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Article Dans Une Revue The Astrophysical Journal Année : 2019

KFPA Examinations of Young STellar Object Natal Environments (KEYSTONE): Hierarchical Ammonia Structures in Galactic Giant Molecular Clouds

Jared Keown
James Di Francesco
Erik Rosolowsky
Ayushi Singh
  • Fonction : Auteur
Charles Figura
  • Fonction : Auteur
Helen Kirk
  • Fonction : Auteur
Michael Chun-Yuan Chen
  • Fonction : Auteur
Davide Elia
  • Fonction : Auteur
Rachel Friesen
  • Fonction : Auteur
Adam Ginsburg
  • Fonction : Auteur
A. Marston
  • Fonction : Auteur
Stefano Pezzuto
Eugenio Schisano
  • Fonction : Auteur
Sylvain Bontemps
Paola Caselli
Hong-Li Liu
  • Fonction : Auteur
Steven Longmore
  • Fonction : Auteur
Philip C. Myers
  • Fonction : Auteur
Stella S. R. Offner
  • Fonction : Auteur
Patricio Sanhueza
Nicola Schneider
  • Fonction : Auteur
  • PersonId : 1031322
Ian Stephens
  • Fonction : Auteur
James Urquhart

Résumé

We present initial results from the K-band focal plane array Examinations of Young STellar Object Natal Environments (KEYSTONE) survey, a large project on the 100-m Green Bank Telescope mapping ammonia emission across eleven giant molecular clouds at distances of $0.9-3.0$ kpc (Cygnus X North, Cygnus X South, M16, M17, MonR1, MonR2, NGC2264, NGC7538, Rosette, W3, and W48). This data release includes the NH$_3$ (1,1) and (2,2) maps for each cloud, which are modeled to produce maps of kinetic temperature, centroid velocity, velocity dispersion, and ammonia column density. Median cloud kinetic temperatures range from $11.4\pm2.2$ K in the coldest cloud (MonR1) to $23.0\pm6.5$ K in the warmest cloud (M17). Using dendrograms on the NH$_3$ (1,1) integrated intensity maps, we identify 856 dense gas clumps across the eleven clouds. Depending on the cloud observed, $40-100\%$ of the clumps are aligned spatially with filaments identified in H$_2$ column density maps derived from SED-fitting of dust continuum emission. A virial analysis reveals that 523 of the 835 clumps ($\sim63\%$) with mass estimates are bound by gravity alone. We find no significant difference between the virial parameter distributions for clumps aligned with the dust-continuum filaments and those unaligned with filaments. In some clouds, however, hubs or ridges of dense gas with unusually high mass and low virial parameters are located within a single filament or at the intersection of multiple filaments. These hubs and ridges tend to host water maser emission, multiple 70$\mu$m-detected protostars, and have masses and radii above an empirical threshold for forming massive stars.

Dates et versions

hal-02282427 , version 1 (10-09-2019)

Identifiants

Citer

Jared Keown, James Di Francesco, Erik Rosolowsky, Ayushi Singh, Charles Figura, et al.. KFPA Examinations of Young STellar Object Natal Environments (KEYSTONE): Hierarchical Ammonia Structures in Galactic Giant Molecular Clouds. The Astrophysical Journal, 2019, 884 (1), pp.id. 4. ⟨10.3847/1538-4357/ab3e76⟩. ⟨hal-02282427⟩
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