Periodic Bursts of Coherent Radio Emission from an Ultracool Dwarf

By G. Hallinan, S. Bourke, C. Lane, A. Antonova, R. Zavala, Walter Brisken, R. Boyle, F. Vrba, J. G. Doyle, A. Golden. 2007

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We report the detection of periodic (p = 1.96 hr) bursts of extremely bright, 100% circularly polarized, coherent radio emission from the M9 dwarf TVLM 513-46546. Simultaneous photometric monitoring observations have established this periodicity to be the rotation period of the dwarf. These bursts, which were not present in previous observations of this target, confirm that ultracool dwarfs can generate persistent levels of broadband, coherent radio emission, associated with the presence of kG magnetic fields in a large-scale, stable configuration. Compact sources located at the magnetic polar regions produce highly beamed emission generated by the electron cyclotron maser instability, the same mechanism known to generate planetary coherent radio emission in our solar system. The narrow beams of radiation pass our line of sight as the dwarf rotates, producing the associated periodic bursts. The resulting radio light curves are analogous to the periodic light curves associated with pulsar radio emission highlighting TVLM 513-46546 as the prototype of a new class of transient radio source.

Subfields: Astronomy and Astrophysics, Computational Mechanics

View Paper: https://www.semanticscholar.org/paper/e32cdcd7adac0e51f4dbc15d64455ca7945a93c3

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Citations in the corpus

Science with a lunar low-frequency array: From the dark ages of the Universe to nearby exoplanets (2009, background): “es. Circular polarization is not aﬀected, but circularly polarized sources are extremely rare at higher frequencies, though cyclotron maser bursts have been observed from certain types of stars (e.g. Hallinan et al., 2007) and is being found in an increasing numberof active galactic nuclei(Gabuzda e”
Confirmation of the Electron Cyclotron Maser Instability as the Dominant Source of Radio Emission from Very Low Mass Stars and Brown Dwarfs (2008, background): “However, we note that, in the case of TVLM 513, multiple pulses were detected that were confined to a range of phase of rotation of the dwarf of width ∼ 0.35 (Hallinan et al. 2007).”
A real-time fast radio burst: polarization detection and multiwavelength follow-up (2014, background): “…radio emission coincident with optical flares (Osten & Bastian 2006, 2008); the brown dwarf TVLM 513−46546 and the Sun have also been observed to emit 100% circularly polarized bursts at GHz frequencies, both attributed to cyclotron maser emission (Hallinan et al. 2007; Melrose & Dulk 1982).”
Magnetospheric accretion on the T Tauri star BP Tauri (2008, background): “…at triggering strong nearly-axisymmetric low-order poloidal surface magnetic topologies (Donati et al. 2006a; Hallinan et al. 2006; Morin et al. 2007; Hallinan et al. 2007, Morin et al., 2008 in preparation) than their more massive partly-convective counterparts (e.g., Donati et al. 2003).”
Science with the Murchison Widefield Array (2012, background): “It has even been suggested that the observed “quiescent” emission from these sources may be the result of low-level, sustained electron cyclotron maser emission (e.g., Hallinan et al. 2007).”