Revisiting the parametrization of equation of state of dark energy via SNIa data |
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Authors: | Dao-Jun Liu Xin-Zhou Li Jiangang Hao Xing-Hua Jin |
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Affiliation: | Centre for Astrophysics, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China;Department of physics, University of Michigan, 500 East University Avenue, Ann Arbor, MI 48109, USA;Cambridge International Centre of Shanghai Normal University, 120 Guilin Road, Shanghai 200234, China |
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Abstract: | In this paper, we revisit the parametrizations of the equation of state of dark energy and point out that comparing merely the χ2 of different fittings may not be optimal for choosing the 'best' parametrization. Another figure of merit for evaluating different parametrizations based on the area of the w ( z ) − z band is proposed. In light of the analysis of some two-parameter parametrizations and models based on available SNIa data, the area of w ( z ) − z band seems to be a good figure of merit, especially in the situation that the value of χ2min for different parametrizations are very close. Therefore, we argue that both the area of the w ( z ) − z band and χ2min should be synthetically considered for choosing a better parametrization of dark energy in the future experiments. |
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Keywords: | cosmological parameters |
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