Multifrequency observations of 4C 39.04: a powerful giant radio galaxy

Observations of the radio source 4C 39.04 have been made at 2695 MHz with the 5-km telescope and at 1407 and 408 MHz with the One-Mile telescope. It is identified with a galaxy which has a redshift z = 0.2107, and has a linear size of 1.9 Mpc; 4C 39.04 has a monochromatic radio luminosity at 178 MHz of P(178) = 1.5 x 1026 W Hz-1 sr-1, and is the most luminous giant radio galaxy yet found. The spectral index increases from 0.7 at the outer ends of the source to approximately 1.2 at the centre. Unless the intergalactic gas surrounding 4C 39.04 has an extremely low density (approximately < 2 x 10-7 cm-3), this implies that the relativistic electrons in the inner regions are renewed or reaccelerated. (author)