Spectacular 240 kpc double-sided relativistic jets in a spiral-hosted narrow-line Seyfert 1 galaxy

¹ Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Vicolo dell’Osservatorio 3, 35122 Padova, Italy
e-mail: amelia.vietri@phd.unipd.it
² European Space Agency, European Space Astronomy Centre, C/Bajo el Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
³ European Southern Observatory (ESO), Alonso de Córdova 3107, Casilla 19, Santiago 19001, Chile
⁴ Departamento de Astronomía, Universidad de Chile, Camino del Observatorio 1515, Las Condes, Santiago, Chile
⁵ Department of Physics, Technion 32000, Haifa 32000, Israel
⁶ Las Campanas Observatory – Carnegie Institution for Science, Colina el Pino, Casilla 601, La Serena, Chile

Received: 10 March 2022
Accepted: 29 March 2022

Abstract

Narrow-line Seyfert 1 (NLS1) galaxies are a peculiar sub-class of active galactic nuclei (AGNe). They have demonstrated that the presence of relativistic jets in an AGN is not strictly related to its radio-loudness, the black hole mass, or their host galaxy type. Here, we present a remarkable example of a radio-quiet NLS1, 6dFGS gJ035432.8−134008 (J0354−1340). In our Karl G. Jansky Very Large Array observations at 5.5 GHz, the source shows a bright core with a flat spectral index and extended emission corresponding to very elongated jets. These are the largest double-sided radio jets found to date in an NLS1, with a de-projected linear size of almost 250 kpc. We also analysed near-infrared and optical images obtained by the Magellan Baade and the European Southern Observatory New Technology Telescope. By means of photometric decomposition and colour maps, we determined that J0354−1340 is hosted by a spiral or disc-like galaxy. Fully evolved relativistic jets have traditionally been associated with high-mass elliptical galaxies hosting the most massive black holes. Instead, our results confirm that powerful jets can also be launched and sustained by less massive black holes in spiral galaxies, implying that the launching of the jets is governed by factors other than those previously believed to be at play.