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

Abstract

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.

Authors:
;  [1];  [2]; ; ; ; ;  [3];  [4];  [5]; ;  [6]; ;  [7]; ;  [8];  [9];  [10];  [11];  [12] more »; « less
  1. NRC Herzberg Astronomy and Astrophysics, 5071 West Saanich Rd, Victoria, BC, V9E 2E7 (Canada)
  2. Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George St., Toronto, Ontario M5S 3H4 (Canada)
  3. Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748, Garching (Germany)
  4. Department of Physics, University of Alberta, Edmonton, AB (Canada)
  5. Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
  6. Department of Astronomy and Astrophysics, University of Toronto, 50 St. George St., Toronto, Ontario, M5S 3H4 (Canada)
  7. Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)
  8. Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Rd., Victoria, BC, V8P 5C2 (Canada)
  9. Jet Propulsion Laboratory, NASA, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States)
  10. Steward Observatory, 933 North Cherry Ave., Tucson, AZ 85721 (United States)
  11. National Radio Astronomy Observatory, Socorro, NM 87801 (United States)
  12. Department of Physics, Engineering Physics and Astronomy, Queen’s University, Kingston, Ontario, K7L 3N6 (Canada)
Publication Date:
OSTI Identifier:
22679857
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 846; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMMONIA; BALANCES; COSMIC GASES; DISPERSIONS; GRAVITATION; MASS; MOLECULES; STARS; TELESCOPES; VELOCITY

Citation Formats

Kirk, Helen, Di Francesco, James, Friesen, Rachel K., Pineda, Jaime E., Caselli, Paola, Alves, Felipe O., Chacón-Tanarro, Ana, Punanova, Anna, Rosolowsky, Erik, Offner, Stella S. R., Matzner, Christopher D., Singh, Ayushi, Myers, Philip C., Chen, How-Huan, Chen, Michael Chun-Yuan, Keown, Jared, Seo, Young Min, Shirley, Yancy, Ginsburg, Adam, Hall, Christine, and and others. The Green Bank Ammonia Survey: Dense Cores under Pressure in Orion A. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8631.
Kirk, Helen, Di Francesco, James, Friesen, Rachel K., Pineda, Jaime E., Caselli, Paola, Alves, Felipe O., Chacón-Tanarro, Ana, Punanova, Anna, Rosolowsky, Erik, Offner, Stella S. R., Matzner, Christopher D., Singh, Ayushi, Myers, Philip C., Chen, How-Huan, Chen, Michael Chun-Yuan, Keown, Jared, Seo, Young Min, Shirley, Yancy, Ginsburg, Adam, Hall, Christine, & and others. The Green Bank Ammonia Survey: Dense Cores under Pressure in Orion A. United States. doi:10.3847/1538-4357/AA8631.
Kirk, Helen, Di Francesco, James, Friesen, Rachel K., Pineda, Jaime E., Caselli, Paola, Alves, Felipe O., Chacón-Tanarro, Ana, Punanova, Anna, Rosolowsky, Erik, Offner, Stella S. R., Matzner, Christopher D., Singh, Ayushi, Myers, Philip C., Chen, How-Huan, Chen, Michael Chun-Yuan, Keown, Jared, Seo, Young Min, Shirley, Yancy, Ginsburg, Adam, Hall, Christine, and and others. Sun . "The Green Bank Ammonia Survey: Dense Cores under Pressure in Orion A". United States. doi:10.3847/1538-4357/AA8631.
@article{osti_22679857,
title = {The Green Bank Ammonia Survey: Dense Cores under Pressure in Orion A},
author = {Kirk, Helen and Di Francesco, James and Friesen, Rachel K. and Pineda, Jaime E. and Caselli, Paola and Alves, Felipe O. and Chacón-Tanarro, Ana and Punanova, Anna and Rosolowsky, Erik and Offner, Stella S. R. and Matzner, Christopher D. and Singh, Ayushi and Myers, Philip C. and Chen, How-Huan and Chen, Michael Chun-Yuan and Keown, Jared and Seo, Young Min and Shirley, Yancy and Ginsburg, Adam and Hall, Christine and and others},
abstractNote = {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.},
doi = {10.3847/1538-4357/AA8631},
journal = {Astrophysical Journal},
number = 2,
volume = 846,
place = {United States},
year = {Sun Sep 10 00:00:00 EDT 2017},
month = {Sun Sep 10 00:00:00 EDT 2017}
}