Physica properties of molecular clouds in the inner disk of M31

Details Physica properties of molecular clouds in the inner disk of M31 Physica properties of molecular clouds in the inner disk of M31

May 1995

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995apj...444..157a&link_type=abstract

Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 444, no. 1, p. 157-164

Astronomy and Astrophysics

Astrophysics

26

Andromeda Galaxy, Emission Spectra, Interstellar Gas, Molecular Clouds, Astronomical Models, Galactic Cosmic Rays, Galactic Radiation, Radiative Transfer, Ultraviolet Radiation

Scientific paper

We discuss recent observations of CO, CS, and NH3 emission lines from two molecular clouds in the inner regions of M31. The intensities of the (12)CO(1-0), (12)CO(2-1), (13)CO(1-0), and (13)CO(2-1) lines have been measured with the IRAM 30 m telescope at the same angular resolution of 23 sec. Upper limits have been obtained in the CS(2-1), CS(3-2) and in the NH3(1, 1) and (2, 2) lines (the latter two with the Effelsberg 100 m telescope). The line intensities and ratios are compared with the predictions of a one-side UV-illuminated plane-parallel model which treats consistently radiative, chemical, and excitation processes of CO and its isotopes. A satisfactory agreement cannot be achieved for a single-density model. It appears that the emission of the (12)CO lines is dominated by a low-density, very cold gas while that of the (13)CO lines comes largely from higher density clumps inside the clouds. The properties of the molecular clouds can be understood as resulting mainly from a very small rate of photodissociation due to a very low UV radiation field, together with a low cosmic-ray density. Typical kinematic temperatures inside the clouds can drop to values less than 5K.

Affiliated with

Also associated with

No associations

Rating

Physica properties of molecular clouds in the inner disk of M31 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Physica properties of molecular clouds in the inner disk of M31, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Physica properties of molecular clouds in the inner disk of M31 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1058348