Bumpy Power Spectra and dT/T

Abstract

With the recent publication of the measurements of the radiation angular power spectrum from the BOOMERanG Antarctic flight (de Bernardis et al. 2000), it has become apparent that the currently favoured spatially-flat cold dark matter model (matter density parameter ${\Omega }_{\mathrm{m}}=0.3$, flatness being restored by a cosmological constant ${\Omega }_{\Lambda }=0.7$, Hubble parameter $h=0.65$, baryon density parameter ${\Omega }_{\mathrm{b}}{h}^2=0.02$) no longer provides a good fit to the data. We describe a phenomenological approach to resurrecting this paradigm. We consider a primordial power spectrum which incorporates a bump, arbitrarily placed at $k_{\mathrm{b}}$, and characterized by a Gaussian in log $k$ of standard deviation ${\sigma }_{\mathrm{b}}$ and amplitude ${\mathrm{A}}_{\mathrm{b}}$, that is superimposed onto a scale-invariant power spectrum. We generate a range of theoretical models that include a bump at scales consistent with cosmic microwave background and large-scale structure observations, and perform a simple ${\chi }^2$ test to compare our models with the $COBE$ DMR data and the recently published BOOMERanG and MAXIMA data. Unlike models that include a high baryon content, our models predict a low third acoustic peak. We find that low $\ell$ observations (20 $<\ell <$ 200) are a critical discriminant of the bumps because the transfer function has a sharp cutoff on the high $\ell$ side of the first acoustic peak...

5 pages, 5 figures, updated references

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• Microwave background constraints on inflationary parameters
• Model Independent Primordial Power Spectrum from Maxima, Boomerang, and DASI Data
• Features in the primordial power spectrum: constraints from the CMB and the limitation of the 2dF and SDSS redshift surveys to detect them
• Bumpy Power Spectra and Galaxy Clusters
• DESIgning concordant distances in the age of precision cosmology: the impact of density fluctuations
• Primordial Feature at the Scale of Superclusters of Galaxies
• Observational Matter Power Spectrum and the Height of the Second Acoustic Peak
• Mapping the Cosmological Confidence Ball Surface
• Early Universe Sources for Cosmic Microwave Background Non-Gaussianity