Reassessment of an origin of the radio structure of J1420-0545

TL;DR

This study investigates whether the radio structure of galaxy J1420-0545 results from restarted jet activity, using new low-frequency observations and modeling to understand its environmental conditions and history.

Contribution

It provides evidence supporting the restarted jet activity hypothesis through spectral analysis and modeling of the galaxy’s radio emission.

Findings

Detection of excess low-frequency emission.

Spectral fitting suggests an old cocoon from previous jet activity.

Environmental conditions inferred from the model.

Abstract

In this paper, we test the possibility that the structure of the largest radio galaxy J1420-0545 may have been formed by restarted rather than primary jet activity. This hypothesis was motivated by the unusual morphological properties of the source consisting of two edge-brightened, narrow, highly collinear, and symmetric lobes, thus suggesting an almost ballistic propagation of powerful jets into a particularly low-density external medium. New observations made with the VLA together with the currently available GLEAM and TGSS ADR1 data releases allow the detection of an excess emission at low frequencies. An extracted part (88 MHz - 200 MHz) of the spectrum of the emission is fitted with the DYNAGE model, giving a forecast for the environmental conditions and the energetic requirements for the presumed old cocoon related to a preceding epoch of jet activity.