The Globular Cluster System of M60 (NGC 4649). I. Canada-France-Hawaii Telescope MOS Spectroscopy and Database
We present radial velocity measurements for globular clusters in M60, a giant elliptical galaxy in the Virgo Cluster. Target globular cluster candidates were selected using Washington photometry based on deep 16' x 16' images taken at the KPNO 4 m telescope and using VI photometry derived...
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Veröffentlicht in: | The Astrophysical journal 2008-02, Vol.674 (2), p.857-868 |
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Zusammenfassung: | We present radial velocity measurements for globular clusters in M60, a giant elliptical galaxy in the Virgo Cluster. Target globular cluster candidates were selected using Washington photometry based on deep 16' x 16' images taken at the KPNO 4 m telescope and using VI photometry derived from Hubble Space Telescope WFPC2 archival images. The spectra of the target objects were obtained with the Multi-Object Spectrograph at the Canada-France-Hawaii Telescope. We have measured the radial velocities of 111 objects in the field of M60: 93 globular clusters (72 blue globular clusters with 1.0 less than or equal to C-T sub(1) < 1.7, and 21 red globular clusters with 1.7 less than or equal to C-T sub(1) < 2.4), 11 foreground stars, six small galaxies, and the nucleus of M60. The measured velocities of the 93 globular clusters range from similar to 500 to similar to 1600 km s super(-1), with a mean value of 1070 super(+) sub(-) super(2) sub(2) super(7) sub(5) km s super(-1), which is in good agreement with the velocity of the nucleus of M60 ( [unk] = 1056 km s super(-1)). Combining our results with data from the literature, we present a master catalog of radial velocities for 121 globular clusters in M60. The velocity dispersion of the clusters in the master catalog is found to be 234 super(+) sub(-) super(1) sub(1) super(3) sub(4) km s super(-1) for the entire sample, 223 super(+) sub(-) super(1) sub(1) super(3) sub(4) km s super(-1) for 83 blue globular clusters, and 258 [unk] km s super(-1) for 38 red globular clusters. |
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ISSN: | 0004-637X 1538-4357 |
DOI: | 10.1086/522956 |