High-Velocity Outflows Without AGN Feedback: Eddington-Limited Star Formation in Compact Massive Galaxies

TL;DR

This paper reports the discovery of high-velocity outflows in compact, obscured star-forming galaxies at z ~ 0.6, suggesting that intense starburst feedback alone can drive such outflows without requiring AGN activity.

Contribution

It demonstrates that radiation pressure and stellar feedback in compact starbursts can produce extreme outflows, challenging the necessity of AGN feedback in such phenomena.

Findings

Star formation rate surface densities approach the Eddington limit.

High-velocity outflows (>1000 km/s) are observed without AGN activity.

Feedback from star formation alone can drive powerful outflows.

Abstract

We present the discovery of compact, obscured star formation in galaxies at z ~ 0.6 that exhibit >1000 km/s outflows. Using optical morphologies from the Hubble Space Telescope and infrared photometry from the Wide-field Infrared Survey Explorer, we estimate star formation rate (SFR) surface densities that approach Sigma_SFR ~ 3000 Msun/yr/kpc^2, comparable to the Eddington limit from radiation pressure on dust grains. We argue that feedback associated with a compact starburst in the form of radiation pressure from massive stars and ram pressure from supernovae and stellar winds is sufficient to produce the high-velocity outflows we observe, without the need to invoke feedback from an active galactic nucleus.