Nuclear concentration of molecular gas in the late-type spiral galaxy NGC 6946 - 300 parsec scale gaseous disk

Journal Article · Fri Jun 01 00:00:00 EDT 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168777· OSTI ID:6690533

Ishizuki, S; Kawabe, R; Ishiguro, M; Morita, K I; Okumura, S K ^[1]

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1. Tokyo Univ. (Japan) Nobeyama Radio Observatory, Minamimaki (Japan) Tokyo Univ. (Japan)

The CO (J = 1-0) emission in the central 65 arcsec (1.7 kpc) region of the nearby late-type spiral galaxy NGC 6946 has been mapped using the Nobeyama Millimeter Array. The synthesized beam is 7.6 x 4.2 arcsec (HPBW) which corresponds to 200 pc x 110 pc at the distance of 5.5 Mpc. A massive nuclear concentration of molecular gas with a scale of 300 pc and a molecular bar structure elongated more than 1.5 kpc were found. The velocity structure suggests that the molecular gas in the nuclear concentration has a circular rotation and the gas in the molecular bar structure has an infall motion. The total H2 mass in the central 65 arcsec region is (4 + or - 2) x 10 to the 8th solar masses, 75 percent of which was found in the 300 pc scale nuclear concentration. The region of the central concentration coincides with a bright H II region and a radio continuum source. It is suggested that the nuclear concentration is a massive nuclear disk of molecular gas which has been formed by efficient gas inflow in an oval potential field. The high H2 density (found in the nuclear concentration) supports active star formation in the nuclear region. 33 refs.

• OSTI ID: 6690533
• Journal Information: Astrophysical Journal; (USA), Vol. 355; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
GALAXIES
SPIRAL CONFIGURATION
GALAXY NUCLEI
COSMIC GASES
CARBON MONOXIDE
COSMIC RADIO SOURCES
EMISSION SPECTRA
GALACTIC EVOLUTION
GAS FLOW
H2 REGIONS
MASS
MORPHOLOGY
STAR EVOLUTION
VELOCITY
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CONFIGURATION
FLUID FLOW
FLUIDS
GASES
OXIDES
OXYGEN COMPOUNDS
SPECTRA
640105* - Astrophysics & Cosmology- Galaxies