Measuring CMB Spectral Distortions from Antarctica with COSMO: Blackbody Calibrator Design and Performance Forecast

CMB spectral distortions from small-scale isocurvature fluctuations

The damping of primordial perturbations at small scales gives rise to distortions of the cosmic microwave background (CMB). Here, the dependence of the distortion on the different types of cosmological initial conditions is explored, covering adiabatic, baryon/cold dark matter isocurvature, neutrino density/velocity isocurvature modes and some mixtures. The radiation transfer functions for each...

Probing early-universe phase transitions with CMB spectral distortions

The CMB spectrum: Perspective of observing spectral distortions

Spectral distortions (deviations from a Planck distribution) of the cosmic microwave background (CMB) are potential sources of information on the thermal history of the Universe. So far however they escaped detection. We suggest a different observational approach useful to discover Bose–Einstein distortions. ! 2006 Elsevier B.V. All rights reserved. PACS: 03.09.05; 03.19.1; 12.03.1

Design and calibration of a cryogenic blackbody calibrator at centimeter wavelengths

We describe the design and calibration of an external cryogenic blackbody calibrator used for the first two flights of the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE) instrument. The calibrator consists of a microwave absorber weakly coupled to a superfluid liquid helium bath. Half-wave corrugations viewed 30° off axis reduce the return loss below −35 dB withi...

Thermalization and Spectral Distortions

Distortions To be continuously transformed with other things is to be untransformed once and for all. The CMB exhibits a perfect blackbody form to the precision of current measurements. The deviations from the intensity of a blackbody are no more than 3 × 10 −4 of the peak intensity [116]. The question arises: how does the blackbody spectrum form and how is it maintained? We have seen in Chapte...