W. C. Jones

Multiple peaks in the angular power spectrum of the cosmic microwave background: Significance and consequences for cosmology

Multiple Peaks in the Angular Power Spectrum of the Cosmic Microwave Background: Significance and Consequences for Cosmology arXiv:astro-ph/0105296 v1 17 May 2001 P. de Bernardis 1 , P.A.R. Ade 2 , J.J. Bock 3 , J.R. Bond 4 , J. Borrill 5 , A. Boscaleri 6 , K. Coble 7 , C.R. Contaldi 4 , B.P. Crill 8 , G. De Troia 1 , P. Farese 7 , K. Ganga 9 , M. Giacometti 1 , E. Hivon 9 , V.V. Hristov 8 , A. Iacoangeli 1 , A.H. Jaffe 10 , W.C. Jones 8 , A.E. Lange 8 , L. Martinis 11 , S. Masi 1 , P. Mason 8 , P.D. Mauskopf 12 , A. Melchiorri 13 , T. Montroy 7 , C.B. Netterfield 14 , E. Pascale 6 , F. Piacentini 1 , D. Pogosyan 4 , G. Polenta 1 , F. Pongetti 15 , S. Prunet 4 , G. Romeo 15 , J.E. Ruhl 7 , F. Scaramuzzi 11 Dipartimento di Fisica, Universita’ La Sapienza, Roma, Italy Queen Mary and Westfield College, London, UK Jet Propulsion Laboratory, Pasadena, CA, USA Canadian Institute for Theoretical Astrophysics, University of Toronto, Canada National Energy Research Scientific Computing Center, LBNL, Berkeley, CA, USA IROE-CNR, Firenze, Italy Dept. of Physics, Univ. of California, Santa Barbara, CA, USA California Institute of Technology, Pasadena, CA, USA IPAC, California Institute of Technology, Pasadena, CA, USA Department of Astronomy, Space Sciences Lab and Center for Particle Astrophysics, University of CA, Berkeley, CA 94720 USA ENEA, Frascati, Italy Dept. of Physics and Astronomy, Cardiff University, Cardiff CF24 3YB, Wales, UK Nuclear and Astrophysics Laboratory, University of Oxford, Keble Road, Oxford, OX 3RH, UK Depts. of Physics and Astronomy, University of Toronto, Canada Istituto Nazionale di Geofisica, Roma, Italy ABSTRACT Three peaks and two dips have been detected in the power spectrum of the cosmic microwave background from the BOOMERANG experiment, at ∼ 210, 540, 840 and ∼ 420, 750, respec- tively. 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 inflation- ary 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 sec- ond 7-dimensional cosmological parameter space, using an independent computational pipeline, and find excellent agreement: Ω tot = 1.02 +0.06 vs. 1.04±0.05, Ω b h 2 = 0.022 −0.003 vs. 0.019 +0.005 , and n s = 0.96 −0.09 vs. 0.90±0.08. The deviation in primordial spectral index n s is a consequence of the strong correlation with the optical depth. Subject headings: Cosmic Microwave Background Anisotropy, Cosmology

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.

Measurement of cosmic microwave background polarization power spectra from two years of BICEP data

Background Imaging of Cosmic Extragalactic Polarization (BICEP) is a bolometric polarimeter designed to measure the inflationary B-mode polarization of the cosmic microwave background (CMB) at degree angular scales. During three seasons of observing at the South Pole (2006 through 2008), BICEP mapped ~2% of the sky chosen to be uniquely clean of polarized foreground emission. Here, we present initial results derived from a subset of the data acquired during the first two years. We present maps of temperature, Stokes Q and U, E and B modes, and associated angular power spectra. We demonstrate that the polarization data are self-consistent by performing a series of jackknife tests. We study potential systematic errors in detail and show that they are sub-dominant to the statistical errors. We measure the E-mode angular power spectrum with high precision at 21 ≤ l ≤ 335, detecting for the first time the peak expected at l ~ 140. The measured E-mode spectrum is consistent with expectations from a ΛCDM model, and the B-mode spectrum is consistent with zero. The tensor-to-scalar ratio derived from the B-mode spectrum is r = 0.02^(+0.31)_(–0.26), or r < 0.72 at 95% confidence, the first meaningful constraint on the inflationary gravitational wave background to come directly from CMB B-mode polarization.

Planck pre-launch status: The HFI instrument, from specification to actual performance

Context. The High Frequency Instrument (HFI) is one of the two focal instruments of the Planck mission. It will observe the whole sky in six bands in the 100 GHz-1 THz range. Aims: The HFI instrument is designed to measure the cosmic microwave background (CMB) with a sensitivity limited only by fundamental sources: the photon noise of the CMB itself and the residuals left after the removal of foregrounds. The two high frequency bands will provide full maps of the submillimetre sky, featuring mainly extended and point source foregrounds. Systematic effects must be kept at negligible levels or accurately monitored so that the signal can be corrected. This paper describes the HFI design and its characteristics deduced from ground tests and calibration. Methods: The HFI instrumental concept and architecture are feasible only by pushing new techniques to their extreme capabilities, mainly: (i) bolometers working at 100 mK and absorbing the radiation in grids; (ii) a dilution cooler providing 100 mK in microgravity conditions; (iii) a new type of AC biased readout electronics and (iv) optical channels using devices inspired from radio and infrared techniques. Results: The Planck-HFI instrument performance exceeds requirements for sensitivity and control of systematic effects. During ground-based calibration and tests, it was measured at instrument and system levels to be close to or better than the goal specification.

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.

Improved measurement of the angular power spectrum of temperature anisotropy in the cosmic microwave background from two new analyses of BOOMERANG observations

We report the most complete analysis to date of observations of the cosmic microwave background (CMB) obtained during the 1998 flight of BOOMERANG. We use two quite different methods to determine the angular power spectrum of the CMB in 20 bands centered at l = 50-1000, applying them to ~50% more data than has previously been analyzed. The power spectra produced by the two methods are in good agreement with each other and constitute the most sensitive measurements to date over the range 300 < l < 1000. The increased precision of the power spectrum yields more precise determinations of several cosmological parameters than previous analyses of BOOMERANG data. The results continue to support an inflationary paradigm for the origin of the universe, being well fitted by a ~13.5 Gyr old, flat universe composed of approximately 5% baryonic matter, 30% cold dark matter, and 65% dark energy, with a spectral index of initial density perturbations ns ~ 1.

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.

Planck pre-launch status: High Frequency Instrument polarization calibration

The High Frequency Instrument of Planck will map the entire sky in the millimeter and sub-millimeter domain from 100 to 857 GHz with unprecedented sensitivity to polarization (ΔP/Tcmb ∼ 4 × 10 −6 for P either Q or U and Tcmb � 2.7 K) at 100, 143, 217 and 353 GHz. It will lead to major improvements in our understanding of the cosmic microwave background anisotropies and polarized foreground signals. Planck will make high resolution measurements of the E-mode spectrum (up to � ∼ 1500) and will also play a prominent role in the search for the faint imprint of primordial gravitational waves on the CMB polarization. This paper addresses the effects of calibration of both temperature (gain) and polarization (polarization efficiency and detector orientation) on polarization measurements. The specific requirements on the polarization parameters of the instrument are set and we report on their pre-flight measurement on HFI bolometers. We present a semi-analytical method that exactly accounts for the scanning strategy of the instrument as well as the combination of different detectors. We use this method to propagate errors through to the CMB angular power spectra in the particular case of Planck-HFI, and to derive constraints on polarization parameters. We show that in order to limit the systematic error to 10% of the cosmic variance of the E-mode power spectrum, uncertainties in gain, polarization efficiency and detector orientation must be below 0.15%, 0.3% and 1 ◦ respectively. Pre-launch ground measurements reported in this paper already fulfill these requirements.

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.