Searching for signs of jet-driven negative feedback in the nearby radio galaxy UGC 05771

TL;DR

This study investigates how jets from a young radio galaxy influence its interstellar medium and star formation, finding evidence of shocked gas and potential star formation regulation, though direct jet impact remains inconclusive.

Contribution

It provides multi-wavelength observational evidence of jet-ISM interactions in a nearby galaxy with a young radio source, highlighting the potential role of jets in star formation regulation.

Findings

Detection of shocked molecular and ionised gas at pc scales

Evidence of large-scale shocked ionised gas extending beyond the radio source

UGC 05771 lies below the Kennicutt-Schmidt star formation relation

Abstract

Hydrodynamical simulations predict that the jets of young radio sources can inhibit star formation in their host galaxies by injecting heat and turbulence into the interstellar medium (ISM). To investigate jet-ISM interactions in a galaxy with a young radio source, we have carried out a multi-wavelength study of the $z = 0.025$ Compact Steep Spectrum radio source hosted by the early-type galaxy UGC 05771. Using Keck/OSIRIS observations, we detected H\textsubscript{2} 1--0 S(1) and [Fe \textsc{ii}] emission at radii of 100s of pc, which traces shocked molecular and ionised gas being accelerated outwards by the jets to low velocities, creating a `stalling wind'. At kpc radii, we detected shocked ionised gas using observations from the CALIFA survey, covering an area much larger than the pc-scale radio source. We found that existing interferometric radio observations fail to recover a large fraction of the source's total flux, indicating the likely existence of jet plasma on kpc scales, which is consistent with the extent of shocked gas in the host galaxy. To investigate the star formation efficiency in UGC 05771, we obtained IRAM CO observations to analyse the molecular gas properties. We found that UGC 05771 sits below the Kennicutt-Schmidt relation, although we were unable to definitively conclude if direct interactions from the jets are inhibiting star formation. This result shows that jets may be important in regulating star formation in the host galaxies of compact radio sources.