A. Iacoangeli

Cosmology from MAXIMA-1, BOOMERANG, and COBE DMR Cosmic Microwave Background Observations

Recent results from BOOMERANG-98 and MAXIMA-1, taken together with COBE DMR, provide consistent and high signal-to-noise measurements of the cosmic microwave background power spectrum at spherical harmonic multipole bands over 2<l less similar to 800. Analysis of the combined data yields 68% (95%) confidence limits on the total density, Omega(tot) approximately 1.11+/-0.07 (+0.13)(-0.12), the baryon density, Omega(b)h(2) approximately 0.032(+0.005)(-0.004) (+0.009)(-0.008), and the scalar spectral tilt, n(s) approximately 1.01(+0.09)(-0.07) (+0.17)(-0.14). These data are consistent with inflationary initial conditions for structure formation. Taken together with other cosmological observations, they imply the existence of both nonbaryonic dark matter and dark energy in the Universe.

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

Measurement of a Peak in the Cosmic Microwave Background Power Spectrum from the North American Test Flight of Boomerang

We describe a measurement of the angular power spectrum of anisotropies in the cosmic microwave background (CMB) at scales of 0&fdg;3 to 5 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 hr test flight of a prototype system in 1997, we mapped more than 200 deg(2) at high Galactic latitudes in two bands centered at 90 and 150 GHz with a resolution of 26&arcmin; and 16&farcm;5 FWHM, respectively. Analysis of the maps gives a power spectrum with a peak at angular scales of 1 degrees with an amplitude 70 µK(CMB).

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.

The BOOMERanG experiment and the curvature of the Universe

We describe the BOOMERanG experiment and its main result, i.e. the measurement of the large scale curvature of the Universe. BOOMERanG is a balloon-borne microwave telescope with sensitive cryogenic detectors. BOOMERanG has measured the angular distribution of the Cosmic Microwave Background on ∼ 3% of the sky, with a resolution of ∼ 10 arcmin and a sensitivity of ∼ 20μK per pixel. The resulting image is dominated by hot and cold spots with rms fluctuations ∼ 80μK and typical size of ∼ 1o. The detailed angular power spectrum of the image features three peaks and two dips at l = (213−13+10), (541−32+20), (845−25+12) and l = (416−12+22), (750−750+20), respectively. Such very characteristic spectrum can be explained assuming that the detected structures are the result of acoustic oscillations in the primeval plasma. In this framework, the measured pattern constrains the density parameter Ω to be 0.85 < Ω < 1.1 (95% confidence interval). Other cosmological parameters, like the spectral index of initial density fluctuations, the density parameter for baryons, dark matter and dark energy, are detected or constrained by the BOOMERanG measurements and by other recent CMB anisotropy experiments. When combined with other cosmological observations, these results depict a new, consistent, cosmological scenario.

The BOOMERANG North America Instrument: A Balloon-borne Bolometric Radiometer Optimized for Measurements of Cosmic Background Radiation Anisotropies from 0.°3 to 4°

We describe the BOOMERANG North America instrument, a balloon-borne bolometric radiometer designed to map the cosmic microwave background (CMB) radiation with 0.3degrees resolution over a significant portion of the sky. This receiver employs new technologies in bolometers, readout electronics, millimeter-wave optics and filters, cryogenics, scan, and attitude reconstruction. All these subsystems are described in detail in this paper. The system has been fully calibrated in flight using a variety of techniques, which are described and compared. Using this system, we have obtained a measurement of the first peak in the CMB angular power spectrum in a single, few hour long balloon flight. The instrument described here was a prototype of the BOOMERANG Long Duration Balloon experiment.

Mapping the CMB sky: The BOOMERanG experiment

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 30 August 1997 in Texas. The level of performance achieved in the test flight was satisfactory and compatible with the requirements for the long duration flight.

Measuring CMB polarization with Boomerang

Boomerang is a balloon-borne telescope designed for long duration (LDB) flights around Antarctica. The second LDB flight of Boomerang took place in January 2003. The primary goal of this flight was to measure the polarization of the CMB. The receiver uses polarization sensitive bolometers at 145 GHz. Polarizing grids provide polarization sensitivity at 245 and 345 GHz. We describe the Boomerang telescope noting changes made for 2003 LDB flight, and discuss some of the issues involved in the measurement of polarization with bolometers. Lastly, we report on the 2003 flight and provide an estimate of the expected results.

The Italian Astrophysical Observatory in Antarctica: OASI

OASI (Infrared and Sub-mm Antarctic Observatory) is the first large telescope permanently installed in Antarctica. It is located close to the Italian Base in Antarctica (Terra Nova Bay Station, latitude: 74.39 S, longitude: 164.09 E). The OASI first light was received in December 1990 when the wobbling secondary mirror was mounted. The telescope is planned to be an open facility which can operate in the wavelengths range between 350 μm and 3mm. The sky coverage from OASI goes down to a declination of about-35° for a 24 hours/day observing time.