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22nd of May 2019
ATNF Colloquium
Simulations of gyrosynchrotron microwave emission from ultracool dwarfs
Alexey Kuznetsov (Institute of Solar-Terrestrial Physics)
Abstract: Ultracool dwarfs (i.e., brown dwarfs and low-mass stars later than M7) represent a curious class of radio sources that are in many aspects more similar to planets than to stars. In particular, their quiescent emission in the microwave range seems to be an up-scaled version of the decimetric radiation of Jupiter, which is produced by high-energy electrons in the planetary radiation belts. In this talk, I present a few examples of observations and demonstrate how the numerical codes developed in application to solar flares can be used to reproduce the microwave emission of ultracool dwarfs and estimate the parameters of the emission sources. I discuss what we can (or cannot) infer from the observations, and what these results tell us about the magnetospheres of ultracool dwarfs. I also discuss possible applications of the same method to radio observations of stellar flares.

The image above shows the microwave spectrum of the L3.5 dwarf 2MASS J00361617+1821104 (recorded with VLA). The red and blue curves represent the simulated gyrosynchrotron spectra for two parameter sets.

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