HUBBLE SPACE TELESCOPE Imaging of the Host Galaxies of High‐Redshift Radio‐loud Quasars

We present rest-frame UV and Ly-alpha images of spatially-resolved structuresaround five high-redshift radio-loud quasars obtained with the WFPC2 camera onthe Hubble Space Telescope. We find that all five quasars are extended and this"fuzz" contains ~5-40% of the total continuum flux and 15-65% of the Ly-alphaflux within a radius of about 1.5 arcsec. The rest-frame UV luminosities of thehosts are log lambda P_lambda = 11.9 to 12.5 solar luminosities (assuming nointernal dust extinction), comparable to the luminous radio galaxies at similarredshifts and a factor 10 higher than both radio-quiet field galaxies at z~2-3and the most UV-luminous low redshift starburst galaxies. The Ly-alphaluminosities of the hosts are (in the log) approximately 44.3-44.9 erg/s whichare also similar to the those of luminous high redshift radio galaxies andconsiderably larger than the Ly-alpha luminosities of high redshift fieldgalaxies. To generate the Ly-alpha luminosities of the hosts would requireroughly a few percent of the total observed ionizing luminosity of the quasar.We find good alignment between the extended Ly-alpha and the radio sources,strong evidence for jet-cloud interactions in two cases, again resembling radiogalaxies, and what is possibly the most luminous radio-UV synchrotron jet inone of the hosts at z=2.110.Comment: 36 pages (latex, aas macros), 3 figures (3 gif and 10 postscript files), accepted for publication in the the Astrophysical Journal Supplement Serie