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Title: SIMILARITIES IN POPULATIONS OF STAR CLUSTERS

Abstract

We compare the observed mass functions and age distributions of star clusters in six well-studied galaxies: the Milky Way, Magellanic Clouds, M83, M51, and Antennae. In combination, these distributions span wide ranges of mass and age: 10{sup 2} {approx}< M/M{sub Sun} {approx}< 10{sup 6} and 10{sup 6} {approx}< {tau}/yr {approx}< 10{sup 9}. We confirm that the distributions are well represented by power laws: dN/dM{proportional_to}M{sup {beta}} with {beta} Almost-Equal-To -1.9 and dN/d{tau}{proportional_to}{tau}{sup {gamma}} with {gamma} Almost-Equal-To -0.8. The mass and age distributions are approximately independent of each other, ruling out simple models of mass-dependent disruption. As expected, there are minor differences among the exponents at a level close to the true uncertainties, {epsilon}{sub {beta}} {approx} {epsilon}{sub {gamma}} {approx} 0.1-0.2. However, the overwhelming impression is the similarity of the mass functions and age distributions of clusters in these different galaxies, including giant and dwarf, quiescent and interacting galaxies. This is an important empirical result, justifying terms such as 'universal' or 'quasi-universal'. We provide a partial theoretical explanation for these observations in terms of physical processes operating during the formation and disruption of the clusters, including star formation and feedback, subsequent stellar mass loss, and tidal interactions with passing molecular clouds. A fullmore » explanation will require additional information about the molecular clumps and star clusters in galaxies beyond the Milky Way.« less

Authors:
 [1];  [2]
  1. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  2. Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States)
Publication Date:
OSTI Identifier:
22037035
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 752; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; COMPARATIVE EVALUATIONS; DISTRIBUTION; MAGELLANIC CLOUDS; MASS; MILKY WAY; STAR CLUSTERS; STAR EVOLUTION; STARS

Citation Formats

Fall, S. Michael, and Chandar, Rupali, E-mail: fall@stsci.edu, E-mail: rupali.chandar@utoledo.edu. SIMILARITIES IN POPULATIONS OF STAR CLUSTERS. United States: N. p., 2012. Web. doi:10.1088/0004-637X/752/2/96.
Fall, S. Michael, & Chandar, Rupali, E-mail: fall@stsci.edu, E-mail: rupali.chandar@utoledo.edu. SIMILARITIES IN POPULATIONS OF STAR CLUSTERS. United States. doi:10.1088/0004-637X/752/2/96.
Fall, S. Michael, and Chandar, Rupali, E-mail: fall@stsci.edu, E-mail: rupali.chandar@utoledo.edu. Wed . "SIMILARITIES IN POPULATIONS OF STAR CLUSTERS". United States. doi:10.1088/0004-637X/752/2/96.
@article{osti_22037035,
title = {SIMILARITIES IN POPULATIONS OF STAR CLUSTERS},
author = {Fall, S. Michael and Chandar, Rupali, E-mail: fall@stsci.edu, E-mail: rupali.chandar@utoledo.edu},
abstractNote = {We compare the observed mass functions and age distributions of star clusters in six well-studied galaxies: the Milky Way, Magellanic Clouds, M83, M51, and Antennae. In combination, these distributions span wide ranges of mass and age: 10{sup 2} {approx}< M/M{sub Sun} {approx}< 10{sup 6} and 10{sup 6} {approx}< {tau}/yr {approx}< 10{sup 9}. We confirm that the distributions are well represented by power laws: dN/dM{proportional_to}M{sup {beta}} with {beta} Almost-Equal-To -1.9 and dN/d{tau}{proportional_to}{tau}{sup {gamma}} with {gamma} Almost-Equal-To -0.8. The mass and age distributions are approximately independent of each other, ruling out simple models of mass-dependent disruption. As expected, there are minor differences among the exponents at a level close to the true uncertainties, {epsilon}{sub {beta}} {approx} {epsilon}{sub {gamma}} {approx} 0.1-0.2. However, the overwhelming impression is the similarity of the mass functions and age distributions of clusters in these different galaxies, including giant and dwarf, quiescent and interacting galaxies. This is an important empirical result, justifying terms such as 'universal' or 'quasi-universal'. We provide a partial theoretical explanation for these observations in terms of physical processes operating during the formation and disruption of the clusters, including star formation and feedback, subsequent stellar mass loss, and tidal interactions with passing molecular clouds. A full explanation will require additional information about the molecular clumps and star clusters in galaxies beyond the Milky Way.},
doi = {10.1088/0004-637X/752/2/96},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 752,
place = {United States},
year = {2012},
month = {6}
}