UNVEILING THE HIDDEN NUCLEUS OF IC-5063 WITH NICMOS

We present high-resolution near-infrared images of the Seyfert 2 galax y IC 5063 obtained using the Neat-Infrared Camera and Multiobject Spec trometer (NICMOS) in broadband filters at 1.1, 1.6, and 2.2 mu m (FWHM approximate to 0''.21 at 2.2 mu m). The images show a very red unreso lved point source at the center of the galaxy, confirming the existenc e of the obscured active nucleus inferred from previous ground-based s tudies. The 2.2 mu m flux, supplemented with ground-based L'-band obse rvations, suggests thermal emission equivalent to a blackbody at a tem perature of 720 K. We ascribe the emission not to direct light from th e nucleus, but to hot dust in the inner part of the torus. The 1.6 mu m emission is only minimally affected by the hot dust emission. The lu minosity of the central source producing most of the 1.6 mu m emission , not corrected for extinction, is 1.5 x 10(41) ergs s(-1), integrated over the F160W filter only. We also present lower spatial resolution images of IC 5063 obtained with NICMOS in the emission lines of [Fe II ] lambda 1.644 mu m, Pa alpha lambda 1.8756 mu m, and H-2 lambda 2.121 8 mu m. These images reveal a linear emission morphology comprised of two bright knots, separated by 1''.8 on either side of a central knot that is at the location of the continuum nucleus. A comparison with hi gh-resolution radio continuum maps shows that there is a one-to-one sp atial correspondence between the radio lobes and the emission-line kno ts, directly implying that the [Fe II] and H-2 emission is created by fast shocks produced by the advancing radio jets. The asymmetry in the [Fe II]/H-2 ratio may suggest a difference in either the shock veloci ties or the molecular mass on the two sides of the nucleus.