22nd of May 2019 |
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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. |