A wide-field photometric survey for extratidal tails around five metal-poor globular clusters in the Galactic halo

Abstract

Wide-field deep gri images obtained with the Megacam of the Canada-France-Hawaii Telescope (CFHT) are used to investigate the spatial configuration of stars around five metal-poor globular cluster M15, M30, M53, NGC 5053, and NGC 5466, in a field-of-view ~3 degree. Applying a mask filtering algorithm to the color-magnitude diagrams of the observed stars, we sorted cluster's member star candidates that are used to examine the characteristics of the spatial stellar distribution surrounding the target clusters. The smoothed surface density maps and the overlaid isodensity contours indicate that all of the five metal-poor globular clusters exhibit strong evidence of extratidal overdensity features over their tidal radii, in the form of extended tidal tails around the clusters. The orientations of the observed extratidal features show signatures of tidal tails tracing the clusters' orbits, inferred from their proper motions, and effects of dynamical interactions with the Galaxy. Our findings include detections of a tidal bridge-like feature and an envelope structure around the pair of globular clusters M53 and NGC 5053. The observed radial surface density profiles of target clusters have a deviation from theoretical King models, for which the profiles show a break at 0.5~0.7r_t, extending the overdensity features out to 1.5~2r_t. Both radial surface density profiles for different angular sections and azimuthal number density profiles confirm the overdensity features of tidal tails around the five metal-poor globular clusters. Our results add further observational evidence that the observed metal-poor halo globular clusters originate from an accreted satellite system, indicative of the merging scenario of the formation of the Galactic halo.

69 pages, 21 figures, accepted for publication in the Astronomical Journal

References in corpus (9)

• Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky Survey
• Discovery of a New, Polar-Orbiting Debris Stream in the Milky Way Stellar Halo
• On the structure of tidal tails
• Kinematic Decoupling of Globular Clusters with Extended Horizontal-Branch
• A 500 Parsec Halo Surrounding the Galactic Globular NGC 1851
• Merging of globular clusters within inner galactic regions. II. The Nuclear Star Cluster formation
• Formation and evolution of clumpy tidal tails around globular clusters
• The Tidal Tails of NGC 5466
• The Blue Straggler population in the globular cluster M53 (NGC5024): a combined HST, LBT, CFHT study

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