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University of Canterbury programs with SALT. Michael Albrow, Mita Brierley 1 , Peter Cottrell, Jeffrey Simpson, Clare Worley 2 1 now at Astronomy Australia Ltd 2 now at Institute of Astronomy, Cambridge
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University of Canterbury programs with SALT Michael Albrow, Mita Brierley 1, Peter Cottrell, Jeffrey Simpson, Clare Worley 2 1 now at Astronomy Australia Ltd 2 now at Institute of Astronomy, Cambridge Other potential users : Jenni Adams, Loretta Dunne, Chris Gordon, John Hearnshaw, Steve Maddox, Karen Pollard, David Wiltshire
Globular Cluster integrated light studies(Albrow/Brierley) • Most spectroscopic studies of extragalactic globular clusters at low resolution metallicity and alpha-element ratios using the Lick index system • Beyond Milky Way & its satellite galaxies, moderate-to-high resolution spectral studies only on globular cluster system of M31 • Purpose of this research acquire moderate-to-high resolution integrated light spectra of globular clusters in the Milky Way and Large Magellanic Cloud these clusters have CMD-derived ages and spectroscopic abundances of individual stars long slit, integrated-light spectra will be used to help calibrate our new high-resolution theoretical stellar populations spectral models
Young LMC clusters NGC 1831 (red, age 600 Myr) and NGC 1978 (blue, age 1.9 Gyr) in the region around H-beta
Old MW globular clusters NGC 362 (blue) and NGC 6218 (red) in the region around H-delta. Each is overlaid with a 10Gy, [Fe/H] = -1.5 model from Brierley (2010). The clusters have similar metallicity ([Fe/H] = -1.15 and [Fe/H] = -1.37 on the Caretta & Gratton 1997 scale) but NGC 6218 is older than NGC 362 by a factor of 1.25 according to the main-sequence fitting results of Marin-Franch et al (2009). The two spectra are very similar and don’t distinguish between the ages of old globular clusters at the 25% level.
Globular Clusters MOS studies(Simpson/Cottrell/Worley) • Large samples are the key to understanding stellar evolution processes in globular clusters • Can medium resolution spectra provide the key signatures of the nulceosynthetic processes? C, N, Fe, s-process, others • Purpose of this research acquire multi-object spectroscopy of a range of globular clusters w Cen, 47 Tuc, NGC 6752, NGC 362
Spectral Matching @ R~1600 in w Cen ~200 & 850 stars with 2dF on AAT Simpson, Cottrell & Worley, 2012, MNRAS, in press ; Simpson & Cottrell, submitted 220 stars 850 stars
SALT MOS R~3000 NGC 362 (31 slits)
Future (personal) programs with SALT RSS Visible • Fabry-Perot High Resolution mode for abundance studies in globular clusters • Spectropolarimetry for exploring dust around R Coronae Borealis stars • More MOS of globular clusters for abundance studies HRS • Various abundance studies • Stellar variability