Constraints on Chaplygin quartessence from the CLASS gravitational lens statistics and supernova data

Free access article

Issue		A&A Volume 417, Number 3, April III 2004


Page(s)		847 - 852
Section		Cosmology (including clusters of galaxies)
DOI		http://dx.doi.org/10.1051/0004-6361:20035627

A&A 417, 847-852 (2004)
DOI: 10.1051/0004-6361:20035627

Constraints on Chaplygin quartessence from the CLASS gravitational lens statistics and supernova data

Abha Dev¹, Deepak Jain² and J. S. Alcaniz³

¹ Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India
e-mail: abha@ducos.ernet.in
² Deen Dayal Upadhyaya College, University of Delhi, Delhi 110015, India
e-mail: deepak@physics.du.ac.in
³ Departamento de Física, Universidade Federal do Rio Grande do Norte, CP 1641, Natal - RN, 59072-970, Brasil

(Received 4 November 2003 / Accepted 31 December 2003 )

Abstract
The nature of the dark components (dark matter and dark energy) that dominate the current cosmic evolution is a completely open question at present. In reality, we do not even know if they really constitute two separated substances. In this paper we use the recent Cosmic All Sky Survey (CLASS) lensing sample to test the predictions of one of the candidates for a unified dark matter/energy scenario, the so-called generalized Chaplygin gas (Cg) which is parametrized by an equation of state $p = -A/\rho_{\rm Cg}^{\alpha}$ where A and $\alpha$ are arbitrary constants. We show that, although the model is in good agreement with this radio source gravitational lensing sample, the limits obtained from CLASS statistics are only marginally compatible with the ones obtained from other cosmological tests. We also investigate the constraints on the free parameters of the model from a joint analysis between CLASS and supernova data.

Key words: cosmology: theory -- cosmology: dark matter -- cosmology: cosmological parameters -- cosmology: distance scale

Offprint request: J. S. Alcaniz, alcaniz@dfte.ufrn.br

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