Fundamental Accretion and Ejection Astrophysics

TL;DR

This paper discusses the fundamental role of disk accretion in astrophysics, including star and galaxy formation, black hole growth, and jet production, highlighting key open questions in the field.

Contribution

It reviews the core processes of accretion and ejection in astrophysical disks and identifies unresolved questions about angular momentum transfer and jet launching mechanisms.

Findings

Accretion disks are central to star and galaxy formation.

Black hole growth and feedback are driven by disk accretion.

Jets and winds are fundamental outcomes of accretion processes.

Abstract

Disk accretion may be the fundamental astrophysical process. Stars and planets form through the accretion of gas in a disk. Black holes and galaxies co-evolve through efficient disk accretion onto the central supermassive black hole. Indeed, approximately 20 percent of the ionizing radiation in the universe is supplied by disk accretion onto black holes. And large-scale structures - galaxy clusters - are dramatically affected by the relativistic jets that result from accretion onto black holes. Yet, we are still searching for observational answers to some very basic questions that underlie all aspects of the feedback between black holes and their host galaxies: How do disks transfer angular momentum to deliver gas onto compact objects? How do accretion disks launch winds and jets?