Program: GN-2019A-DD-109

We request Gemini/GNIRS DDT observations of a newly discovered luminous quasar at z=7.5. It is identified in our 2019A classical Gemini observing run on May 17th. It is the second quasar ever known at z>=7.5, deep into the reionization. It is 1.5 times more luminous than the other z~7.5 quasar and possibly host a 1.7 billion solar mass supermassive black hole (SMBH). The proposed DDT observations will allow us to constrain the neutral hydrogen fraction in the intergalactic medium (IGM) at z=7.5, to securely measure the BH mass, to constrain the seed BH mass and BH growth mechanisms, to investigate the metal enrichment in the broad line region (BLR) of the quasar, and to timely publish this exciting discovery. In addition, the high quality GNIRS spectrum is the key to plan future followup observations and to search distant metal absorbers in the early Universe.