NGC 3432 appears to provide a counter-example to the notion that high latitude Hα emission, either in the form of an extended diffuse layer (DIG) or in discrete features, correlates with the existance of a strong non-thermal radio contiuum halo. VLA data displays a radio halo extending up to 5.3 kpc above the plane as well as radio ``spurs''. These latter features do not appear, in general, to align with regions of star formation in the disk nor with discrete ionized features. If this near edge-on galaxy had a DIG component similar to that of NGC 891, it would likely be detected in our narrowband Hα CCD images acquired at Mont Megantic (sensitivity = 1.2 x 10(-16) \ erg \ cm(2) \ s(-1) \ arcsec(-2) ). Our non-detection of an ionized halo is consistent with the suggestion that only galaxies with FIR luminosities greater than 3 x \ 10(43) \ erg\ s(-1) have both a thick radio continuum disk and a thick ionized layer. Since there is no strong correlation between star formation regions and the morphology of the radio halo, this extended radio continuum may be a product of the interaction between NGC 3432 and UGC 5983 rather than the result of a connection between the disk and halo of NGC 3432.
American Astronomical Society Meeting Abstracts #188
- Pub Date:
- May 1996