A new period of activity in the core of NGC660

TL;DR

This paper reports the discovery of a new period of active galactic nucleus (AGN) activity in the core of NGC660, evidenced by a bright radio source, jet-like features, and spectral analysis, indicating a recent energetic outburst.

Contribution

It presents multi-wavelength radio and X-ray observations revealing the onset of AGN activity in NGC660's core, with detailed imaging and spectral analysis.

Findings

Detection of a new compact radio source at the galaxy's center

Observation of jet-like features indicating active outflows

Evidence supporting recent AGN activity in NGC660

Abstract

The core of the nearby galaxy NGC660 has recently undergone a spectacular radio outburst; using a combination of archival radio and Chandra X-ray data, together with new observations, the nature of this event is investigated. Radio observations made using e-MERLIN in mid-2013 show a new compact and extremely bright continuum source at the centre of the galaxy. High angular resolution observations carried out with the European VLBI Network show an obvious jet-like feature to the north east and evidence of a weak extension to the west, possibly a counter-jet. We also examine high angular resolution HI spectra of these new sources, and the radio spectral energy distribution using the new wide-band capabilities of e-MERLIN. We compare the properties of the new object with possible explanations, concluding that we are seeing a period of new AGN activity in the core of this polar ring galaxy.