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

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 (2017)

Publication Status: Published

Publication Type: Journal article

Publication year: 2017

Journal

Monthly Notices of the Royal Astronomical Society Oxford University Press

Publisher: OXFORD UNIV PRESS

Book Volume: 471

Pages Range: 2703-2714

Journal Issue: 3

DOI: 10.1093/mnras/stx1730

Abstract

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.

Authors with CRIS profile

Jörn Wilms Professur für Astronomie und Astrophysik

Involved external institutions

Yebes Observatory ES Spain (ES) INAF-Osservatorio Astronomico di Cagliari IT Italy (IT) INAF - Institute for Radio Astronomy of Bologna / Istituto di Radioastronomia di Bologna (IRA) IT Italy (IT) Nicolaus Copernicus University (NCU) / Uniwersytet Mikołaja Kopernika w Toruniu (UMK) PL Poland (PL) National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF) IT Italy (IT) Sabanci University TR Turkey (TR) Rechenzentrum Garching der Max-Planck-Gesellschaft (MPCDF) / Max Planck Computing & Data Facility DE Germany (DE) University of Maryland US United States (USA) (US) University of Amsterdam NL Netherlands (NL) University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot FR France (FR) Chalmers University of Technology / Chalmers tekniska högskola SE Sweden (SE) European Space Research and Technology Centre (ESTEC, ESA) NL Netherlands (NL)

How to cite

APA:

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. https://dx.doi.org/10.1093/mnras/stx1730

MLA:

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.

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