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Hierarchical Star Formation in Turbulent Media: Evidence from Young Star Clusters

Grasha, K. and Elmegreen, B. G. and Calzetti, D. and Adamo, A. and Aloisi, A. and Bright, S. N. and Cook, D. O. and Dale, D. A. and Fumagalli, M. and Gallagher, J. S., III and Gouliermis, D. A. and Grebel, E. K. and Kahre, L. and Kim, H. and Krumholz, M. R. and Lee, J. C. and Messa, M. and Ryon, J. E. and Ubeda, L. (2017) Hierarchical Star Formation in Turbulent Media: Evidence from Young Star Clusters. Astrophysical Journal, 842 (1). Art. No. 25. ISSN 1538-4357. doi:10.3847/1538-4357/aa740b.

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We present an analysis of the positions and ages of young star clusters in eight local galaxies to investigate the connection between the age difference and separation of cluster pairs. We find that star clusters do not form uniformly but instead are distributed so that the age difference increases with the cluster pair separation to the 0.25–0.6 power, and that the maximum size over which star formation is physically correlated ranges from ~200 pc to ~1 kpc. The observed trends between age difference and separation suggest that cluster formation is hierarchical both in space and time: clusters that are close to each other are more similar in age than clusters born further apart. The temporal correlations between stellar aggregates have slopes that are consistent with predictions of turbulence acting as the primary driver of star formation. The velocity associated with the maximum size is proportional to the galaxy's shear, suggesting that the galactic environment influences the maximum size of the star-forming structures.

Item Type:Article
Related URLs:
URLURL TypeDescription
Grasha, K.0000-0002-3247-5321
Elmegreen, B. G.0000-0002-1723-6330
Calzetti, D.0000-0002-5189-8004
Adamo, A.0000-0002-8192-8091
Aloisi, A.0000-0003-4137-882X
Cook, D. O.0000-0002-6877-7655
Dale, D. A.0000-0002-5782-9093
Fumagalli, M.0000-0001-6676-3842
Gallagher, J. S., III0000-0001-8608-0408
Gouliermis, D. A.0000-0002-2763-0075
Grebel, E. K.0000-0002-1891-3794
Kahre, L.0000-0002-2037-3096
Krumholz, M. R.0000-0003-3893-854X
Lee, J. C.0000-0002-2278-9407
Messa, M.0000-0003-1427-2456
Additional Information:© 2017 American Astronomical Society. Received 2016 December 8. Accepted 2017 May 16. Published 2017 June 8. We are indebted to an anonymous referee for careful reading of this manuscript and for providing comments that have improved the scientific outcome and quality of the paper. We also appreciate the very useful discussions and comments on this work by R. Klessen, D. Kruijssen, and B. Gaches. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, under NASA Contract NAS 5–26555. These observations are associated with Program 13364 (LEGUS). Support for Program 13364 was provided by NASA through a grant from the Space Telescope Science Institute. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. D.A.G. kindly acknowledges financial support by the German Research Foundation (DFG) through program GO 1659/3-2.
Funding AgencyGrant Number
NASANAS 5–26555
Deutsche Forschungsgemeinschaft (DFG)GO 1659/3-2
Subject Keywords:galaxies: star clusters: general; galaxies: star formation; galaxies: stellar content; galaxies: structure; stars: formation; ultraviolet: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:20170713-104625485
Persistent URL:
Official Citation:K. Grasha et al 2017 ApJ 842 25
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:79080
Deposited By: Ruth Sustaita
Deposited On:13 Jul 2017 19:55
Last Modified:15 Nov 2021 17:45

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