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dc.contributor.authorChoudhury, S.
dc.contributor.authorPineda, J.E.
dc.contributor.authorCaselli, P.
dc.contributor.authorOffner, S.S.R.
dc.contributor.authorRosolowsky, E.
dc.contributor.authorFriesen, R.K.
dc.contributor.authorRedaelli, E.
dc.contributor.authorChacón-Tanarro, A.
dc.contributor.authorShirley, Y.
dc.contributor.authorPunanova, A.
dc.contributor.authorKirk, H.
dc.identifier.citationChoudhury, S., Pineda, J. E., Caselli, P., Offner, S. S. R., Rosolowsky, E., Friesen, R. K., Redaelli, E., Chacón-Tanarro, A., Shirley, Y., Punanova, A., & Kirk, H. (2021). Transition from coherent cores to surrounding cloud in L1688. Astronomy and Astrophysics, 648.
dc.description.abstractContext. Stars form in cold dense cores showing subsonic velocity dispersions. The parental molecular clouds display higher temperatures and supersonic velocity dispersions. The transition from core to cloud has been observed in velocity dispersion, but temperature and abundance variations are unknown. Aims. We aim to measure the temperature and velocity dispersion across cores and ambient cloud in a single tracer to study the transition between the two regions. Methods. We use NH3 (1,1) and (2,2) maps in L1688 from the Green Bank Ammonia Survey, smoothed to 1′, and determine the physical properties by fitting the spectra. We identify the coherent cores and study the changes in temperature and velocity dispersion from the cores to the surrounding cloud. Results. We obtain a kinetic temperature map extending beyond dense cores and tracing the cloud, improving from previous maps tracing mostly the cores. The cloud is 4-6 K warmer than the cores, and shows a larger velocity dispersion (Δσv = 0.15-0.25 km s-1). Comparing to Herschel-based dust temperatures, we find that cores show kinetic temperatures that are ≈1.8 K lower than the dust temperature, while the gas temperature is higher than the dust temperature in the cloud. We find an average p-NH3 fractional abundance (with respect to H2) of (4.2 ± 0.2) × 10-9 towards the coherent cores, and (1.4 ± 0.1) × 10-9 outside the core boundaries. Using stacked spectra, we detect two components, one narrow and one broad, towards cores and their neighbourhoods. We find the turbulence in the narrow component to be correlated with the size of the structure (Pearson-r = 0.54). With these unresolved regional measurements, we obtain a turbulence-size relation of σv,NT ∝ r0.5, which is similar to previous findings using multiple tracers. Conclusions. We discover that the subsonic component extends up to 0.15 pc beyond the typical coherent boundaries, unveiling larger extents of the coherent cores and showing gradual transition to coherence over ∼0.2 pc. © S. Choudhury et al. 2021.
dc.publisherEDP Sciences
dc.rightsCopyright © S. Choudhury et al. 2021. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (
dc.subjectISM: individual objects: L1688
dc.subjectISM: kinematics and dynamics
dc.subjectISM: molecules
dc.subjectStars: formation
dc.titleTransition from coherent cores to surrounding cloud in L1688
dc.contributor.departmentSteward Observatory, University of Arizona
dc.identifier.journalAstronomy and Astrophysics
dc.description.noteOpen access article
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at
dc.eprint.versionFinal published version
dc.source.journaltitleAstronomy and Astrophysics

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Copyright © S. Choudhury et al. 2021. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (
Except where otherwise noted, this item's license is described as Copyright © S. Choudhury et al. 2021. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (