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted by Astrophysical Journal