P\={o}niu\={a}'ena: A Luminous $z=7.5$ Quasar Hosting a 1.5 Billion Solar Mass Black Hole

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We report the discovery of a luminous quasar, J1007+2115 at $z=7.515$ ("P\={o}niu\={a}'ena"), from our wide-field reionization-era quasar survey.

• J1007+2115 is the second quasar now known at $z>7.5$, deep into the reionization epoch.
• The quasar is powered by a $(1.5\pm0.2)\times10^9$ $M_{\odot}$ supermassive black hole (SMBH), based on its broad MgII emission-line profile from Gemini and Keck near-IR spectroscopy.
• The SMBH in J1007+2115 is twice as massive as that in quasar J1342+0928 at $z=7.54$, the current quasar redshift record holder.