Dynamically evolving Mg II broad absorption line flow in SDSS
  J133356.02+001229.1
  We report a dynamically evolving low ionization broad absorption line flow in
the QSO SDSS J133356.02+001229.1 (at z_em = 0.9197). These observations are
part of our ongoing monitoring of low ionization broad absorption line (BAL)
QSOs with the 2m telescope at IUCAA Girawali observatory (IGO). The broad Mg II
absorption with an ejection velocity of 1.7x10^4 km/s, found in the Sloan
Digital Sky Survey (SDSS) spectra, has disappeared completely in our IGO
spectra. We found an emerging new component at an ejection velocity of 2.8 x
10^4 km/s. During our monitoring period this component has shown strong
evolution both in its velocity width and optical depth and nearly disappeared
in our latest observations. Acceleration of a low velocity component seen in
SDSS spectrum to a higher velocity is unlikely as the Mg II column densities
are always observed to be higher for the new component. We argue that the
observed variations may not be related to ionization changes and are consistent
with absorption produced by multi-streaming flow transiting across our line of
sight. We find a possible connection between flux variation of the QSO and N(Mg
II) of the newly emerged component. This could mean the ejection being
triggered by changes in the accretion disk or dust reddening due to the
outflowing gas.
