Constraints on the formation of the globular cluster IC 4499 from multiwavelength photometry

Walker, A. R.; Kunder, A. M.; Andreuzzi, G.; di Cecco, A.; Stetson, P. B.; Monelli, M.; Cassisi, S.; Bono, G.; de Propris, R.; Dall'Ora, M.; Nemec, J. M.; Zoccali, M.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, Volume 415, Issue 1, pp. 643-654.

Advertised on:
7
2011
Number of authors
12
IAC number of authors
1
Citations
30
Refereed citations
28
Description
We present new multiband photometry for the Galactic globular cluster IC 4499 extending well past the main-sequence turn-off in the U, B, V, R, I and DDO 51 bands. This photometry is used to determine that IC 4499 has an age of 12 ± 1 Gyr and a cluster reddening of E(B-V) = 0.22 ± 0.02. Hence, IC 4499 is coeval with the majority of Galactic globular clusters, in contrast to suggestions of a younger age. The density profile of the cluster is observed to not flatten out to at least r˜ 800 arcsec, implying that either the tidal radius of this cluster is larger than previously estimated, or that IC 4499 is surrounded by a halo. Unlike the situation in some other, more massive, globular clusters, no anomalous colour spreads in the ultraviolet are detected among the red giant branch stars. The small uncertainties in our photometry should allow the detection of such signatures apparently associated with variations of light elements within the cluster, suggesting that IC 4499 consists of a single stellar population. Based in part on observations made with the European Southern Observatory telescopes obtained from the ESO/ST-ECF Science Archive Facility.
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