Host galaxies of z ~ 4.7 QSOs

Abstract

2 micron broad- and narrow-band imaging with the Gemini-N telescope of five z~4.7 QSOs, has resolved both the host galaxies and [O II] emission-line gas. The resolved fluxes of the host galaxies fall within the extrapolated spread of the K-z relationship for radio galaxies at lower redshifts, and their resolved morphology is irregular. The [O II] images indicate knots coincident with many continuum features and also some bright jet-like features near the nucleus. The line emission total fluxes indicate overall equivalent widths of 5 to 10 A at rest wavelengths. Two of the QSOs are in a local environment of faint galaxies of similar magnitude to the hosts, and three have nearby galaxies with excess narrow-band flux, which would be [O II] if they are at the QSO redshift.

18 pages, including 2 tables. 5 diagrams. To appear in AJ