Is There a Possibility of a Very Extended Reionization Epoch?

[wolram]

http://arxiv.org/PS_cache/astro-ph/pdf/0506/0506486.pdf

Title: A very extended reionization epoch ?
Authors: A. Melchiorri, T. Roy Choudhury, P. Serra, A. Ferrara
Comments: 5 pages, 5 figures

The recent observations of cross temperature-polarization power spectra of the Cosmic Microwave Background (CMB) made by the WMAP satellite are in better agreement with a high value of the Thomson scattering optical depth \tau \approx 0.17. This value is close to \tau = 0.3, which is taken as the upper limit in the parameter extraction analysis made by the WMAP team. However, models with \tau \sim 0.3 provide a good fit to current CMB data and are not significantly excluded when combined with Large Scale Structure data. By making use of a self-consistent reionization model, we verify the astrophysical feasibility of models with \tau \sim 0.3. It turns out that current data on various observations related to the thermal and ionization history of the intergalactic medium are not able to rule out \tau \sim 0.3. The possibility of a very extended reionization epoch can significantly undermine the WMAP constraints on crucial cosmological parameters such as the Hubble constant, the spectral index of primordial fluctuations and the amplitude of dark matter clustering.

 

[AndyW]

Dear forum members,

As a scientist who specializes in cosmology and reionization, I find this paper very interesting. The authors present a compelling argument for the possibility of a very extended reionization epoch, which could have significant implications for our understanding of the early universe and cosmological parameters.

The recent observations by the WMAP satellite have provided us with a better understanding of the CMB and the Thomson scattering optical depth \tau. The value of \tau \approx 0.17 is in good agreement with the upper limit of \tau = 0.3 set by the WMAP team. However, the authors argue that models with \tau \sim 0.3 are still viable and cannot be ruled out by current data when combined with Large Scale Structure data.

Their self-consistent reionization model supports the idea that \tau \sim 0.3 is feasible, and this could have significant implications for the constraints on cosmological parameters such as the Hubble constant, spectral index, and dark matter clustering. It is important to further investigate this possibility and see if it can provide a better fit to current data.

I believe that this paper raises important questions and opens up new avenues for research in the field of cosmology and reionization. I look forward to seeing more studies on this topic and how it could potentially change our understanding of the early universe. Thank you to the authors for their contributions to this area of research.