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

Sang Hyun Chun, Jae Woo Kim, Sangmo T. Sohn, Jang Hyun Park, Wonyong Han, Ho Il Kim, Young-Wook Lee, Myung Gyoon Lee, Sang Gak Lee, Young-Jong Sohn

Research output: Contribution to journalArticle

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Abstract

Wide-field deep g′r′i′ images obtained with the Megacam of the Canada-France-Hawaii Telescope are used to investigate the spatial configuration of stars around five metal-poor globular clusters M15, M30, M53, NGC5053, and NGC5466, in a field-of-view ∼ 3°. 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 NGC5053. 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 1.5-2rt . 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.

Original languageEnglish
Pages (from-to)606-625
Number of pages20
JournalAstronomical Journal
Volume139
Issue number2
DOIs
Publication statusPublished - 2010 Jan 28

Fingerprint

galactic halos
globular clusters
field survey
metal
metals
profiles
stars
field of view
color-magnitude diagram
proper motion
tracing
France
Canada
diagram
spatial distribution
halos
envelopes
masks
signatures
telescopes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Chun, Sang Hyun ; Kim, Jae Woo ; Sohn, Sangmo T. ; Park, Jang Hyun ; Han, Wonyong ; Kim, Ho Il ; Lee, Young-Wook ; Lee, Myung Gyoon ; Lee, Sang Gak ; Sohn, Young-Jong. / A wide-field photometric survey for extratidal tails around five metal-poor globular clusters in the galactic halo. In: Astronomical Journal. 2010 ; Vol. 139, No. 2. pp. 606-625.
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title = "A wide-field photometric survey for extratidal tails around five metal-poor globular clusters in the galactic halo",
abstract = "Wide-field deep g′r′i′ images obtained with the Megacam of the Canada-France-Hawaii Telescope are used to investigate the spatial configuration of stars around five metal-poor globular clusters M15, M30, M53, NGC5053, and NGC5466, in a field-of-view ∼ 3°. 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 NGC5053. 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 1.5-2rt . 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.",
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A wide-field photometric survey for extratidal tails around five metal-poor globular clusters in the galactic halo. / Chun, Sang Hyun; Kim, Jae Woo; Sohn, Sangmo T.; Park, Jang Hyun; Han, Wonyong; Kim, Ho Il; Lee, Young-Wook; Lee, Myung Gyoon; Lee, Sang Gak; Sohn, Young-Jong.

In: Astronomical Journal, Vol. 139, No. 2, 28.01.2010, p. 606-625.

Research output: Contribution to journalArticle

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T1 - A wide-field photometric survey for extratidal tails around five metal-poor globular clusters in the galactic halo

AU - Chun, Sang Hyun

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AU - Sohn, Sangmo T.

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AU - Han, Wonyong

AU - Kim, Ho Il

AU - Lee, Young-Wook

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AU - Lee, Sang Gak

AU - Sohn, Young-Jong

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