KECK HIRES Spectroscopy of APM 08279+5255

Abstract

With an optical R-band magnitude of 15.2, the recently discovered z=3.911 BAL quasar APM 08279+5255 is an exceptionally bright high redshift source. Its brightness has allowed us to acquire a high signal-to-noise ratio (~100), high resolution (~6 km/s) spectrum using the HIRES echelle spectrograph on the 10-m Keck I telescope. Given the quality of the data, these observations provide an unprecedented view of associated and intervening absorption systems. Here we announce the availability of this spectrum to the general astronomical community and present a brief analysis of some of its main features.