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We present mm-wave observations obtained by the BOOMERanG experiment of Galactic emission at intermediate and high (b < -20 deg) Galactic latitudes. We find that this emission is well correlated with extrapolation of the IRAS-DIRBE maps, and is spectrally consistent with thermal emission from interstellar dust (ISD). The ISD brightness in the 410 GHz map has an angular power spectrum c_l = A l^{-beta} with 2 < beta < 3. At 150 GHz and at multipoles ell \sim 200 the angular power spectrum of the IRAS-correlated dust signal is estimated to be l(l+1)c_l/2 pi = (3.7 \pm 2.9) uK^2. This is negligible with respect to the CMB signal measured by the same experiment l(l+1)c_l/2 pi = (4700 \pm 540) uK^2. For the uncorrelated dust signal we set an upper limit to the contribution to the CMB power at 150GHz and l \sim 200 of l(l+1)c_l/2 pi < 3 uK^2 at 95% C.L. .

We discuss instrumental and analytic methods that have been developed for the first generation of bolometric cosmic microwave background (CMB) polarimeters. The design, characterization, and analysis of data obtained using Polarization Sensitive Bolometers (PSBs) are described in detail. This is followed by a brief study of the effect of various polarization modulation techniques on the recovery of sky polarization from scanning polarimeter data. Having been successfully implemented on the sub-orbital Boomerang experiment, PSBs are currently operational in two terrestrial CMB polarization experiments (QUaD and the Robinson Telescope). We investigate two approaches to the analysis of data from these experiments, using realistic simulations of time ordered data to illustrate the impact of instrumental effects on the fidelity of the recovered polarization signal. We find that the analysis of difference time streams takes full advantage of the high degree of common mode rejection afforded by the PSB design. In addition to the observational efforts currently underway, this discussion is directly applicable to the PSBs that constitute the polarized capability of the Planck HFI instrument., 23 pages, 11 figures. for submission to A&A

Polarized diffuse emission observations at 2.3 GHz in a high Galactic latitude area are presented. The 2\degr X 2\degr field, centred in (\alpha=5^h,\delta=-49\degr), is located in the region observed by the BOOMERanG experiment. Our observations has been carried out with the Parkes Radio telescope and represent the highest frequency detection done to date in low emission areas. Because of a weaker Faraday rotation action, the high frequency allows an estimate of the Galactic synchrotron contamination of the Cosmic Microwave Background Polarization (CMBP) that is more reliable than that done at 1.4 GHz. We find that the angular power spectra of the E- and B-modes have slopes of \beta_E = -1.46 +/- 0.14 and \beta_B = -1.87 +/- 0.22, indicating a flattening with respect to 1.4 GHz. Extrapolated up to 32 GHz, the E-mode spectrum is about 3 orders of magnitude lower than that of the CMBP, allowing a clean detection even at this frequency. The best improvement concerns the B-mode, for which our single-dish observations provide the first estimate of the contamination on angular scales close to the CMBP peak (about 2 degrees). We find that the CMBP B-mode should be stronger than synchrotron contamination at 90 GHz for models with T/S > 0.01. This low level could move down to 60-70 GHz the optimal window for CMBP measures., Comment: 5 pages, 6 figures, accepted for publication in MNRAS Letters

We discuss the algorithmic information approach to the analysis of the observational data on the Universe. Kolmogorov complexity is proposed as a descriptor of the Cosmic Microwave Background (CMB) radiation maps. An algorithm of computation of the complexity is described, applied, first, to toy models and then, to the data of the Boomerang experiment. The sky maps obtained via the summing of two independent Boomerang channels reveal threshold independent behavior of the mean ellipticity of the anisotropies, thus indicating correlations present in the sky signal and possibly carrying crucial information on the curvature and the non-Friedmannian, i.e. accelerated expansion of the Universe. Similar effect has been detected for COBE-DMR 4 year maps. Finally, as another application of these concepts, we consider the possible link between the CMB properties, curvature of the Universe and arrows of time., Talk at XXII Solvay Conference on Physics "The Physics of Communication" (Delphi, November 24-29, 2001); the discussion included

This paper presents a measurement of the angular power spectrum of the Cosmic Microwave Background from l=75 to l=1025 (~10' to 5 degrees) from a combined analysis of four 150 GHz channels in the BOOMERANG experiment. The spectrum contains multiple peaks and minima, as predicted by standard adiabatic-inflationary models in which the primordial plasma undergoes acoustic oscillations. These results significantly constrain the values of Omega_tot, Omega_b h^2, Omega_c h^2 and n_s., Comment: changes to reflect version accepted by ApJ

Three peaks and two dips have been detected in the power spectrum of the cosmic microwave background from the BOOMERANG experiment, at $\ell \sim 210, 540, 840$ and $\ell \sim 420, 750$, respectively. Using model-independent analyses, we find that all five features are statistically significant and we measure their location and amplitude. These are consistent with the adiabatic inflationary model. We also calculate the mean and variance of the peak and dip locations and amplitudes in a large 7-dimensional parameter space of such models, which gives good agreement with the model-independent estimates, and forecast where the next few peaks and dips should be found if the basic paradigm is correct. We test the robustness of our results by comparing Bayesian marginalization techniques on this space with likelihood maximization techniques applied to a second 7-dimensional cosmological parameter space, using an independent computational pipeline, and find excellent agreement: $\Omega_{\rm tot} = 1.02^{+0.06}_{-0.05}$ {\it vs.} $1.04 \pm 0.05$, $\Omega_b h^2 = 0.022^{+0.004}_{-0.003}$ {\it vs.} $0.019^{+0.005}_{-0.004}$, and $n_s = 0.96^{+0.10}_{-0.09}$ {\it vs.} $0.90 \pm 0.08$. The deviation in primordial spectral index $n_s$ is a consequence of the strong correlation with the optical depth., Comment: 15 pages, 6 figures, submitted to Ap.J

BOOMERanG has recently resolved structures on the last scattering surface at redshift ˜ 1100 with high signal to noise ratio. We review the technical advances which made this possible, and we focus on the current results for maps and power spectra, with special attention to the determination of the total mass-energy density in the Universe and of other cosmological parameters.

We report the first results from the BOOMERanG experiment, which mapped at 90, 150, 240 and 410 GHz a wide (3%) region of the microwave sky with minimal local contamination. From the data of the best 150 GHz detector we find evidence for a well defined peak in the power spectrum of temperature fluctuations of the Cosmic Microwave Background, localized at $\ell = 197 \pm 6$, with an amplitude of $(68 \pm 8) \mu K_{CMB}$. The location, width and amplitude of the peak is suggestive of acoustic oscillations in the primeval plasma. In the framework of inflationary adiabatic cosmological models the measured spectrum allows a Bayesian estimate of the curvature of the Universe and of other cosmological parameters. With reasonable priors we find $\Omega = (1.07 \pm 0.06)$ and $n_s = (1.00 \pm 0.08)$ (68%C.L.) in excellent agreement with the expectations from the simplest inflationary theories. We also discuss the limits on the density of baryons, of cold dark matter and on the cosmological constant., Comment: Proc. of the CAPP2000 conference, Verbier, 17-28 July 2000

We have performed a likelihood analysis of the recent data on the Cosmic Microwave Background Radiation (CMBR) anisotropy taken by the Boomerang experiment. We find that this data places a strong upper bound on the radiation density present at recombination. Expressed in terms of the equivalent number of neutrino species the $2\sigma$ bound is N_nu < 13, and the standard model prediction, N_nu = 3.04, is completely consistent the the data. This bound is complementary to the one found from Big Bang nucleosynthesis considerations in that it applies to any type of radiation, i.e. it is not flavour sensitive. It also applies to the universe at a much later epoch, and as such places severe limits on scenarios with decaying neutrinos. The bound also yields a firm upper limit on the lepton asymmetry in the universe., Comment: 4 pages, 2 postscript figures, matches version to appear in PRL

We use the angular power spectrum of the Cosmic Microwave Background, measured during the North American test flight of the BOOMERANG experiment, to constrain the geometry of the universe. Within the class of Cold Dark Matter models, we find that the overall fractional energy density of the universe, Omega, is constrained to be 0.85 < Omega < 1.25 at the 68% confidence level. Combined with the COBE measurement and the high redshift supernovae data we obtain new constraints on the fractional matter density and the cosmological constant., 4 pages, 3 figures LaTeX, emulateapj.sty

We describe a measurement of the angular power spectrum of anisotropies in the Cosmic Microwave Background (CMB) from 0.3 degrees to ~10 degrees from the North American test flight of the BOOMERANG experiment. BOOMERANG is a balloon-borne telescope with a bolometric receiver designed to map CMB anisotropies on a Long Duration Balloon flight. During a 6-hour test flight of a prototype system in 1997, we mapped > 200 square degrees at high galactic latitudes in two bands centered at 90 and 150 GHz with a resolution of 26 and 16.6 arcmin FWHM respectively. Analysis of the maps gives a power spectrum with a peak at angular scales of ~1 degree with an amplitude ~70 uK., 5 pages, 1 figure LaTeX, emulateapj.sty

The BOOMERanG experiment is a stratospheric balloon telescope intended to measure the Cosmic Microwave Background anisotropy at angular scales between a few degrees and ten arcminutes. The experiment features a wide focal plane with 16 detectors in the frequency bands centered at 90, 150, 220, 400 GHz, with FWHM ranging between 18 and 10 arcmin. It will be flown on a long duration (7-14 days) flight circumnavigating Antarctica at the end of 1998. The instrument was flown with a reduced focal plane (6 detectors, 90 and 150 GHz bands, 25 to 15 arcmin FWHM) on a qualification flight from Texas, in August 1997. A wide (~300 sq. deg, i.e. about 5000 independent beams at 150 GHz) sky area was mapped in the constellations of Capricornus, Aquarius, Cetus, with very low foreground contamination. The instrument was calibrated using the CMB dipole and observations of Jupiter. The LDB version of the instrument has been qualified and shipped to Antarctica., 12 pages, 9 figures

We describe the BOOMERanG experiment, a stratospheric balloon telescope intended to measure the Cosmic Microwave Background anisotropy at angular scales between a few degrees and ten arcminutes. The experiment has been optimized for a long duration (7 to 14 days) flight circumnavigating Antarctica at the end of 1998. A test flight was performed on Aug.30, 1997 in Texas. The level of performance achieved in the test flight was satisfactory and compatible with the requirements for the long duration flight., 11 pages, 6 figures

In the 1998-99 flight, BOOMERanG has produced maps of $\sim 4 %$ of the sky at high Galactic latitudes, at frequencies of 90, 150, 240 and 410 GHz, with resolution $\simgt 10'$. The faint structure of the Cosmic Microwave Background at horizon and sub-horizon scales is evident in these maps. These maps compare well to the maps recently obtained at lower frequencies by the WMAP experiment. Here we compare the amplitude and morphology of the structures observed in the two sets of maps. We also outline the polarization sensitive version of BOOMERanG, which was flown early this year to measure the linear polarization of the microwave sky at 150, 240 and 350 GHz., Comment: IAU Symposium 216: Maps of the Cosmos. Sydney 14-17 July 2003 - ASP Conference Series