Origin of molecular cloud rings in spiral galaxies: CO observations of NGC 7331 and NGC 2841

Journal Article · Wed Sep 15 04:00:00 EDT 1982 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/183866· OSTI ID:6576293

Young, J S; Scoville, N

CO emission has been mapped along the major axis of two Sb galaxies, NGC 7331 and NGC 2841, using the 14 m FCRAO telescope (HPBW = 50''). Molecular rings were discovered in both galaxies, with peaks at radii of approx.4 kpc. The previously measured H..cap alpha.. and HI rotation curves reach their maximum velocities at the same radii as the molecular rings. The lack of CO toward the centers of these galaxies is linked to the presence of significant nuclear bulges; the gas originally at small radii may have been used up to form stars in the central bulge. In these Sb galaxies, the interstellar medium constitutes only 2%--5% of the total mass, a factor of 2--3 less than the contribution seen in our sample of Sc galaxies. The H/sub 2/ surface densities at the peaks of the two molecular rings are 3--5 times greater than those of H I.

• Research Organization: Five College Radio Astronomy Observatory, University of Massachusetts
• OSTI ID: 6576293
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 260:2; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COSMIC GASES
COSMIC RADIO SOURCES
DISTRIBUTION
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
FLUIDS
GALAXIES
GASES
H1 REGIONS
INTERSTELLAR GRAINS
MASS
OXIDES
OXYGEN COMPOUNDS
PARTICLES
RADIATIONS
RADIOWAVE RADIATION
SPATIAL DISTRIBUTION
SPECTRA