Are Massive Dense Clumps Truly Subvirial? A New Analysis Using Gould Belt Ammonia Data
| Autor: | Peter G. Martin, James Di Francesco, Jared Keown, Alok Singh, Michael Chun-Yuan Chen, Christopher D. Matzner, Ana Chacón-Tanarro, Youngmin Seo, Adam Ginsburg, Yancy L. Shirley, Alyssa A. Goodman, Philip C. Myers, Rachel Friesen, Paola Caselli, Spandan Choudhury, Helen Kirk, Erik Rosolowsky, Héctor G. Arce, Jaime E. Pineda, Anna Punanova, Elena Redaelli, Felipe O. Alves, Stella S. R. Offner, How-Huan Chen |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
astronomy data analysis
Physics interstellar dynamics 010308 nuclear & particles physics ASTRONOMY DATA ANALYSIS Astronomy FOS: Physical sciences Astronomy and Astrophysics molecular clouds Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics - Astrophysics of Galaxies 01 natural sciences INTERSTELLAR DYNAMICS Ammonia chemistry.chemical_compound Astrophysics - Solar and Stellar Astrophysics chemistry Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences MOLECULAR CLOUDS 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics |
| Zdroj: | Astrophys. J. Astrophysical Journal |
| Popis: | Dynamical studies of dense structures within molecular clouds often conclude that the most massive clumps contain too little kinetic energy for virial equilibrium, unless they are magnetized to an unexpected degree. This raises questions about how such a state might arise, and how it might persist long enough to represent the population of massive clumps. In an effort to re-examine the origins of this conclusion, we use ammonia line data from the Green Bank Ammonia Survey and Planck-calibrated dust emission data from Herschel to estimate the masses and kinetic and gravitational energies for dense clumps in the Gould Belt clouds. We show that several types of systematic error can enhance the appearance of low kinetic-to-gravitational energy ratios: insufficient removal of foreground and background material; ignoring the kinetic energy associated with velocity differences across a resolved cloud; and over-correcting for stratification when evaluating the gravitational energy. Using an analysis designed to avoid these errors, we find that the most massive Gould Belt clumps harbor virial motions, rather than sub-virial ones. As a byproduct, we present a catalog of masses, energies, and virial energy ratios for 85 Gould Belt clumps. Comment: Submitted to ApJ |
| Databáze: | OpenAIRE |
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