High-angular resolution observations of methanol in the infrared dark cloud core G11.11-0.12P1

TL;DR

This study uses high-angular resolution interferometric observations to analyze the physical and chemical structure of a core in the infrared dark cloud G11.11-0.12, revealing methanol distribution, abundance variations, and evidence of outflows and interactions.

Contribution

It provides detailed spatial and chemical characterization of a star-forming core in an IRDC using combined interferometric and single-dish data, highlighting outflow activity.

Findings

Extended methanol emission with three maxima over 1 pc

Enhanced methanol abundance at the core's center (~3x10^-8)

Evidence of outflows and outflow-cloud interaction

Abstract

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.