LEGUS & Ha-LEGUS obs. of NGC4449 star clusters Virtual Observatory Resource

Authors
  1. Whitmore B.C.
  2. Chandar R.
  3. Lee J.
  4. Ubeda L.
  5. Adamo A.
  6. Aloisi A.,Calzetti D.
  7. Cignoni M.
  8. Cook D.
  9. Dale D.
  10. Elmegreen B.G.
  11. Gouliermis D.,Grebel E.K.
  12. Grasha K.
  13. Johnson K.E.
  14. Kim H.
  15. Sacchi E.
  16. Smith L.J.,Tosi M.
  17. Wofford A.
  18. Published by
    CDS
Abstract

We present a new catalog and results for the cluster system of the starburst galaxy NGC 4449, based on multiband imaging observations taken as part of the LEGUS and H_{alpha}_-LEGUS surveys. We improve the spectral energy fitting method used to estimate cluster ages, and find that the results, particularly for older clusters, are in better agreement with those from spectroscopy. The inclusion of H{alpha} measurements, the role of stochasticity for low-mass clusters, the assumptions about reddening, and the choices of SSP model and metallicity all have important impacts on the age dating of clusters. A comparison with ages derived from stellar color-magnitude diagrams for partially resolved clusters shows reasonable agreement, but large scatter in some cases. The fraction of light found in clusters relative to the total light (i.e., T_L_) in the U, B, and V filters in 25 different ~kiloparsec-size regions throughout NGC 4449 correlates with both the specific region luminosity, R_L_, and the dominant age of the underlying stellar population in each region. The observed cluster age distribution is found to decline over time as dN/d{tau}{propto}{tau}^{gamma}^, with {gamma}=-0.85+/-0.15, independent of cluster mass, and is consistent with strong, early cluster disruption. The mass functions of the clusters can be described by a power law with dN/dM{propto}M^{beta}^ and {beta}=-1.86+/-0.2, independent of cluster age. The mass and age distributions are quite resilient to differences in age-dating methods. There is tentative evidence for a factor of 2-3 enhancement in both the star and cluster formation rate ~100-300Myr ago, indicating that cluster formation tracks star formation generally. The enhancement is probably associated with an earlier interaction event.

Keywords
  1. globular-star-clusters
  2. hst-photometry
  3. visible-astronomy
  4. galaxies
  5. stellar-ages
  6. stellar-masses
Bibliographic source Bibcode
2020ApJ...889..154W
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/889/154
IVOA Identifier IVOID
ivo://CDS.VizieR/J/ApJ/889/154
Document Object Identifer DOI
doi:10.26093/cds/vizier.18890154

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http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/889/154
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History

2021-08-10T09:22:56Z
Resource record created
2021-08-10T09:22:56Z
Created
2022-11-03T07:03:19Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr