AAS 205th Meeting, 9-13 January 2005
Session 23 Globular Clusters in and around the Milky Way
Poster, Monday, January 10, 2005, 9:20am-6:30pm, Exhibit Hall

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[23.11] Searching For Extra-Tidal Stars Around Globular Clusters

C. Moskowitz (Wesleyan University), S. R. Majewski, R. R. Munoz, R. J. Patterson (University of Virginia), D. Geisler, J. Arenas (Universidad de Concepcion), K. V. Johnston (Wesleyan University)

Globular Clusters around the Milky Way are thought to be undergoing destruction due to both evaporation and tidal stripping. We search for evidence of escaping stars around ten globular clusters. Our strategy is to distinguish between giant stars that are likely to be from the cluster and foreground field stars (mainly late type dwarfs) by the use of large area CCD photometry in the Washington M,T2+DDO51 system, a filter combination that allows surface gravity sensitivity for late type stars through the M-DDO51 color. Once a sample of giant star candidates is isolated, we apply the second criterion that cluster giants should lie along the red giant locus in the color-magnitude diagram as well-defined by the cluster core. We derive King-model parameters using the surface density profiles generated from the selected cluster giant stars. Cluster giants lying beyond the model tidal radius are taken to be indications of unbound stars. Eight of these ten clusters show evidence for extra-tidal material (our data for the other two does not extend beyond the tidal radius), and we are in the process of taking follow-up spectra of these candidates to confirm their membership to the cluster+debris system.

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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.