Mon. Not. R. Astron. Soc., 347, L79-L82 (2004/February-1)
J1432+158: the most distant giant quasar.
SINGAL A.K., KONAR C. and SAIKIA D.J.
Abstract (from CDS):
We present low-frequency, Giant Metrewave Radio Telescope (GMRT) observations at 333 and 617 MHz of the most distant giant quasar, J1432+158, which is at a redshift of 1.005. The radio source has a total angular extent of 168 arcsec, corresponding to a projected linear size of 1.35 Mpc. This makes it presently the largest single object observed beyond a redshift of 1. The objectives of the GMRT observations were to investigate the possibility of detecting a bridge of emission at low frequencies, which may be suppressed due to inverse-Compton losses against the cosmic microwave background radiation. We detect a jet-like structure connecting the core to the western hotspot, while the eastern hotspot is found to be largely tailless with no significant bridge emission. The estimated lifetime for the radiating electrons in the tail of the western lobe appears smaller than the travel time of the radiating particles from the hotspot, suggesting either in situ acceleration or dissipation of energy by the jet at this location. The pressure of the intergalactic medium at z ∼ 1 estimated from the minimum energy density calculations appears to be marginally lower than the value extrapolated from nearby giant radio galaxies.
galaxies: active - galaxies: jets - galaxies: nuclei - quasars: general - radio continuum: galaxies