Volume 550, February 2013
|Number of page(s)||9|
|Section||Interstellar and circumstellar matter|
|Published online||23 January 2013|
Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/Service
d’Astrophysique, CEA Saclay,
Orme des Merisiers,
e-mail: firstname.lastname@example.org; email@example.com
2 School of Physics & Astronomy, Cardiff University, Cardiff, CF29, 3AA, UK
3 Jeremiah Horrocks Institute, University of Central Lancashire, PR1 2HE, UK
4 Institut d’Astrophysique Spatiale, UMR 8617, CNRS/Université Paris-Sud 11, 91405 Orsay, France
5 Université de Bordeaux, Laboratoire d’Astrophysique de Bordeaux, CNRS/INSU, UMR 5804, BP 89, 33271 Floirac Cedex, France
6 INAF – IAPS, via Fosso del Cavaliere 100, 00133 Roma, Italy
7 National Research Council of Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria BC, V9E 2E7, Canada
8 Department of Physics and Astronomy, University of Victoria, PO Box 355, STN CSC, Victoria BC, V8W 3P6, Canada
9 Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON, M5S 3H8, Canada
10 Space Science and Technology Department, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, UK
11 Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
Accepted: 19 November 2012
We present first results from the Herschel Gould Belt survey for the B211/L1495 region in the Taurus molecular cloud. Thanks to their high sensitivity and dynamic range, the Herschel images reveal the structure of the dense, star-forming filament B211 with unprecedented detail, along with the presence of striations perpendicular to the filament and generally oriented along the magnetic field direction as traced by optical polarization vectors. Based on the column density and dust temperature maps derived from the Herschel data, we find that the radial density profile of the B211 filament approaches power-law behavior, ρ ∝ r−2.0± 0.4, at large radii and that the temperature profile exhibits a marked drop at small radii. The observed density and temperature profiles of the B211 filament are in good agreement with a theoretical model of a cylindrical filament undergoing gravitational contraction with a polytropic equation of state: P ∝ ργ and T ∝ ργ−1, with γ = 0.97 ± 0.01 < 1 (i.e., not strictly isothermal). The morphology of the column density map, where some of the perpendicular striations are apparently connected to the B211 filament, further suggests that the material may be accreting along the striations onto the main filament. The typical velocities expected for the infalling material in this picture are ~0.5–1 km s-1, which are consistent with the existing kinematical constraints from previous CO observations.
Key words: stars: formation / ISM: individual objects: B211 / ISM: clouds / ISM: structure / evolution / submillimeter: ISM
Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Figures 1, 7, and Appendices are available in electronic form at http://www.aanda.org
© ESO, 2013
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