Molecular line tracers of high-mass star forming regions

Zsofia Nagy, Floris Van der Tak, Volker Ossenkopf, Edwin Bergin, John Black, Alexandre Faure, Gary Fuller, Maryvonne Gerin, Javier Goicoechea, Christine Joblin, Jacques Le Bourlot, Franck Le Petit, Zoltan Makai, Rene Plume, Markus Roellig, Marco Spaans, Volker Tolls

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademic


High-mass stars influence their environment in different ways including feedback via their FUV radiation. The penetration of FUV photons into molecular clouds creates Photon Dominated Regions (PDRs) with different chemical layers where the mainly ionized medium changes into mainly molecular. Different chemical layers in PDRs are traced by different species observable at sub-mm and Far Infrared wavelengths. In this poster we present results from two molecular line surveys. One of them is the James Clerk Maxwell Telescope (JCMT) Spectral Legacy Survey (SLS) toward the luminous (>10^7 L_Sun), massive (~10^6 M_Sun), and distant (11.4 kpc) star-forming region W49A. The SLS images a 2x2 arcminute field toward W49A in the 330-373 GHz frequency range. The detected molecular lines reveal a complex chemistry and the importance of FUV-irradiation in the heating and chemistry of the region. The other line survey presented in the poster is part of the HEXOS (Herschel observations of EXtra-Ordinary Sources, PI: E. Bergin) key program using the Herschel Space Observatory and is toward the nearby (~420 pc) prototypical edge-on Orion Bar PDR and the dense molecular condensation Orion S. Reactive ions, such as CH+, SH+, and CO+, detected as a part of this line survey trace the warm (~500-1000 K) surface region of PDRs. Spectrally resolved HIFI and spectrally unresolved PACS spectra give constraints on the chemistry and excitation of reactive ions in these regions.
Original languageEnglish
Title of host publicationProtostars and Planets VI, Heidelberg, July 15-20, 2013. Poster #1B023
Publication statusPublished - Jul-2013

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