FURTHER DEFINITION OF THE MASS-METALLICITY RELATION IN GLOBULAR CLUSTER SYSTEMS AROUND BRIGHTEST CLUSTER GALAXIES
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada)
- Utrecht University, P.O. Box 80125, 3508 TC Utrecht (Netherlands)
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
- Naval Research Laboratory, Code 7211, 4555 Overlook Ave. SW, Washington, DC 20375 (United States)
We combine the globular cluster (GC) data for 15 brightest cluster galaxies and use this material to trace the mass-metallicity relations (MMRs) in their globular cluster systems (GCSs). This work extends previous studies which correlate the properties of the MMR with those of the host galaxy. Our combined data sets show a mean trend for the metal-poor subpopulation that corresponds to a scaling of heavy-element abundance with cluster mass Z {approx} M {sup 0.30{+-}}{sup 0.05}. No trend is seen for the metal-rich subpopulation which has a scaling relation that is consistent with zero. We also find that the scaling exponent is independent of the GCS specific frequency and host galaxy luminosity, except perhaps for dwarf galaxies. We present new photometry in (g',i') obtained with Gemini/GMOS for the GC populations around the southern giant ellipticals NGC 5193 and IC 4329. Both galaxies have rich cluster populations which show up as normal, bimodal sequences in the color-magnitude diagram. We test the observed MMRs and argue that they are statistically real, and not an artifact caused by the method we used. We also argue against asymmetric contamination causing the observed MMR as our mean results are no different from other contamination-free studies. Finally, we compare our method to the standard bimodal fitting method (KMM or RMIX) and find our results are consistent. Interpretation of these results is consistent with recent models for GC formation in which the MMR is determined by GC self-enrichment during their brief formation period.
- OSTI ID:
- 21301642
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 138, Issue 3; Other Information: DOI: 10.1088/0004-6256/138/3/758; Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
Similar Records
Globular cluster systems and their host galaxies: comparison of spatial distributions and colors
THE AGES, METALLICITIES, AND ALPHA ELEMENT ENHANCEMENTS OF GLOBULAR CLUSTERS IN THE ELLIPTICAL NGC 5128: A HOMOGENEOUS SPECTROSCOPIC STUDY WITH GEMINI/GEMINI MULTI-OBJECT SPECTROGRAPH