The First Acoustics Peak CMBR and Cosmic Total Density

dc.creatorZhang, De-Hai
dc.date2000-07-16
dc.date.accessioned2026-07-07T01:54:25Z
dc.date.available2026-07-07T01:54:25Z
dc.descriptionBoomerang measured the first peak in CMBR to be at location of $l_D=196\pm 6$, which excites our strong interesting in it. A widely cited formula is $l_D\simeq 200Ω_T^{-0.50}$ to estimate the cosmic total density. Weinberg shows it is not correct and should be $l_D\propto Ω_T^{-1.58}$ near the interest point $(Ω_m,Ω_Λ)=(0.3,0.7)$. We show further that it should be $l_D\propto Ω_T^{-1.43}Ω_m^{-0.147}$ or $Ω_T^{-1.92}Ω_Λ^{0.343}$ near the same point in the more veracious sense if we consider the effect from the sound horizon. We draw a contour graph for the peak location, show that the recent data favor to a closed universe with about $Ω_T\simeq 1.03$. If we insist on obtaining a flat universe, a point $(0.36,0.64)$, i.e., more matter and less vacuum energy, is still possible, which has a more right-side first peak $l_D=208$ in CMBR and a smaller acceleration parameter $-q_0=0.10$ for the $z=0.4$ redshift SNIa.
dc.description7 pages, 1 figure, Latex
dc.identifierhttps://arxiv.org/abs/astro-ph/0007218
dc.identifierhttp://arxiv.org/abs/astro-ph/0007218
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/1339
dc.subjectAstrophysics
dc.titleThe First Acoustics Peak CMBR and Cosmic Total Density
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