Planck 2014: The Results That Weren’t….
A big conference started today in Ferrara, Italy, which my duties here at the University of Sussex unfortunately did not allow me to attend. The purpose of the meeting was to announce the latest science results and data products from the Planck mission. There was quite a lot of excitement in advance of today’s session as there was supposed to be a press conference at which some exciting results would be announced. Although I’m in Sussex rather than Italy, I have been doing my best to keep up with some of the goings-on via Twitter.
From what I have gathered, it has so far been a bit of an anti-climax. For a start, it was announced some time ago that the full data sets would not be released during this meeting after all, with the effect the conference would just give a preview of the final Planck results. Here’s an explanation from the Planck website:
– The data products and scientific results will be presented at a public conference in Ferrara.
– It is planned to release full mission data products and scientific papers to the public before the end of 2014. A few of the derived products will need a little more time to be readied for release, but will be made public within the month of January 2015.
So the results were to be “presented”, but not “released”. Hmm..
The press conference scheduled for this morning didn’t actually happen either, so we had to wait for the science sessions for juicy information. Not being there in person I had to pick up what I could from Twitter, which included only a few images with accompanying text (only in French).
Here, for example are the main power-spectra for temperature (TT), E-mode polarization (EE) and the cross-spectrum between the two (TE), together with a picture of the temperature pattern across the sky:
Lovely results of course – look how accurately the data fit the theoretical model curves – but notice that both the TE and EE spectra are cut off at low l. That’s because the polarization signal on large angular scales is so heavily affected by systematics that measurements for l<30 are unreliable. It’s not clear when, if ever, those systematic issues will be resolved. There’s no measurement of the primordial B-mode spectrum to compare with BICEP2, either, although there is a strong detection of a B-mode lensing signal obtained by cross-correlating Planck data with galaxy maps.
Still, that doesn’t mean that there is no polarization data at all. There is for example, this rather beautiful visualization of the polarized emission at 353 GHz, together with the Galactic magnetic field, shown over a thirty-degree square region of the sky:
The science results that I’ve been able to glean from social media largely amount to minor corrections to last year’s results, with only small changes (less than ~1σ) to the cosmological parameters derived from them. Good science, of course, but nothing to get too worked up about. What with the “now you see it, now you don’t” press conference, the decision not to release the data, and the polarization data still being in a mess, I can’t help feeling distinctly underwhelmed by the whole thing. This might be a bit harsh, but I think it’s been a bit of a farce…
Still, at least I’m no longer sad I couldn’t make the conference!Follow @telescoper