Quiescent Radio Emission from Southern Late-Type M Dwarfs and a Spectacular Radio Flare from the M8 Dwarf DENIS 1048–3956

@article{Burgasser2005QuiescentRE,
  title={Quiescent Radio Emission from Southern Late-Type M Dwarfs and a Spectacular Radio Flare from the M8 Dwarf DENIS 1048–3956},
  author={Adam J. Burgasser and Mary E. Putman},
  journal={The Astrophysical Journal},
  year={2005},
  volume={626},
  pages={486 - 497}
}
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 3003 and the M8 V DENIS 1048-3956, were detected in quiescent emission at 4.80 GHz. The observed emission is consistent with optically thin gyrosynchrotron emission from mildly relativistic (~1-10 keV) electrons with source densities ne ≲ 109 cm-3 in B ≳ 10 G… 

Figures and Tables from this paper

RADIO EMISSION AND ORBITAL MOTION FROM THE CLOSE-ENCOUNTER STAR–BROWN DWARF BINARY WISE J072003.20–084651.2

We report the detection of radio emission and orbital motion from the nearby star–brown dwarf binary WISE J072003.20–084651.2AB. Radio observations across the 4.5–6.5 GHz band with the Very Large

QUASI-QUIESCENT RADIO EMISSION FROM THE FIRST RADIO-EMITTING T DWARF

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

AURORAL RADIO EMISSION FROM LATE L AND T DWARFS: A NEW CONSTRAINT ON DYNAMO THEORY IN THE SUBSTELLAR REGIME

We have observed six 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

Radio Observations of a Large Sample of Late M, L, and T Dwarfs: The Distribution of Magnetic Field Strengths

I present radio observations of 90 dwarf stars and brown dwarfs of spectral type M5-T8. Three sources exhibit radio activity, in addition to the six objects previously detected in quiescence and

THE 5 GHz ARECIBO SEARCH FOR RADIO FLARES FROM ULTRACOOL DWARFS

We present the results of a 4.75 GHz survey of 33 brown dwarfs and one young exoplanetary system for flaring radio emission, conducted with the 305 m Arecibo radio telescope. The goal of this program

CONTEMPORANEOUS XMM-NEWTON INVESTIGATION OF A GIANT X-RAY FLARE AND QUIESCENT STATE FROM A COOL M-CLASS DWARF IN THE LOCAL CAVITY

We report the serendipitous detection of a giant X-ray flare from the source 2XMM J043527.2−144301 during an XMM-Newton observation of the high latitude molecular cloud MBM20. The source has not been

Simultaneous Multiwavelength Observations of Magnetic Activity in Ultracool Dwarfs. I. The Complex Behavior of the M8.5 Dwarf TVLM 513–46546

We present the first simultaneous radio, X-ray, ultraviolet, and optical spectroscopic observations of the M8.5 dwarf TVLM 513–46546, with a duration of 9 hr. These observations are part of a program

PERIODIC RADIO AND Hα EMISSION FROM THE L DWARF BINARY 2MASSW J0746425+200032: EXPLORING THE MAGNETIC FIELD TOPOLOGY AND RADIUS OF AN L DWARF

We present an 8.5 hr simultaneous radio, X-ray, UV, and optical observation of the L dwarf binary 2MASSW J0746425+200032. We detect strong radio emission, dominated by short-duration periodic pulses

A Chandra X-ray detection of the L dwarf binary Kelu-1 - Simultaneous Chandra and Very Large Array observations

Context. Magnetic activity in ultracool dwarfs, as measured in X-rays and Hα, shows a steep decline after spectral type M7-M8. So far, no L dwarf has been detected in X-rays. In contrast, L dwarfs

Radio detections of southern ultracool dwarfs

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
...

References

SHOWING 1-10 OF 106 REFERENCES

Flaring up All Over—Radio Activity in Rapidly Rotating Late M and L Dwarfs

We present Very Large Array observations of 12 late M and L dwarfs in the solar neighborhood. The observed sources were chosen to cover a wide range of physical characteristics—spectral type,

Microwave emission from the coronae of late-type dwarf stars

We present VLA microwave observatios of 14 late-type dwarf and subgiant stars ad binary systems. In this extensive set of observations we detected four sources at 6 cm (chi/sup 1/ Ori, UV Cet, YY

Discovery of radio emission from the brown dwarf LP944-20

It is shown that LP944-20 has an unusually weak magnetic field in comparison to active M-dwarf stars, which might explain the previous null optical and X-rays results, as well as the strength of the radio emissions compared to those at X-ray wavelengths.

New Neighbors from 2MASS: Activity and Kinematics at the Bottom of the Main Sequence

We have combined 2MASS and POSS II data in a search for nearby ultracool (later than M6.5) dwarfs with Ks < 12. Spectroscopic follow-up observations identify 53 M7–M9.5 dwarfs and seven L dwarfs. The

Deep infrared imaging and spectroscopy of the nearby late M- dwarf DENIS-P J104814-395606

We obtained deep H- and K-band images of DENIS-P J104814–395606 using SofI and the speckle camera SHARP-I at the ESO-3.5m-NTT as well as QUIRC at the Mauna Kea 2.2m telescope between December 2000

A Search for Variability in the Active T Dwarf 2MASS 1237+6526

We present spectroscopic and imaging observations of the active T dwarf 2MASS 1237+6526, intended to investigate the emission mechanism of this cool brown dwarf. The Hα emission line, first detected

Activity in Very Cool Stars: Magnetic Dissipation in Late M and L Dwarf Atmospheres

Recent observations show that chromospheric Hα activity in late M and L dwarfs is much lower than in the earlier M types. This is particularly surprising given that the late M and L dwarfs are

Accretion and Outflow in the Substellar Domain: Magellan Spectroscopy of LS-RCrA 1

We present low-, medium-, and high-resolution optical spectra, obtained with the Magellan Baade 6.5 m telescope, of LS-RCrA 1, a late-type object identified recently by Fernández & Comerón in the R

A Flaring L5 Dwarf: The Nature of Hα Emission in Very Low Mass (Sub)Stellar Objects

Time series spectrophotometry of the L5 dwarf 2MASS J01443536-0716142 showed strong Hα emission that declined by nearly 75% in four consecutive exposures. The line was not detected in emission on a

Microwave plasma emission of a flare on AD Leo

An intense radio flare on the dMe star AD Leo, observed with the Eelsberg radio telescope and spectrally resolved in a band of 480 MHz centred at 4.85 GHz is analysed. A lower limit of the brightness
...