An FeLoBAL binary quasar

In an ongoing infrared imaging survey of quasars at the Keck Observatory, we have discovered that the z = 1.285 quasar SDSS J233646.2-010732.6 comprises two point sources with a separation of 1″.67. Resolved spectra show that one component is a standard quasar with a blue continuum and broad emission lines; the other is a broad absorption line (BAL) quasar, specifically, a BAL QSO with prominent absorption from Mg II and metastable Fe II, making it a member of the "FeLoBAL" class. The number of known FeLoBALs has recently grown dramatically from a single example to more than a dozen, including a gravitationally lensed example and the binary member presented here, suggesting that this formerly rare object may be fairly common. Additionally, the presence of this BAL quasar in a relatively small separation binary adds to the growing evidence that the BAL phenomenon is not due to viewing a normal quasar at a specific orientation but rather that it is an evolutionary phase in the life of many, if not all, quasars and is particularly associated with conditions found in interacting systems.