1995A&A...298..343C

We report on photometry and bidimensional spectroscopy of the double-nucleus galaxy Mkn 463 (E and W). The high spatial resolution and large wavelength coverage of the integral field spectrograph SILFID under sub-arcsec resolution conditions allow us to map the kinematics and ionization structure of the extended emitting gas and subsequently to identify the individual components of this complex system. Detailed spectroscopy of the nuclear regions confirms the Seyfert 2 characteristics of the E (east) component (known to be a "hidden" Seyfert 1) while placing the W (west) component on the Veilleux-Osterbrock diagrams in the region between Seyfert 2s and LINERs. The highest ionization occurs in and around the east nucleus. 3-4" to the north the line widths seem to correlate with the strength of the low ionization lines, this being suggestive of an additional ionizing mechanism operating in these regions. The N-S collimated emission originating from the E nucleus is a striking feature on the [OIII]₅₀₀₇ and Hα reconstructed images and on the V-R colour map. The relatively high ionization of the emitting gas ∼14" south of the E nucleus may be due either to beamed ionizing radiation from the nucleus or to ionization by "in situ" generated continuum. The velocity maps constructed for the [OIII]₅₀₀₇, Hα and Hβ lines at the peak 80% and 50% intensity levels reveal a SE-NW velocity gradient of ∼450km/s with a sharply blue-shifted region within 2" NE of the E nucleus. This velocity gradient, previously undetected, is discussed in relation with the presence of a radio component in the same region. The optical jet of the E nucleus and a very blue region westwards of the W nucleus, discovered on HST images, are detected on our direct images and the B-V colour map. We discuss some further correlations between the kinematical and physical conditions and discuss the implications of these new results for the understanding of this complex system.