A Second “Taffy” Galaxy Pair

Abstract

Like the original ``taffy'' galaxies UGC 12914/5, the postcollision spiral galaxies UGC 813/6 are joined by a synchrotron radio bridge whose brightness contours resemble stretching bands of taffy. Other features shared by both pairs are unusually low far-infrared/radio flux ratios and very steep bridge continuum spectra. New total-intensity, polarization, and spectral-index images indicate that the bridge magnetic fields and relativistic electrons were torn from the disks of UGC 813 and UGC 00816 during a major collision about 5×107 yr ago. A significant fraction of the system H also lies between the disks. These ``taffy'' systems provide unique observational diagnostics for both normal galaxies and major mergers, but new numerical models are needed to simulate interpenetrating disks containing dense molecular clouds anchoring magnetic fields strong enough to affect gas flows.