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dc.contributor.authorWilliams, P. K. G.
dc.contributor.authorCasewell, Sarah L.
dc.contributor.authorStark, Craig Ronald
dc.contributor.authorLittlefair, S. P.
dc.contributor.authorHelling, Christiane
dc.contributor.authorBerger, E.
dc.identifier.citationWilliams , P K G , Casewell , S L , Stark , C R , Littlefair , S P , Helling , C & Berger , E 2015 , ' The first millimeter detection of a non-accreting ultracool dwarf ' , Astrophysical Journal , vol. 815 , no. 1 .
dc.identifier.otherPURE: 240205472
dc.identifier.otherPURE UUID: a520ca6b-9a67-4e90-93b2-3714a4f531de
dc.identifier.otherScopus: 84951290077
dc.identifier.otherWOS: 000367105000064
dc.descriptionWe acknowledge support for this work from the National Science Foundation through Grant AST-1008361. Ch.H. acknowledges support from the European Community under the FP7 by the ERC starting grant 257431.en
dc.description.abstractThe well-studied M9 dwarf TVLM 513–46546 is a rapid rotator (Prot ∼ 2 hr) hosting a stable, dipolar magnetic field of ∼3 kG surface strength. Here we report its detection with ALMA at 95 GHz at a mean flux density of 56 ± 12 μJy, making it the first ultracool dwarf detected in the millimeter band, excluding young, disk-bearing objects. We also report flux density measurements from unpublished archival VLA data and new optical monitoring data from the Liverpool Telescope. The ALMA data are consistent with a power-law radio spectrum that extends continuously between centimeter and millimeter wavelengths. We argue that the emission is due to the synchrotron process, excluding thermal, free–free, and electron cyclotron maser emission as possible sources. During the interval of the ALMA observation that phases with the maximum of the object’s optical variability, the flux density is higher at a ∼1.8σ significance level. These early results show how ALMA opens a new window for studying the magnetic activity of ultracool dwarfs, particularly shedding light on the particle acceleration mechanism operating in their immediate surroundings.
dc.relation.ispartofAstrophysical Journalen
dc.rights© 2015. The American Astronomical Society. All rights reserved. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at:
dc.subjectBrown dwarfsen
dc.subjectRadio continuum : starsen
dc.subjectStars: individual (TVLM 513-46546)en
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleThe first millimeter detection of a non-accreting ultracool dwarfen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews.School of Physics and Astronomyen
dc.description.statusPeer revieweden

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