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Rotating Radio Transients (RRATs) are neutron stars emitting sporadic radio pulses. The unique emission of RRATs has been proposed to resemble those of known pulsar types, such as extreme nulling pulsars or pulsars with giant pulses.…

High Energy Astrophysical Phenomena · Physics 2024-11-18 S. B. Zhang , X. Yang , J. J. Geng , Y. P. Yang , X. F. Wu

A fraction of very low mass stars and brown dwarfs are known to be radio active, in some cases producing periodic pulses. Extensive studies of two such objects have also revealed optical periodic variability and the nature of this…

Solar and Stellar Astrophysics · Physics 2015-06-17 Leon K. Harding , Gregg Hallinan , Richard P. Boyle , Aaron Golden , Navtej Singh , Brendan Sheehan , Robert T. Zavala , Ray F. Butler

J191213.72-441045.1 is a binary system composed of a white dwarf and an M-dwarf in a 4.03-hour orbit. It shows emission in radio, optical, and X-ray, all modulated at the white dwarf spin period of 5.3 min, as well as various orbital…

Aims. With the aim to reveal the effects of the magnetic field to the multi-band activity of dwarf stars, we search for associated radio emission for an extensive list of 14 915 brown dwarfs and 15 124 flaring stars. Methods. We utilised…

Solar and Stellar Astrophysics · Physics 2025-06-30 K. Perger , B. Seli , K. Vida

Recently detected coherent low-frequency radio emission from M dwarf systems shares phenomenological similarities with emission produced by magnetospheric processes from the gas giant planets of our Solar System. Such beamed…

We present radio observations of a comprehensive sample of 90 dwarf stars and brown dwarfs ranging from spectral type M5 to T8. We detect three radio active sources in addition to the six objects previously detected in quiescence and…

Astrophysics · Physics 2008-11-26 Edo Berger

We have observed 6 late-L and T dwarfs with the Karl G. Jansky Very Large Array (VLA) to investigate the presence of highly circularly polarized radio emission, associated with large-scale auroral currents. Previous surveys encompassing ~60…

Solar and Stellar Astrophysics · Physics 2016-02-17 Melodie M. Kao , Gregg Hallinan , J. Sebastian Pineda , Ivanna Escala , Adam Burgasser , Stephen Bourke , David Stevenson

We report the results of a radio monitoring program conducted at the Australia Telescope Compact Array to search for quiescent and flaring emission from seven nearby Southern late-type M and L dwarfs. Two late-type M dwarfs, the M7 V LHS…

Astrophysics · Physics 2009-11-10 Adam J. Burgasser , Mary E. Putman

The high-frequency radio sky is bursting with synchrotron transients from massive stellar explosions and accretion events, but the low-frequency radio sky has so far been quiet beyond the Galactic pulsar population and the long-term…

High Energy Astrophysical Phenomena · Physics 2025-03-12 N. Hurley-Walker , X. Zhang , A. Bahramian , S. J. McSweeney , T. N. O'Doherty , P. J. Hancock , J. S. Morgan , G. E. Anderson , G. H. Heald , T. J. Galvin

We have discovered that the brown dwarf WISEJ014656.66+423410.0 is a close binary (0.0875$\pm$0.0021 arcsec, 0.93$^{+0.12}_{-0.16}$ AU) from Keck laser guide star adaptive optics imaging. Our photometry for this system reveals that both…

Solar and Stellar Astrophysics · Physics 2015-06-23 Trent J. Dupuy , Michael C. Liu , S. K. Leggett

We present the results of a series of short radio observations of six ultracool dwarfs made using the upgraded VLA in S (2--4GHz) and C (4--7GHz) bands. LSR J1835+3259 exhibits a 100 percent right-hand circularly polarised burst which shows…

Solar and Stellar Astrophysics · Physics 2016-12-21 Y. T. Metodieva , A. A. Kuznetsov , A. E. Antonova , J. G. Doyle , G. Ramsay , K. Wu

Coherent radio bursts detected from M dwarfs have some analogy with solar radio bursts, but reach orders of magnitude higher luminosities. These events trace particle acceleration, powered by magnetic reconnection, shock fronts (such as…

Solar and Stellar Astrophysics · Physics 2019-02-13 Jackie Villadsen , Gregg Hallinan

We model the spectra of two brown dwarfs observed with the low resolution spectropolarimeter LRIS (Keck observatory) during several rotational phases in order to infer their magnetic properties. The spectra modeled include the intensity…

Solar and Stellar Astrophysics · Physics 2013-09-19 O. Kuzmychov , S. Berdyugina , D. Harrington , J. Kuhn

We aim to detect low-frequency radio emission from exoplanetary systems, which can provide insights into planetary magnetic fields, star-planet interactions, stellar activity, and exo-space weather. The HD 189733 system, hosting a…

[Abridged] We present the first simultaneous radio, X-ray, ultraviolet, and optical spectroscopic observations of the M8.5 dwarf TVLM513-46546, with a duration of 9 hours. These observations are part of a program to study the origin of…

In this paper we simulate the cyclic circularly-polarised pulses of the ultra-cool dwarf TVLM513-46546, observed with the VLA at 4.88 and 8.44 GHz on May 2006, by using a 3D model of the auroral radio emission from the stellar…

Solar and Stellar Astrophysics · Physics 2017-06-21 P. Leto , C. Trigilio , C. S. Buemi , G. Umana , A. Ingallinera , L. Cerrigone

Magnetized exoplanets can serve as the source of auroral radio emissions, allowing us to characterize the magnetospheric properties of these planets. Successful detections of auroral radio emissions from brown dwarfs, as well as from…

Earth and Planetary Astrophysics · Physics 2023-12-27 Yuta Shiohira , Yuka Fujii , Hajime Kita , Tomoki Kimura , Yuka Terada , Keitaro Takahashi

We present deep observations of the nearby T-type brown dwarf binary $\epsilon$ Indi Bab in radio with the Australia Telescope Compact Array and in X-rays with the Chandra X-ray Observatory. Despite long integration times, the binary…

Astrophysics · Physics 2009-11-11 M. Audard , A. Brown , K. R. Briggs , M. Guedel , A. Telleschi , J. E. Gizis

Pulsars radiate radio signals when they rotate. However, some old pulsars often stop radiating for some periods. The underlying mechanism remains unknown, while the magnetosphere during nulling phases is hard to probe due to the absence of…

High Energy Astrophysical Phenomena · Physics 2023-08-21 X. Chen , Y. Yan , J. L. Han , C. Wang , P. F. Wang , W. C. Jing , K. J. Lee , B. Zhang , R. X. Xu , T. Wang , Z. L. Yang , W. Q. Su , N. N. Cai , W. Y. Wang , G. J. Qiao , J. Xu , D. J. Zhou

The multiplicity properties of brown dwarfs are critical empirical constraints for formation theories, while multiples themselves provide unique opportunities to test evolutionary and atmospheric models and examine empirical trends. Studies…