We report the discovery of five quasars with redshifts of 4.67-5.27 and z′-band magnitudes of 19.5-20.7 (MB ∼ -27). All were originally selected as distant quasar candidates in optical/near-infrared photometry from the Sloan Digital Sky Survey (SDSS), and most were confirmed as probable high-redshift quasars by supplementing the SDSS data with J and K measurements. The quasars possess strong, broad Lyα emission lines, with the characteristic sharp cutoff on the blue side produced by Lyα forest absorption. Three quasars contain strong, broad absorption features, and one of them exhibits very strong N v emission. The amount of absorption produced by the Lyα forest increases toward higher redshift, and that in the z = 5.27 object (DA ≈ 0.7) is consistent with a smooth extrapolation of the absorption seen in lower redshift quasars. The high luminosity of these objects relative to most other known objects at z ≳ 5 makes them potentially valuable as probes of early quasar properties and of the intervening intergalactic medium.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science