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Hierarchical star formation across the grand-design spiral NGC 1566

Gouliermis, Dimitrios A. and Elmegreen, Bruce G. and Elmegreen, Debra M. and Calzetti, Daniela and Cignoni, Michele and Gallagher, John S., III and Kennicutt, Robert C. and Klessen, Ralf S. and Sabbi, Elena and Thilker, David and Ubeda, Leonardo and Aloisi, Alessandra and Adamo, Angela and Cook, David O. and Dale, Daniel and Grasha, Kathryn and Grebel, Eva K. and Johnson, Kelsey E. and Sacchi, Elena and Shabani, Fayezeh and Smith, Linda J. and Wofford, Aida (2017) Hierarchical star formation across the grand-design spiral NGC 1566. Monthly Notices of the Royal Astronomical Society, 468 (1). pp. 509-530. ISSN 0035-8711. doi:10.1093/mnras/stx445.

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We investigate how star formation is spatially organized in the grand-design spiral NGC 1566 from deep Hubble Space Telescope photometry with the Legacy ExtraGalactic UV Survey. Our contour-based clustering analysis reveals 890 distinct stellar conglomerations at various levels of significance. These star-forming complexes are organized in a hierarchical fashion with the larger congregations consisting of smaller structures, which themselves fragment into even smaller and more compact stellar groupings. Their size distribution, covering a wide range in length-scales, shows a power law as expected from scale-free processes. We explain this shape with a simple ‘fragmentation and enrichment’ model. The hierarchical morphology of the complexes is confirmed by their mass–size relation that can be represented by a power law with a fractional exponent, analogous to that determined for fractal molecular clouds. The surface stellar density distribution of the complexes shows a lognormal shape similar to that for supersonic non-gravitating turbulent gas. Between 50 and 65 per cent of the recently formed stars, as well as about 90 per cent of the young star clusters, are found inside the stellar complexes, located along the spiral arms. We find an age difference between young stars inside the complexes and those in their direct vicinity in the arms of at least 10 Myr. This time-scale may relate to the minimum time for stellar evaporation, although we cannot exclude the in situ formation of stars. As expected, star formation preferentially occurs in spiral arms. Our findings reveal turbulent-driven hierarchical star formation along the arms of a grand-design galaxy.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Gouliermis, Dimitrios A.0000-0002-2763-0075
Elmegreen, Bruce G.0000-0002-1723-6330
Elmegreen, Debra M.0000-0002-1392-3520
Calzetti, Daniela0000-0002-5189-8004
Cignoni, Michele0000-0001-6291-6813
Gallagher, John S., III0000-0001-8608-0408
Kennicutt, Robert C.0000-0001-5448-1821
Klessen, Ralf S.0000-0002-0560-3172
Sabbi, Elena0000-0003-2954-7643
Aloisi, Alessandra0000-0003-4137-882X
Adamo, Angela0000-0002-8192-8091
Cook, David O.0000-0002-6877-7655
Dale, Daniel0000-0002-5782-9093
Grasha, Kathryn0000-0002-3247-5321
Grebel, Eva K.0000-0002-1891-3794
Johnson, Kelsey E.0000-0001-8348-2671
Sacchi, Elena0000-0001-5618-0109
Smith, Linda J.0000-0002-0806-168X
Additional Information:© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Received 11 January 2017; revision received 09 February 2017; accepted 17 February 2017; published 21 February 2017. DAG kindly acknowledges financial support by the German Research Foundation (DFG) through programme GO 1659/3-2. He would also like to thank S. Hony for the long discussions (and debates) on star formation and the derived MF. 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 the National Aeronautics and Space Administration. This research has also made use of the SIMBAD data base (Wenger et al. 2000), operated at CDS, Strasbourg, France. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute (STScI). STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. These observations are associated with programme GO-13364. Support for programme 13364 was provided by NASA through grants from STScI. This research made use of the topcat application (Taylor 2005), the r environment for statistical computing and graphics (R Core Team 2015) and NASA Astrophysics Data System (ADS) bibliographic services.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Deutsche Forschungsgemeinschaft (DFG)GO 1659/3-2
NASANAS 5-26555
Space Telescope Science Institute (STScI)UNSPECIFIED
Subject Keywords:Methods: statistical; Stars: formation; Galaxies: individual: NGC 1566; Galaxies: spiral; Galaxies: stellar content; Galaxies: structure
Issue or Number:1
Record Number:CaltechAUTHORS:20170428-105356377
Persistent URL:
Official Citation:Dimitrios A. Gouliermis, Bruce G. Elmegreen, Debra M. Elmegreen, Daniela Calzetti, Michele Cignoni, John S. Gallagher, III, Robert C. Kennicutt, Ralf S. Klessen, Elena Sabbi, David Thilker, Leonardo Ubeda, Alessandra Aloisi, Angela Adamo, David O. Cook, Daniel Dale, Kathryn Grasha, Eva K. Grebel, Kelsey E. Johnson, Elena Sacchi, Fayezeh Shabani, Linda J. Smith, Aida Wofford; Hierarchical star formation across the grand-design spiral NGC 1566. Mon Not R Astron Soc 2017; 468 (1): 509-530. doi: 10.1093/mnras/stx445
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:77055
Deposited By: Melissa Ray
Deposited On:28 Apr 2017 18:35
Last Modified:15 Nov 2021 17:05

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