期刊
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
卷 -, 期 12, 页码 -出版社
IOP Publishing Ltd
DOI: 10.1088/1475-7516/2015/12/045
关键词
supernova type Ia - standard candles; gravitational lensing; high redshift galaxies; dark energy theory
资金
- UGC Non-NET scheme (Govt. of India)
- CTP (Jamia Milia Islamia, New Delhi)
- Research Council, University of Delhi, Delhi
In this paper, we use the cosmokinematics approach to study the accelerated expansion of the Universe. This is a model independent approach and depends only on the assumption that the Universe is homogeneous and isotropic and is described by the FRW metric. We parametrize the deceleration parameter, q(z), to constrain the transition redshift (z(t)) at which the expansion of the Universe goes from a decelerating to an accelerating phase. We use three different parametrizations of q(z) namely, q(1)(z) = q(1) + q(2)z, qII(z) = q(3) + q(4) ln(1 + z) and qIII(z) = 1/2 + q5/(1+z)(2). A joint analysis of the age of galaxies, strong lensing and supernovae la data indicates that the transition redshift is less than unity i.e. z(t) < 1. We also use a nonparametric approach (LOESS+SIMEX) to constrain z(t). This too gives z(t) < 1 which is consistent with the value obtained by the parametric approach.
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