English

The First Acoustics Peak CMBR and Cosmic Total Density

Astrophysics 2007-05-23 v1

Abstract

Boomerang measured the first peak in CMBR to be at location of lD=196±6l_D=196\pm 6, which excites our strong interesting in it. A widely cited formula is lD200ΩT0.50l_D\simeq 200\Omega_T^{-0.50} to estimate the cosmic total density. Weinberg shows it is not correct and should be lDΩT1.58l_D\propto \Omega_T^{-1.58} near the interest point (Ωm,ΩΛ)=(0.3,0.7)(\Omega_m,\Omega_\Lambda)=(0.3,0.7). We show further that it should be lDΩT1.43Ωm0.147l_D\propto \Omega_T^{-1.43}\Omega_m^{-0.147} or ΩT1.92ΩΛ0.343\Omega_T^{-1.92}\Omega_\Lambda^{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 ΩT1.03\Omega_T\simeq 1.03. If we insist on obtaining a flat universe, a point (0.36,0.64)(0.36,0.64), i.e., more matter and less vacuum energy, is still possible, which has a more right-side first peak lD=208l_D=208 in CMBR and a smaller acceleration parameter q0=0.10-q_0=0.10 for the z=0.4z=0.4 redshift SNIa.

Keywords

Cite

@article{arxiv.astro-ph/0007218,
  title  = {The First Acoustics Peak CMBR and Cosmic Total Density},
  author = {De-Hai Zhang},
  journal= {arXiv preprint arXiv:astro-ph/0007218},
  year   = {2007}
}

Comments

7 pages, 1 figure, Latex