Astronomy and Astrophysics – Astronomy
Scientific paper
Mar 1995
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995a%26a...295..302b&link_type=abstract
Astronomy and Astrophysics (ISSN 0004-6361), vol. 295, no. 2, p. 302-308
Astronomy and Astrophysics
Astronomy
15
Carbon Monoxide, Emission Spectra, Irregular Galaxies, Line Spectra, Radio Astronomy, Radio Spectra, Velocity Distribution, Extremely High Frequencies, H Alpha Line, Millimeter Waves, Molecular Clouds, Radial Velocity, Star Formation, Starburst Galaxies
Scientific paper
High angular resolution CO (2-1) and (1-0) observations are reported from the central region of the Magellanic-type irregular galaxy NGC 4214. CO (2-1) spectra were obtained with a beam size of 13 sec (340 pc at D = 5.4 Mpc) toward 20 positions. At eight positions, emission was detected from a molecular cloud complex with a size of 1000 pc x 700 pc (at the 0.7 K km/s contour) and a mass of a few approximately 107 solar mass. The ICO(2-1)/ICO(1-0) line intensity ratio is 0.4, indicating emission from optically thick subthermally excited lines. Comparing virial masses with masses deduced from the integrated CO intensities yields an NH2/ICO conversion factor, which is a few times the standard Galactic value of 2.3 x 1020 (sq cm K km/s)-1. On the basis of radial velocity, the huge CO complex is resolved into a western, a central, and an eastern component. The radial velocities, 298, 308, and 305 km/s, demonstrate that the E-W velocity change across the central bar is not smooth on linear scales less than 1 kpc. A prominent loop of hydrogen alpha emission (diamter: approximately 250 pc) is found at the interface between the western and eastern complex. A narrow linewidth and a lack of associated hydrogen alpha emission indicates that the western CO complex is in a quiescent state. The eastern region, being located close to the starburst knot at the optical center of the galaxy, exhibits broader CO lines and intense hydrogen alpha emission and must form massive stars.
Becker Robert
Bomans Dominik J.
Henkel Carsten
Wilson Thomas L.
No associations
LandOfFree
CO in the Magellanic-type irregular galaxy NGC 4214 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 CO in the Magellanic-type irregular galaxy NGC 4214, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and CO in the Magellanic-type irregular galaxy NGC 4214 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-881248