Published in

Oxford University Press (OUP), Publications of Astronomical Society of Japan, 2019

DOI: 10.1093/pasj/psz102

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First clear detection of the CCS Zeeman splitting toward the pre-stellar core, Taurus Molecular Cloud 1

This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

Full text: Unavailable

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Data provided by SHERPA/RoMEO

Abstract

Abstract We report the first clear detection of the Zeeman splitting of a CCS emission line at 45 GHz toward the nearby pre-stellar dense filament, Taurus Molecular Cloud 1 (TMC-1). We observed HC$_3$N non-Zeeman lines simultaneously with the CCS line, and did not detect any significant splitting of the HC$_3$N lines. Thus, we conclude that our detection of CCS Zeeman splitting is robust. The derived line-of-sight magnetic field strength is about $117 ± 21 \, μ$G, which corresponds to a normalized mass-to-magnetic flux ratio of 2.2 if we adopt an inclination angle of 45$^∘$. Thus, we conclude that the TMC-1 filament is magnetically supercritical. Recent radiative transfer calculations of the CCS and HC$_3$N lines along the line of sight suggest that the filament is collapsing with a speed of $∼$0.6 km s$^{-1}$, which is comparable to three times the isothermal sound speed. This infall velocity appears to be consistent with the evolution of a gravitationally infalling core.

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