The structure and dynamics of the nucleus of the hot SPOT galaxy NGC 2997

Giant and radiatively ionized H II regions, blue OB associations younger than 10 million years, and lanes of neutral dusty material are found, in a combination of U, B and V band photographs of the NGC 2997 nuclear regions with high low dispersion spectra, to form inner spiral arms projecting from an amorphous nucleus of red stars older than about one billion years. Rotational velocities begin at 175 km/sec for a radius of more than about 630 pc, decrease to 116 km/sec over the annular OB association region, and remain constant until, at less than about 73 pc from the center, rotational velocity precipitously falls to zero. Total masses are predicted of 900 million solar masses in the annular region, 220 million solar masses in the central amorphous region, and 1.1 million solar masses in the ionized gas of the annulus. A total emission rate of 2.7 x 10 to the 51st photons/sec in the Lyman continuum from the OB associations is given.