Related papers: Radio emission in a nearby ultracool dwarf binary:…
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 was to detect and characterize the…
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…
BL and UV Ceti are a nearby (2.7 pc) binary system with similar masses, spectral types, and rapid rotation rates, but very different magnetic activity. UV Ceti's much stronger large-scale magnetic field may cause this difference,…
The radio-quiet quasar SDSS J1536+0441A shows two broad-line emission systems, recently interpreted as a binary black hole (BBH) system with a subparsec separation; as a double-peaked emitter; or as both types of systems. The NRAO VLBA was…
This paper reports Giant Metrewave Radio Telescope (GMRT) observations of the binary system HD 41004 that are among the deepest images ever obtained at 150~MHz and 400 MHz in the search for radio emission from exoplanets. The HD 41004…
V1298 Tau is a very young and magnetically active star which hosts a benchmark multi-planetary system to study planet formation and evolutionary history at the earliest stages. We selected V1298 Tau for a first targeted follow-up at radio…
We present multi-epoch astrometric observations of the M9 ultra-cool dwarf TVLM513-46546 that is placed at the brown dwarf boundary. The new observations have been performed with the European VLBI Network (EVN) at 6cm band. The target has…
High-mass binary systems involve extreme environments that produce non-thermal emission from radio to gamma rays. Only three types of these systems are known to emit persistent gamma-ray emission: colliding-wind binaries, high-mass X-ray…
We report on an unusual radio source J180526-292953, initially identified as a steep spectrum, polarized point source toward the Galactic bulge and found to coincide with the nearby K dwarf HD317101A. We conducted a multi-wavelength radio…
Aims: We investigate the photometric properties of the M7.5 equal-mass binary VHS J1256-1257AB, which, combined with the late-L dwarf VHS J1256-1257 b, forms one of the few young triple systems of ultra-cool dwarfs currently known. Methods:…
We report the discovery of very-high-energy (VHE) gamma-ray emission of the binary system PSR B1259-63/SS 2883 of a radio pulsar orbiting a massive, luminous Be star in a highly eccentric orbit. The observations around the 2004 periastron…
We discuss the interpretation of transient, unpulsed radio emission detected from the unique pulsar/Be-star binary system PSR B1259-63. Extensive monitoring of the 1994 and 1997 periastron passages has shown that the source flares over a…
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…
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,…
Using the low-resolution mode of the Space Telescope Imaging Spectrograph (STIS) aboard the \emph{Hubble Space Telescope} (HST), we have obtained spatially resolved spectra of 20 ultracool dwarfs. 18 of them belong to 9 known very low-mass…
We present new Very Large Array observations at five frequencies, from 1.4 to 22GHz, of the extremely low-metallicity blue compact dwarf SBS0335-052. The radio spectrum shows considerable absorption at 1.49GHz, and a composite…
We present multi-epoch simultaneous radio, optical, H{\alpha}, UV, and X-ray observations of the active, young, low-mass binary NLTT 33370 AB (blended spectral type M7e). This system is remarkable for its extreme levels of magnetic…
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…
An interesting question about ultracool dwarfs recently raised in the literature is whether their emission is purely internally driven or partially powered by external processes similar to planetary aurora known from the solar system. In…
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…