The Green Bank Ammonia Survey: Dense Cores under Pressure in Orion A

Helen Kirk, Rachel K. Friesen, Jaime E. Pineda, Erik Rosolowsky, Stella S.R. Offner, Christopher D. Matzner, Philip C. Myers, James Di Francesco, Paola Caselli, Felipe O. Alves, Ana Chacón-Tanarro, How Huan Chen, Michael Chun Yuan Chen, Jared Keown, Anna Punanova, Young Min Seo, Yancy Shirley, Adam Ginsburg, Christine Hall, Ayushi SinghHéctor G. Arce, Alyssa A. Goodman, Peter Martin, Elena Redaelli

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


We use data on gas temperature and velocity dispersion from the Green Bank Ammonia Survey and core masses and sizes from the James Clerk Maxwell Telescope Gould Belt Survey to estimate the virial states of dense cores within the Orion A molecular cloud. Surprisingly, we find that almost none of the dense cores are sufficiently massive to be bound when considering only the balance between self-gravity and the thermal and non-thermal motions present in the dense gas. Including the additional pressure binding imposed by the weight of the ambient molecular cloud material and additional smaller pressure terms, however, suggests that most of the dense cores are pressure-confined.

Original languageEnglish (US)
Article number144
JournalAstrophysical Journal
Issue number2
StatePublished - Sep 10 2017


  • ISM: kinematics and dynamics
  • radio lines: ISM
  • stars: formation
  • submillimeter: ISM Supporting material: machine-readable table

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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  • Virial analysis of the dense cores in Orion A

    Kirk, H. (Creator), Friesen, R. K. (Creator), Pineda, J. E. (Creator), Rosolowsky, E. (Creator), Offner, S. S. R. (Contributor), Matzner, C. D. (Creator), Myers, P. C. (Creator), Di Francesco, J. (Creator), Caselli, P. (Creator), Alves, F. O. (Creator), Chacón-Tanarro, A. (Contributor), Chen, H. (Creator), Chen, M. C. (Creator), Keown, J. (Creator), Punanova, A. (Creator), Seo, Y. M. (Creator), Shirley, Y. L. (Creator), Ginsburg, A. (Creator), Hall, C. (Creator), Singh, A. (Creator), Arce, H. G. (Creator), Goodman, A. A. (Creator), Martin, P. (Creator), Redaelli, E. (Creator), Pineda, J. E. (Creator), Caselli, P. (Creator) & Ginsburg, A. (Creator), Centre de Donnees Strasbourg (CDS), 2018


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