DEEP SPECTROSCOPY UNDER HIGH SPATIAL-RESOLUTION OF THE HIGH-REDSHIFT RADIO-SOURCE 3CR-368 - THE MONSTER ELUCIDATED

New spectroscopic measurements of 3CR 368 under unmatched spatial resolution are presented. 3CR 368 had been previously widely studied at all frequencies and had been taken as an "archetype" of the high-z radio galaxies. However, we found that the brightest optical component of 3CR 368 is a foreground object and is likely to be a Galactic star-possibly a M5 dwarf-rather than a foreground galaxy. Removing the foreground object decreases the 3CR 368 luminosity substantially especially at red and infrared wavelengths. The spectral energy distribution of the 3CR 368 optical counterpart is also substantially modified. It may also alter the radio properties and the previously reported optical polarization. The residual source at z = 1.13 actually shows very strong and somewhat broad emission lines associated with a flat and slightly reddened continuum. 3CR 368 therefore resembles more an AGN associated with an extended emission-line region rather than a distant galaxy dominated by stellar emission. This result emphasizes the danger in interpreting such peculiar and rare distant radio sources as multiple-component high-redshift galaxies without paying attention to the possible contamination by foreground objects, such as Galactic stars or faint galaxies.