THE RADIO STRUCTURE OF NGC 4410A


NGC 4410A is a radio galaxy with two large lobes visible in radio continuum maps, one extending 200 kpc to the north, the other 80 kpc to the south. The southern lobe appears to be very distorted. In the high spatial resolution radio continuum map of this system of Hummel et al. (1986); this lobe shows an apparent 70 degree bend.

We suggest that the distortion of the NGC 4410 radio lobes was caused by ram pressure from the interstellar medium in the system, due to the motion of the interstellar matter relative to the radio source during the gravitational interaction of NGC 4410A with NGC 4410B. An alternative possibility is that the peculiar radio morphology is due to motion through an intragroup medium, however, the small radial velocity of NGC 4410A relative to the group and the lack of diffuse X-ray emission in the group makes this scenario somewhat less likely, unless the group is not virialized or is merging with another group.

This image is a 20 centimeter radio continuum map of the NGC 4410 group (contours; from the Very Large Array), superposed on the optical Digitized Sky Survey image (greyscale). The first contour is 0.75 mJy/beam; the contour intervals increase by multiples of the square root of 2. The beamsize is 59.4 arcsec X 54.7 arcsec.