Wide-field LOFAR imaging of the field around the double-double radio galaxy B1834+620 A fresh view on a restarted AGN and doubeltjes
Artikel i vetenskaplig tidskrift, 2015

Context. The existence of double-double radio galaxies (DDRGs) is evidence for recurrent jet activity in active galactic nuclei (AGN), as expected from standard accretion models. A detailed study of these rare sources provides new perspectives for investigating the AGN duty cycle, AGN-galaxy feedback, and accretion mechanisms. Large catalogues of radio sources, on the other hand, provide statistical information about the evolution of the radio-loud AGN population out to high redshifts. Aims. Using wide-field imaging with the LOFAR telescope, we study both a well-known DDRG as well as a large number of radio sources in the field of view. Methods. We present a high resolution image of the DDRG B1834 + 620 obtained at 144MHz using LOFAR commissioning data. Our image covers about 100 square degrees and contains over 1000 sources. Results. The four components of the DDRG B1834 + 620 have been resolved for the first time at 144 MHz. Inner lobes were found to point towards the direction of the outer lobes, unlike standard FR II sources. Polarized emission was detected at + 60 rad m(-2) in the northern outer lobe. The high spatial resolution allows the identification of a large number of small double-lobed radio sources; roughly 10% of all sources in the field are doubles with a separation smaller than 1'. Conclusions. The spectral fit of the four components is consistent with a scenario in which the outer lobes are still active or the jets recently switched off, while emission of the inner lobes is the result of a mix-up of new and old jet activity. From the presence of the newly extended features in the inner lobes of the DDRG, we can infer that the mechanism responsible for their formation is the bow shock that is driven by the newly launched jet. We find that the density of the small doubles exceeds the density of FR II sources with similar properties at 1.4 GHz, but this difference becomes smaller for low flux densities. Finally, we show that the significant challenges of wide-field imaging (e.g., time and frequency variation of the beam, directional dependent calibration errors) can be solved using LOFAR commissioning data, thus demonstrating the potential of the full LOFAR telescope to discover millions of powerful AGN at redshift z similar to 1.

instrumentation: interferometers

techniques: interferometric

galaxies: active

radiation

Författare

E. Orru

Radboud Universiteit

Netherlands Institute for Radio Astronomy (ASTRON)

S. van Velzen

Radboud Universiteit

Johns Hopkins University

R. F. Pizzo

Netherlands Institute for Radio Astronomy (ASTRON)

S. Yatawatta

Kapteyn Astronomical Institute

Netherlands Institute for Radio Astronomy (ASTRON)

R. Paladino

Istituto nazionale di astrofisica (INAF)

Universita di Bologna

M. Iacobelli

Netherlands Institute for Radio Astronomy (ASTRON)

M. Murgia

INAF Osservatorio Astronomico di Cagliari

H. Falcke

Max-Planck Institut für Radioastronomie

Radboud Universiteit

Netherlands Institute for Radio Astronomy (ASTRON)

R. Morganti

Kapteyn Astronomical Institute

Netherlands Institute for Radio Astronomy (ASTRON)

A. G. de Bruyn

Kapteyn Astronomical Institute

Netherlands Institute for Radio Astronomy (ASTRON)

C. Ferrari

Université Nice Sophia Antipolis (UNS)

J. Anderson

Deutsches GeoForschungsZentrum (GFZ)

A. Bonafede

Universität Hamburg

D. Mulcahy

University of Manchester

A. Asgekar

Shell Technology Center

Netherlands Institute for Radio Astronomy (ASTRON)

I. M. Avruch

Kapteyn Astronomical Institute

Netherlands Institute for Space Research (SRON)

R. Beck

Max-Planck Institut für Radioastronomie

M. E. Bell

Commonwealth Scientific and Industrial Research Organisation (CSIRO)

I. van Bemmel

Joint Institute for VLBI in Europe (JIVE)

Netherlands Institute for Radio Astronomy (ASTRON)

M. J. Bentum

Netherlands Institute for Radio Astronomy (ASTRON)

Universiteit Twente

G. Bernardi

Harvard-Smithsonian Center for Astrophysics

P. Best

University of Edinburgh

F. Breitling

Leibniz-Institut Für Astrophysik Potsdam

J. W. Broderick

University of Southampton

M. Brüggen

Universität Hamburg

H. R. Butcher

Australian National University

B. Ciardi

Max-Planck-Institut für Astrophysik

John Conway

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

A. Corstanje

Radboud Universiteit

E. de Geus

SmarterVision BV

Netherlands Institute for Radio Astronomy (ASTRON)

A. Deller

Netherlands Institute for Radio Astronomy (ASTRON)

S. Duscha

Netherlands Institute for Radio Astronomy (ASTRON)

J. Eisloffel

Thüringer Landessternwarte Tautenburg

D. Engels

Hamburger Sternwarte

W. Frieswijk

Netherlands Institute for Radio Astronomy (ASTRON)

M. A. Garrett

Netherlands Institute for Radio Astronomy (ASTRON)

Universiteit Leiden

J. Griessmeier

Universite d'Orleans

A. W. Gunst

Netherlands Institute for Radio Astronomy (ASTRON)

J. P. Hamaker

Netherlands Institute for Radio Astronomy (ASTRON)

G. Heald

Netherlands Institute for Radio Astronomy (ASTRON)

M. Hoeft

Thüringer Landessternwarte Tautenburg

A. J. van der Horst

George Washington University

H. Intema

National Radio Astronomy Observatory

Universiteit Leiden

E. Juette

Ruhr-Universität Bochum

J. Kohler

Max-Planck Institut für Radioastronomie

V. I. Kondratiev

Radboud Universiteit

Astro Space Center of Lebedev Physical Institute

M. Kuniyoshi

National Astronomical Observatory of Japan

G. Kuper

Netherlands Institute for Radio Astronomy (ASTRON)

M. Loose

Netherlands Institute for Radio Astronomy (ASTRON)

P. Maat

Netherlands Institute for Radio Astronomy (ASTRON)

G. Mann

Leibniz-Institut Für Astrophysik Potsdam

S. Markoff

Universiteit Van Amsterdam

R. McFadden

Netherlands Institute for Radio Astronomy (ASTRON)

D. McKay-Bukowski

Oulun Yliopisto

STFC Rutherford Appleton Laboratory

G. Miley

Universiteit Leiden

J. Moldon

Netherlands Institute for Radio Astronomy (ASTRON)

G. Molenaar

Universiteit Van Amsterdam

H. Munk

Netherlands Institute for Radio Astronomy (ASTRON)

A. Nelles

Radboud Universiteit

H. Paas

Rijksuniversiteit Groningen

M. Pandey-Pommier

Observatoire de Lyon

V. N. Pandey

Netherlands Institute for Radio Astronomy (ASTRON)

G. Pietka

University of Oxford

A. G. Polatidis

Netherlands Institute for Radio Astronomy (ASTRON)

W. Reich

Max-Planck Institut für Radioastronomie

H. Rottgering

Universiteit Leiden

A. Rowlinson

Commonwealth Scientific and Industrial Research Organisation (CSIRO)

A. Scaife

University of Manchester

A. Schoenmakers

Netherlands Institute for Radio Astronomy (ASTRON)

D. Schwarz

Universität Bielefeld

M. Serylak

University of Oxford

A. Shulevski

Netherlands Institute for Radio Astronomy (ASTRON)

Kapteyn Astronomical Institute

O. Smirnov

Rhodes University

Square Kilometre Array, South Africa

M. Steinmetz

Leibniz-Institut Für Astrophysik Potsdam

A. Stewart

University of Oxford

J. Swinbank

Universiteit Van Amsterdam

M. Tagger

Universite d'Orleans

C. Tasse

Observatoire de Paris-Meudon

S. Thoudam

Radboud Universiteit

M. C. Toribio

Netherlands Institute for Radio Astronomy (ASTRON)

R. Vermeulen

Netherlands Institute for Radio Astronomy (ASTRON)

C. Vocks

Leibniz-Institut Für Astrophysik Potsdam

R. J. van Weeren

Harvard-Smithsonian Center for Astrophysics

Ramj Wijers

Universiteit Van Amsterdam

M. W. Wise

Netherlands Institute for Radio Astronomy (ASTRON)

Universiteit Van Amsterdam

O. Wucknitz

Max-Planck Institut für Radioastronomie

Astronomy and Astrophysics

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

Vol. 584 A112

Ämneskategorier

Astronomi, astrofysik och kosmologi

Infrastruktur

Onsala rymdobservatorium

DOI

10.1051/0004-6361/201526501

Mer information

Senast uppdaterat

2021-07-06