The globular cluster system of the young elliptical NGC 6702 |
| |
| Authors: | Antonis E Georgakakis Duncan A Forbes Jean P Brodie |
| |
| Institution: | ;1School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT;2Astrophysics &Supercomputing, Swinburne University, Hawthorn, VIC 3122, Australia;3Lick Observatory, University of California, Santa Cruz, CA 95064, USA |
| |
| Abstract: | We study the globular cluster (GC) system of the dust-lane elliptical galaxy NGC 6702, using B -, V - and I -band imaging observations carried out at the Keck telescope. This galaxy has a spectroscopic age of ≈2 Gyr suggesting recent star formation. We find strong evidence for a bimodal GC colour distribution, with the blue peak having a colour similar to that of the Galactic halo GCs. Assuming that the blue GCs are indeed old and metal-poor, we estimate an age of 2–5 Gyr and supersolar metallicity for the red GC subpopulation. Despite the large uncertainties, this is in reasonable agreement with the spectroscopic galaxy age. Additionally, we estimate a specific frequency of S N =2.3±1.1 for NGC 6702. We predict that passive evolution of NGC 6702 will further increase its specific frequency to S N ≈2.7 within 10 Gyr, in closer agreement to that of typical present-day ellipticals. We also discuss evidence that the merger/accretion event that took place a few Gyr ago involved a high gas fraction. |
| |
| Keywords: | globular clusters: general galaxies: individual: NGC 6702 galaxies: star clusters |
|
|
