The molecular front in galaxies. I. CO VS HI in position-velocity diagrams.

Details The molecular front in galaxies. I. CO VS HI in position-velocity diagrams. The molecular front in galaxies. I. CO VS HI in position-velocity diagrams.

Apr 1995

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995a%26a...296...33s&link_type=abstract

Astronomy and Astrophysics, v.296, p.33

Astronomy and Astrophysics

Astrophysics

30

Galaxies: Ism, Galaxies: Spiral, Ism: Molecules, Radio Lines: Galaxies

Scientific paper

We have obtained composite position-velocity (PV) diagrams of the HI and CO line emissions for edge-on galaxies NGC 891, NGC 4565, NGC 5907, and NGC 3079. Using a de-convolving method of the PV diagram, we have obtained radial distributions of HI and H_2_ gas densities, and the radial variation of the molecular fraction as defined by the mass ratio of the molecular (H_2_) to total (HI+H_2_) gas density has been calculated. Radial variations of the molecular fraction shows that the galaxy disk is almost totally molecular in the central few kpc region. However, the molecular fraction decreases suddenly in a narrow range of radius, beyond which the interstellar gas is almost totally HI, and we call this critical radius the `molecular front'. We point out that the molecular and atomic gases in disk galaxies are clearly separated by this front, which will be the place where the phase transition from HI to H_2_, and vice versa, is taking place in the galactic scale. We discuss the implication of the molecular-front phenomenon for the evolution of interstellar gas in galaxies based on the phase-transition theory of the ISM.

Affiliated with

Also associated with

No associations

Rating

The molecular front in galaxies. I. CO VS HI in position-velocity diagrams. 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 The molecular front in galaxies. I. CO VS HI in position-velocity diagrams., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The molecular front in galaxies. I. CO VS HI in position-velocity diagrams. will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1826276