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Mass Segregation in the Globular Cluster Palomar 5 and its Tidal Tails

A. Koch·E. K. Grebel·M. Odenkirchen·D. Martinez-Delgado·J. A. R. Caldwell
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Abstract

We present the stellar main sequence luminosity function (LF) of the disrupted, low-mass, low-concentration globular cluster Palomar 5 and its well-defined tidal tails, which emanate from the cluster as a result of its tidal interaction with the Milky Way. The results of our deep (B ~ 24.5) wide-field photometry unequivocally indicate that preferentially fainter stars were removed from the cluster so that the LF of the cluster's main body exhibits a significant degree of flattening compared to other globular clusters. There is clear evidence of mass segregation, which is reflected in a radial variation of the LFs. The LF of the tidal tails is distinctly enhanced with faint, low-mass stars. Pal 5 exhibits a binary main sequence, and we estimate a photometric binary frequency of roughly 10%. Also the binaries show evidence of mass segregation with more massive binary systems being more strongly concentrated toward the cluster center.

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A. Koch, E. K. Grebel, M. Odenkirchen, D. Martinez-Delgado, J. A. R. Caldwell. 2004-08-11. Mass Segregation in the Globular Cluster Palomar 5 and its Tidal Tails. https://doi.org/10.1086/425046

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