Median composite spectra following Vanden Berk et al. (2001)

coadd_dr7_ctrl_zhw.fits: 
for the control sample drawn from the SDSS-DR7 quasar catalog
using the Hewett&Wild redshifts

coadd_spec_zsys.fits:
for the GNIRS high-z sample using improved systemic redshifts

coadd_spec_zold.fits:
for the GNIRS high-z sample using old redshifts

hiz_median_coadd.txt:
ascii composite spectrum for the GNIRS high-z sample