Probing extreme black-hole outflows on short timescales via high spectral-resolution X-ray imagers

TL;DR

This paper explores how future high-resolution soft X-ray instruments can study black hole outflows across different regimes, revealing wind properties and mechanisms in ULXs, TDEs, and X-ray binaries.

Contribution

It demonstrates the potential of next-generation X-ray imagers to probe black hole outflows and distinguish wind mechanisms across various accretion regimes.

Findings

High spectral resolution enables identification of ultrafast winds.

Next-gen instruments can differentiate wind mechanisms.

Observations can track wind property changes over time.

Abstract

We investigate outflows and the physics of super-Eddington versus sub-Eddington regimes in black hole systems. Our focus is on prospective science using next-generation high-resolution soft X-ray instruments. We highlight the properties of black hole ultraluminous X-ray source (ULX) systems in particular. Owing to scale invariance in accreting black holes, ULX accretion properties including their outflows, inform our understanding not only of the closely-related population of (similar-mass) X-ray binary systems, but also of tidal disruption events (TDEs) around supermassive black holes. A subsample of TDEs are likely to transcend super-Eddington to sub-Eddington regimes as they evolve, offering an important unifying analog to ULXs and sub-Eddington X-ray binaries. We demonstrate how next-generation soft X-ray observations with resolving power > 1000 and collecting area > 1000 cm^2 can simultaneously identify ultrafast and more typical wind components, distinguish between different wind mechanisms, and constrain changing wind properties over characteristic variability timescales.