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

Keown, J, Francesco, JD, Rosolowsky, E, Singh, A, Figura, C, Kirk, H, Anderson, LD, Chen, MC-Y, Elia, D, Friesen, R, Ginsburg, A, Marston, A, Pezzuto, S, Schisano, E, Bontemps, S, Caselli, P, Liu, H-L, Longmore, SN, Motte, F, Myers, PC , Offner, SSR, Sanhueza, P, Schneider, N, Stephens, I, Urquhart, J and collaboration, TKEYSTONE (2019) KFPA Examinations of Young STellar Object Natal Environments (KEYSTONE): Hierarchical Ammonia Structures in Galactic Giant Molecular Clouds. Astophysical Journal, 884 (1). ISSN 0004-637X

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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.

Item Type: Article
Uncontrolled Keywords: astro-ph.GA; astro-ph.GA; astro-ph.SR
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: IOP Publishing LTD
Related URLs:
Date Deposited: 04 Sep 2019 07:58
Last Modified: 04 Sep 2021 08:57
DOI or Identification number: 10.3847/1538-4357/ab3e76
URI: https://researchonline.ljmu.ac.uk/id/eprint/11264

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