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With the growing subset of magnetic massive stars, it is now possible to conduct a systematic survey of radio emission from magnetic hot stars to better understand the underlying emission mechanisms. Previous surveys of radio emission from…

Solar and Stellar Astrophysics · Physics 2026-05-25 Ayan Biswas , Gregg A. Wade , Barnali Das , Veronique Petit , Matthew E. Shultz

We have carried out a study of radio emission from a small sample of magnetic O- and B-type stars using the Giant Metrewave Radio Telescope, with the goal of investigating their magnetospheres at low frequencies. These are the lowest…

Solar and Stellar Astrophysics · Physics 2015-08-06 P. Chandra , G. A. Wade , J. O. Sundqvist , D. Oberoi , J. H. Grunhut , A. ud-Doula , V. Petit , D. H. Cohen , M. E. Oksala , A. David-Uraz

Numerous magnetic hot stars exhibit gyrosynchrotron radio emission. The source electrons were previously thought to be accelerated to relativistic velocities in the current sheet formed in the middle magnetosphere by the wind opening…

Magnetic BA stars host dipole-like magnetospheres. When detected as radio sources, their luminosities correlate with the magnetic field and rotation. Rotation is crucial because the mechanism undergirding the relativistic electron…

With the improvements in radio interferometry sensitivity, the quest for coherent radio emission from exoplanets and ultra-cool dwarfs, which is indicative of their magnetic fields, has gained significant momentum in recent years. We…

Magnetic massive stars are stars of spectral types O, B and A that harbour $\sim$ kG strength (mostly dipolar) surface magnetic fields. Their non-thermal radio emission has been demonstrated to be an important magnetospheric probe, provided…

Context: Some O stars are suspected to have to have (weak) magnetic fields because of the observed cyclical variability in their UV wind-lines. However, direct detections of these magnetic fields using optical spectropolarimetry have proven…

In this paper we present a three-dimensional numerical model for the radio emission of Magnetic Chemically Peculiar stars, on the hypothesis that energetic electrons emit by the gyrosynchrotron mechanism. For this class of radio stars,…

Astrophysics · Physics 2009-11-10 C. Trigilio , P. Leto , G. Umana , F. Leone , C. S. Buemi

Plasma flow-obstacle interactions, such as those between an exoplanet's magnetosphere and the host star's stellar wind, may lead to detectable radio emissions. Despite many attempts to detect magnetospheric (auroral) radio emissions from…

Earth and Planetary Astrophysics · Physics 2024-05-01 Matthew Route

Although the majority of hot magnetic stars have extremely stable, $\sim$kG strength surface magnetic fields with simple topologies, a subset undergo small-scale explosions due to centrifugal breakout (CBO). The resulting small-scale flares…

Solar and Stellar Astrophysics · Physics 2023-10-18 E. Polisensky , B. Das , W. Peters , M. E. Shultz , E. Semenko , T. E. Clarke

Magnetic B-stars often exhibit circularly polarized radio emission thought to arise from gyrosynchrotron emission by energetic electrons trapped in the circumstellar magnetosphere. Recent empirical analyses show that the onset and strength…

Solar and Stellar Astrophysics · Physics 2022-05-04 Stanley P Owocki , Matt E. Shultz , Asif ud-Doula , Poonam Chandra , Barnali Das , Paulo Leto

The radiative mechanism of coherent radio emission has remained an enigma since the discovery of pulsars, even the emergence of fast radio bursts (FRBs), which exhibit similarities to the single-pulse behavior of pulsars and have opened a…

We briefly review the various proposed scenarios that may lead to nonthermal radio emissions from exoplanetary systems (planetary magnetospheres, magnetosphere-ionosphere and magnetosphere-satellite coupling, and star-planet interactions),…

Instrumentation and Methods for Astrophysics · Physics 2019-04-03 Philippe Zarka , Di Li , Jean-Mathias Grießmeier , Laurent Lamy , Julien N. Girard , Sébastien L. G. Hess , T. Joseph W. Lazio , Gregg Hallinan

Aims. Fast Radio Bursts are bright radio transients whose origin has not yet explained. The search for a multi-wavelength counterpart of those events can put a tight constrain on the emission mechanism and the progenitor source. Methods. We…

'Main-sequence radio pulse-emitters' (MRPs) are magnetic early-type stars from which periodic radio pulses, produced via electron cyclotron maser emission (ECME), are observed. Despite the fact that these stars can naturally offer suitable…

HD 133880 is one of the six hot magnetic stars known to produce coherent pulsed radio emission by the process of electron cyclotron maser emission (ECME). In this paper, we present observations of ECME from this star over a wide frequency…

Solar and Stellar Astrophysics · Physics 2020-10-21 Barnali Das , Poonam Chandra , Gregg A. Wade

HR 5907 (HD 142184) stands out among magnetic OB stars for its rapid rotation, exceptionally hard X-ray emission, and strong magnetic field. High-frequency (>5 GHz) radio emission from the star exhibits an approximately flat spectrum that…

Solar and Stellar Astrophysics · Physics 2025-01-22 Ayan Biswas , Barnali Das , James A. Barron , Gregg A. Wade , Gonzalo Holgado

We present new radio/millimeter measurements of the hot magnetic star HR5907 obtained with the VLA and ALMA interferometers. We find that HR5907 is the most radio luminous early type star in the cm-mm band among those presently known. Its…

Solar and Stellar Astrophysics · Physics 2018-02-14 P. Leto , C. Trigilio , L. M. Oskinova , R. Ignace , C. S. Buemi , G. Umana , A. Ingallinera , F. Leone , N. M. Phillips , C. Agliozzo , H. Todt , L. Cerrigone

The presence of non-thermal electrons and large scale magnetic fields in the intra-cluster medium (ICM) is known through the detection of mega-parsec (Mpc) scale diffuse radio synchrotron emission. Although a significant amount of progress…

High Energy Astrophysical Phenomena · Physics 2020-11-04 Ramij Raja , Majidul Rahaman , Abhirup Datta , Reinout J. van Weeren , Huib T. Intema , Surajit Paul

We conducted a survey of seven magnetic O and eleven B-type stars with masses above $8M_{\odot}$ using the Very Large Array in the 1cm, 3cm and 13cm bands. The survey resulted in a detection of two O and two B-type stars. While the detected…

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