Unveiling the AGN in IC883: discovery of a parsec-scale radio jet

Research output: Contribution to journalArticle

  • External authors:
  • C Romero-Cañizales
  • A Alberdi
  • C. Ricci
  • P. Arévalo
  • M. A. Pérez-Torres
  • J. E. Conway
  • M. Bondi
  • Thomas Muxlow
  • F E Bauer
  • A. Efstathiou
  • R Herrero-Illana
  • S. Mattila
  • S D Ryder

Abstract

IC883 is a luminous infrared galaxy (LIRG) classified as a starburst-active galactic nucleus (AGN) composite. In a previous study we detected a low-luminosity AGN (LLAGN) radio candidate. Here we report on our radio follow-up at three frequencies which provides direct and unequivocal evidence of the AGN activity in IC883. Our analysis of archival X-ray data, together with the detection of a transient radio source with luminosity typical of bright supernovae, give further evidence of the ongoing star formation activity, which dominates the energetics of the system. At sub-parsec scales, the radio nucleus has a core-jet morphology with the jet being a newly ejected component showing a subluminal proper motion of 0.6–1 c. The AGN contributes less than two per cent of the total IR luminosity of the system. The corresponding Eddington factor is ∼ 10−3, suggesting this is a low-accretion rate engine, as often found in LLAGNs. However, its high bolometric luminosity (∼ 1044 erg s−1) agrees betterwith a normalAGN. This apparent discrepancymay just be an indication of the transition
nature of the nucleus froma systemdominated by star-formation, to anAGN dominated system. The nucleus has a strongly inverted spectrum and a turnover at ∼ 4.4GHz, thus qualifying as a candidate for the least luminous (L5.0GHz ∼ 6.3 × 1028 erg s−1 Hz−1) and one of the youngest (∼ 3 × 103 yr) gigahertz-peaked spectrum (GPS) sources. If the GPS origin for the IC883 nucleus is confirmed, then advanced mergers in the LIRG category are potentially key environments to unveil the evolution of GPS sources into more powerful radio galaxies.

Bibliographical metadata

Original languageEnglish
Pages (from-to)2504-2516
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume467
Issue number2
Early online date27 Jan 2017
DOIs
StatePublished - May 2017