Deep 1.4-GHz observations of diffuse polarized emission

Accepted xx xx xx. Received yy yy yy; in original form zz zz zz Polarized diffuse emission observations at 1.4-GHz in a high Galactic latitude area of the northern Celestial hemisphere are presented. The 3.2 ◦ × 3.2 ◦ field, centred at RA = 10 h 58 m, Dec = +42 ◦ 18 ′ (B1950), has Galactic coordinates l ∼ 172 ◦ , b ∼ +63 ◦ and is located in the region selected as northern target of the BaR-SPOrt experiment. Observations have been performed with the Effelsberg 100-m telescope. We find that the angular power spectra of the E – and B–modes have slopes of βE = −1.79 ± 0.13 and βB = −1.74 ± 0.12, respectively. Because of the very high Galactic latitude and the smooth emission, a weak Faraday rotation action is expected, which allows both a fair extrapolation to Cosmic Microwave Background Polarization (CMBP) frequencies and an estimate of the contamination by Galactic synchrotron emission. We extrapolate the E–mode spectrum up to 32-GHz and confirm the possibility to safely detect the CMBP E–mode signal in the Ka band found in another low emission region (Carretti et al. 2005b). Extrapolated up to 90-GHz, the Galactic synchrotron