The Astrophysical Journal (Jan 2023)
Universal Upper End of the Stellar Initial Mass Function in the Young and Compact LEGUS Clusters
- Dooseok Escher Jung,
- Daniela Calzetti,
- Matteo Messa,
- Mark Heyer,
- Mattia Sirressi,
- Sean T. Linden,
- Angela Adamo,
- Rupali Chandar,
- Michele Cignoni,
- David O. Cook,
- Clare L. Dobbs,
- Bruce G. Elmegreen,
- Aaron S. Evans,
- Michele Fumagalli,
- John S. Gallagher III,
- Deidre A. Hunter,
- Kelsey E. Johnson,
- Robert C. Kennicutt Jr.,
- Mark R. Krumholz,
- Daniel Schaerer,
- Elena Sabbi,
- Linda J. Smith,
- Monica Tosi,
- Aida Wofford
Affiliations
- Dooseok Escher Jung
- ORCiD
- Department of Astronomy, University of Massachusetts Amherst , 710 North Pleasant Street, Amherst, MA 01003, USA ; [email protected]
- Daniela Calzetti
- ORCiD
- Department of Astronomy, University of Massachusetts Amherst , 710 North Pleasant Street, Amherst, MA 01003, USA ; [email protected]
- Matteo Messa
- ORCiD
- Observatoire de Genève, Université de Genève , 51 Ch. des Maillettes, CH-1290 Versoix, Switzerland
- Mark Heyer
- ORCiD
- Department of Astronomy, University of Massachusetts Amherst , 710 North Pleasant Street, Amherst, MA 01003, USA ; [email protected]
- Mattia Sirressi
- ORCiD
- Department of Astronomy, Oscar Klein Centre, Stockholm University , AlbaNova, SE-106 91 Stockholm, Sweden
- Sean T. Linden
- ORCiD
- Department of Astronomy, University of Massachusetts Amherst , 710 North Pleasant Street, Amherst, MA 01003, USA ; [email protected]
- Angela Adamo
- ORCiD
- Department of Astronomy, Oscar Klein Centre, Stockholm University , AlbaNova, SE-106 91 Stockholm, Sweden
- Rupali Chandar
- ORCiD
- Ritter Astrophysical Research Center, University of Toledo , Toledo, OH 43606, USA
- Michele Cignoni
- ORCiD
- Department of Physics, University of Pisa , Largo Pontecorvo, 3, I-56127 Pisa, Italy
- David O. Cook
- ORCiD
- Caltech/IPAC , 1200 E. California Boulevard, Pasadena, CA 91125, USA
- Clare L. Dobbs
- ORCiD
- School of Physics and Astronomy, University of Exeter , Stocker Road, Exeter EX4 4QL, UK
- Bruce G. Elmegreen
- ORCiD
- IBM T.J. Watson Research Center , 1101 Kitchawan Road, Yorktown Heights, NY 10598, USA
- Aaron S. Evans
- ORCiD
- Department of Astronomy, University of Virginia , 530 McCormick Road, Charlottesville, VA 22904, USA
- Michele Fumagalli
- ORCiD
- Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano-Bicocca , Piazza della Scienza 3, I-20126 Milano, Italy; INAF—Osservatorio Astronomico di Trieste , via G.B. Tiepolo 11, I-34143 Trieste, Italy
- John S. Gallagher III
- ORCiD
- Department of Astronomy, University of Wisconsin , 475 N. Charter Street, Madison, WI 53706, USA
- Deidre A. Hunter
- ORCiD
- Lowell Observatory , 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA
- Kelsey E. Johnson
- ORCiD
- Department of Astronomy, University of Virginia , 530 McCormick Road, Charlottesville, VA 22904, USA
- Robert C. Kennicutt Jr.
- ORCiD
- Department of Astronomy and Steward Observatory, University of Arizona , Tucson, AZ 85721, USA; Department of Physics and Astronomy, Texas A&M University , College Station, TX 77843, USA; Institute of Astronomy, University of Cambridge , Madingley Road, Cambridge CB3 0HA, UK
- Mark R. Krumholz
- ORCiD
- Research School of Astronomy and Astrophysics, Australian National University , Canberra ACT 2601, Australia
- Daniel Schaerer
- ORCiD
- Observatoire de Genève, Université de Genève , Chemin Pegasi 51, 1290 Versoix, Switzerland; CNRS, IRAP , 14 Avenue E. Belin, F-31400 Toulouse, France
- Elena Sabbi
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Linda J. Smith
- ORCiD
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA
- Monica Tosi
- ORCiD
- INAF—OAS Osservatorio di Astrofisica e Scienza dello Spazio , I-40129 Bologna, Italy
- Aida Wofford
- ORCiD
- Instituto de Astronomia, Universidad Nacional Autonoma de Mexico , Unidad Académica en Ensenada, 22860 Ensenada, Mexico
- DOI
- https://doi.org/10.3847/1538-4357/aceb5c
- Journal volume & issue
-
Vol. 954,
no. 2
p. 136
Abstract
We investigate the variation in the upper end of the stellar initial mass function (uIMF) in 375 young and compact star clusters in five nearby galaxies within ∼5 Mpc. All the young stellar clusters (YSCs) in the sample have ages ≲ 4 Myr and masses above 500 M _⊙ , according to standard stellar models. The YSC catalogs were produced from Hubble Space Telescope images obtained as part of the Legacy ExtraGalactic UV Survey (LEGUS) Hubble treasury program. They are used here to test whether the uIMF is universal or changes as a function of the cluster’s stellar mass. We perform this test by measuring the H α luminosity of the star clusters as a proxy for their ionizing photon rate, and charting its trend as a function of cluster mass. Large cluster numbers allow us to mitigate the stochastic sampling of the uIMF. The advantage of our approach relative to previous similar attempts is the use of cluster catalogs that have been selected independently of the presence of H α emission, thus removing a potential sample bias. We find that the uIMF, as traced by the H α emission, shows no dependence on cluster mass, suggesting that the maximum stellar mass that can be produced in star clusters is universal, in agreement with previous findings.
Keywords
