BINA

Abstract

This research focuses on understanding the physical processes governing the feedback dynamics of massive stars during their late evolutionary phases. In these stages, the intense radiation fields of massive stars drive powerful supersonic winds by expelling and accelerating their outer layers. As these winds propagate, they interact either with the winds of a companion star in binary systems (wind-wind interaction) or with the surrounding interstellar medium (wind-ISM interaction). These interactions inject substantial mechanical energy into the ISM, generating strong adiabatic shocks that are conducive to relativistic particle acceleration. In the shocked regions, these relativistic particles interact with local magnetic fields, producing synchrotron radiation — a key signature of particle acceleration. This emission is particularly dominant in low-frequency radio bands. Thus, In their late evolutionary stages, massive stars present unique laboratories for investigating particle acceleration. As part of the BINA collaboration within the PANTERA-stars framework, we conducted extensive investigations of massive stellar systems, particularly Wolf-Rayet stars, using the upgraded Giant Metrewave Radio Telescope (uGMRT) in India. With its high sensitivity and resolution in the low radio frequency range, uGMRT is instrumental in detecting signatures of particle acceleration.

Collaborators

Name	Affiliation & Contact
Anandmayee Tej (P.I.)	Indian Institute of Space Science and Technology (IIST) (Thiruvananthapuram, Kerala, India) Tej
Anindya Saha	Indian Institute of Space Science and Technology (IIST) (Thiruvananthapuram, Kerala, India) Saha
Michael De Becker P.I.)	Space sciences, Technologies and Astrophysics Research unit – STAR, University of Liège, Liège, Belgium M DeBecker

Publications

"Search for particle acceleration in two massive Wolf–Rayet stars using uGMRT observations"
Anindya Saha, Anandmayee Tej, Santiago del Palacio, Michaël De Becker, Paula Benaglia, C. H. Ishwara-Chandra and Prachi Prajapati, 2023, Monthly Notices of the Royal Astronomical Society, 526, 750 - 757

"Insight into the occurrence of particle acceleration through the investigation of Wolf–Rayet stars using uGMRT observations"
AB Blanco, Michaël De Becker, A Saha, Anandmayee Tej and Paula Benaglia , 2024, Astronomy & Astrophysics 690, A78

Presentations

Contributed talk, 3rd BINA Meeting, Bhimtal, Nainital, India,
"Study of Wolf-Rayet stars using uGMRT"
Anindya Saha, Anandmayee Tej, Santiago del Palacio, Michaël De Becker, Paula Benaglia, Ishwara Chandra CH, Prachi Prajapati

Proposals for telescope-time

• Investigating particle acceleration associated with putative single Wolf-Rayet stars;
  Anindya Saha, Anandmayee Tej, Santiago del Palacio, Michaël De Becker, Paula Benaglia, C. H. Ishwara-Chandra and Prachi Prajapati
  Telescope: uGMRT * Observing cycle: 38 * Time requested: 30 hrs * Time allocated: 18 hrs
• The synchrotron/binarity correlation as a tool to investigate the multiplicity of Wolf-Rayet stars
  Michaël De Becker, Anandmayee Tej, Agustina Blanco, Paula Benaglia
  Telescope: uGMRT * Observing cycle: 44 * Time requested: 24 hrs * Time allocated: 24 hrs
• Wolf-Rayet bubbles as potential particle accelerators
  Anindya Saha, Anandmayee Tej, Santiago del Palacio, Michaël De Becker, Paula Benaglia, C. H. Ishwara-Chandra
  Telescope: uGMRT * Observing cycle: 44 * Time requested: 28 hrs * Time allocated: 12 hrs