First light for Planck

Figure 1: The false-colour strip superimposed on an optical map of the Milky Way indicates the region of the Planck First Light Survey. The two squares indicate regions for which detailed images are available - see below. Credit: ESA, LFI & HFI Consortia (Planck), Background image: Axel Mellinger Click on the image to enlarge it [en]Figure 1: Artist’s view of the satellite PLANCK. Planck will be launched on an Ariane-5 from the Guiana Space Centre, Kourou, French Guiana, at the end of July 2008. It will be launched together with ESA’s Herschel spacecraft, in a dual launch configuration. About 2.5 hours after launch, Planck separates from Herschel, and then starts its cruise to L2 (second Lagrangian point in space), its destination, where it will arrive in less than 6 months. Credit ESA Click on the image to enlarge it

Following launch on 14 May 2009, check-outs of the satellite’s subsystems were started in parallel with the cool-down of the instruments’ detectors. The detectors are looking for variations in the temperature of the CMB that are about a million times smaller than one degree. a feat comparable to measuring from Earth the body heat of a rabbit sitting on the Moon. To achieve this, Planck’s detectors must be cooled to extremely low temperatures, some very close to absolute zero (-273.15°C, or 0 K). A team from LERMA, reinforced by visitors from Caltech and JPL, has performed the delicate tuning of the bolometer of the High Frequency Instrument. The HFI and the Low Frequency Instrument have demonstrated excellent characteristics so far, fulfilling expectations from ground tests. In preparation for routine scientific operations, their long-term stability has been verified by conducting a first ’trial’ survey. the First Light Survey.

The First Light Survey, which began on 13 August 2009, covers a two-week period during which Planck surveyed the sky continuously. It was carried out to verify the stability of the instruments and the ability to calibrate them over long periods to the exquisite accuracy needed. The satellite rotates around its axis, surveying the entire sky over time and in the process measuring tiny fluctuations in the temperature of the Cosmic Microwave Background (CMB). Each map is a ring about 15 degrees wide, stretching across the full sky. Preliminary analysis indicates that the quality of the data is excellent. The first Light survey was completed on 27 August, yielding maps of a strip of the sky, one for each of Planck.s nine frequencies. The maps are taken in 9 bands at frequencies ranging from 30 GHz to 1000 GHz, i.e. wavelengths from 0.3 mm to 1 cm.

Figure 2: This mosaic of maps zooms in on a small part (20ox20o) of the First Light Survey, in which our own Milky Way shines very brightly. Credit: ESA, LFI & HFI Consortia (Planck). Click on the image to enlarge it [en]Figure 2: George F.Smoot, Nobel Prize for Physics in 2006, views the Planck satellite in the Alcatel Alenia Space facilities in Cannes, France, on 1 February 2007. Smoot, from the Lawrence Berkeley National Lab., Univ of California, shares the Nobel prize with John C. Mather (NASA) for the discovery of the blackbody form and anisotropy of the Cosmic Background Radiation - Planck’s object of study. The telescope has an effective diameter of 1.5m and will be cooled passively down to about 40 Kelvin. The Planck satellite can be seen in the background. It can be contained in a volume of 64 cubic meter. Credit ESA, S. Corvaja Click on the image to enlarge it

Figure 3: A zoom in on an approximately 10ox10o region of the First Light Survey where the Milky Way is not the predominant signal shows clearly the features which are of most interest to Planck, i.e. the Cosmic Microwave Background. Credit: ESA, LFI & HFI Consortia (Planck). Click on the image to enlarge it

Planck is an ESA satellite developed with national agencies, especially CNES and CNRS (INSU and IN2P3) for the HFI, and ASI and INAF for the LFI. Credits are available in this pdf document on the International Participation in Herschel and Planck.

Know more

Contact