C. J. MacTavish

A Measurement of the CMB EE Spectrum from the 2003 Flight of BOOMERANG

We report measurements of the CMB polarization power spectra from the 2003 January Antarctic flight of BOOMERANG. The primary results come from 6 days of observation of a patch covering 0.22% of the sky centered near R.A. = 825, decl. = -45

A measurement of the angular power spectrum of the CMB temperature anisotropy from the 2003 flight of Boomerang

We report on observations of the cosmic microwave background (CMB) obtained during the 2003 January flight of BOOMERANG. These results are derived from 195 hr of observation with four 145 GHz polarization-sensitive bolometer (PSB) pairs, identical in design to the four 143 GHz Planck High Frequency Instrument (HFI) polarized pixels. The data include 75 hr of observations distributed over 1.84% of the sky with an additional 120 hr concentrated on the central portion of the field, which represents 0.22% of the full sky. From these data we derive an estimate of the angular power spectrum of temperature fluctuations of the CMB in 24 bands over the multipole range 50 ≤ l ≤ 1500. A series of features, consistent with those expected from acoustic oscillations in the primordial photon-baryon fluid, are clearly evident in the power spectrum, as is the exponential damping of power on scales smaller than the photon mean free path at the epoch of last scattering (l ≳ 900). As a consistency check, the collaboration has performed two fully independent analyses of the time-ordered data, which are found to be in excellent agreement.

Cosmological parameters from the 2003 flight of BOOMERANG

We present the cosmological parameters from the CMB intensity and polarization power spectra of the 2003 Antarctic flight of the BOOMERANG telescope. The BOOMERANG data alone constrain the parameters of the ΛCDM model remarkably well and are consistent with constraints from a multiexperiment combined CMB data set. We add LSS data from the 2dF and SDSS redshift surveys to the combined CMB data set and test several extensions to the standard model including running of the spectral index, curvature, tensor modes, the effect of massive neutrinos, and an effective equation of state for dark energy. We also include an analysis of constraints to a model that allows a CDM isocurvature admixture.

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

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 , Dec ~ −45°) and a survey of ~300 square degrees across the Galactic plane at , 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 ~ . 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 CDM 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.

PROPERTIES OF GALACTIC CIRRUS CLOUDS OBSERVED BY BOOMERANG

The physical properties of galactic cirrus emission are not well characterized. BOOMERANG is a balloon-borne experiment designed to study the cosmic microwave background at high angular resolution in the millimeter range. The BOOMERANG 245 and 345 GHz channels are sensitive to interstellar signals, in a spectral range intermediate between FIR and microwave frequencies. We look for physical characteristics of cirrus structures in a region at high galactic latitudes (b ~ –40°) where BOOMERANG performed its deepest integration, combining the BOOMERANG data with other available data sets at different wavelengths. We have detected eight emission patches in the 345 GHz map, consistent with cirrus dust in the Infrared Astronomical Satellite maps. The analysis technique we have developed allows us to identify the location and the shape of cirrus clouds, and to extract the flux from observations with different instruments at different wavelengths and angular resolutions. We study the integrated flux emitted from these cirrus clouds using data from Infrared Astronomical Satellite (IRAS), DIRBE, BOOMERANG and Wilkinson Microwave Anisotropy Probe in the frequency range 23-3000 GHz (13 mm-100 μm wavelength). We fit the measured spectral energy distributions with a combination of a gray body and a power-law spectra considering two models for the thermal emission. The temperature of the thermal dust component varies in the 7-20 K range and its emissivity spectral index is in the 1-5 range. We identified a physical relation between temperature and spectral index as had been proposed in previous works. This technique can be proficiently used for the forthcoming Planck and Herschel missions data.

SPIDER: A balloon-borne CMB polarimeter for large angular scales

We describe SPIDER, a balloon-borne instrument to map the polarization of the millimeter-wave sky with degree angular resolution. Spider consists of six monochromatic refracting telescopes, each illuminating a focal plane of large-format antenna-coupled bolometer arrays. A total of 2,624 superconducting transition-edge sensors are distributed among three observing bands centered at 90, 150, and 280 GHz. A cold half-wave plate at the aperture of each telescope modulates the polarization of incoming light to control systematics. SPIDERs first flight will be a 20-30-day Antarctic balloon campaign in December 2011. This flight will map ~8% of the sky to achieve unprecedented sensitivity to the polarization signature of the gravitational wave background predicted by inflationary cosmology. The SPIDER mission will also serve as a proving ground for these detector technologies in preparation for a future satellite mission.

Spider optimization: Probing the systematics of a large-scale B-mode experiment

Spider is a long-duration, balloon-borne polarimeter designed to measure large-scale cosmic microwave background (CMB) polarization with very high sensitivity and control of systematics. The instrument will map over half the sky with degree angular resolution in the I, Q, and U Stokes parameters in four frequency bands from 96 to 275 GHz. Spiders ultimate goal is to detect the primordial gravity-wave signal imprinted on the CMB B-mode polarization. One of the challenges in achieving this goal is the minimization of the contamination of B-modes by systematic effects. This paper explores a number of instrument systematics and observing strategies in order to optimize B-mode sensitivity. This is done by injecting realistic-amplitude, time-varying systematics into a set of simulated time streams. Tests of the impact of detector noise characteristics, pointing jitter, payload pendulations, polarization angle offsets, beam systematics, and receiver gain drifts are shown. Spiders default observing strategy is to spin continuously in azimuth, with polarization modulation achieved by either a rapidly spinning half-wave plate or a rapidly spinning gondola and a slowly stepped half-wave plate. Although the latter is more susceptible to systematics, the results shown here indicate that either mode of operation can be used by Spider.

Instrumental and analytic methods for bolometric polarimetry

Aims. 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. Methods. 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. Results. 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.

BOOMERanG constraints on primordial non-Gaussianity from analytical Minkowski functionals

We use Minkowski functionals (MFs) to constrain a primordial non-Gaussian contribution to the cosmic microwave background intensity field as observed in the 150- and 145-GHz BOOMERanG maps from the 1998 and 2003 flights, respectively, performing for the first time a joint analysis of the two data sets. A perturbative expansion of the MF formulae in the limit of a weakly non-Gaussian field yields analytical formulae, derived by Hikage et al., which can be used to constrain the coupling parameter fNL without the need for non-Gaussian simulations. We find −770 < fNL < 500 at 95 per cent CL, significantly improving the previous constraints by De Troia et al. on the BOOMERanG 2003 data set. These are the best fNL limits to date for suborbital probes.

SPIDER: a new balloon-borne experiment to measure CMB polarization on large angular scales

We describe SPIDER, a novel balloon-borne experiment designed to measure the polarization of the Cosmic Microwave Background (CMB) on large angular scales. The primary goal of SPIDER is to detect the faint signature of inflationary gravitational waves in the CMB polarization. The payload consists of six telescopes, each operating in a single frequency band and cooled to 4 K by a common LN/LHe cryostat. The primary optic for each telescope is a 25 cm diameter lens cooled to 4 K. Each telescope feeds an array of antenna coupled, polarization sensitive sub-Kelvin bolometers that covers a 20 degree diameter FOV with diffraction limited resolution. The six focal planes span 70 to 300 GHz in a manner optimized to separate polarized galactic emission from CMB polarization, and together contain over 2300 detectors. Polarization modulation is achieved by rotating a cryogenic half-wave plate in front of the primary optic of each telescope. The cryogenic system is designed for 30 days of operation. Observations will be conducted during the night portions of a mid-latitude, long duration balloon flight which will circumnavigate the globe from Australia. By spinning the payload at 1 rpm with the six telescopes fixed in elevation, SPIDER will map approximately half of the sky at each frequency on each night of the flight.