Evidence for two distinct stellar initial mass functions: Revisiting the effects of cluster dynamical evolution

Dennis F Zaritsky, Janet E. Colucci, Peter M. Pessev, Rebecca A. Bernstein, Rupali Chandar

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

We measure the velocity dispersions of six galactic globular clusters using spatially integrated spectra, to test for the effects of internal dynamical evolution in the stellar mass-to-light ratios, Υ*, of star clusters. In particular, we revisit whether the low values of Υ* that we found in our previous study, from which we concluded that there are at least two population of stellar clusters with distinct stellar initial mass functions, are artificially depressed by relaxation driven mass loss. The combination of our previous sample of five old clusters and these six now provide an order of magnitude range in cluster mass with which to explore this issue. We find no relationship between cluster mass, or relaxation time, and Υ*. Because relaxation is mass dependent, we conclude that the values of Υ* for these clusters are not strongly affected by dynamical effects, and so confirm the presence of the population of clusters with low Υ*.

Original languageEnglish (US)
Article number121
JournalAstrophysical Journal
Volume770
Issue number2
DOIs
StatePublished - Jun 20 2013

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mass to light ratios
star clusters
globular clusters
stellar mass
effect
relaxation time
loss
test

Keywords

  • galaxies: evolution
  • galaxies: fundamental parameters
  • stars: formation
  • stars: luminosity function, mass function

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Evidence for two distinct stellar initial mass functions : Revisiting the effects of cluster dynamical evolution. / Zaritsky, Dennis F; Colucci, Janet E.; Pessev, Peter M.; Bernstein, Rebecca A.; Chandar, Rupali.

In: Astrophysical Journal, Vol. 770, No. 2, 121, 20.06.2013.

Research output: Contribution to journalArticle

Zaritsky, Dennis F ; Colucci, Janet E. ; Pessev, Peter M. ; Bernstein, Rebecca A. ; Chandar, Rupali. / Evidence for two distinct stellar initial mass functions : Revisiting the effects of cluster dynamical evolution. In: Astrophysical Journal. 2013 ; Vol. 770, No. 2.
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