Bibcode
Beasley, M. A.; Sharples, R. M.; Bridges, T. J.; Hanes, D. A.; Zepf, S. E.; Ashman, K. M.; Geisler, D.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 318, Issue 4, pp. 1249-1263.
Fecha de publicación:
11
2000
Número de citas
50
Número de citas referidas
40
Descripción
We have derived ages and metallicities from co-added spectra of 131
globular clusters associated with the giant elliptical galaxy NGC 4472.
Based upon a calibration with Galactic globular clusters, we find that
our sample of globular clusters in NGC 4472 span a metallicity range of
approximately -1.6<=[Fe/H]<=0dex. There is evidence of a radial
metallicity gradient in the globular cluster system which is steeper
than that seen in the underlying starlight. Determination of the
absolute ages of the globular clusters is uncertain, but formally, the
metal-poor population of globular clusters has an age of 14.5+/-4Gyr and
the metal-rich population is 13.8+/-6Gyr old. Monte Carlo simulations
indicate that the globular cluster populations present in these data are
older than 6Gyr at the 95per cent confidence level. We find that within
the uncertainties, the globular clusters are old and coeval, implying
that the bimodality seen in the broadband colours primarily reflects
metallicity and not age differences.