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

Abstract

view Abstract Citations (48) References (31) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Nuclear Concentration of Molecular Gas in the Late-Type Spiral Galaxy NGC 6946: 300 Parsec Scale Gaseous Disk Ishizuki, S. ; Kawabe, R. ; Ishiguro, M. ; Okumura, S. K. ; Morita, K. -I. ; Chikada, Y. ; Kasuga, T. ; Doi, M. Abstract The CO (J = 1-0) emission in the central 65" (1.7 kpc) region of the nearby late-type spiral galaxy NGC 6946 has been mapped using the Nobeyama Millimeter Array (NMA). The synthesized beam is 7.6" x 4.2" (HPBW) which corresponds to 200 pc x 110 pc at the distance of 5.5 Mpc. We have found a massive nuclear concentration of molecular gas with a scale of 300 pc and a molecular bar structure elongated more than 1.5 kpc. 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 H_2_ mass in the central 65" region is (4 +/- 2) x 10^8^ M_sun_, 75% [(3 +/- 1.5) x 10^8^ M_sun_] of which was found in the 300 pc scale nuclear concentration. The averaged molecular gas density is estimated to be as high as (2 +/- 1) x 10^3^ H_2_ cm^-3^ in the 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, and the high H_2_ density supports active star formation in the nuclear region. Publication: The Astrophysical Journal Pub Date: June 1990 DOI: 10.1086/168777 Bibcode: 1990ApJ...355..436I Keywords: Galactic Nuclei; Galactic Structure; Molecular Gases; Nuclear Astrophysics; Spiral Galaxies; Carbon Monoxide; Emission Spectra; Galactic Evolution; H Ii Regions; Molecular Clouds; Astrophysics; GALAXIES: INDIVIDUAL NGC NUMBER: NGC 6946; GALAXIES: INTERNAL MOTIONS; GALAXIES: INTERSTELLAR MATTER; GALAXIES: NUCLEI; GALAXIES: STRUCTURE full text sources ADS | data products SIMBAD (1) NED (1)