The tumultous period after the original announcement that the BICEP2 experiment had supposedly detected strong evidence of cosmological inflation in the form of B-mode polarization in the cosmic microwave background brought a lot of excitement and speculation. It seems that now, more than half a year later, the dust is finally starting to settle (har-har-har).
In all seriousness though: There have been a lot of rumor going around about the possibility that BICEP2's signal could be purely due to dust. At my university, one of the founding fathers of inflationary theory has been publicly proclaiming that the BICEP2 experimenters are 'crap', and that the claimed discovery is 'nonsense'. With the new data release by Planck, it may be time for a new, possibly decisive, analysis of the claimed discovery. Was it real? Was it dust? Is there still room for speculation?
I'm looking for an in-depth exposition of the credibility of the BICEP2 'discovery' of B-mode polarizations, in light of the latest data (if anyone feels other data than Planck latest dataset is relevant here, feel free to discuss it!). How much, if any, faith should we still put in the claimed discovery? Can (part of) the signal be dismissed as coming from galactic dust? Have we seen inflation?
Answer
OK, I found a recent link:
Planck versus BICEP2
Despite the new data, the collaboration did not give any insights into the recent controversy surrounding the possible detection of primordial "B-mode" polarization of the CMB by astronomers working on the BICEP2 telescope. If verified, the BICEP2 observation would be "smoking-gun" evidence for the rapid "inflation" of the early universe – the extremely rapid expansion that cosmologists believe the universe underwent a mere 10^–35 s after the Big Bang. A new analysis of polarized dust emission in our galaxy, carried out by Planck earlier in September, showed that the part of the sky observed by BICEP2 has much more dust than originally anticipated, and while this did not completely rule out BICEP2's original claim, it established that the dust emission is nearly as big as the entire BICEP2 signal. Both Planck and BICEP2 have since been working together on joint analysis of their data, but a result is still forthcoming.
This article was updated on 5 December 2014
Now as the BICEP2 paper had used published Planck data available at that time on the dust in their window of the sky, maybe this means that Planck had underestimated dust at that time? The forthcoming paper should surely clear this up.
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