Abstract
ABS ACT. Speckle interferometric observations of the Seyfert galaxy NGC 1068 have been carried out at 3.61 jiti in two perpendicular directions, at P.A.=450 and P.A.=1350. Three different thods, giving basically the same results, have been used to compute the phase of the spectrum of the object. Also, for each direction, the solutions of three algorithms of object reconstruction are compared. The reconstructed onedimensional spatial profiles reveal two distinct zones: (i) a nuclear region composed of an unresolved core, and a component of 0.18+0.06 arcsec in size that emits 0.95j0.15 Jy in the L band; and (ii) an extended region of 0.7x1.5 arcsec in size, contributing 0.75j0.08 Jy in the L band, and elongated at P.A.=450. The emission of the nuclear region is essentially nonthermal with an unreddened spectral index 0K-8.3pifl -1.9, while the emission of the extended region has probably a thermal origin. The speckle flux together with additional near IR photometry show that the unresolved component is variable, and is confined inside the inner 0.15 Pc. The optical, IR and radio data of the nucleus can be interpreted as follows: a nuclear core, with a maximum size of 0.15 Pc and a maximum mass of 5x108 , an optically thick halo of scatter ing electrons with a diameter of 18 pc and a maximum mass of 10 , that can be identified with the barely resolved 2 at radio nucleus. A disk of gas and dust with a scale height of 4 Pc and a minimum mass of 10 prevents us from a direct view of the visible and U\J continua arising from the unresolved nuclear core, the latter being directly seen through dust in the IR. The change in polarization from the visible to the near IR could be explained in terms of scattering by electron clouds and transmission through strongly aligned dust. The extended emission could have its origin in a shock induced starburst. A full version of this work has been su) nitted to Astronomy and Astr physics Main Journal. o'td :IMAGE - INFRARED PADLATION - INTERFEROMETRY - GALAXIES-SEYFERT - GALAXIES-NUCLEI OF
