A Radio Continuum Survey of Ring Galaxies

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Session 12 -- Starburst Galaxies
Display presentation, Monday, 30, 1994, 9:20-6:30

[12.05] A Radio Continuum Survey of Ring Galaxies

F.D.Ghigo (NRAO), P.N.Appleton (Iowa State U.)

As part of a multi-wavelength study of interacting galaxies with ring-like structure, we observed 13 systems with the VLA in D-array at 8.4 GHz. Four objects were also observed at 1.4 GHz and 4.8 GHz. Snapshots of 15-20 minutes were done to identify candidates for future deeper and higher resolution observations. Nine of the 13 objects were detected at X-band above a threshhold of about 0.2 mJy. Results will be compared with H-alpha and infrared observations of these objects to study star formation processes in the wake of a density wave resulting from a collision. The regions of recently formed O/B stars are expected to be bright in H-alpha and radio thermal bremstrahlung radiation. The internal optical extinction in the star formation regions can in principle be estimated by comparisons of H-alpha and radio thermal flux, thus allowing the stellar composition of the star clusters in these regions to be deduced. We expect that diffusion of relatavistic electrons from supernova sites results in non-thermal radiation that lags behind the sites of young star formation, the latter being richer in thermal radiation. Our preliminary results for ARP 10 are consistent with this scenario in that we find the flattest spectrum part of the radio map coincides with the region of brightest H-alpha flux.

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