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C. H. Ishwara-Chandra, Paula Benaglia, Michaël De Becker & Anandmayee Tej

GMRT survey of Cygnus OB2 region

(Volume 88 - Année 2019 — Actes de colloques — 2nd Belgo-Indian Network for Astronomy & Astrophysics (BINA) workshop - October 2018 - Brussels, Belgium)
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Mots-clés : galaxie, clusters ouverts, Cygnus OB2, 8, 9, continuum radio


A good fraction of very high energy (VHE; > 100 GeV) sources do not have confirmed counterparts at any of the other branches of electromagnetic spectrum. In the extra-galactic sky, most of the VHE sources with counter-parts are blazars, a sub-class of active galactic nuclei. However, VHE sources with identified counterparts in our Galaxy do have a wide range of categories, ranging such as supernovae remnants, colliding wind binaries, pulsar wind nebulae, micro-quasars, etc. The VHE emission and radio emission due to synchrotron process do occur from the same population of relativistic electrons in several type of sources, so the radio band is the first band to search for possible counterparts to unidentified VHE sources. In addition, the radio spectral index also gives important constraints on compactness and energetics of the electron population. In this work we present a two-frequency radio survey, at frequencies 325 MHz and 610 MHz, of the Cygnus OB2 region with the Giant Metrewave Radio Telescope (GMRT) in order to address several astrophysical problems. The survey covers a wide area (~ 5 square degrees) at sub-mJy sensitivity which helps to discover faint radio sources to several objects for the first time. Also this is the first deep wide area radio survey of the region below 1.4 GHz, and the low radio frequency will preferentially pickup more non-thermal radio sources as compared to high radio frequencies. Here, we present the early results from this survey.

Keywords : galaxy, open clusters and associations, Cygnus OB2, 8, 9, radio continuum

To cite this article

C. H. Ishwara-Chandra, Paula Benaglia, Michaël De Becker & Anandmayee Tej, «GMRT survey of Cygnus OB2 region», Bulletin de la Société Royale des Sciences de Liège [En ligne], Volume 88 - Année 2019, Actes de colloques, 2nd Belgo-Indian Network for Astronomy & Astrophysics (BINA) workshop - October 2018 - Brussels, Belgium, 166-173 URL :

About: C. H. Ishwara-Chandra

NCRA-TIFR, Post Bag No. 3, Ganeshkhind, Pune - 411007, India,

About: Paula Benaglia

Instituto Argentino de Radioastronomia, CONICET & CICPBA, CC5 (1897), Villa Elisa, Prov. de Buenos Aires, Argentina

About: Michaël De Becker

Space sciences, Technologies and Astrophysics Research (STAR) Institute, University of Liége, Quartier Agora, 19c, Allée du 6 Aôut, B5c, B-4000 Sart Tilman, Belgium

About: Anandmayee Tej

Indian Institute Of Space Science And Technology, Thiruvananthapuram 695 547, Kerala, India