Lecture 6 Flashcards
Why do we want to go to space to study the CMB?
Because it’s in between the windows where the atmosphere is transparent.
What kind of spectrum signifies the CMB?
Black-body spectrum
What part of the spectrum is the CMB in?
\lambda = 3 mm, \nu = 100GHz
What are the three spatial components of the CMB?
A monopole at 2.7K, A cosmological dipole at \deltaT=3mK, anisotropies at about \deltaT=50 \muK
Who discovered the CMB and with what?
Penzias and Wilson in 1964, Horn antenna.
What was COBE?
Developed by nasa to measure the CMB in space (1989).
What were the three instruments of COBE?
FIRAS: Far-infrared absolute spectrometer, supposed to measure the sprectrum of the CMB precisely.
DMR: Differential microwavve radiometer. Designed to detect anisotropy.
DIRBE: Diffuse infrared background experiment. Designed to measure the absolute brightness at ten wavelengths and polarisation at three shortest.
What was WMAP?
The Wilkinson Microwave Anisotropy Probe, designed to make fundamental cosmological parameter measurements
What is the effect of differential design?
It achieves Thermal stability. It makes sure the noise spectrum is gaussian.
What was PLANCK?
A telescope sent up by ESA in 2009 to survey the CMB.
