Multi-Epoch Observations of Extremely High-Velocity Emergent Broad Absorption

We present the discovery of the highest velocity C IV broad absorption line to date in the z = 2.47 quasar SDSS J023011.28+005913.6, hereafter J0230. In comparing the public DR7 and DR9 spectra of J0230, we discovered an emerging broad absorption trough outflowing at ∼60 000 km s−1, which we refer to as trough A. In pursuing follow up observations of trough A, we discovered a second emergent C IV ...