Ultraviolet Imaging of the Starburst Disk in NGC1068

Previous abstract Next abstract

Session 31 -- Star-Forming Galaxies
Display presentation, Tuesday, 9:30-6:30, Heller Lounge Room

[31.01] Ultraviolet Imaging of the Starburst Disk in NGC1068

S. G. Neff (GSFC), M. N. Fanelli (NRC/GSFC), L. J. Roberts (HSTX), R. C. Bohlin (STScI), R. W. O'Connell (UVa), M. S. Roberts (NRAO), A. M. Smith, T. P. Stecher (GSFC)

We present broadband ultraviolet images of NGC1068 made at 152 and 249nm with 3 arcsec resolution; the images were made by the Ultraviolet Imaging Telescope (UIT) in December 1990. In addition to the (unresolved) bright active nucleus, we find the UV continuum emission to be extended to the NE. We also detect and resolve many luminous HII regions, at both UV wavelengths; most were previously identified in H$\alpha$\ work. The HII regions are superposed on a UV-bright disk which extends 4 kpc from the nucleus; annular photometry of the underlying disk shows that the UV light follows an exponential light profile in both UV bands. This UV-bright disk is unique in spiral galaxies observed by UIT.

An ultraviolet color map of the NGC1068 inner disk shows over a magnitude variation in UV color and suggests non-uniform extinction, a strong contribution to the UV light from emission lines, a non-symmetric disk, or (probably) all of the above. Bluer regions of the disk appear to be associated with the high-ionization gas and the radio jet extending NE from the active nucleus; redder regions appear coincident with high CO velocity dispersions to the S and W of the nucleus. The UV colors of the HII regions suggest that they are dominated by young stars.

We also detect a faint outer disk which appears to be coincident with the outer (13kpc) optical disk; the outer disk is detected at 249nm but not at 152nm.

Tuesday program listing