The Intrinsic Far-UV Spectrum of B1422+231
  We present new spectroscopy of the z=3.62 gravitationally lensed quasar
B1422+117 from the Gemini North GMOS integral field spectrograph. We observe
significant differential magnifications between the broad emission lines and
the continuum, as well as across the velocity structure of the Lyman-alpha
line. We take advantage of this differential microlensing to algebraically
decompose the quasar spectrum into the absorbed broad emission line and
absorbed continuum components. We use the latter to derive the intrinsic
Ly-alpha forest absorption spectrum. The proximity effect is clearly detected,
with a proximity zone edge of 8.6-17.3 Mpc from the quasar, implying (perhaps
intermittent) activity over at least 28 Myrs. The Ly-alpha line profile
exhibits a blue excess that is inconsistent with a symmetric fit to the
unabsorbed red side. This has important implications for the use of this
fitting technique in estimating the absorbed blue Ly-alpha wings of
Gunn-Peterson trough quasars.
