Jet-triggered star formation in young radio galaxies

TL;DR

This study uses high-resolution UV imaging to explore how radio jets in young radio galaxies may trigger star formation, revealing spatially aligned UV emission with radio jets in most CSS sources.

Contribution

It provides observational evidence supporting jet-triggered star formation in young radio galaxies, a novel insight into radio-mode feedback effects.

Findings

UV emission regions align with radio jets in CSS galaxies

Six out of seven CSS sources show UV emission near jets

Supports jet-triggered star formation hypothesis

Abstract

Emission in the ultraviolet continuum is a salient signature of the hot, massive and consequently short-lived, stellar population that traces recent or ongoing star formation. With the aim of mapping star forming regions and morphologically separating the generic star formation from that associated with the galaxy-scale jet activity, we obtained high-resolution HST/UV imaging for a sample of nine compact radio sources. Out of these, seven are known Compact Steep Spectrum (CSS) galaxies that host young, kpc-scale radio sources and hence are the best candidates for studying radio-mode feedback on galaxy scales, while the other two form a control sample of larger sources. Extended UV emission regions are observed in six of the seven CSS sources showing close spatial alignment with the radio-jet orientation. If other mechanisms possibly contributing to the observed UV emission are ruled out, this could be evidence in support of jet-triggered star formation in the CSS phase of radio galaxy evolution.