Structural Parameters of the M87 Globular Clusters
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Fecha
2009
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Facultad/escuela
Idioma
en
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Licencia CC
Licencia CC
Resumen
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 rh) and ellipticities are determined from PSF-convolved King-model profile fitting. We find that the rh distribution closely resembles the inner Milky Way clusters, peaking at rh ≃ 2.5 pc and with virtually no clusters more compact than rh ≃ 1 pc. The metal-poor clusters have on average an rh 24% larger 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 also derived a color magnitude diagram for the M87 globular cluster system which show a striking bimodal distribution.
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Palabras clave
Galaxies: star clusters ; galaxies: individual (M87) ; galaxies: elliptical and lenticular, cD ; globular clusters: general, Galaxies: individual (M87), Galaxies: elliptical and lenticular, cD, Globular clusters: general
Citación
Astrophys.J.705:237-244,2009