Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-01-15
Astrophys.J. 642 (2006) 307-318
Astronomy and Astrophysics
Astrophysics
Accepted by ApJ, 35pages including 14 figures
Scientific paper
10.1086/500797
We have carried out large scale 12CO and 13CO observations with a mm/sub-mm telescope NANTEN toward a loop-like structure in far infrared whose angular extent is about 20x20 degrees around (l, b) ~ (109, -45) in Pegasus. The 12CO distribution is found to consist of 78 small clumpy clouds whose masses range from 0.04 Mo to 11 Mo. About 83% of the 12CO clouds have very small masses less than 1.0 Mo. 13CO emission shown in the 19 of the 78 12CO clouds was detected in the region where the column density of H2 derived from 12CO is greater than 5x10(20) cm(-2), corresponding to Av of ~ 1 mag, which takes into account that of HI. We find no indication of star formation in these clouds in IRAS and 2MASS Point Source Catalogs. The very low mass clouds, M < 1 Mo, identified are unusual in the sense that they have very weak 12CO peak temperature of 0.5 K to 2.7 K and that they aggregate in a region of a few pc with no main massive clouds of ~ 100 Mo. A comparison with a theoretical work on molecular cloud formation (Koyama & Inutsuka 2002) suggests that the very low-mass clouds may have been formed in the shocked layer through the thermal instability. The star HD886 (B2IV) may be the source of the mechanical luminosity via stellar winds to create shocks, forming the loop-like structure where the very low-mass clouds are embedded.
Fukui Yasuo
Kawamura Akiko
Mizuno Norikazu
Onishi Toshikazu
Tachihara Kengo
No associations
LandOfFree
Large Scale CO Observations of a Far-Infrared Loop in Pegasus; Detection of a Large Number of Very Small Molecular Clouds Possibly Formed via Shocks 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 Large Scale CO Observations of a Far-Infrared Loop in Pegasus; Detection of a Large Number of Very Small Molecular Clouds Possibly Formed via Shocks, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Large Scale CO Observations of a Far-Infrared Loop in Pegasus; Detection of a Large Number of Very Small Molecular Clouds Possibly Formed via Shocks will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-523616