Program: GN-2009B-DD-5

We request K-band spectroscopy with NIRI to observe the MgII broad emission line to determine the systemic redshift and black hole mass for a newly discovered quasar at z=6.44 discovered last week at Gemini-South. This quasar has the highest known redshift breaking the z=6.42 record jointly held by SDSS J1148+5251 and CFHQS J2329-0301. The proposed observations will confirm the record redshift (because MgII redshifts are more reliable in high-z quasars where neutral hydrogen absorbs much of Ly-alpha). The accurate systemic redshift will allow studies of the ionized zone near the quasar (using the GMOS spectrum) which probes reionization. The black hole mass will be determined from the MgII line and this quasar will be added to our study of the black hole masses of CFHQS and SDSS quasars which shows that quasars at z=6 have much higher accretion rates than at z=2.