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Stellar populations in Luminous Red Galaxies: cosmic chronometers?

Published online by Cambridge University Press:  13 April 2010

A. L. Ratsimbazafy
Affiliation:
Physics Dept., Univ. of the Western Cape, Bag X17, Cape Town 7535, South Africa email: [email protected] Centre for High Performance Computing, 15 Lower Hope St, Rosebank, Cape Town, SA
C. M. Cress
Affiliation:
Physics Dept., Univ. of the Western Cape, Bag X17, Cape Town 7535, South Africa email: [email protected] Centre for High Performance Computing, 15 Lower Hope St, Rosebank, Cape Town, SA
S. L. Blyth
Affiliation:
Astronomy Dept., Univ. of Cape Town, Bag X3, Cape Town 7701, SA
S. M. Crawford
Affiliation:
SA Astronomical Observatory, P.O.Box 9, Observatory 7935, Cape Town, SA
E. A. Olivier
Affiliation:
Physics Dept., Univ. of the Western Cape, Bag X17, Cape Town 7535, South Africa email: [email protected] SA Astronomical Observatory, P.O.Box 9, Observatory 7935, Cape Town, SA
K. J. van der Heyden
Affiliation:
Astronomy Dept., Univ. of Cape Town, Bag X3, Cape Town 7701, SA
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Abstract

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The expansion rate of the Universe can potentially be measured using age-dating of Luminous Red Galaxies (LRGs). Here, we explore the validity of the assumptions implicit in this method using LRGs identified in the Millenium Simulation (MS). We use stellar population modelling and spectral synthesis to estimate the errors on ages that can be expected and discuss optimization of such an experiment. We find that H(z) using simulated galaxies from MS can be recovered with high accuracy. Using single stellar populations (SSPs) to age-date LRGs is not sufficient but if the MS star formation histories of galaxies are used, accurate ages are obtainable. We discuss an observing program to carry out this experiment using SALT (Southern African Large Telescope).

Type
Poster Papers
Copyright
Copyright © International Astronomical Union 2010

References

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