Near/Mid Infrared-Wavelength Study of the Interacting Galaxy Pair UGC 12914/5 -- "Taffy"

We report on an infrared 1 to 17 micron study of the nearby (cz = 4600 km/s) interacting spiral galaxy system, UGC 12914/12915, using the ground-based Palomar 200" telescope and PFIRCAM near-infrared detector and space-based mid-infrared imaging and spectral observations using ISOCAM and Phot-S on the Infrared Space Observatory (ISO). Strong line emission from aromatic band features at 6.2, 7.7 and 11.3 microns are seen in both the mid-IR imaging and Phot-S spectro-photometry centered on the nuclei. In the connecting bridge, the mid-infrared imaging reveals dust grains intermixed with the atomic hydrogen gas. The heating mechanism for the hot dust is likely to be UV photons diffusing out from the galactic disks and the H II complex located along the extreme northeastern portion of the bridge: The dust emission, or mid-infrared intensity per atomic hydrogen column density ratio, is consistent with heating from the local (bridge) interstellar radiation field.