The Metallicity Distribution of Intracluster Stars in Virgo

Williams, Benjamin F.; Ciardullo, Robin; Durrell, Patrick R.; Vinciguerra, Matt; Feldmeier, John J.; Jacoby, George H.; Sigurdsson, Steinn; von Hippel, Ted; Ferguson, Henry C.; Tanvir, Nial R.; Arnaboldi, Magda; Gerhard, Ortwin; Aguerri, J. Alfonso L.; Freeman, Ken
Bibliographical reference

The Astrophysical Journal, Volume 656, Issue 2, pp. 756-769.

Advertised on:
2
2007
Number of authors
14
IAC number of authors
1
Citations
96
Refereed citations
82
Description
We have used the Hubble Space Telescope's Advanced Camera for Surveys (ACS) to detect and measure ~5300 stars in a single intracluster field in the Virgo Cluster. By performing F606W and F814W photometry on these stars, we have determined their metallicity distribution function and constrained the types of stars present in this portion of Virgo's intracluster space. Based on the small number of stars detected that were brighter than the red giant branch (RGB) tip, we suggest that in this region, Virgo's intracluster stars are mostly old (>~10 Gyr). Through analysis of the RGB stars themselves, we determine that the population contains the full range of metallicities probed (-2.3<=[M/H]<=0.0). We also present evidence that the younger (<=10 Gyr) component of the population is more metal-rich, with [M/H]>-0.5. The spatial distribution of the most metal-poor stars in the field shows significantly more structure than that of the metal-rich stars, indicating that the intracluster population is not well mixed. We discuss the implications that these observations have for the production of intracluster stars and the dynamical evolution of the Virgo Cluster.