EVIDENCE FOR A NEW SUPERWIND GALAXY - NGC-4666

Multi-wavelength observations of the edge-on galaxy NGC 4666 have led to the detection of an outflow cone associated with a galactic superwi nd, emanating from a central starburst with a radial diameter of about 6.5 kpc. The outflow is traced up to 7.5 kpc above the plane by optic al emission line filaments, nonthermal radio continuum emission, assoc iated magnetic fields perpendicular to the galactic plane, and soft X- ray emission from hot gas. Optical spectroscopy exhibits the kinematic signature of an outflow and the observed line ratios indicate that sh ock heating is the most likely excitation mechanism for the emission l ine gas. The outflow is well approximated by a 6.5 kpc base (the exten t of the central starburst) plus a cone with an opening angle of 30 de grees +/- 10 degrees. In the outer disk of NGC 4666 numerous luminous H II regions were detected, which lead to additional outflows (galacti c fountains or chimneys) of gas into the halo. Radially the radio halo is much more extended than the central outflow cone and it has an exp onential z-scale height at 1.43 GHz of 1.7 +/- 0.28 kpc. NGC 4666 is i n many respects very similar to NGC 4631, another edge-on galaxy with an extended gaseous halo.