First Science from Planck

It’s been quite a long wait for results to emerge from the Planck satellite, which was launched in May 2009, but today the first science results have at last been released. These aren’t to do with the cosmological aspects of the mission – those will have to wait another two years – but things we cosmologists tend to think of as “foregrounds”, although they are of great astrophysical interest in themselves.

For an overview, with lots of pretty pictures,  see the European Space Agency’s Planck site and the UK Planck outreach site; you can also watch this morning’s press briefing in full here.

A repository of all 25 science papers can be found here and there’ll no doubt be a deluge of them on the arXiv tomorrow.

A few of my Cardiff colleagues are currently in Paris living it up at the junket working hard at the serious scientific conference at which these results are being discussed. I, on the other hand, not being one of the in-crowd, am back here in Cardiff, only have a short window in between meetings, project vivas and postgraduate lectures  to comment on the new data. I’m also sure there’ll be a huge amount of interest in the professional media and in the blogosphere for some time to come. I’ll therefore just mention a couple of things that struck me immediately as I went quickly through the papers while I was eating my sandwich; the following was cobbled together from the associated ESA press release.

The first concerns the so-called  ‘anomalous microwave emission’ (aka Foreground X) , which is a diffuse glow most strongly associated with the dense, dusty regions of our Galaxy. Its origin has been a puzzle for decades, but data collected by Planck seem to confirm the theory that it comes from rapidly spinning dust grains. Identifying the source of this emission will help Planck scientists remove foreground contamination which much greater precision, enabling them to construct much cleaner maps of the cosmic microwave background and thus, among other things, perhaps clarify the nature of the various apparent anomalies present in current cosmological data sets.

Here’s a nice composite image of a region of anomalous emission, alongside individual maps derived from low-frequency radio observations as well as two of the Planck channels (left).

Credits: ESA/Planck Collaboration

The colour composite of the Rho Ophiuchus molecular cloud highlights the correlation between the anomalous microwave emission, most likely due to miniature spinning dust grains observed at 30 GHz (shown here in red), and the thermal dust emission, observed at 857 GHz (shown here in green). The complex structure of knots and filaments, visible in this cloud of gas and dust, represents striking evidence for the ongoing processes of star formation. The composite image (right) is based on three individual maps (left) taken at 0.4 GHz from Haslam et al. (1982) and at 30 GHz and 857 GHz by Planck, respectively. The size of the image is about 5 degrees on a side, which is about 10 times the apparent diameter of the full Moon.

The second of the many other exciting results presented today that I wanted to mention is a release of new data on clusters of galaxies – the largest structures in the Universe, each containing hundreds or even thousands of galaxies. Owing to the Sunyaev-Zel’dovich Effect these show up in the Planck data as compact regions of lower temperature in the cosmic microwave background. By surveying the whole sky, Planck stands the best chance of finding the most massive examples of these clusters. They are rare and their number is a sensitive probe of the kind of Universe we live in, how fast it is expanding, and how much matter it contains.

Credits: ESA/Planck Collaboration; XMM-Newton image: ESA

This image shows one of the newly discovered superclusters of galaxies, PLCK G214.6+37.0, detected by Planck and confirmed by XMM-Newton. This is the first supercluster to be discovered through its Sunyaev-Zel’dovich effect. The effect is the name for the cluster’s silhouette against the cosmic microwave background radiation. Combined with other observations, the Sunyaev-Zel’dovich effect allows astronomers to measure properties such as the temperature and density of the cluster’s hot gas where the galaxies are embedded. The right panel shows the X-ray image of the supercluster obtained with XMM-Newton, which reveals that three galaxy clusters comprise this supercluster. The bright orange blob in the left panel shows the Sunyaev-Zel’dovich image of the supercluster, obtained by Planck. The X-ray contours are also superimposed on the Planck image.

UPDATES: For other early perspectives on the early release results, see the blogs of Andrew Jaffe and Stuart Lowe; as usual, Jonathan Amos has done a very quick and well-written news piece for the BBC.


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8 Responses to “First Science from Planck”

  1. [...] This post was mentioned on Twitter by Sean Carroll. Sean Carroll said: First science results from the Planck satellite. [...]

  2. [...] kaum auffallen. Weitere Pressemitteilungen von JPL, UKSA und NASA und Artikel von Nature, BBC, Telescoper, Jaffe, WeirdWarp und [...]

  3. [...] as yet, so I’ll just point you to more interesting resources — e.g. blog posts by Peter Coles or Andrew Jaffe, or this BBC article if you prefer your media more mainstream. Note that these are [...]

  4. Mark McCaughrean Says:

    Thanks for covering this, Peter. It was good to be there to see the first results being presented and discussed, both at the science meeting and the press event. That said, it was a bit of challenge when being interviewed by some rather insistent journalists who wanted us to draw all of the various scientific topics into a single 20 second sound-bite for the readers of USA Today: difficult, given the diversity of the science.

    Similarly, I was put a little on the back foot when I was asked to provide a layman’s description of why B-mode polarisation, if measured by Planck, would be such a key tool for understanding the role of inflation. I mean, yes, I can say that it does, but explaining why is something else … a little more background reading needed before 2013, methinks.

    Very much tongue in cheek, I’m pleased to see that you thought highly enough of the sentences in the ESA press release about the SZ clusters starting “By surveying the whole sky …” and ending “… and how much matter it contains”, that you pasted them verbatim into your blog post. Tsk, tsk; what would your students think? … :-) (Or did “we” lift them from somewhere else … ?)

    • telescoper Says:

      Yes, I plead guilty. I did cut and paste a couple of bits of the press release (and also copied the pictures from there). That’s what press releases are for, especially when you’ve only got a half-hour lunchbreak to write a piece!

    • telescoper Says:

      ps. I shouldn’t worry about explaining the B-mode polarisation. Planck’s not going to measure it. :)

  5. [...] the goodness as yet, so I’ll just point you to moreinteresting resources — e.g. blog posts by PeterColes or Andrew Jaffe, or thisBBC article if youprefer your media more mainstream. Note that these are [...]

  6. [...] ago, a clutch of early release papers from the Planck satellite came out; I blogged about them here. Among these results were some interesting new insights concerning the nature of the Anomalous [...]

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