CaltechAUTHORS
Published November 2021 | Version Accepted Version + Published
Journal Article Open

The dependence of the hierarchical distribution of star clusters on galactic environment

Creators

  • 1. ROR icon Australian National University
  • 2. ROR icon Centre of Excellence for All-Sky Astrophysics
  • 3. ROR icon IBM Research - Thomas J. Watson Research Center
  • 4. ROR icon University of Massachusetts Amherst
  • 5. ROR icon Valencian International University
  • 6. ROR icon Stockholm University
  • 7. ROR icon University of Geneva
  • 8. ROR icon California Institute of Technology
  • 9. ROR icon Infrared Processing and Analysis Center
  • 10. ROR icon University of Wyoming
  • 11. ROR icon Heidelberg University
  • 12. ROR icon University of Milano-Bicocca
  • 13. ROR icon Trieste Astronomical Observatory
  • 14. ROR icon Space Telescope Science Institute
  • 15. ROR icon University of Virginia
  • 16. ROR icon University of Arizona
  • 17. ROR icon Texas A&M University

Abstract

We use the angular two-point correlation function (TPCF) to investigate the hierarchical distribution of young star clusters in 12 local (3–18 Mpc) star-forming galaxies using star cluster catalogs obtained with the Hubble Space Telescope (HST) as part of the Treasury Program Legacy ExtraGalactic UV Survey. The sample spans a range of different morphological types, allowing us to infer how the physical properties of the galaxy affect the spatial distribution of the clusters. We also prepare a range of physically motivated toy models to compare with and interpret the observed features in the TPCFs. We find that, conforming to earlier studies, young clusters (⁠T ≲ 10 Myr⁠) have power-law TPCFs that are characteristic of fractal distributions with a fractal dimension D₂, and this scale-free nature extends out to a maximum scale l_(corr) beyond which the distribution becomes Poissonian. However, l_(corr), and D₂ vary significantly across the sample, and are correlated with a number of host galaxy physical properties, suggesting that there are physical differences in the underlying star cluster distributions. We also find that hierarchical structuring weakens with age, evidenced by flatter TPCFs for older clusters (⁠T ≳ 10 Myr⁠), that eventually converges to the residual correlation expected from a completely random large-scale radial distribution of clusters in the galaxy in ∼100 Myr⁠. Our study demonstrates that the hierarchical distribution of star clusters evolves with age, and is strongly dependent on the properties of the host galaxy environment.

Additional Information

© 2021 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2021 August 6. Received 2021 August 5; in original form 2021 June 22. Published: 23 August 2021. We thank the anonymous referee for a constructive review that improved the quality of the paper. SHM would like to thank Dimitrios Gouliermis, James Beattie, and Piyush Sharda for insightful discussions during the course of the project. 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, Inc., under NASA contract NAS 5-26555. These observations are associated with program # 13364. CF acknowledges funding provided by the Australian Research Council through Future Fellowship FT180100495, and the Australia-Germany Joint Research Cooperation Scheme (UA-DAAD). MRK acknowledges funding from the Australian Research Council through its Discovery Projects and Future Fellowship funding schemes, awards DP190101258 and FT180100375. MM acknowledges the support of the Swedish Research Council, Vetenskapsrådet (internationell postdok 2019-00502). This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 757535). The following software tools were used for analysis and plotting: NUMPY (Harris et al. 2020), SCIPY (Virtanen et al. 2020), MATPLOTLIB (Hunter 2007), and CORNER (Foreman-Mackey 2016). Some of the figures used in this work make use of the CMASHER package (van der Velden 2020). This research made use of ASTROPY,8 a community-developed core PYTHON package for Astronomy (Astropy Collaboration 2013, 2018). This research has also made use of NASA's Astrophysics Data System (ADS) Bibliographic Services. Data Availability: The data (cluster catalogs) underlying this article are publicly available online on the MAST9 for all galaxies except NGC 3627 and NGC 5457, which will be published in a forthcoming paper (Linden et al., in preparation). The tools and code to reproduce the analysis and plots of the paper are publicly available at https://github.com/shm-1996/legus-tpcf.

Attached Files

Published - stab2413.pdf

Accepted Version - 2108.04387.pdf

Files

2108.04387.pdf

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Additional details

Identifiers

Eprint ID
111752
Resolver ID
CaltechAUTHORS:20211104-154229618

Related works

Describes
https://arxiv.org/abs/2108.04387 (URL)
https://github.com/shm-1996/legus-tpcf (URL)

Funding

NASA
NAS 5-26555
Australian Research Council
FT180100495
Australia-Germany Joint Research Cooperation Scheme (UA-DAAD)
Australian Research Council
DP190101258
Australian Research Council
FT180100375
Swedish Research Council
2019-00502
European Research Council (ERC)
757535

Dates

Created
2021-11-04
Created from EPrint's datestamp field
Updated
2021-11-04
Created from EPrint's last_modified field

Caltech Custom Metadata

Caltech groups
Infrared Processing and Analysis Center (IPAC)