BAre Galaxy Clusters Altering the Primordial Echoes from the Big Bang?

[wolram]

http://www.ras.org.uk/html/press/pn0401ras.html

Date: 2 February 2004

Issued by Peter Bond, RAS Press Officer (Space Science).

Contact details for this release are listed at the end.

CORRUPTED ECHOS FROM THE BIG BANG?

Are Galaxy Clusters Corrupting the Echoes from the Big Bang?

In recent years, astronomers have obtained detailed measurements of the cosmic microwave background radiation - the 'echo' from the birth of the Universe during the Big Bang.

These results appear to indicate with remarkable precision that our Universe is dominated by mysterious 'cold dark matter' and 'dark energy'. But now a group of UK astronomers has found evidence that the primordial microwave echoes may have been modified or 'corrupted' on their 13 billion year journey to the Earth.

 

[ohwilleke]

Bad WMAP data probably does not cripple the CDM paradigm since galactic dynamics and lensing which are more direct forms of evidence for it, aren't affected by any flaws in WMAP intepretation.

I'm not sure how much dark energy is hurt either. If the paper is correct and you screen for effects of clusters on the background radiation, my intuition is that space would look even flatter, which brings omega total closer to 1, and the Hubble constant and matter density estimates are determined to a significant extent from non-WMAP data.

The biggest impact, it would seem to me, would be to interpretations of what happened in the very early universe. The spatial distribution of imhomogenities in the WMAP data is very important to models that look at large scale structure as a product of quantum fluxuation in the early universe, and people have been tuning their models to fit the WMAP data. The significant change in the spatial distribution of imhomogenities in large scale structure and decline in overall imhomogenities, and suggestion that ancient data may be corrupted more the expected by the stuff floating around prior to major stellar formation may send all of those models to FUBAR land.

 

[Garth]

Quote from that press release

"Our results may ultimately undermine the belief that the Universe is dominated by an elusive cold dark matter particle and the even more enigmatic dark energy," said Professor Shanks.

Although the observational evidence for the standard model of cosmology remains strong, the model does contain very uncomfortable aspects. These arise first because it is based on two pieces of "undiscovered physics" - cold dark matter and dark energy - neither of which has been detected in the laboratory. Indeed, the introduction of these two new components greatly increases the complication of the standard Big Bang inflationary model.

At least the confidence in "precision cosmology" is being questionned - that is much healthier.

If the paper is correct and you screen for effects of clusters on the background radiation, my intuition is that space would look even flatter, which brings omega total closer to 1, and the Hubble constant and matter density estimates are determined to a significant extent from non-WMAP data.

That seems to me to be a curious intuition, DE is invented to make up the mass density to fit the WMAP data of a spacially flat
universe. (Actually conformally flat - but that's another matter) Any change to the data would perturb the analysis of the data away from flatness IMHO.

The biggest impact, it would seem to me, would be to interpretations of what happened in the very early universe. The spatial distribution of imhomogenities in the WMAP data is very important to models that look at large scale structure as a product of quantum fluxuation in the early universe, and people have been tuning their models to fit the WMAP data. The significant change in the spatial distribution of imhomogenities in large scale structure and decline in overall imhomogenities, and suggestion that ancient data may be corrupted more the expected by the stuff floating around prior to major stellar formation may send all of those models to FUBAR land.

Agreed, but FUBAR?? (Pardon my ignorance!)

Garth

 

[SpaceTiger]

Date: 2 February 2004

There's your problem. See here:

http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2004PhRvD..70f3002H&db_key=AST

and here:

http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005astro.ph..2227H&db_key=PRE

 

[hellfire]

To make any claim about the influence of SZ effect on the anisotropies of the CMB, one has to make sure that the observed anisotropies are actually due to SZ effect. This is obvious, but to me this seams a challenging tasks, since one has to correlate existing clusters with lower temperature spots in the CMB (lower temperature spots because the detectors work on the Rayleigh-Jeans part of the spectrum). For scales less or equal than one angular degree (most of the clusters subtend one or several arcmins in the sky) the influence of the SZ effect on the anisotropies may be probably stronger (SZ angular power spectrum) than for the scales which were measured or correlated up to now. But for these scales the correlations are more difficult to obtain. The scale of one angular degree corresponds to the first peak, which delivers information about the baryon and matter content of the universe. I am not aware of the realiability of the methods used to make such correlations as well as estimations of the SZ power, but, as SpaceTiger pointed out, this seams to be at least disputed.

 

[ohwilleke]

Agreed, but FUBAR?? (Pardon my ignorance!)

Military jargon. Google is your friend.

 

[Garth]

Military jargon. Google is your friend.

Now i understand! - I had a FUBAR car once! (Well more than once actually)
Garth