Planck (spacecraft) - Objectives

Objectives

The mission has a wide variety of scientific aims, including:

• High resolution detections of both the total intensity and polarization of the primordial CMB anisotropies
• Creation of a catalogue of galaxy clusters through the Sunyaev-Zel'dovich effect
• Observations of the gravitational lensing of the CMB, as well as the integrated Sachs–Wolfe effect
• Observations of bright extragalactic radio (active galactic nuclei) and infrared (dusty galaxy) sources
• Observations of the Milky Way, including the interstellar medium, distributed synchrotron emission and measurements of the Galactic magnetic field.
• Studies of the Solar System, including planets, asteroids, comets and the zodiacal light.

Planck represents an advance over WMAP in several respects:

• It has higher resolution, allowing it to probe the power spectrum of the CMB to much smaller scales (×3).
• It has higher sensitivity (×10).
• It observes in 9 frequency bands rather than 5, with the goal of improving the astrophysical foreground models.

It is expected that most Planck measurements will be limited by how well foregrounds can be subtracted, rather than by the detector performance or length of the mission. This is particularly important for the polarization measurements. The dominant foreground depends on frequency, but examples include synchrotron radiation from the Milky Way Galaxy at low frequencies, and dust at high frequencies.