NEWLY DISCOVERED z similar to 5 QUASARS BASED ON DEEP LEARNING AND BAYESIAN INFORMATION CRITERION

We report the discovery of four quasars with M1450 ???25.0 mag at z ??? 5 and supermas-sive black hole mass measurement for one of the quasars. They were selected as promising high-redshift quasar candidates via deep learning and Bayesian information criterion, which are expected to be effec-tive in discriminating quasars from the late-type stars and high-redshift galaxies. The candidates were observed by the Double Spectrograph on the Palomar 200-inch Hale Telescope. They show clear Ly?? breaks at about 7000???8000 ??A, indicating they are quasars at 4.7 < z < 5.6. For HSC J233107-001014, we measure the mass of its supermassive black hole (SMBH) using its C Iv ??1549 emission line. The SMBH mass and Eddington ratio of the quasar are found to be ???108 M??? and ???0.6, respectively. This suggests that this quasar possibly harbors a fast growing SMBH near the Eddington limit despite its faintness (LBol < 1046 erg s???1). Our 100% quasar identification rate supports high efficiency of our deep learning and Bayesian information criterion selection method, which can be applied to future surveys to increase high-redshift quasar sample. Superscript/Subscript AvailableMore