CMB Polarization Systematics, Cosmological Birefringence and the Gravitational Waves Background

Cosmic Microwave Background experiments must achieve very accurate calibration of their polarization reference frame to avoid biasing the cosmological parameters. In particular, a wrong or inaccurate calibration might mimic the presence of a gravitational wave background, or a signal from cosmological birefringence, a phenomenon characteristic of several non-standard, symmetry breaking theories of electrodynamics that allow for \textit{in vacuo} rotation if the polarization direction of the photon. Noteworthly, several authors have claimed that the BOOMERanG 2003 (B2K) published polarized power spectra of the CMB may hint at cosmological birefringence. Such analyses, however, do not take into account the reported calibration uncertainties of the BOOMERanG focal plane. We develop a formalism to include this effect and apply it to the BOOMERanG dataset, finding a cosmological rotation angle $\alpha=-4.3^\circ\pm4.1^\circ$. We also investigate the expected performances of future space borne experiment, finding that an overall miscalibration larger then $1^\circ$ for Planck and $0.2\circ$ for EPIC, if not properly taken into account, will produce a bias on the constraints on the cosmological parameters and could misleadingly suggest the presence of a GW background.Comment: 10 pages, 3 figure

Images of the Early Universe from the BOOMERanG experiment

The CMB is the fundamental tool to study the properties of the early universe and of the universe at large scales. In the framework of the Hot Big Bang model, when we look to the CMB we look back in time to the end of the plasma era, at a redshift ~ 1000, when the universe was ~ 50000 times younger, ~ 1000 times hotter and ~ 10^9 times denser than today. The image of the CMB can be used to study the physical processes there, to infer what happened before, and also to study the background geometry of our Universe

Cosmological constraints on the matter equation of state

We investigate the impact of a nonstandard time evolution of the dark matter component on current cosmological bounds from cosmic microwave background (CMB) anisotropies. We found that a less than 0.1% variation in the effective dark matter equation of state w(dm) can drastically change current CMB bounds on the matter density, the Hubble parameter and the age of the Universe. A flat universe without dark energy could provide an excellent fit to current CMB data, providing that w(dm) similar to -10(-2)

OLIMPO: a few arcmin resolution survey at mm and sub-mm wavelengths

OLIMPO is a 2.6 meter on-axis millimeter-wave Cassegrain telescope, mounted on an attitude controlled stratospheric balloon payload. This telescope is designed to be flown with a > 10 days Long Duration CircumPolar flight. The system contains 4 arrays of bolometers in the wavelength bands centered at 150, 220, 350, 600 GHz. The instrument will be diffraction limited at 150 GHz (3.5 arcminutes FWHM). It is currently planned to have a test flight from Trapani in 2003/4

OLIMPO: A few arcmin resolution survey of the sky at mm and sub-mm wavelengths

OLIMPO is a 2.6 meter on-axis millimeter-wave Cassegrain telescope, mounted on an attitude controlled stratospheric balloon payload. This telescope is designed to be flown with a > 10 days Long Duration CircumPolar flight. The system contains 4 arrays of bolometers in the wavelength bands centered at 150, 220, 350, 600 GHz. The instrument will be diffraction limited at 150 GHz (3.5 arcminutes FWHM

OLIMPO: A few arcmin resolution survey of the sky at mm and sub-mm wavelengths

OLIMPO is a 2.6 meter on-axis millimeter-wave Cassegrain telescope, mounted on an attitude controlled stratospheric balloon payload. This telescope is designed to be flown with a > 10 days Long Duration CircumPolar flight. The system contains 4 arrays of bolometers in the wavelength bands centered at 150, 220, 350, 600 GHz. The instrument will be diffraction limited at 150 GHz (3.5 arcminutes FWHM). It is currently planned to have a test flight from Trapani in 2003/4

OLIMPO: a balloon-borne, arcminute-resolution survey of the sky at mm and sub-mm wavelengths

We describe OLIMPO, a balloon-borne telescope devoted to cosmological and astrophysical surveys in the mm and sub-mm range. We summarize the relevant science (principally surveys of SZ clusters, of the sub-mm cosmic background and observations of galactic and cirrus dust) and the innovative sub-systems we have developed. The test flight of the telescope is planned for July 2004; the long duration flight is planned for the end of 2005

OLIMPO: a multi-frequency survey of galaxy clusters and of the cosmic millimetric background

non disponibil

OLIMPO: a multi-frequency survey of galaxy clusters and of the cosmic millimetric background

International School of Physics "Enrico Fermi", Course CLI