HST resolved image and spectra of z=2 QSO 1345+584

Abstract

The QSO 1345+584 has been spatially resolved by direct images and in spectral images, and has extended flux asymmetrically to the W, where its inner radio structure is seen. The brightest knots in the resolved flux correspond closely with knots in the curved radio jet, and the brightest knot has velocity of approach of some 3000 km/s with respect to the nucleus. Other parts of the line-emitting material appear to follow a systematic velocity field with values up to 1000 km/s with respect to the nucleus. The signal from the resolved continuum is not detected spectroscopically but accounts for 2/3 of the (rest UV) flux, so that it is likely to originate in hot stars. The QSO lies in or behind a compact group of galaxies of comparable brightness and irregular and knotty morphology, which probably form a dense physical group with very young stellar populations.