Faint γ-ray sources at low-redshift: the radio galaxy IC 1531

DOI: 
10.1093/mnras/sty2622
Publication date: 
01/09/2018
Main author: 
Bassi, T.
IAA authors: 
Pérez-Torres, M. A.
Authors: 
Bassi, T.;Migliori, G.;Grandi, P.;Vignali, C.;Pérez-Torres, M. A.;Baldi, R. D.;Torresi, E.;Siemiginowska, A.;Stanghellini, C.
Journal: 
Monthly Notices of the Royal Astronomical Society
Refereed: 
Yes
Publication type: 
Article
Pages: 
2507
Abstract: 
We present a multi-wavelength study of IC 1531 (z=0.02564), an extragalactic radio source associated with the γ-ray object 3FGL J0009.9-3206 and classified as a blazar of uncertain type in the Third Fermi Large Area Telescope AGN Catalog (3LAC). A core-jet structure, visible in radio and X-rays, is enclosed within a ̃220 kpc wide radio structure. The morphology and spectral characteristics of the kiloparsec jet in radio and X-rays are typical of Fanaroff-Riley type I galaxies. The analysis of the radio data and optical spectrum and different diagnostic methods based on the optical, infrared and γ-ray luminosities also support a classification as a low-power radio galaxy seen at moderate angles (θ =10°γ-20°). In the framework of leptonic models, the high-energy peak of the non-thermal nuclear spectral energy distribution can be explained in terms of synchrotron-self-Compton emission from a jet seen at θ ̃15°. Similarly to other misaligned AGNs detected by Fermi, the required bulk motion is lower (Γ<SUB>bulk</SUB> =4) than the values inferred in BL Lac objects, confirming that, because of the de-boosting of emission from the highly-relativistic blazar region, these nearby systems are valuable targets to probe the existence of multiple sites of production of the most energetic emission in the jets.
Database: 
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2018MNRAS.481.5236B/abstract
ADS Bibcode: 
2018MNRAS.481.5236B
Keywords: 
galaxies: active;galaxies: individual: IC 1531 galaxies: jets;gamma-rays: galaxies;radio continuum: galaxies