Prestellar core modeling in the presence of a filament - The dense heart of L1689B

Abstract

Short version: We apply a new synergetic radiative transfer method: the derived 1D density profiles are both consistent with a cut through the Herschel PACS/SPIRE and JCMT SCUBA-2 continuum maps of L1689B and with a derived local interstellar radiation field. Choosing an appropriate cut along the filament major axis, we minimize the impact of the filament emission on the modeling. For the bulk of the core (5000-20000 au) an isothermal sphere model with a temperature of around 10 K provides the best fits. We show that the power law index of the density profile, as well as the constant temperature can be derived directly from the radial surface brightness profiles. For the inner region (< 5000 au), we find a range of densities and temperatures that are consistent with the surface brightness profiles and the local interstellar radiation field. Based on our core models, we find that pixel-by-pixel single temperature spectral energy distribution fits are incapable of determining dense core properties. We conclude that, to derive physical core properties, it is important to avoid an azimuthal average of core and filament. Correspondingly, derived core masses are too high since they include some mass of the filament, and might introduce errors when determining core mass functions. The forward radiative transfer methods also avoids the loss of information owing to smearing of all maps to the coarsest spatial resolution. We find the central core region to be colder and denser than estimated in recent inverse radiative transfer modeling, possibly indicating the start of star formation in L1689B.

arXiv comment13 pages, 21 figures, accepted for publication in A&A

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• Parameterizing the interstellar dust temperature
• JCMT POL-2 and BISTRO Survey observations of magnetic fields in the L1689 molecular cloud
• Oxygen fractionation in dense molecular clouds
• Gas and dust temperature in pre-stellar cores revisited: New limits on cosmic-ray ionization rate
• Synthetic observations of star formation and the interstellar medium
• Detection of Complex Organic Molecules in Young Starless Core L1521E
• AVIATOR: Morphological object reconstruction in 3D. An application to dense cores
• Dust properties of the cometary globule Barnard 207 (LDN 1489)
• The 15273 Å diffuse interstellar band in the dark cloud Barnard 68
• Constraining the Dust Opacity Law in Three Small and Isolated Molecular Clouds
• Constraining Spatial Densities of Early Ice Formation in Small Dense Molecular Cores from Extinction Maps
• Mass estimates for very cold (< 8 K) gas in molecular cloud cores
• Cosmic-ray induced sputtering of interstellar formaldehyde ices
• The JCMT BISTRO Survey: The magnetised evolution of star-forming cores in the Ophiuchus Molecular Cloud interpreted using Histograms of Relative Orientation