A young, dusty, compact radio source within a Ly|*alpha*| halo

TL;DR

This paper reports the discovery of a young, dusty radio-loud quasar at high redshift within a large Lyman-alpha halo, indicating recent jet activity and delayed jet triggering relative to black hole accretion.

Contribution

It presents the first detailed observation of a young, dusty radio source within a Lyman-alpha halo, highlighting the timing of jet triggering in relation to black hole growth.

Findings

Radio jets triggered less than 10^4 years ago

Central quasar obscured by dusty torus with Av ~ 3.0

Large Lyman-alpha halo indicates established black hole before jet emergence

Abstract

We report here on the discovery of a red quasar, J004929.4+351025.7 at a redshift of z = 2.48, situated within a large Lya emission-line halo. The radio spectral energy distribution implies that the radio jets were triggered < 10^4 years prior to the time at which the object is observed, suggesting that the jet triggering of the active galactic nucleus is recent. The loosely biconical structure of the emission-line halo suggests that it is ionised by photons emitted by the central quasar nucleus and that the central nucleus is obscured by a dusty torus with Av ~ 3.0. The large spatial extent of the Lya halo relative to the radio emission means this could only have occurred if the radio jets emerged from an already established highly-accreting black hole. This suggests that the radio-jet triggering is delayed with respect to the onset of accretion activity on to the central supermassive black hole.