Resolving the Multiple Component Outflows in PG 1211+143: II. The Soft X-ray View of the Ultra Fast Outflow

TL;DR

This study analyzes high-resolution soft X-ray spectra of the quasar PG 1211+143, revealing multiple velocity components of ultra fast outflows and supporting a clumpy, stratified wind structure with implications for wind driving mechanisms.

Contribution

First simultaneous high-resolution soft X-ray and Fe K observations of PG 1211+143, revealing multiple outflow components and a density profile consistent with a clumpy, stratified wind structure.

Findings

Detected three lower ionization outflow components at different velocities.

Found the outflow density varies with radius as r^{-5/3}.

Provided evidence for the clumpy nature of accretion disk winds.

Abstract

The nearby quasar, PG 1211+143, has one of the prototype examples of an ultra fast outflow (UFO), as seen in several past XMM-Newton and Chandra observations. In December 2024, PG 1211+143 was observed simultaneously with XRISM Resolve and XMM-Newton, allowing both the Fe K and soft X-ray outflows to be examined at high resolution simultaneously. The Resolve spectrum revealed a forest of Fe K band absorption lines from the UFO (Mizumoto et al. 2026), comprising of up to six discrete velocity components ranging from $v/c=-0.074$ to $v/c=-0.40$. Here we present the simultaneous XMM-Newton RGS (Reflection Grating Spectrometer) spectrum, where three lower ionization counterparts of the Fe K velocity zones are observed; at $v/c=-0.074, -0.12$ and $-0.33$. The soft X-ray absorbers tend to be somewhat less ionized than their Fe K counterparts, with their opacity mainly arising from Fe L shell lines and highly ionized Oxygen. From comparing the Resolve and RGS absorbers, we show that the outflow can be parameterized with a density profile varying with radius as $r^{-5/3}$, while the lower ionization zones likely originate from denser clumps of gas. Pure electron scattering appears insufficient to provide enough thrust to power the wind, unless sufficient low ionization gas capable of radiative line driving exists outside of the line of sight. Overall, PG 1211+143 provides further evidence for the clumpy nature of accretion disk winds, as was recently revealed in the quasar PDS 456 with XRISM.