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http://hdl.handle.net/11375/9328
Title: | Structural Parameters of the M87 Globular Cluster System |
Authors: | Gamboa, Madrid Juan |
Advisor: | Harris, William E. |
Department: | Physics and Astronomy |
Keywords: | Astrophysics and Astronomy;Physics;Astrophysics and Astronomy |
Publication Date: | Jul-2009 |
Abstract: | <p>We derive structural parameters for ~2000 globular clusters in the giant Virgo elliptical M87 using extremely deep Hubble Space Telescope images in F606W (V) and F814W (I) taken with the ACS/WFC. The cluster scale sizes (half-light radii r<sub>h</sub>) and ellipticities are determined from PSF-convolved King-model profile fitting. We find that the r<sub>h</sub> distribution closely resembles the inner Milky Way clusters, peaking at r<sub>h</sub> ≃ 2.5 pc and with virtually no clusters more compact than r<sub>h</sub> ≃ 1 pc. The metal-poor clusters average 24% larger in r<sub>h</sub> than the metal-rich ones. The cluster scale size shows a gradual and noticeable increase with galactocentric distance. Clusters are very slightly larger in the bluer waveband V, a possible hint that we may be beginning to see the effects of mass segregation within the clusters. We derive a color magnitude diagram for the M87 globular cluster system which show a clear bimodal distribution. We analyzed in the detail the sub-structure of the CMD by applying statistical fits to the color distribution. We obtain a Globular Cluster Luminosity Function for all M87 clusters and for its red and blue subpopulations. The best statistical fits describing the Luminosity Functions were also calculated. The metal-poor subpopulation has a brighter peak (mean) than the metal-rich subpopulation.</p> |
URI: | http://hdl.handle.net/11375/9328 |
Identifier: | opendissertations/4461 5481 2044916 |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Size | Format | |
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fulltext.pdf | 2.19 MB | Adobe PDF | View/Open |
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