2010ApJ...724L.203K

We report the emergence of a high-velocity, broad absorption line outflow in the luminous quasar Ton 34, at z_q= 1.928. The outflow is detected through an ultraviolet C IV broad absorption line, in a spectrum obtained in 2006 January by the Sloan Digital Sky Survey. No absorption trough was present in two different spectra acquired in 1981 at Las Campanas and Palomar observatories, indicating the emergence of the outflow in less than ∼8 yr (rest frame). The absorption line spans a velocity range from ∼5000 to 25,000 km/s, and resembles typical troughs found in broad absorption line quasars (BALQSOs). We measure a balnicity index ≳600 (though this value might be an underestimation due to a conservative placing of the continuum). The absorption trough is likely saturated, with the absorbing gas covering ∼25% of the emitting region. We explore different scenarios for the emergence of this outflow, and find an existing wind moving across our line of sight to the source as the most likely explanation. This indicates that high-velocity outflows (producing broad absorption troughs in BALQSOs) might be ubiquitous in quasars, yet only become observable when the wind accidentally crosses our line of vision to the central source.