English

Is the present cosmic expansion decelerating?

Cosmology and Nongalactic Astrophysics 2010-12-15 v1

Abstract

We probe the recent cosmic expansion by directly reconstructing the deceleration parameter q(z)q(z) at recent times with a linear expansion at z=0z=0 using the low redshift SNIa and BAO data. Our results show that the observations seem to favor a slowing down of the present cosmic acceleration. Using only very low redshift SNIa data, for example, those within z<0.1z<0.1 or 0.20.2, we find that our Universe may have already entered a decelerating expansion era since a positive q(0)q(0) seems to be favored. This result is further supported by a different approach which aims to reconstruct q(z)q(z) in the whole redshift region. So, the accelerating cosmic expansion may be just a transient phenomenon.

Keywords

Cite

@article{arxiv.1012.3032,
  title  = {Is the present cosmic expansion decelerating?},
  author = {Puxun Wu and Hongwei Yu},
  journal= {arXiv preprint arXiv:1012.3032},
  year   = {2010}
}

Comments

8 pages, 2 figures

R2 v1 2026-06-21T16:58:25.863Z