Instrument, method, brightness, and polarization maps from the 2003 flight of BOOMERanG

Abstract

Aims. We present the boomerang-03 experiment, and the maps of the Stokes parameters I, Q, U of the microwave sky obtained during a 14 day balloon flight in 2003. Methods. Using a balloon-borne mm-wave telescope with polarization sensitive bolometers, three regions of the southern sky were surveyed: a deep survey (∼90 square degrees) and a shallow survey (∼750 square degrees) at high Galactic latitudes (both centered at RA 5.5h, Dec −45• ) and a survey of ∼300 square degrees across the Galactic plane at RA 9.1h, dec −47• . All three surveys were carried out in three wide frequency bands centered at 145, 245 and 345 GHz, with an angular resolution of ∼10 . Results. The 145 GHz maps of Stokes I are dominated by Cosmic Microwave Background (CMB) temperature anisotropy, which is mapped with high signal to noise ratio. The measured anisotropy pattern is consistent with the pattern measured in the same region by boomerang-98 and by WMAP. The 145 GHz maps of Stokes Q and U provide a robust statistical detection of polarization of the CMB when subjected to a power spectrum analysis. The amplitude of the detected polarization is consistent with that of the CMB in the ΛCDM cosmological scenario. At 145 GHz, in the CMB surveys, the intensity and polarization of the astrophysical foregrounds are found to be negligible with respect to the cosmological signal. At 245 and 345 GHz we detect ISD emission correlated to the 3000 GHz IRAS/DIRBE maps, and give upper limits for any other non-CMB component. When compared to monitors of different interstellar components, the intensity maps of the surveyed section of the Galactic plane show that a variety of emission mechanisms is present in that region.

A cryogenic waveplate rotator for polarimetry at mm and submm wavelengths

“…Here, the signal caused by interstellar dust at high galactic latitudes is roughly similar to the level of the CMB anisotropy (Masi et al 2001(Masi et al , 2006Ponthieu et al 2005). Higher frequency surveys are more sensitive to the polarization signal of interstellar dust (see Fig.…”

“…1. Measurements of rms fluctuations in interstellar dust emission at Galactic latitudes above 20 • (data points with error bars) from BOOMERanG (filled circles, Masi et al 2001Masi et al , 2006 and Archeops (empty circle, Ponthieu et al 2005). The continuous line is a thermal spectrum with T d = 18 K and ν 2 emissivity.…”

“…Polarization-sensitive bolometers (PSB, Jones et al 2003) have been used in B03 (Masi et al 2006) & Planck (Delabrouille & Kaplan 2001).…”

On the effect of cosmic rays in bolometric cosmic microwave background measurements from the stratosphere

“…We thus estimate the angular power spectrum using cROMAster, a pseudo-C estimator based on MASTER (Hivon et al 2002), which was originally developed for (and applied to) BOOMERanG-B03 (Jones et al 2006;Piacentini et al 2006;Montroy et al 2006;Masi et al 2006) and later improved for PLANCK data analysis. cROMAster can estimate both auto-and cross-power spectra, where the former are more efficient but require noise removal and the latter are less efficient but are naturally unbiased (Polenta et al 2005), therefore residual bias is not expected in the pure cross-spectrum case.…”

“…For filtering purposes, the masked data can be filled with constrained realizations of noise with the same properties as the surrounding data (see e.g. Masi et al 2006). However, in the absence of independent cosmic rays monitors, a number of low level events will remain unidentified, hidden in the noise.…”