Max-Planck-Institut für Radioastronomie,
Auf dem Hügel 69,
e-mail: email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org
2 California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125, USA
Received: 14 December 2010
Accepted: 7 March 2011
Recent studies suggest that infrared dark clouds (IRDCs) have the potential of harboring the earliest stages of massive star formation and indeed evidence for this is found toward distinct regions within them. We present a study with the Plateau de Bure Interferometer of a core in the archetypal filamentary IRDC G11.11-0.12 of a few arcsecond resolution to determine its physical and chemical structures. The data consist of continuum and line observations covering the C34S 2 → 1 line and the methanol 2k → 1k vt = 0 lines at 3 mm and the methanol 5k → 4k vt = 0 lines at 1 mm. Our observations show extended emission in the continuum at 1 and 3 mm. The methanol 2k → 1kvt = 0 emission has three maxima extending over a 1 pc scale (when merged with single-dish short-spacing observations); one of the maxima is spatially coincident with the continuum emission. The fitting results show an enhanced methanol fractional abundance (~3 × 10-8) at the central peak with respect to the other two peaks, where it decreases by about an order of magnitude (~4−6 × 10-9). Evidence of extended 4.5 μm emission, “wings” in the CH3OH 2k → 1k spectra, and CH3OH abundance enhancements point to the presence of an outflow in the east-west direction. In addition, we find a gradient of ~4 km s-1 in the same direction, which we interpret as being produced by an outflow(s)-cloud interaction.
Key words: ISM: abundances / ISM: individual objects: G11.11-0.12P1 / ISM: molecules / techniques: interferometric / stars: formation
Based on observations carried out with the IRAM Plateau de Bure Interferometer and the IRAM 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).
Fits images associated with the 1 mm and 3 mm continuum maps of Fig. 1 and the integrated intensity maps of Figs. 3−5, and 9 can be queried from the CDS via anonymous ftp to cdsarc.u-strasbg.fr (220.127.116.11) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/529/A161
© ESO, 2011