THE BLUE COMPANION OF 3C-65 - A STAR-FORMING GALAXY WITH A PROBABLE REDSHIFT OF 2.8

We present BVRIK images and photometry of the z = 1.175 radio galaxy 3 C 65 and its extended blue companion, along with a 6 cm radio map. The se data are used to test the hypotheses that the companion is scatteri ng the continuum of a hidden active nucleus within the radio galaxy an d/or is undergoing a starburst triggered by interaction with its radio plasma. However, we find that the object's spectral energy distributi on (SED) is best fitted by a model of constant star formation with mod erate dust extinction for a redshift of approximately 2.8, while no fi t to the SED can be obtained for redshifts equal to or below that of 3 C 65. The object thus appears to be part of the recently discovered po pulation of star-forming galaxies at z similar to 3, which is also con sistent with its morphology and size as revealed by Hubble Space Teles cope WFPC2 images. The age of the object is not well-constrained by th e model fits and could range from 0.2 to 3.5 Gyr. Our best-fitting mod el has an age of 1.4 Gyr, which at z congruent to 2.8 does not violate standard cosmologies.