In the Dark

Credit to Andrew Jaffe for alerting me to the fact that ESA’s first press release concerning Planck has now been, well, released…

I last blogged about Planck when it had reached its orbit around L2 and cooled down to its working temperature of 100 milliKelvin. Over the ensuing weeks it has been tested and calibrated, prodded and poked (electronically of course) and generally tuned up. More recently it has completed a “mini-survey” to check that it’s all working as planned.

The way Planck scans means that it takes about six months to cover the whole sky, which is much longer than the two-week period allowed for the mini-survey. This explains the fact that a relatively narrow slice of the celestial sphere has been mapped. However, you can see the foreground emission from the Galactic plane quite clearly. Here is the region shown in the box split into the nine separate frequency channels that Planck observes:

The High Frequency Instrument (HFI) is more sensitive to dust, while the Low Frequency Instrument (LFI) detects more radio emission. It all seems to be working as expected!

And finally here’s a blow up of the smaller square above the Galactic plane shown as seen by  LFI and HFI:

This region is much less prone to foreground emission. The fact that similar structures are seen in the two completely independent receivers shows that the structure is not just instrument noise. In other words, Planck is seeing the cosmic microwave background!

Now Planck will carry out its full survey, scanning the sky for another year or so. There will then be an intense period of data analysis for about another year after which the key science results will be published. Exciting times.

This entry was posted on September 17, 2009 at 12:35 pm and is filed under The Universe and Stuff with tags Cosmic Microwave Background, Cosmology, European Space Agency, Planck. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.