Velocity shift of Mg II and Al III broad absorption lines in quasar SDSS J134444.33+315007.6

TL;DR

This study reports the first observed synchronized velocity shift of Mg II and Al III broad absorption lines in a quasar, indicating possible outflow acceleration driven by radiation pressure, based on multi-epoch observations.

Contribution

It presents the first detection of synchronized velocity shifts in Mg II and Al III BALs in a quasar, linking these shifts to radiation-driven outflow acceleration.

Findings

Detected a velocity shift of ~-1100 km/s over 3.21 years.

Observed coordinated variations in emission and absorption lines.

Indicated outflow acceleration influenced by the quasar's radiation.

Abstract

We report, for the first time, a synchronized velocity shift of Mg II and Al III broad absorption lines (BALs) in quasar SDSS J134444.33+315007.6 (hereafter J1344+3150). We found this quasar from a sample of 134 Mg II BAL quasars with multi-epoch observations. This quasar contains three low-ionization BAL systems, the fastest of which at $\sim$$-17, 000\,\rm km\,s^{-1}$ shows a kinematic shift of $\sim$$-1101\,\rm km\,s^{-1}$ and $\sim$$-1170\,\rm km\,s^{-1}$ in its Mg II and Al III ions, respectively, during a rest-frame time of about 3.21 yr. Meanwhile, this quasar also shows other various variation characteristics, including an obvious weakening in its continuum, a coordinated enhancement in multiple emission lines (Mg II, C III and Al III), and a coordinated enhancement in three Al III absorption troughs. These variation characteristics convincingly indicate that the BAL outflows of J1344+3150 are under the influence from the background radiation energy. Thus, we infer that the velocity shift displayed in system A in the quasar J1344+3150 may indicate an actual line-of-sight acceleration of an outflow due to the radiation pressure from the central source.