Dramatic Change in the Spectrum of FeLoBAL SDSS J163255.46+420407.7

We serendipitiously found that the iron-rich low-ionization broad absorption-line (FeLoBAL) quasar SDSS J 163255.46+420407.7 showed a dramatic change in its spectrum over 3.4 years in the rest frame of the quasar. A simple photoionization model suggests the increase in the nuclear radiation caused these changes. Given the recombination coefficient of Fe⁺, the relaxation time of the absorbing gas suggests n_e > 10⁴ cm^-3.