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Related papers: A Mini-survey of Ultracool Dwarfs at 4.9 GHz

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We present 325 MHz (90 cm wavelength) radio observations of ultracool dwarfs TVLM 513-46546 and 2MASS J0036+1821104 using the Very Large Array (VLA) in June 2007. Ultracool dwarfs are expected to be undetectable at radio frequencies, yet…

Solar and Stellar Astrophysics · Physics 2012-01-31 T. R. Jaeger , R. A. Osten , T. J. Lazio , N. Kassim , R. L. Mutel

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

We conducted a volume-limited survey at 4.9 GHz of 32 nearby ultracool dwarfs with spectral types covering the range M7 -- T8. A statistical analysis was performed on the combined data from the present survey and previous radio observations…

Solar and Stellar Astrophysics · Physics 2015-06-12 A. Antonova , G. Hallinan , J. G. Doyle , S. Yu , A. Kuznetsov , Y. Metodieva , A. Golden , K. L. Cruz

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

The well-studied M9 dwarf TVLM 513-46546 is a rapid rotator (P_rot ~ 2 hr) hosting a stable, dipolar magnetic field of ~3 kG surface strength. Here we report its detection with ALMA at 95 GHz at a mean flux density of $56 \pm 12$ uJy,…

Solar and Stellar Astrophysics · Physics 2015-12-11 P. K. G. Williams , S. L. Casewell , C. R. Stark , S. P. Littlefair , Ch. Helling , E. Berger

Radio activity has been observed in a large variety of stellar objects, including in the last few years, ultra-cool dwarfs. To explore the extent of long-term radio activity in ultra-cool dwarfs, we use data taken over an extended period of…

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

Radio detections of ultracool dwarfs provide insight into their magnetic fields and the dynamos that maintain them, especially at the very bottom of the main sequence, where other activity indicators dramatically weaken. Until recently,…

Solar and Stellar Astrophysics · Physics 2013-04-08 Peter K. G. Williams , Edo Berger , B. Ashley Zauderer

[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…

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 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

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 report the detection of radio emission from the unusually active L5e + T7 binary 2MASS J13153094-2649513AB made with the Australian Telescope Compact Array. Observations at 5.5 GHz reveal an unresolved source with a continuum flux of…

Solar and Stellar Astrophysics · Physics 2015-06-12 Adam J. Burgasser , Carl Melis , B. Ashley Zauderer , 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

We describe our second installment of the 4.75 GHz survey of ultracool dwarfs (UCDs) conducted with the Arecibo radio telescope, which has observed 27 such objects and resulted in the detection of sporadic flaring from the T6 dwarf, WISEPC…

Solar and Stellar Astrophysics · Physics 2016-10-26 Matthew Route , Alexander Wolszczan

We report the detection of periodic (p = 1.96 hours) bursts of extremely bright, 100% circularly polarized, coherent radio emission from the M9 dwarf TVLM 513-46546. Simultaneous photometric monitoring observations have established this…

Observations of radio emission in about 10 per cent of ultra-cool dwarfs (UCDs) indicate the presence of strong, persistent magnetic fields in these stars. These results are in contrast to early theoretical expectations on fully-convective…

Solar and Stellar Astrophysics · Physics 2018-11-26 Andrew Zic , Christene Lynch , Tara Murphy , David L. Kaplan , Poonam Chandra

We report the results of a volume-limited survey using the Australia Telescope Compact Array to search for transient and quiescent radio emission from 15 southern hemisphere ultracool dwarfs. We detect radio emission from 2MASSW…

Solar and Stellar Astrophysics · Physics 2016-01-11 C. Lynch , T. Murphy , V. Ravi , G. Hobbs , K. Lo , C. Ward

The Very Large Array was used to observe the ultracool, rapidly rotating M9 dwarf TVLM 513-46546 simultaneously at 4.88 GHz and 8.44 GHz. The radio emission was determined to be persistent, variable and periodic at both frequencies with a…

Astrophysics · Physics 2008-11-26 G. Hallinan , A. Antonova , J. G. Doyle , S. Bourke , W. F. Brisken , A. Golden

With the purpose to investigate the radio emission of new ultracool objects, we carried out a targeted search in the recently discovered system VHS J125601.92$-$125723.9 (hereafter VHS 1256$-$1257); this system is composed by an equal-mass…

Solar and Stellar Astrophysics · Physics 2018-02-21 J. C. Guirado , R. Azulay , B. Gauza , M. A. Pérez-Torres , R. Rebolo , J. B. Climent , M. R. Zapatero-Osorio

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…

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