Year: 2018
Type: article
Abstract: In this paper, by considering an absorption probability independent of photon wavelength, we show that current type Ia supernovae (SNe Ia) and gamma-ray burst (GRB) observations plus high-redshift measurements of the cosmic microwave background (CMB) radiation temperature support cosmic acceleration regardless of the transparent-universe assumption. Two flat scenarios are considered in our analyses: the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model and a kinematic model. We consider $\ensuremath{\tau}(z)=2\mathrm{ln}(1+z{)}^{ϵ}$, where $\ensuremath{\tau}(z)$ denotes the opacity between an observer at $z=0$ and a source at $z$. This choice is equivalent to deforming the cosmic distance duality relation as ${D}_{L}{D}_{A}^{\ensuremath{-}1}=(1+z{)}^{2+ϵ}$ and, if the absorption probability is independent of photon wavelength, the CMB temperature evolution law is ${T}_{\mathrm{CMB}}(z)={T}_{0}(1+z{)}^{1+2ϵ/3}$. By marginalizing on the $ϵ$ parameter, our analyses rule out a decelerating universe at 99.99% C.L. for all scenarios considered. Interestingly, by considering only SNe Ia and GRBs observations, we obtain that a decelerated universe---indicated by ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{\ensuremath{\Lambda}}}\ensuremath{\le}0.33$ and ${q}_{0}>0$---is ruled out around $1.5\ensuremath{\sigma}$ C.L. and $2\ensuremath{\sigma}$ C.L., respectively, regardless of the transparent-universe assumption.
Authors: R. F. L. Holanda, S. H. Pereira, Deepak Jain
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2782553060