BAL phosphorus abundance and evidence for immense ionic column densities in quasar outflows: VLT X-Shooter observations of quasar SDSS J1512+1119

TL;DR

This study analyzes quasar SDSS J1512+1119's outflow using VLT X-Shooter data, revealing high ionic column densities and super-solar phosphorus abundance, with implications for understanding BAL outflow properties.

Contribution

It provides the first reliable measurements of phosphorus and SIV/SIV* column densities in this quasar's outflow, constraining elemental abundances and optical depths.

Findings

Phosphorus abundance is 0.5-4 times solar.

True CIV optical depth is about 1000 times greater than apparent.

Large optical depths imply dense, metal-rich outflows.

Abstract

We present spectroscopic analysis of the broad absorption line outflow in quasar SDSS J1512+1119. In particular, we focus our attention on a kinematic component in which we identify PV and SIV/SIV* absorption troughs. The shape of the unblended phosphorus doublet troughs and the three SIV/SIV* troughs allow us to obtain reliable column density measurements for these two ions. Photoionization modelling using these column densities and those of HeI* constrain the abundance of phosphorus to the range of 0.5-4 times the solar value. The total column density, ionization parameter and metalicity inferred from the PV and SIV column densities leads to large optical depth values for the common transition observed in BAL outflows. We show that the true CIV optical depth, is about 1000 times greater in the core of the absorption profile than the value deduced from its apparent optical depth.