Seven `representative' cosmological models

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The angular power spectrum of CMB temperature anisotropies for seven representative cosmological models, together with experimental observations. Vertical error bars show estimates of 68% confidence level (CL), while upper limits are at 95% CL. Horizontal bars give roughly the uncertainty in angular multipoles for each particular experiment, with points giving $\delta {\rm T}_\ell$ averaged on this $\ell$-range. [data compilation courtesy of M. Tegmark]. From left to right we have:

• Cold+Hot Dark Matter (CHDM) with $\Omega_{\rm C}=0.7$, $\Omega_{\rm B}=0.1$, $\Omega_{\nu}=0.2$ and $\Omega_{\Lambda}=0$; [Here and below C, $\nu$, B and $\Lambda$ stand for CDM, HDM in the form of massive neutrinos, baryons and a cosmological constant, respectively.]

 
• $\Lambda$ + CHDM ($\Lambda$CHDM) with $\Omega_{\rm C}=0.2825$, $\Omega_{\rm B}=0.05$, $\Omega_{\nu}=0.0175$ and $\Omega_{\Lambda}=0.65$; [These two first models assume one family of massive neutrinos.]

 
• Standard (or simple!) CDM (SCDM) with $\Omega_{\rm C}=0.95$, $\Omega_{\rm B}=0.05$ and $\Omega_{\nu}=\Omega_{\Lambda}=0$;

 
• Tilted CDM (TCDM) with $\Omega_{\rm C}=0.9$, $\Omega_{\rm B}=0.1$ and $\Omega_{\nu}=\Omega_{\Lambda}=0$;

 
• Cosmic Strings + $\Lambda$ ($\Lambda$Strings) model [Battye et al, PRL 80, 4847 (1998)] with $\Omega_{\rm C}=0.25$, $\Omega_{\rm B}=0.05$, $\Omega_{\nu}=0$ and $\Omega_{\Lambda}=0.7$;

 
• Low-density (`open') CDM (OCDM) with $\Omega_{\rm C}=0.45$, $\Omega_{\rm B}=0.05$ and $\Omega_{\nu}=\Omega_{\Lambda}=0$;

 
• Global Texture model (Textures) with $\Omega_{\rm C}=0.95$, $\Omega_{\rm B}=0.05$ and $\Omega_{\nu}=\Omega_{\Lambda}=0$, normalized to $\delta {\rmT}_{\ell = 10} = 27.9\mu{\rm K}$ [courtesy of U. Seljak];

The reduced Hubble parameter is always $h=0.5$ except for OCDM ($h=0.6$) and $\Lambda$CHDM ($h=0.65$). Scalar spectral index is $n_{\rm S}=1$ except for TCDM where $n_{\rm S}=0.8$ was taken instead. Normalization to COBE and large-scale structure distribution of galaxies follows [Gawiser and Silk, Science 280, 1405 (1998)]. Note that all models without nonbaryonic dark matter are ruled out by present observations. Even without including the Boomerang-LDB and Maxima-1 data (absent from this diagram) degree-scale experiments currently favour a high first acoustic peak near $\ell\sim 200$.
 

Boomerang-LDB : Link to Plat comme l'Univers, Alejandro Gangui and Laurent Verstraete, `Pour la Science' (Perspective Scientifique), pages 17-20, June 2000. Journal site here. Link to the article here.

Update : Link to CMB anisotropies: tantalizingly close to expectations, by Sean Carroll, MOG fall 2000.

Update : Link to ``In Support of Inflation'', Perspective: Cosmology published in Science 291, 837-838 (2001), by Alejandro Gangui (2 February 2001 issue). Article also accessible from the Science web site just through this page.

Update : Link to ``Radiación de fondo y modelos cosmológicos'' (Review Article in Spanish published in the Journal ``Investigación y Ciencia'', pages 40-46, june 2001, by Alejandro Gangui - local link here). ...and ``press release'' on El Clarín, 30 June 2001 (local link here).

 

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The URL of this page is www.iafe.uba.ar/relatividad/gangui/seven_cmb/ .
Edited by Alejandro Gangui