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Atomic and Molecular Gas in the Starburst Galaxy NGC4945

M. Ott·J. B. Whiteoak·C. Henkel·R. Wielebinski
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Abstract

Spatial and kinematical correlations between HI and CO (2-1) emission of the southern spiral galaxy NGC4945 are studied with a common angular (23 arcsec) and velocity resolution (7 km/s). The 21cm continuum emission is also observed. The HI kinematics yield a galaxy mass of 1.4x10^{11} Mo within a radius of 380 arcsec, with molecular and neutral atomic gas each contributing 2%. Nuclear HI absorption at velocities 80 km/s higher than systemic indicates gas flowing towards the centre. HI features at each end of the major axis (R ~ 600 arcsec) are interpreted as spiral arms that are viewed tangentially and that also cause prominent emission features in the radio continuum, HI, and CO further inside the galaxy. A central elongated region showing non-circular motions is interpreted as a bar which fuels the nuclear starburst. HI and CO position-velocity data have been analysed using linear resonance theory and possible locations of resonances are identified.

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M. Ott, J. B. Whiteoak, C. Henkel, R. Wielebinski. 2001-09-12. Atomic and Molecular Gas in the Starburst Galaxy NGC4945. https://doi.org/10.1051/0004-6361%3A20010505

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