NUclei of GAlaxies. V. Radio emission in 7 NUGA sources

M. Krips (1) , Andreas Eckart (1) , Thomas P. Krichbaum (2) , Jörg-Uwe Pott (1) , Sylvie Léon (3) , Roberto Neri (4) , Santiago García-Burillo (5) , Françoise Combes (6, 7) , Frédéric Boone (6, 7) , Andrew J. Baker (8) , L. J. Tacconi (9) , Eva Schinnerer (10) , Leslie K. Hunt (11)

1 Physikalisches Institut, Universität zu Köln
2 MPIfR - Max-Planck-Institut für Radioastronomie
3 IAA - Instituto de Astrofísica de Andalucía
4 IRAM - Institut de RadioAstronomie Millimétrique
5 Observatorio Astronomico Nacional, Madrid
6 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
7 Galaxies et cosmologie
8 Department of Physics and Astronomy, State University of New Jersey
9 MPE - Max-Planck-Institut für Extraterrestriche Physik
10 MPIA - Max-Planck-Institut für Astronomie
11 Istituto di Radioastronomia, Firenze

We present high angular resolution radio snap-shot observations of seven nearby low-luminosity active galaxies (LLAGN) from the NUclei of GAlaxies (NUGA) survey. The observations were conducted with MERLIN and EVN/VLBI at 18 cm and 6 cm. At all observed angular resolutions and frequencies, we find indications for extended emission in about ~40% of the sources, consistent with the decrease of flux with increasing angular resolution. The extended components resemble jet emission in a majority of cases, consistent with the optically thin synchrotron emission implied by their steep spectra. We consider the compact 6 cm EVN/VLBI radio emission of our sources in the context of the "fundamental plane" that previous LLAGN studies identified within the three-dimensional parameter space of radio luminosity, X-ray luminosity, and black hole mass. We demonstrate, using NGC 7217 and NGC 1068 as particular examples, that high-resolution, multi-epoch radio observations offer useful information about the origin of offsets from the fundamental plane.

Domaines: Astrophysique [astro-ph]

M. Krips, Andreas Eckart, Thomas P. Krichbaum, Jörg-Uwe Pott, Sylvie Léon, et al.. NUclei of GAlaxies. V. Radio emission in 7 NUGA sources. Astronomy and Astrophysics - A&A, 2007, 464, pp.553-563. ⟨10.1051/0004-6361:20065037⟩. ⟨hal-03786288⟩