Single-dish and VLBI observations of Cygnus X-3 during the 2016 giant flare episode

Journal article

Publication Details

Author(s): Egron E, Pellizzoni A, Giroletti M, Righini S, Stagni M, Orlati A, Migoni C, Melis A, Concu R, Barbas L, Buttaccio S, Cassaro P, De Vicente P, Gawronski MP, Lindqvist M, Maccaferri G, Stanghellini C, Wolak P, Yang J, Navarrini A, Loru S, Pilia M, Bachetti M, Iacolina MN, Buttu M, Corbel S, Rodriguez J, Markoff S, Wilms J, Pottschmidt K, Bel MC, Kalemci E, Belloni T, Grinberg V, Marongiu M, Vargiu GP, Trois A
Journal: Monthly Notices of the Royal Astronomical Society
Publication year: 2017
Volume: 471
Journal issue: 3
Pages range: 2703-2714
ISSN: 0035-8711
eISSN: 1365-2966


In 2016 September, the microquasar Cygnus X-3 underwent a giant radio flare, which was monitored for 6 d with the Medicina Radio Astronomical Station and the Sardinia Radio Telescope. Long observations were performed in order to follow the evolution of the flare on an hourly scale, covering six frequency ranges from 1.5 to 25.6 GHz. The radio emission reached a maximum of 13.2 +/- 0.7 Jy at 7.2 GHz and 10 +/- 1 Jy at 18.6 GHz. Rapid flux variations were observed at high radio frequencies at the peak of the flare, together with rapid evolution of the spectral index: a steepened from 0.3 to 0.6 (with S-nu alpha nu(-alpha)) within 5 h. This is the first time that such fast variations are observed, giving support to the evolution from optically thick to optically thin plasmons in expansion moving outward from the core. Based on the Italian network (Noto, Medicina and SRT) and extended to the European antennas (Torun, Yebes, Onsala), very long baseline interferometry (VLBI) observations were triggered at 22 GHz on five different occasions, four times prior to the giant flare, and once during its decay phase. Flux variations of 2 h duration were recorded during the first session. They correspond to a mini-flare that occurred close to the core 10 d before the onset of the giant flare. From the latest VLBI observation we infer that 4 d after the flare peak the jet emission was extended over 30 mas.

FAU Authors / FAU Editors

Wilms, Jörn Prof. Dr.
Professur für Astronomie und Astrophysik

External institutions with authors

Chalmers University of Technology / Chalmers tekniska högskola
European Space Research and Technology Centre (ESTEC, ESA)
INAF - Institute for Radio Astronomy of Bologna / Istituto di Radioastronomia di Bologna (IRA)
INAF-Osservatorio Astronomico di Cagliari
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
Nicolaus Copernicus University / Uniwersytet Mikołaja Kopernika w Toruniu (UMK)
Rechenzentrum Garching der Max-Planck-Gesellschaft (MPCDF) / Max Planck Computing & Data Facility
Sabanci University
University of Amsterdam
University of Maryland
University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot
Yebes Observatory

How to cite

Egron, E., Pellizzoni, A., Giroletti, M., Righini, S., Stagni, M., Orlati, A.,... Trois, A. (2017). Single-dish and VLBI observations of Cygnus X-3 during the 2016 giant flare episode. Monthly Notices of the Royal Astronomical Society, 471(3), 2703-2714.

Egron, Elise, et al. "Single-dish and VLBI observations of Cygnus X-3 during the 2016 giant flare episode." Monthly Notices of the Royal Astronomical Society 471.3 (2017): 2703-2714.


Last updated on 2019-26-07 at 09:33