English
Related papers

Related papers: The Second Arecibo Search for 5 GHz Radio Flares f…

200 papers

Empirical trends in stellar X-ray and radio luminosities suggest that low mass ultracool dwarfs (UCDs) should not produce significant radio emission. Defying these expectations, strong non-thermal emission has been observed in a few UCDs in…

Solar and Stellar Astrophysics · Physics 2021-07-16 A. G. Hughes , A. C. Boley , R. A. Osten , J. A. White , M. Leacock

[Abridged] As part of our on-going investigation into the magnetic field properties of ultracool dwarfs, we present simultaneous radio, X-ray, and H-alpha observations of three M9.5-L2.5 dwarfs (BRI0021-0214, LSR060230.4+391059, and…

Solar and Stellar Astrophysics · Physics 2014-11-20 E. Berger , G. Basri , T. A. Fleming , M. S. Giampapa , J. E. Gizis , J. Liebert , E. L. Martin , N. Phan-Bao , R. E. Rutledge

Brown dwarfs display Jupiter-like auroral phenomena such as magnetospheric H$\alpha$ emission and coherent radio emission. Coherent radio emission is a probe of magnetospheric acceleration mechanisms and provides a direct measurement of the…

Solar and Stellar Astrophysics · Physics 2023-07-12 H. K. Vedantham , Trent J. Dupuy , E. L. Evans , A. Sanghi , J. R. Callingham , T. W. Shimwell , W. M. J. Best , M. C. Liu , P. Zarka

We detect radio emission in an additional two epochs of the ultracool dwarf binary LP 349- 25, finding that the observed emission is broadband and steady on timescales between 10s and 10.7 hours, as well as on timescales of 0.6 and 1.6…

Solar and Stellar Astrophysics · Physics 2009-07-24 R. A. Osten , N. Phan-Bao , S. L. Hawley , I. Neill Reid , R. Ojha

We report on radio observations of the M8.5 dwarf LSR J1835+3259 and the L3.5 dwarf 2MASS J00361617+1821104, which provide the strongest evidence to date that the electron cyclotron maser instability is the dominant mechanism producing…

Astrophysics · Physics 2009-11-13 G. Hallinan , A. Antonova , J. G. Doyle , S. Bourke , C. Lane , A. Golden

Well-characterized binary systems will provide valuable opportunities to study the conditions that are necessary for the onset of both auroral and non-auroral magnetospheric radio emission in the ultracool dwarf regime. We present new…

Solar and Stellar Astrophysics · Physics 2022-06-22 Melodie M. Kao , J. Sebastian Pineda

Photometric variability attributed to cloud phenomena is common in L/T transition brown dwarfs. Recent studies show that such variability may also trace aurorae, suggesting that localized magnetic heating may contribute to observed brown…

Solar and Stellar Astrophysics · Physics 2020-11-11 Tyler Richey-Yowell , Melodie M. Kao , J. Sebastian Pineda , Evgenya L. Shkolnik , Gregg Hallinan

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 present multi-epoch radio and optical observations of the M7 dwarf 2MASS J13142039+1320011. We detect a ~1 mJy source at 1.43, 4.86, 8.46 and 22.5 GHz, making it the most luminous radio emission over the widest frequency range detected…

Solar and Stellar Astrophysics · Physics 2015-05-28 M. McLean , E. Berger , J. Irwin , J. Forbrich , A. Reiners

A number of radio-loud ultra cool dwarf stars (UCD) exhibit both continuous broadband and highly polarized pulsed radio emission. In order to determine the nature of the emission and the physical characteristics in the source region, we…

Solar and Stellar Astrophysics · Physics 2015-06-19 C. Lynch , R. L. Mutel , M. Gudel

The substellar triple system VHS J125601.92$-$125723.9 is composed by an equal-mass M7.5 brown dwarf binary and a L7 low-mass substellar object. In this work, we aim to identify the origin of the radio emission occurring in the central…

At the sub-stellar boundary, signatures of magnetic fields begin to manifest at radio wavelengths, analogous to the auroral emission of the magnetised solar system planets. This emission provides a singular avenue for measuring magnetic…

Earth and Planetary Astrophysics · Physics 2024-12-04 Robert D Kavanagh , Harish K Vedantham , Kovi Rose , Sanne Bloot

We report the white light flare rates for 10 ultracool dwarfs (UCDs) using \textit{Kepler K2} short cadence data. Among our sample stars, two have spectral type M6, three are M7, three are M8 and two are L0. Most of our targets are old low…

Solar and Stellar Astrophysics · Physics 2018-06-06 Rishi R. Paudel , John E. Gizis , D. J. Mullan , Sarah J. Schmidt , Adam J. Burgasser , Peter K. G. Williams , Edo Berger

Surveys have shown that up to one tenth of all ultracool dwarfs (UCDs) are appreciable radio emitters, with their emission attributed to a combination of gyrosynchrotron radiation and the electron cyclotron maser instability (ECMI). 2M…

Solar and Stellar Astrophysics · Physics 2020-07-03 Qicheng Zhang , Gregg Hallinan , Walter Brisken , Stephen Bourke , Aaron Golden

We present the serendipitous discovery of 8 distant ($>$ 50 pc) late M dwarfs with plausible associated radio emission at 144 MHz. The M dwarf nature of our sources has been confirmed with optical spectroscopy performed using HET/LRS2 and…

We present Very Large Array observations of twelve late M and L dwarfs in the Solar neighborhood. The observed sources were chosen to cover a wide range of physical characteristics - spectral type, rotation, age, binarity, and X-ray and…

Astrophysics · Physics 2009-11-07 E. Berger

[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…

Magnetospheric processes seen in gas-giants such as aurorae and circularly-polarized cyclotron maser radio emission have been detected from some brown dwarfs. However, previous radio observations targeted known brown dwarfs discovered via…

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

We present the detection of rotationally modulated, circularly polarized radio emission from the T8 brown dwarf WISE J062309.94-045624.6 between 0.9 and 2.0 GHz. We detected this high proper motion ultracool dwarf with the Australian SKA…