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The XLENS Project: Do More Massive Early-Type Galaxies Have More Dark Matter or Different Stellar IMFs?

Published online by Cambridge University Press:  17 July 2013

Chiara Spiniello
Chiara Spiniello*
Affiliation:
Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen, the Netherlands email: spiniello@astro.rug.nl
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Abstract

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The X-shooter Lens Survey (XLENS) aims to study the interplay of dark matter (DM) and stellar content in the inner regions of massive early-type galaxies (ETGs) by combining strong gravitational lensing, dynamical models, and spectroscopic stellar population analysis. XLENS targets a sample of ETGs from the SLACS survey (The Sloan Lens ACS Survey, e.g. Bolton et al. 2006) with velocity dispersions ≥250 kms−1 using the X-Shooter spectrograph on ESO's Very Large Telescope. Recent observations indicate that the internal dark-matter fraction of ETGs increases rapidly with galaxy mass, although some hints for a varying initial mass function (IMF) have also been suggested, where the low-mass end of the stellar IMF steepens with galaxy mass. XLENS first results unambiguously confirm that DM plays an important role already within one effective radius for very massive systems (Spiniello et al. 2011). Moreover, studying equivalent widths of certain red spectral features which are indicators of low-mass stars in massive ETGs (e.g. NaI and TiO2) as a function of age and metallicity (i.e. Mgb, Fe, Hβ), and as function of stellar velocity dispersion, has shown that the IMF slope is varying mildly with galaxy mass (Spiniello et al. 2012).

Keywords

dark mattergalaxiesIMFstructureevolution
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 8 , Symposium S295: The intriguing life of massive galaxies , August 2012 , pp. 221 - 224
Copyright
Copyright © International Astronomical Union 2013 

References

Auger, M. W., Treu, T., Bolton, A. S., et al. 2009, ApJ, 705, 1099Google Scholar
Auger, M. W., Treu, T., Gavazzi, R., et al. 2010, ApJL, 721, L163Google Scholar
Auger, M. W., Treu, T., Bolton, A. S., et al. 2010, ApJ, 724, 511Google Scholar
Barnabè, M., Czoske, O., Koopmans, L. V. E., et al. 2011, MNRAS, 415, 2215Google Scholar
Bastian, N., Covey, K. R., & Meyer, M. R. 2010, ARAA, 48, 339CrossRefGoogle Scholar
Bolton, A. S., Burles, S., Koopmans, L. V. E., et al. 2006, ApJ, 638, 703CrossRefGoogle Scholar
Cappellari, M., McDermid, R. M., Alatalo, K., et al. 2012, Nature, 484, 485Google Scholar
Chabrier, G. 2003, PASP, 115, 763Google Scholar
Conroy, C. & van Dokkum, P. 2012, ApJ, 747, 69Google Scholar
Davé, R. 2008, MNRAS, 385, 147CrossRefGoogle Scholar
Dutton, A. A., Mendel, J. T., & Simard, L. 2012, MNRAS, 422, L33Google Scholar
Kroupa, P. 2001, MNRAS, 322, 231Google Scholar
Graves, G. J., Faber, S. M., & Schiavon, R. P. 2009, ApJ, 698, 1590CrossRefGoogle Scholar
Napolitano, N. R., Romanowsky, A. J., & Tortora, C. 2010, MNRAS, 405, 2351Google Scholar
Spiniello, C., Koopmans, L. V. E., Trager, S. C., Czoske, O., & Treu, T. 2011, MNRAS, 417, 3000Google Scholar
Spiniello, C., Trager, S. C., Koopmans, L. V. E., & Chen, Y. P. 2012, ApJL, 753, L32CrossRefGoogle Scholar
Trager, S. C., Faber, S. M., Worthey, G., & González, J. J. 2000, AJ, 120, 165CrossRefGoogle Scholar
Treu, T., Auger, M. W., Koopmans, L. V. E., et al. 2010, ApJ, 709, 1195CrossRefGoogle Scholar
van Dokkum, P. G. 2008, ApJ, 674, 29Google Scholar
van Dokkum, P. G. & Conroy, C. 2010, Nature, 468, 940Google Scholar
Worthey, G. 1992, in: Barbuy, B., Renzini, A. (eds.), IAU Symposium 149, The Stellar Populations of Galaxies, 149, 507CrossRefGoogle Scholar