An Eddington Limited Accretion Disk Wind in the narrow line Seyfert 1, PG 1448+273

TL;DR

This study presents new high-quality X-ray observations of PG 1448+273, revealing a fast, Eddington-limited accretion disk wind with velocities up to 0.43c, one of the fastest known in nearby AGN, indicating significant mass outflow.

Contribution

First detection of a highly blue-shifted, broad iron K absorption profile in PG 1448+273, modeling it as a near-Eddington accretion disk wind with unprecedented velocity.

Findings

Detected a broad, blue-shifted iron K absorption profile.

Measured maximum wind velocity of approximately 0.43c.

Indicated the wind's mass outflow rate approaches the Eddington accretion rate.

Abstract

PG 1448+273 is a luminous, nearby ($z=0.0645$), narrow line Seyfert 1 galaxy, which likely accretes close to the Eddington limit. Previous X-ray observations of PG 1448 with XMM-Newton in 2017 and NuSTAR in 2022 revealed the presence of an ultra fast outflow, as seen through its blueshifted iron K absorption profile, where the outflow velocity appeared to vary in the range $0.1-0.3c$. In this work, new X-ray observations of PG 1448 are presented, in the form of four simultaneous XMM-Newton and NuSTAR observations performed in July and August 2023. The X-ray spectra appeared at a similar flux in each observation, making it possible to analyze the mean 2023 X-ray spectrum at high signal to noise. A broad ($\sigma=1$ keV) and highly blue-shifted ($E=9.8\pm0.4$ keV) iron K absorption profile is revealed in the mean spectrum. The profile can be modeled by a fast, geometrically thick accretion disk wind, which reveals a maximum terminal velocity of $v_{\infty}=-0.43\pm0.03c$, one of the fastest known winds in a nearby AGN. As a result, the inferred mass outflow rate of the wind may reach a significant fraction of the Eddington accretion rate.