R. C. Brüns et al. 2009 ApJ 702 1268 doi:10.1088/0004-637X/702/2/1268
R. C. Brüns1, P. Kroupa1 and M. Fellhauer2
Show affiliationsIn the lenticular galaxy NGC 1023 a third population of globular clusters (GCs), called faint fuzzies (FFs), was discovered next to the blue and red GC populations by Larsen & Brodie. While these FFs have colors comparable to the red population, the new population is fainter, larger (R eff>7 pc) and, most importantly, shows clear signs of corotation with the galactic disk of NGC 1023. We present N-body simulations verifying the hypothesis that these disk-associated FFs are related to the young massive cluster complexes (CCs) observed by Bastian et al. in M51, who discovered a mass-radius relation for these CCs. Our models have an initial configuration based on the observations from M51 and are placed on various orbits in a galactic potential derived for NGC 1023. All computations end up with a stable object containing 10%-60% of the initial CC mass after an integration time of 5 Gyr. A conversion to visual magnitudes demonstrates that the resulting objects cover exactly the observed range for FFs. Moreover, the simulated objects show projected half-mass radii between 3.6 and 13.4 pc, in good agreement with the observed FF sizes. We conclude that objects like the young massive CCs in M51 are likely progenitors of the FFs observed in NGC 1023.
galaxies: evolution; galaxies: individual (NGC 1023, M51); galaxies: star clusters; globular clusters: general; methods: N-body simulations
Issue 2 (2009 September 10)
Received 2009 May 11, accepted for publication 2009 July 28
Published 2009 August 19
R. C. Brüns et al. 2009 ApJ 702 1268
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