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ID: 5932.0, MPI für extraterrestrische Physik / Infrared and Submillimeter Astronomy
Dynamical masses of young star clusters in NGC 4038/4039
Authors:Mengel, S.; Lehnert, M. D.; Thatte, N.; Genzel, R.
Date of Publication (YYYY-MM-DD):2002-02
Title of Journal:Astronomy & Astrophysics
Journal Abbrev.:Astron. Astrophys.
Issue / Number:1
Start Page:137
End Page:152
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:In order to estimate the masses of the compact, young star clusters in the merging galaxy pair, NGC 4038/4039 ("the Antennae"), we have obtained medium and high resolution spectroscopy using ISAAC on VLT-UT1 and UVES on VLT-UT2 of five such clusters. The velocity dispersions were estimated using the stellar absorption features of CO at 2.29 mum and metal absorption lines at around 8500 Angstrom, including lines of the Calcium Triplet. The size scales and light profiles were measured from HST images. From these data and assuming Virial equilibrium, we estimated the masses of five clusters. The resulting masses range from 6.5x10(5) to 4.7x10(6) M-circle dot. These masses are large, a factor of a few to more than 10 larger than the typical mass of a globular cluster in the Milky Way. The mass-to-light ratios for these clusters in the V- and K-bands in comparison with stellar synthesis models suggest that to first order the IMF slopes are approximately consistent with Salpeter for a mass range of 0.1 to 100 Mcircle dot. However, the clusters show a significant range of possible IMF slopes or lower mass cut-offs and that these variations may correlate with the interstellar environment of the cluster. Comparison with the results of Fokker-Planck simulations of compact clusters with properties similar to the clusters studied here suggest that they are likely to be long-lived and may lose a substantial fraction of their total mass. This mass loss would make the star clusters obtain masses which are comparable to the typical mass of a globular cluste
Free Keywords:galaxies : star clusters; galaxies : individual : NGC 4038/4039; IMF; galaxies : clusters : general; stars : fondamental parameters
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für extraterrestrische Physik
External Affiliations:Leiden Observ, POB 9513, NL-2300 RA Leiden, Netherlands; Max Planck Inst Extraterr Phys, D-85748 Garching, Germany
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