Home List of Titles The globular cluster system of NGC 5846 revisited: colours, sizes and x-ray counterparts
Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/43988
- The globular cluster system of NGC 5846 revisited: colours, sizes and x-ray counterparts
- Chies-Santos, Ana L.; Santiago, Basilio X.; Pastoriza, Miriani G.; Forbes, Duncan A.
- NGC5846 is a giant elliptical galaxy with a previously well studied globular cluster system (GCS) (e.g.  and ), known to have a bimodal colour distribution with a remarkably high red fraction. Here we revisit the central galaxy regions searching for new globular cluster (GC) candidates using archival Hubble Space Telescope WFPC2 images, from which we modelled and subtracted the host light distribution and increased the available sample of GCs. We measured V and I magnitudes following Forbes, Brodie and Huchra  and calibrated with their sample. The colour distribution shows a hint of becoming bluer in the very central galaxy regions. Figure 1 shows the colour distributions of GCs with V < 26.5 for two different rings from the center. The inner population is shifted slightly towards bluer colours relative to the one located further out to the center of the galaxy. The inner regions have a mean (V–I)= 1.17 ± 0.04 compared to (V–I) = 1.24 ± 0.07 in the next radial bin. Thus the difference (δ(V–I) = 0.07) is small enough to place both regions within the metal-rich GC subpopulation and it is of only marginal statistical significance. If real it could be due to a combination of age and/or metallicity effects. We measured sizes following ishape . This code convolves the WFPC2/ HST PSF with model king profile in 2-D. The resulting model image is compared to real GCs and an estimate of the size is derived from the fit. Reliable sizes are obtained for about 60 GCs; their typical effective radii are in the range 3–5 pc. The largest clusters are located in the central regions. No clear evidence for a size-colour relation is found.
- Publication type
- Conference paper
- Research centre
- Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing
- ESO astrophysics symposia: Globular clusters: guides to galaxies: Proceedings of the Joint ESO-FONDAP Workshop on Globular Clusters, Concepcion, Chile, 06-10 March 2006 / Markus Kissler-Patig (ed.), pp. 295-296
- Publication year
- GCs; Globular clusters; Elliptical galaxies; HST; Hubble Space Telescope; NGC 5846; WFPC2; Wide Field and Planetary Camera 2
- 1431-2433 (series ISSN)
- 9783540769606, 3540769609
- Publisher URL
- Copyright © 2009 Springer-Verlag Berlin Heidelberg.
- Peer reviewed