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arXiv · 1007.2806

The Tidal Tails of the Ultra-Faint Globular Cluster Palomar 1

M. Niederste-Ostholt·V. Belokurov·N. W. Evans·S. Koposov·M. Gieles·M. J. Irwin
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Abstract

Using the Optimal Filter Technique applied to Sloan Digital Sky Survey photometry, we have found extended tails stretching about 1 degree (or several tens of half-light radii) from either side of the ultra-faint globular cluster Palomar 1. The tails contain roughly as many stars as does the cluster itself. Using deeper Hubble Space Telescope data, we see that the isophotes twist in a chacteristic S-shape on moving outwards from the cluster centre to the tails. We argue that the main mechanism forming the tails may be relaxation driven evaporation and that Pal 1 may have been accreted from a now disrupted dwarf galaxy ~500 Myr ago.

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M. Niederste-Ostholt, V. Belokurov, N. W. Evans, S. Koposov, M. Gieles, M. J. Irwin. 2010-08-11. The Tidal Tails of the Ultra-Faint Globular Cluster Palomar 1. https://doi.org/10.1111/j.1745-3933.2010.00931.x

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