Comparative analysis of two formation scenarios of bursty radio emission from ultracool dwarfs

Abstract

Recently, a number of ultracool dwarfs have been found to produce periodic radio bursts with high brightness temperature and polarization degree; the emission properties are similar to the auroral radio emissions of the magnetized planets of the Solar System. We simulate the dynamic spectra of radio emission from ultracool dwarfs. The emission is assumed to be generated due to the electron-cyclotron maser instability. We consider two source models: the emission caused by interaction with a satellite and the emission from a narrow sector of active longitudes; the stellar magnetic field is modeled by a tilted dipole. We have found that for the dwarf TVLM 513-46546, the model of the satellite-induced emission is inconsistent with the observations. On the other hand, the model of emission from an active sector is able to reproduce qualitatively the main features of the radio light curves of this dwarf; the magnetic dipole seems to be highly tilted (by about 60 degrees) with respect to the rotation axis.

Accepted for publication in ApJ

References in corpus (17)

• Large-scale magnetic topologies of late M dwarfs
• Simulations of dynamo action in fully convective stars
• The First Direct Measurements of Magnetic Fields on Very Low-Mass Stars
• Confirmation of the Electron Cyclotron Maser Instability as the Dominant Source of Radio Emission from Very Low Mass Stars and Brown Dwarfs
• Magnetic field generation in fully convective rotating spheres
• Radio Observations of a Large Sample of Late-M, L, and T Dwarfs: The Distribution of Magentic Field Strengths
• Periodic Bursts of Coherent Radio Emission from an Ultracool Dwarf
• Rotational Modulation of the Radio Emission from the M9 Dwarf TVLM 513-46546: Broadband Coherent Emission at the Substellar Boundary?
• Properties of Saturn Kilometric Radiation measured within its source region
• Simultaneous Multi-Wavelength Observations of Magnetic Activity in Ultracool Dwarfs. II. Mixed Trends in VB10 and LSR1835+32 and the Possible Role of Rotation
• Simultaneous Multi-Wavelength Observations of Magnetic Activity in Ultracool Dwarfs. I. The Complex Behavior of the M8.5 Dwarf TVLM513-46546
• Sporadic Long-term Variability in Radio Activity from a Brown Dwarf
• Discovery of Radio Emission from the Tight M8 Binary: LP 349-25
• A Mini-survey of Ultracool Dwarfs at 4.9 GHz
• Steady and Transient Radio Emission from Ultracool Dwarfs
• The magnetosphere of the ultracool dwarf DENIS 1048-3956
• Kinetic Simulation of the Electron-Cyclotron Maser Instability: Relaxation of Electron Horseshoe Distributions

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