Using a phenomenological model to test the coincidence problem of dark energy

Details Using a phenomenological model to test the coincidence problem of dark energy Using a phenomenological model to test the coincidence problem of dark energy

2010-01-11

arxiv.org/abs/1001.1489v2

Astrophys.J. 711: 439-444 ,2010

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

6 pages, 5 figures, accepted for publication in ApJ

Scientific paper

10.1088/0004-637X/711/1/439

By assuming a phenomenological form for the ratio of the DE and DM densities $\rho_X\propto \rho_{m} a^{\xi}$ (Dalal et al.2001), we discuss the cosmic coincidence problem in light of current observational data. $\xi$ is a key parameter to denote the severity of the coincidence problem. In this scenario, $\xi=3$ and $\xi=0$ correspond to $\Lambda$CDM and the self-similar solution without coincidence problem, respectively. Hence, any solution with a scaling parameter $0<\xi<3$ makes the coincidence problem less severe. In addition, the standard cosmology without interaction between DE and DM is characterized by $\xi+3\omega_X=0$, whereas the inequality $\xi+3\omega_X\neq 0$ represents non-standard cosmology. We place observational constraints on the parameters $(\Omega_{X,0},\omega_{X},\xi)$ of this model, by using the Constitution Set, the CMB shift parameter from the 5-year WMAP and the SDSS baryon acoustic peak. Combining the three samples, we get $\Omega_{X,0}=0.72\pm0.02$, $\omega_{X}=-0.98\pm0.07$ and $\xi=3.06\pm0.35$ at 68.3% confidence level. The result shows that the $\Lambda$CDM model still remains a good fit to the recent observational data, as well as, the coincidence problem indeed exists and is quite severe, in the framework of this simple phenomenological model. We further constrain the model with the transition redshift (deceleration / acceleration). It shows that if the transition from deceleration to acceleration happens at the redshit $z > 0.73$, within the framework of this model, we can conclude that the interaction between DE and DM is necessary.

Affiliated with

Also associated with

No associations

Rating

Using a phenomenological model to test the coincidence problem of dark energy does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Using a phenomenological model to test the coincidence problem of dark energy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Using a phenomenological model to test the coincidence problem of dark energy will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-718657