1999/06/30 by J. A. Garcia-Barreto, Garcia-Barreto, J. A., F. Combes +5
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9906492
9 pages, 11 figures, accepted in Astronomy and Astrophysics
arxiv created 1999/06/30 · arxiv updated 2009/12/01
We have mapped the emission from atomic hydrogen at 21 cm from the galaxy NGC 3783 with the Australia Telescope Compact Array. Our main results are: a) the HI morphology is irregular and perturbed, gathered in three blobs apparently unrelated to the optical morphology; b) the observed HI velocity distribution indicates a normal disk in differential rotation with a constant velocity out to a radius of 160'' (30 kpc), c) the inclination of the disk is about 25 deg with the kinematic major axis at a position angle slightly different from that of the stellar bar, d) the HI mass inside a radius of 18'' is only 2.1 107 Msun, the total HI mass within 180'' is 1.1 109 Msun and the dynamical mass is 2 1011 Msun. The bulk of the gas in NGC 3783 is outside the diameter of the stellar bar; e) Numerical simulations of the gas flow in the barred potential derived from the red image indicate that the pattern speed is Omegap = 38 km/s/kpc: the ring of Halpha emitting regions encircling the bar would then correspond to UHR, and the Halpha accumulation in the center to a nuclear ring. Various possibilities are discussed to account for the active nucleus fuelling.