Dual curved jets in the tailed radio galaxy 1638 + 538 /4C53.37/

Abstract

VLA observations at 4.9 GHz and Green Bank interferometer observations at 2.7 and 8.1 GHz are presented for the tailed radio galaxy 1638+538. Twin curved radio jets emanating from opposite sides of a flat spectrum (..cap alpha../sup 8.1//sub 4.9/approx. =0.1 +- 0.2) nuclear component appear on the high resolution (approx. =1 arcsec) VLA map. The unresolved jets terminate abruptly at the edges of much larger regions of radio emission (approx. =16 arcsec diameter) which form the more extended radio tails. From the distribution of polarized emission at 2.7 and 4.9 GHz, we suggest that the extended blobs are Faraday thick (i.e., Faraday depth approx. =7 at 4.9 GHz); an upper limit to the electron density (n/sub e/< or approx. =10/sup -3/ cm/sup -3/) is computed assuming Faraday depolarization. The morphology and luminosity of 1638+538 are compared with the predictions of two recently proposed beam models of head-tail sources. These models suggest bulk flow velocities as large as 10/sup 4/ km/s and mass outflow rates of < or approx. =0.5M/sub sun//yr in the jets of 1638+538. Possible mechanisms to produce the sharp transition between the jets and the extended tails are discussed within the context of these models.