16 research outputs found

    Funding Universal Service Obligations with an Essential Facility: Charges vs. Taxes and Subsidies

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    This paper compares three schemes for funding Universal Service Obligations in network industries with an essential facility: an uplift to the network access charge, the establishment of a Universal Service (US) fund financed through a lump-sum tax and a US fund financed through a unit tax. The comparison is made under a duopoly structure with a potential entrant and an incumbent, which owns the essential facility and is responsible for universal service. The incumbent is also constrained to offer the same price on all markets. Using a social welfare criteria, we show that the US fund financed with a lump sum tax dominates the other two schemes, while the US fund with unit tax is equivalent to the access charge uplift.UNIVERSAL SERVICE OBLIGATIONS; ACCESS CHARGES; REGULATION

    First Detection of Polarization of the Submillimetre Diffuse Galactic Dust Emission by Archeops

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    We present the first determination of the Galactic polarized emission at 353 GHz by Archeops. The data were taken during the Arctic night of February 7, 2002 after the balloon--borne instrument was launched by CNES from the Swedish Esrange base near Kiruna. In addition to the 143 GHz and 217 GHz frequency bands dedicated to CMB studies, Archeops had one 545 GHz and six 353 GHz bolometers mounted in three polarization sensitive pairs that were used for Galactic foreground studies. We present maps of the I, Q, U Stokes parameters over 17% of the sky and with a 13 arcmin resolution at 353 GHz (850 microns). They show a significant Galactic large scale polarized emission coherent on the longitude ranges [100, 120] and [180, 200] deg. with a degree of polarization at the level of 4-5%, in agreement with expectations from starlight polarization measurements. Some regions in the Galactic plane (Gem OB1, Cassiopeia) show an even stronger degree of polarization in the range 10-20%. Those findings provide strong evidence for a powerful grain alignment mechanism throughout the interstellar medium and a coherent magnetic field coplanar to the Galactic plane. This magnetic field pervades even some dense clouds. Extrapolated to high Galactic latitude, these results indicate that interstellar dust polarized emission is the major foreground for PLANCK-HFI CMB polarization measurement.Comment: Submitted to Astron. & Astrophys., 14 pages, 12 Fig., 2 Table

    The Cosmic Microwave Background Anisotropy Power Spectrum measured by Archeops

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    We present a determination by the Archeops experiment of the angular power spectrum of the cosmic microwave background anisotropy in 16 bins over the multipole range l=15-350. Archeops was conceived as a precursor of the Planck HFI instrument by using the same optical design and the same technology for the detectors and their cooling. Archeops is a balloon-borne instrument consisting of a 1.5 m aperture diameter telescope and an array of 21 photometers maintained at ~100 mK that are operating in 4 frequency bands centered at 143, 217, 353 and 545 GHz. The data were taken during the Arctic night of February 7, 2002 after the instrument was launched by CNES from Esrange base (Sweden). The entire data cover ~ 30% of the sky.This first analysis was obtained with a small subset of the dataset using the most sensitive photometer in each CMB band (143 and 217 GHz) and 12.6% of the sky at galactic latitudes above 30 degrees where the foreground contamination is measured to be negligible. The large sky coverage and medium resolution (better than 15 arcminutes) provide for the first time a high signal-to-noise ratio determination of the power spectrum over angular scales that include both the first acoustic peak and scales probed by COBE/DMR. With a binning of Delta(l)=7 to 25 the error bars are dominated by sample variance for l below 200. A companion paper details the cosmological implications.Comment: A&A Letter, in press, 6 pages, 4 figures, see also http://www.archeops.or

    Temperature and polarization angular power spectra of Galactic dust radiation at 353 GHz as measured by Archeops

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    We present the first measurement of temperature and polarization angular power spectra of the diffuse emission of Galactic dust at 353 GHz as seen by Archeops on 20% of the sky. The temperature angular power spectrum is compatible with that provided by the extrapolation to 353 GHz of IRAS and DIRBE maps using \cite{fds} model number 8. For Galactic latitudes ∣bâˆŁâ‰„5|b| \geq 5 deg we report a 4 sigma detection of large scale (3≀ℓ≀83\leq \ell \leq 8) temperature-polarization cross-correlation (ℓ+1)CℓTE/2π=76±21ÎŒKRJ2(\ell+1)C_\ell^{TE}/2\pi = 76\pm 21 \mu\rm{K_{RJ}}^2 and set upper limits to the EE and BB modes at 11ÎŒKRJ211 \mu\rm{K_{RJ}}^2. For Galactic latitudes ∣bâˆŁâ‰„10|b| \geq 10 deg, on the same angular scales, we report a 2 sigma detection of temperature-polarization cross-correlation (ℓ+1)CℓTE/2π=24±13ÎŒKRJ2(\ell+1)C_\ell^{TE}/2\pi = 24\pm 13 \mu\rm{K_{RJ}}^2. These results are then extrapolated to 100 GHz to estimate the contamination in CMB measurements by polarized diffuse Galactic dust emission. The TETE signal is then 1.7±0.51.7\pm0.5 and 0.5±0.3ÎŒKCMB20.5\pm0.3 \mu\rm{K^2_{CMB}} for ∣bâˆŁâ‰„5|b| \geq 5 and 10 deg. respectively. The upper limit on EE and BB becomes 0.2ÎŒKCMB2(2σ)0.2 \mu\rm{K^2_{CMB}} (2\sigma). If polarized dust emission at higher Galactic latitude cuts is similar to the one we report here, then dust polarized radiation will be a major foreground for determining the polarization power spectra of the CMB at high frequencies above 100 GHz.Comment: 11 pages, 8 figures, submitted to A

    Archeops: A High Resolution Large Sky Balloon Experiment for Mapping CMB Anisotropies

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    Archeops is a balloon-borne instrument dedicated to measuring cosmic microwave background (CMB) temperature anisotropies at high angular resolution (8 arcminutes) over a large fraction (25%) of the sky in the millimetre domain. Based on Planck High Frequency Instrument (HFI) technology, cooled bolometers (0.1 K) scan the sky in total power mode with large circles at constant elevation. During the course of a 24-hour Arctic-night balloon flight, Archeops will observe a complete annulus on the sky in four frequency bands centered at 143, 217, 353 and 545 GHz with an expected sensitivity to CMB fluctuations of \~100muK for each of the 90 thousand 20 arcminute average pixels. We describe the instrument and its performance obtained during a test flight from Trapani (Sicily) to Spain in July 1999

    Certified Complexity (CerCo)

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    We provide an overview of the FET-Open Project CerCo (‘Certified Complexity’). Our main achievement is the development of a technique for analysing non-functional properties of programs (time, space) at the source level with little or no loss of accuracy and a small trusted code base. The core component is a C compiler, verified in Matita, that produces an instrumented copy of the source code in addition to generating object code. This instrumentation exposes, and tracks precisely, the actual (non-asymptotic) computational cost of the input program at the source level. Untrusted invariant generators and trusted theorem provers may then be used to compute and certify the parametric execution time of the code

    Archeops in-flight performance, data processing, and map making

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    International audienceAims:Archeops is a balloon-borne experiment inspired by the Planck satellite and its high frequency instrument (HFI). It is designed to measure the cosmic microwave background (CMB) temperature anisotropies at high angular resolution (~12 arcmin) over a large fraction of the sky (around 30%) at 143, 217, 353, and 545 GHz. The Archeops 353 GHz channel consists of three pairs of polarized sensitive bolometers designed to detect the polarized diffuse emission of Galactic dust. Methods: In this paper we present an update of the instrumental setup, as well as the flight performance for the last Archeops flight campaign (February 2002 from Kiruna, Sweden). We also describe the processing and analysis of the Archeops time-ordered data for that campaign, which led to measurement of the CMB anisotropy power spectrum in the multipole range ℓ = 10-700 and to the first measurements of both the polarized emission of dust at large angular scales and its power spectra in the multipole range ℓ = 3-70 Results: We present maps covering approximately 30% of the sky. These maps contain Galactic emission, including the Galactic plane, in the four Archeops channels at 143, 217, 353, and 545 GHz and CMB anisotropies at 143 and 217 GHz. These are one of the first sub-degree-resolution maps in the millimeter and submillimeter ranges of the large angular-scale diffuse Galactic dust emission and CMB temperature anisotropies, respectively
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