Investigating the complex velocity structures within dense molecular cloud cores with GBT-Argus

Che Yu Chen, Shaye Storm, Zhi Yun Li, Lee G. Mundy, David Frayer, Jialu Li, Sarah Church, Rachel Friesen, Andrew I. Harris, Leslie W. Looney, Stella Offner, Eve C. Ostriker, Jaime E. Pineda, John Tobin, Hope H.H. Chen

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4 Scopus citations

Abstract

We present the first results of high-spectral resolution (0.023 km s−1) N2H+ observations of dense gas dynamics at core scales (∼0.01 pc) using the recently commissioned Argus instrument on the Green Bank Telescope (GBT). While the fitted linear velocity gradients across the cores measured in our targets nicely agree with the well-known power-law correlation between the specific angular momentum and core size, it is unclear if the observed gradients represent core-scale rotation. In addition, our Argus data reveal detailed and intriguing gas structures in position–velocity (PV) space for all five targets studied in this project, which could suggest that the velocity gradients previously observed in many dense cores actually originate from large-scale turbulence or convergent flow compression instead of rigid-body rotation. We also note that there are targets in this study with their star-forming discs nearly perpendicular to the local velocity gradients, which, assuming the velocity gradient represents the direction of rotation, is opposite to what is described by the classical theory of star formation. This provides important insight on the transport of angular momentum within star-forming cores, which is a critical topic on studying protostellar disc formation.

Original languageEnglish (US)
Pages (from-to)527-539
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume490
Issue number1
DOIs
StatePublished - Jan 1 2019

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • ISM: kinematics and dynamics
  • ISM: molecules
  • Radio lines: ISM
  • Stars: formation
  • Stars: protostars

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    Chen, C. Y., Storm, S., Li, Z. Y., Mundy, L. G., Frayer, D., Li, J., Church, S., Friesen, R., Harris, A. I., Looney, L. W., Offner, S., Ostriker, E. C., Pineda, J. E., Tobin, J., & Chen, H. H. H. (2019). Investigating the complex velocity structures within dense molecular cloud cores with GBT-Argus. Monthly Notices of the Royal Astronomical Society, 490(1), 527-539. https://doi.org/10.1093/mnras/stz2633