Archive for March 17, 2010

Planck and the Cold Galaxy

Posted in The Universe and Stuff with tags , , , , , , on March 17, 2010 by telescoper

Just a quick post to show a cool result from Planck which has just been released by the European Space Agency (ESA). It will be a while before any real cosmological results are available, but in the meantime here are a couple of glimpses into the stuff we cosmologists think of as foreground contamination but which are of course of great interest in themselves to other kinds of astronomers.

The beautiful image above (courtesy of ESA and the HFI Consortium) covers a portion of the sky about 55 degrees across. It is a three-colour combination constructed from Planck’s two shortest wavelength channels (540 and 350 micrometres, corresponding to frequencies of 545 and 857 GHz respectively), and an image at 100 micrometres obtained with the Infrared Astronomical Satellite (IRAS). This combination effectively traces the dust temperature: reddish tones correspond to temperatures as cold as 12 degrees above absolute zero, and whitish tones to significantly warmer ones (a few tens of degrees above absolute zero) in regions where massive stars are currently forming. Overall, the image shows local dust structures within 500 light years of the Sun.

Our top man in the HFI Consortium,  Professor Peter Ade, is quoted as saying

..the HFI is living up to our most optimistic pre-flight expectations.  The wealth of the data is seen in these beautiful multicolour images exposing previously unseen detail in the cold dust components of our galaxy.  There is much to be learned from detailed interpretation of the data which will significantly enhance our understanding of the star formation processes and galactic morphology.

This Planck image was obtained during the first Planck all-sky survey which began in mid-August 2009. By mid-March 2010 more than 98% of the sky has been observed by Planck. Because of the way Planck scans the sky 100% sky coverage for the first survey will take until late-May 2010.

Other new results and a more detailed discussion of this one can be found here and here.