High-angular resolution observations of methanol in the infrared dark
  cloud core G11.11-0.12P1
  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 at few arcsecond resolution to determine its physical and chemical
structure. The data consist of continuum and line observations covering the
C34S 2-1 line and the methanol 2_k-1_k v_t=0 lines at 3mm and the methanol
5_k-4_k v_t =0 lines at 1mm. Our observations show extended emission in the
continuum at 1 and 3 mm. The methanol 2_k-1_k v_t=0 emission presents three
maxima extending over 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 enhanced methanol fractional abundance
(~3x10^-8) at the central peak with respect to the other two peaks, where it
decreases by about an order of magnitude (~4-6x10^-9). Evidence of extended 4.5
microns emission, "wings" in the CH3OH 2_k-1_k spectra, and CH3OH abundance
enhancement point to the presence of an outflow in the East-West direction. In
addition, we find a gradient of ~4 km/s in the same direction, which we
interpret as being produced by an outflow(s)-cloud interaction.
