ASTE CO(3-2) Mapping toward the Whole Optical Disk of M 83: Properties of Inter-arm GMAs

Details ASTE CO(3-2) Mapping toward the Whole Optical Disk of M 83: Properties of Inter-arm GMAs ASTE CO(3-2) Mapping toward the Whole Optical Disk of M 83: Properties of Inter-arm GMAs

2009-10-15

arxiv.org/abs/0910.2866v2

Astrophys.J.706:1213,2009

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

42 pages, 16 figures, ApJ in press, version with high resolution figures is available via http://www.nro.nao.ac.jp/~kmuraoka

Scientific paper

We present a new on-the-fly (OTF) mapping of CO(J=3-2) line emission with the Atacama Submillimeter Telescope Experiment (ASTE) toward the 8' x 8' (or 10.5 x 10.5 kpc at the distance of 4.5 Mpc) region of the nearby barred spiral galaxy M 83 at an effective resolution of 25''. Due to its very high sensitivity, our CO(J=3-2) map can depict not only spiral arm structures but also spur-like substructures extended in inter-arm regions. This spur-like substructures in CO(J=3-2) emission are well coincident with the distribution of massive star forming regions traced by Halpha luminosity and Spitzer/IRAC 8 um emission. We have identified 54 CO(J=3-2) clumps as Giant Molecular-cloud Associations (GMAs) employing the CLUMPFIND algorithm, and have obtained their sizes, velocity dispersions, virial masses, and CO luminosity masses. We found that the virial parameter alpha, which is defined as the ratio of the virial mass to the CO luminosity mass, is almost unity for GMAs in spiral arms, whereas there exist some GMAs whose alpha are 3 -- 10 in the inter-arm region. We found that GMAs with higher $\alpha$ tend not to be associated with massive star forming regions, while other virialized GMAs are. Since alpha mainly depends on velocity dispersion of the GMA, we suppose the onset of star formation in these unvirialized GMAs with higher alpha are suppressed by an increase in internal velocity dispersions of Giant Molecular Clouds within these GMAs due to shear motion.

Affiliated with

Also associated with

No associations

Rating

ASTE CO(3-2) Mapping toward the Whole Optical Disk of M 83: Properties of Inter-arm GMAs 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 ASTE CO(3-2) Mapping toward the Whole Optical Disk of M 83: Properties of Inter-arm GMAs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and ASTE CO(3-2) Mapping toward the Whole Optical Disk of M 83: Properties of Inter-arm GMAs will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-620159