We report an infrared 1-1.8 micron (J+H-bands), low-resolution (R=450)
spectrogram of the highest-redshift radio-loud quasar currently known, SDSS
J083643.85+005453.3, obtained during the spectroscopic commissioning run of the
FLAMINGOS multi-object, near-infrared spectrograph at the 8m Gemini-South
Observatory. These data show broad emission from both CIV 1549 and CIII] 1909,
with strengths comparable to lower-redshift quasar composite spectra. The
implication is that there is substantial enrichment of the quasar environment,
even at times less than a billion years after the Big Bang. The redshift
derived from these features is z = 5.774 +/- 0.003, more accurate and slightly
lower than the z = 5.82 reported in the discovery paper based on the
partially-absorbed Lyman-alpha emission line. The infrared continuum is
significantly redder than lower-redshift quasar composites. Fitting the
spectrum from 1.0 to 1.7 microns with a power law f(nu) ~ nu^(-alpha), the
derived power law index is alpha = 1.55 compared to the average continuum
spectral index = 0.44 derived from the first SDSS composite quasar.
Assuming an SMC-like extinction curve, we infer a color excess of E(B-V) = 0.09
+/- 0.01 at the quasar redshift. Only approximately 6% of quasars in the
optically-selected Sloan Digital Sky Survey show comparable levels of dust
reddening.Comment: 10 pages, 1 figure; to appear in the Astrophysical Journal Letter