The intrinsic far-UV spectrum of the high-redshift quasar B1422 231

Abstract

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-a 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 α forest absorption spectrum. The proximity effect is clearly detected, with a proximity zone edge of 8.6-17.3Mpc from the quasar, implying (perhaps intermittent) activity over at..