------------------------------------------------------------------------ ms.tex ApJLett, January 2010 Message-ID: MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="8323328-610749498-1265150664=:4284" X-MailScanner-Information: Please contact the postmaster@aoc.nrao.edu for more information X-MailScanner: Found to be clean X-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=-200, required 5, autolearn=disabled, NRAO_HEADER_PRESENT -100.00, USER_IN_WHITELIST -100.00) X-MailScanner-From: lsjouwer@nrao.edu X-Spam-Status: No This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323328-610749498-1265150664=:4284 Content-Type: TEXT/PLAIN; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8BIT \documentclass[iop,apjl]{emulateapj}\usepackage{apjfonts} \begin{document} \title{Expanded VLA Detection of 36.2 GHz Class\,I Methanol Masers in Sagittarius\,A} \author{Lor\'ant~O.~Sjouwerman$^1$, Ylva~M.~Pihlstr\"om$^{2\footnote{\rm Also an Adjunct Astronomer at the National Radio Astronomy Observatory}}$, Vincent~L.~Fish$^3$} \affil{$^1$ National Radio Astronomy Observatory, P.O.~Box O, Socorro, NM 87801} \affil{$^2$ Department of Physics and Astronomy, University of New Mexico, 800 Yale Boulevard NE, Albuquerque NM 87131} \affil{$^3$ Massachusetts Institute of Technology, Haystack Observatory, Route 40, Westford, MA 01886} \begin{abstract} We report on the interferometric detection of 36.2 GHz Class\,I methanol emission with the new 27--40 GHz Ka band receivers available on the Expanded Very Large Array (EVLA). The brightness temperatures of the interferometric 36 GHz detections unambiguously indicate for the first time that the emission is maser emission. The 36 GHz methanol masers are not co-spatial with 1720 MHz OH masers, indicating that the two species trace different shocks. The 36 GHz and 44 GHz methanol masers, which both are collisionally pumped, do not necessarily co-exist and may trace different methanol gas. The methanol masers seem correlated with NH$_3$(3,3) density peaks. We favor an explanation in which the 36 GHz Class\,I methanol masers outline regions of cloud-cloud collisions, perhaps just before the onset of the formation of individual massive stars. The transition of the Very Large Array (VLA) to the EVLA is well under way, and these detections demonstrate the bright future of this completely renewed instrument. \end{abstract} \end{document} Regards, Loránt Sjouwerman - Scientific Services - lsjouwerman@nrao.edu -------------------------------------------------------------- c/o NRAO Array Operations Center Phone: +1-575-835-7332 P.O. Box 0 (1003 Lopezville Rd) Switch: +1-575-835-7000 Socorro NM 87801 Fax: +1-575-835-7027 --8323328-610749498-1265150664=:4284--