Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/111605
Title: Ubiquitous NH3 Supersonic Component in L1688 Coherent Cores
Authors: Choudhury, S.
Pineda, J. E.
Caselli, P.
Ginsburg, A.
Offner, S. S. R.
Rosolowsky, E.
Friesen, R. K.
Alves, F. O.
Chacón-Tanarro, A.
Punanova, A.
Redaelli, E.
Kirk, H.
Myers, P. C.
Martin, P. G.
Shirley, Y.
Chun-Yuan Chen, M.
Goodman, A. A.
Di Francesco, J.
Issue Date: 2020
Publisher: EDP Sciences
EDP Sciences
Citation: Ubiquitous NH3 Supersonic Component in L1688 Coherent Cores / S. Choudhury, J. E. Pineda, P. Caselli et al. — DOI 10.1134/S0081543820020091 // Astronomy and Astrophysics. — 2020. — Vol. 640. — L6.
Abstract: Context. Star formation takes place in cold dense cores in molecular clouds. Earlier observations have found that dense cores exhibit subsonic non-thermal velocity dispersions. In contrast, CO observations show that the ambient large-scale cloud is warmer and has supersonic velocity dispersions. Aims. We aim to study the ammonia (NH3) molecular line profiles with exquisite sensitivity towards the coherent cores in L1688 in order to study their kinematical properties in unprecedented detail. Methods. We used NH3 (1,1) and (2,2) data from the first data release (DR1) in the Green Bank Ammonia Survey (GAS). We first smoothed the data to a larger beam of 10 to obtain substantially more extended maps of velocity dispersion and kinetic temperature, compared to the DR1 maps. We then identified the coherent cores in the cloud and analysed the averaged line profiles towards the cores. Results. For the first time, we detected a faint (mean NH3(1,1) peak brightness 0.25K in TMB), supersonic component towards all the coherent cores in L1688. We fitted two components, one broad and one narrow, and derived the kinetic temperature and velocity dispersion of each component. The broad components towards all cores have supersonic linewidths (MS 1). This component biases the estimate of the narrow dense core component's velocity dispersion by 28% and the kinetic temperature by 10%, on average, as compared to the results from single-component fits. Conclusions. Neglecting this ubiquitous presence of a broad component towards all coherent cores causes the typical singlecomponent fit to overestimate the temperature and velocity dispersion. This aects the derived detailed physical structure and stability of the cores estimated from NH3 observations. © S. Choudhury et al. 2020.
Keywords: ISM: INDIVIDUAL OBJECTS: L1688
ISM: KINEMATICS AND DYNAMICS
ISM: MOLECULES
OPHIUCHUS
STARS: FORMATION
DISPERSIONS
KINETICS
VELOCITY
KINETIC TEMPERATURES
MOLECULAR CLOUDS
MOLECULAR LINES
PHYSICAL STRUCTURES
SINGLE COMPONENTS
STAR FORMATIONS
SUPERSONIC VELOCITIES
VELOCITY DISPERSION
AMMONIA
URI: http://hdl.handle.net/10995/111605
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85091516584
PURE ID: 13697423
ISSN: 0004-6361
DOI: 10.1134/S0081543820020091
metadata.dc.description.sponsorship: Acknowledgements. AP is supported by the Russian Ministry of Science and Higher Education via the State Assignment Project FEUZ-2020-0038. AP is a member of the Max Planck Partner Group at the Ural Federal University. SSRO acknowledges support from NSF CAREER grant. AC-T acknowledges support from MINECO project AYA2016-79006-P.
NSF project card: NSF CAREER grant
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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