Sensitive VLBI observations of the ULIRG IRAS 17208-0014

We present sensitive VLBI (VLBA + Phased VLA) results on the radio continuum of, and the 21 cm H I absorption toward, the ULIRG IRAS 17208-0014 at 1382 MHz. The high-resolution continuum images reveal a nuclear starburst region in this galaxy. This nuclear region is composed of diffuse emission that extends over 670 x 340 pc on the plane of the sky, and a number of compact sources. The compact sources are likely to be clustered supernova remnants and/or luminous radio supernovae. We derive a massive star formation rate of similar to 84 M-circle dot yr(-1), and a supernova rate of similar to 4 yr(-1). The HI absorption line associated with this galaxy is very wide (Delta V-20% = 696 km s(-1)). It is composed of multiple components with optical depths between 0.3 and 2.5. The H I absorption shows a strong velocity gradient of 453 km s(-1) across 0."36. Assuming Keplerian motion, the enclosed dynamical mass is about 2.3 x 10(9) (sin(-2)i) M-circle dot, comparable to the mass estimated from CO observations.