Kinematics of the Ionized Gas in NGC 253

M. Arnaboldi (MSSSO, Australia; Observatoire de Paris, DEMIRM, France),
M. Capaccioli (Osservatorio Astronomico di Capodimonte, Italia; Dipartimento di Astronomia, Università di Padova, Italia),
E. Cappellaro (Osservatorio Astronomico di Padova, Italia),
E.V. Held (Osservatorio Astronomico di Bologna, Italia),
B. Koribalski (ATNF)

(1995) AJ 110, 199

Abstract. High resolution optical spectra acquired with the ESO New Technology Telescope (NTT) + the ESO Multi Mode Instrument (EMMI) along the major axis of the barred Sc starburst galaxy NGC 253 give detailed information on the kinematics of the galaxy at different scales from the inner nuclear region up to distances of 10 arcmin. We find strong evidence for a nuclear ring about 20 arcsec in diameter, with a circular velocity of 110 km/s, which is possibly responsible for the gas supply to the nuclear starburst region of the galaxy. The analysis of the dynamics of the bar in NGC 253 indicates that the nuclear ring is related to the presence of an inner Lindblad resonance at about 300 pc In this framework, the observed velocities indicate a mass in the central 10 arcsec of 3 x 10e8 solar masses . Good agreement is obtained between the new optical data and published HI rotation curves at larger radii.

Keywords. galaxies:individual (NGC 253) - galaxies: active - galaxies: ISM - galaxies: kinematics and dynamics

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--> Movie of a rotating cube of NGC 253

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