Sub-milliarcsecond imaging of a bright flare and ejection event in the extragalactic jet 3C 111
Artikel i vetenskaplig tidskrift, 2020

Context
Flares in radio-loud active galactic nuclei are thought to be associated with the injection of fresh plasma into the compact jet base. Such flares are usually strongest and appear earlier at shorter radio wavelengths. Hence, very long baseline interferometry (VLBI) at millimeter(mm)-wavelengths is the best-suited technique for studying the earliest structural changes of compact jets associated with emission flares.
Aims
We study the morphological changes of the parsec-scale jet in the nearby (z = 0.049) γ-ray bright radio galaxy 3C 111 following a flare that developed into a major radio outburst in 2007.
Methods 
We analyse three successive observations of 3C 111 at 86 GHz with the Global mm-VLBI Array (GMVA) between 2007 and 2008 which yield a very high angular resolution of ∼45  μas. In addition, we make use of single-dish radio flux density measurements from the F-GAMMA and POLAMI programmes, archival single-dish and VLBI data.
Results
We resolve the flare into multiple plasma components with a distinct morphology resembling a bend in an otherwise remarkably straight jet. The flare-associated features move with apparent velocities of ∼4.0c to ∼4.5c and can be traced also at lower frequencies in later epochs. Near the base of the jet, we find two bright features with high brightness temperatures up to ∼1011 K, which we associate with the core and a stationary feature in the jet.
Conclusions
The flare led to multiple new jet components indicative of a dynamic modulation during the ejection. We interpret the bend-like feature as a direct result of the outburst which makes it possible to trace the transverse structure of the jet. In this scenario, the components follow different paths in the jet stream consistent with expectations for a spine-sheath structure, which is not seen during intermediate levels of activity. The possibility of coordinated multiwavelength observations during a future bright radio flare in 3C 111 makes this source an excellent target for probing the radio-γ-ray connection.

Galaxies: active

Galaxies: individual: 3C 111

Galaxies: jets

Techniques: high angular resolution

Författare

R. Schulz

Friedrich-Alexander-Universität Erlangen Nurnberg (FAU)

Netherlands Institute for Radio Astronomy (ASTRON)

Julius-Maximilians Universität Würzburg

M. Kadler

Julius-Maximilians Universität Würzburg

Eduardo Ros

Max-Planck-Gesellschaft

M. Perucho

Universitat de Valencia

T.P. Krichbaum

Max-Planck-Gesellschaft

I. Agudo

CSIC - Instituto de Astrofísica de Andalucía (IAA)

T. Beuchert

Friedrich-Alexander-Universität Erlangen Nurnberg (FAU)

European Southern Observatory (ESO)

Julius-Maximilians Universität Würzburg

Anton Pannekoek Institute for Astronomy

Michael Lindqvist

Chalmers, Rymd-, geo- och miljövetenskap, Onsala rymdobservatorium, Observationssupport

K. Mannheim

Julius-Maximilians Universität Würzburg

J. Wilms

Friedrich-Alexander-Universität Erlangen Nurnberg (FAU)

A.J. Zensus

Max-Planck-Gesellschaft

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 644 December 2020 A85

Ämneskategorier

Subatomär fysik

Astronomi, astrofysik och kosmologi

Fusion, plasma och rymdfysik

DOI

10.1051/0004-6361/202037737

Mer information

Senast uppdaterat

2021-01-05