8 November 2010
CMB part two
Sofia Sivertsson
✤
Relikt experiment on the Soviet Prognoz 9 satellite, launched 1 July 1983.
✤
Measured at only one frequency, 37 GHz.
✤
COBE launched 18 November 1989.
✤
”Anisotropy of the microwave background radiation”, submitted 19 January 1992
✤
”Structure in the COBE differential microwave radiometer first-year maps”, submitted 21 April 1992
✤
For some russian opinion and Relikt sky maps, see talk by Alexander Zakharov.
Relikt experiment
6 × 10
−6< ∆T
2/T < 3.3 × 10
−53.3 × 10
−6< ∆T
2/T < 6.2 × 10
−6Absolute calibration in FIRAS
✤
One internal (ICAL) and one external (XCAL) calibrator.
✤
Temperature controlled by a servo loop using an electrical heater and a germanium resistance
thermometer.
✤
ICAL always mounted at the reference horn and XCAL moved onto the aperture for calibration 3 days per month.
✤
Exact measurement of black body spectrum more
important than absolute temperature scale.
Free-free radiation = Bremsstrahlung
✤
Free electron collides with free ion and sends out bremsstrahlung.
✤
Thermal bremsstrahlung (micro - X-ray).
✤
Bremsstrahlung from cosmic ray
electrons (gamma).
Why Planck?
✤
First planned at similar time as WMAP.
✤
Main scientific advantage is the polarization measurement which could detect gravitational waves from inflation.
✤
Measurable also for ”normal” inflationary models.
✤
See figures 28 and 23 in: TASI lectures of inflation.
References
✤ Strukov, Brukhanov, Skulachev & Sazhin ”Anisotropy of the microwave background radiation”, Soviet Astronomy Letters, Vol. 18, p.153 (1992), http://adsabs.harvard.edu/full/1992SvAL...18..153S
✤ Smoot et. al. ”Structure in the COBE differential microwave radiometer first year maps”, ApJ 396, L1-L5 (1992)
✤ Talk by Alexander Zakharov at symposium in Islamabad 2007:
http://www.ncp.edu.pk/docs/iscp/
Constraints_on_alternative_theories_of_gravity_and_cosmology_Zakharov_Islamabad.pdf
✤ Baumann ”TASI Lectures on inflation”, arXiv:0907.5424
✤ Lars Bergstöm, private communication.
✤ Mather et. al. ”Calibrator Design for the COBE Far-Infrared Absolute Spectrophotometer (FIRAS)”, ApJ 512: 511-520 (1999)
