G. Guarini

A ground-based experiment for CMBR anisotropy observations: MITO

Ground-based observations at millimeter wavelengths are still competitive with space observatories if inevitable foreground contamination is considered at all stages of data acquisition and analysis. Technical solutions together with carefully chosen cosmological targets and observational strategies are the key points in the development of the MITO experiment.

A short-wavelength measurement of the cosmic background radiation anisotropy

The results of a measurement of the cosmic microwave background (CMB) anisotropy at wavelengths between 0.4 and 2 mm, carried out using a balloon-borne 1.2 m telescope, are reported. A high Galactic latitude region about 15 deg wide with a 25 arcmin FWHM beam, switching in the sky with an amplitude of 108 arcmin, was observed. A sky signal correlated with the 100-micron diffuse emission mapped by the IRAS satellite was detected and used for calibration. After removal of this contribution, the residual intensity fluctuations give an upper limit to the anisotropy of the CMB at an equivalent frequency of 9.0/cm. 17 refs.

LIMITATIONS TO THE ACCURACY OF COSMIC BACKGROUND RADIATION ANISOTROPY MEASUREMENTS: ATMOSPHERIC FLUCTUATIONS

We discuss the ultimate limits posed by atmospheric fluctuations to observations of cosmic background anisotropies (CBAs) in ground-based and balloon-borne experiments both in the radio and millimetric regions. We present correlation techniques useful in separating CBAs from atmospheric fluctuations. An experimental procedure is discussed for testing a site in view of possible CBA observations. Four sites with altitudes ranging from 0 up to 3.5 km have been tested.

A balloon borne millimetric telescope: experimental study of the thermal gradients on the primary mirror

Abstract We describe the results of an experiment carried out at balloon altitude in order to monitor the presence of thermal gradients on the surface of the aluminum primary mirror of a Cassegrain telescope.

The TIR project: A balloon telescope for the measurement of CBR anisotropies

We describe the TIR telescope: a 2.6 m telescope which can be carried to balloon altitude, to perform far infrared (FIR) and millimetric (mm) observations. The telescope has been optimized for the search of Cosmic Background Radiation (CBR) Anisotropies and of faint, diffuse mm and FIR sources. We illustrate the scientific problems which this system can deal with and the technical solutions which were considered during the project. Flight experience with a smaller (1.2 m) prototype (the ARGO 1989 telescope) is also described.

High-latitude galactic emission and the search for anisotropies of the cosmic background radiation

The anisotropies of the diffuse radiation in the mm and sub-mm spectral region are studied. These are produced by insterstellar dust emission and radio continuum emission, and can contaminate the measurements of the cosmological background anisotropies. Two high Galactic latitude cosmological windows permit searches for cosmic background radiation anisotropies at a level of Delta-T/T of about 10 to the -6th, at angular scales between about 0.5 and 5 deg, in the spectral interval between 2 and 9/cm. 23 refs.

A Balloon-Borne Experiment Devoted to the Search for Extragalactic Background Anisotropies in the Far IR

Several cosmological scenarios have been proposed, in which a strong extragalactic background in the far infrared region is expected (see Bond, Carr, Hogan (1986) for a review). The Berkeley-Nagoya group claimed to have detected such an emission in a recent rocket-borne experiment carried out in the submillimetre range (Matsumoto et al. (1988)).