Megahertz Emission of Massive Early-Type Stars in the Cygnus Region
Publications of the Astronomical Society of Australia (PASA) doi: 10.1017/pas.2020.xxx. Megahertz emission of massive early-type stars in the Cygnus region P. Benaglia1,2, M. De Becker3, C. H. Ishwara-Chandra4, H. Intema5,6 and N. L. Isequilla2 1Instituto Argentino de Radioastronomia, CONICET & CICPBA, CC5 (1897) Villa Elisa, Prov. de Buenos Aires, Argentina 2Facultad de Ciencias Astronómicas y Geofísicas, UNLP, Paseo del Bosque s/n, (1900) La Plata, Argentina 3Space sciences, Technologies and Astrophysics Research (STAR) Institute, University of Liège, Quartier Agora, 19c, Allée du 6 Août, B5c, B-4000 Sart Tilman, Belgium 4National Centre for Radio Astrophysics (NCRA-TIFR), Pune, 411 007, India 5International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102, Australia 6Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, the Netherlands Abstract Massive, early type stars have been detected as radio sources for many decades. Their thermal winds radiate free-free continuum and in binary systems hosting a colliding-wind region, non-thermal emission has also been detected. To date, the most abundant data have been collected from frequencies higher than 1 GHz. We present here the results obtained from observations at 325 and 610 MHz, carried out with the Giant Metrewave Radio Telescope, of all known Wolf-Rayet and O-type stars encompassed in area of ∼15 sq degrees centred on the Cygnus region. We report on the detection of 11 massive stars, including both Wolf-Rayet and O-type systems. The measured flux densities at decimeter wavelengths allowed us to study the radio spectrum of the binary systems and to propose a consistent interpretation in terms of physical processes affecting the wide-band radio emission from these objects.
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