C. Burigana

Simultaneous Planck, Swift, and Fermi observations of X-ray and γ-ray selected blazars

We present simultaneous Planck, Swift, Fermi, and ground-based data for 105 blazars belonging to three samples with flux limits in the soft X-ray, hard X-ray, and -ray bands, and we compare our results to those of a companion paper presenting simultaneous Planck and multi-frequency observations of 104 radio-loud northern active galactic nuclei selected at radio frequencies. While we confirm several previous results, our unique data set has allowed us to demonstrate that the selection method strongly influences the results, producing biases that cannot be ignored. Almost all the BL Lac objects have been detected by Fermi Large Area Telescope (LAT), whereas 30 to 40% of the flat-spectrum radio quasars (FSRQs) in the radio, soft X-ray, and hard X-ray selected samples are still below the -ray detection limit even after integrating 27 months of Fermi-LAT data. The radio to sub-millimetre spectral slope of blazars is quite flat, withh i 0 up to about 70 GHz, above which it steepens toh i 0:65. BL Lacs have significantly flatter spectra than FSRQs at higher frequencies. The distribution of the rest-frame synchrotron peak frequency ( S ) in the spectral energy distribution (SED) of FSRQs is the same in all the blazar samples withh S i = 10 13:1 0:1 Hz, while the mean inverse-Compton peak frequency,h IC i, ranges from 10 21 to 10 22 Hz. The distributions of S and of IC of BL Lacs are much broader and are shifted to higher energies than those of FSRQs; their shapes strongly depend on the selection method. The Compton dominance of blazars ranges from less than 0.2 to nearly 100, with only FSRQs reaching values larger than about 3. Its distribution is broad and depends strongly on the selection method, with -ray selected blazars peaking at 7 or more, and radio-selected blazars at values close to 1, thus implying that the common assumption that the blazar power budget is largely dominated by high-energy emission is a selection e ect. A comparison of our multi-frequency data with theoretical predictions shows that simple homogeneous SSC models cannot explain the simultaneous SEDs of most of the -ray detected blazars in all samples. The SED of the blazars that were not detected by Fermi-LAT may instead be consistent with SSC emission. Our data challenge the correlation between bolometric luminosity and S predicted by the blazar sequence.

All-sky astrophysical component separation with Fast Independent Component Analysis (FASTICA)

We present a new, fast, algorithm for the separation of astrophysical components superposed in maps of the sky. The algorithm, based on the Independent Component Analysis (ICA) technique, is aimed at recovering both the spatial pattern and the frequency scalings of the emissions from statistically independent astrophysical processes, present along the line-of-sight, from multi-frequency observations, without any a priori assumption on properties of the components to be separated, except that all of them, but at most one, must have non-Gaussian distributions. The analysis starts from very simple toy-models of the sky emission in order to assess the quality of the reconstruction when inputs are well known and controlled. In particular we study the dependence of the results of separation conducted on and off the Galactic plane independently, showing that optimal separation is achieved for sky regions where components are smoothly distributed. Then we move to more realistic applications on simulated observations of the microwave sky with angular resolution and instrumental noise at the mean nominal levels for the Planck satellite. We consider several Planck observation channels containing the most important known diffuse signals: the Cosmic Microwave Background (CMB), Galactic synchrotron, dust and free-free emissions. A method for calibrating the reconstructed maps of each component at each frequency has been devised. The spatial pattern of all the components have been recovered on all scales probed by the instrument. In particular, the CMB angular power spectra is recovered at the percent level up to lmax ≃ 2000. Frequency scalings and normalization have been recovered with better than 1% precision for all the components at frequencies and in sky regions where their signalto-noise ratio > ∼ 1.5; the error increases at ∼ 10% level for signal-to-noise ratios ≃ 1.

WMAP and the generalized Chaplygin gas

We compare the WMAP temperature power spectrum and SNIa data to models with a generalized Chaplygin gas as dark energy. The generalized Chaplygin gas is a component with an exotic equation of state, pX = −A/ραX (a polytropic gas with negative constant and exponent). Our main result is that, restricting to a flat universe and to adiabatic pressure perturbations for the generalized Chaplygin gas, the constraints at 95% CL to the present equation of state wX = pX/ρX and to the parameter α are −1 ≤ wX < −0.8, 0 ≤ α < 0.2, respectively. Moreover, we show that a Chaplygin gas (α = 1) is ruled out as a candidate for dark energy by our analysis at more than the 99.99% CL. A generalized Chaplygin gas appears much less likely as a unified dark matter candidate (ΩCDM = 0) than as a dark energy model, although its χ2 is only two sigma away from the expected value.

A radio catalog of Galactic HII regions for applications from decimeter to millimeter wavelengths

LBNL, SSL, Physics Department, University of California, Berkeley, CA 94720, USAReceived July 27, 2002; accepted October 10, 2002Abstract. By collecting the information from 24 previously published lists and catalogs, we produce a compre-hensive catalog (Master Catalog) of 1442 Galactic HII regions. For each object, we quote the original fluxes anddiameters as well as the available information on radio line velocities, line widths and line temperatures andthe errors on these quantitities. References to the original works are also reported. By exploiting all these datawe produce a Synthetic Catalog of fluxes and diameters (with corresponding errors) at 2.7 GHz. This choiceis motivated by the extensive, although not complete, information available at this frequency, widely spreadamong many different catalogs, and by its relevance for both detailed studies on Galactic HII regions and theextrapolation up to millimetric wavelengths. The catalog can be used for detailed studies of Galactic HII regionsand, by extrapolation, for investigations of HII regions up to millimetric wavelengths. In particular, we discussthe study of the effects of microwave emission from HII regions on the new generation of Cosmic MicrowaveBackground (CMB) experiments. We present simulations of the detection of HII regions in the Planck highresolution CMB survey, and briefly analize some of the typical applications of our catalog to the evaluation ofCMB anisotropy experiments such as calibration, beam reconstruction and straylight effects. The Master Catalogand the Synthetic Catalog are available via ftp at: cdsarc.u-strasbg.fr. This work is related to Planck-LFIactivities.Key words. HII Regions – Catalogs – cosmic microwave background

1=f noise and other systematic effects in the Planck-LFI radiometers

We use an analytic approach to study the susceptibility of the Planck Low Frequency Instrument radiometers to various systematic eects. We examine the eects of fluctuations in amplifier gain, in amplifier noise temperature and in the reference load temperature. We also study the eect of imperfect gain modulation, non-ideal matching of radiometer parameters, imperfect isolation in the two legs of the radiometer and back-end 1=f noise. We find that with proper gain modulation 1=f gain fluctuations are suppressed, leaving fluctuations in amplifier noise temperature as the main source of 1=f noise. We estimate that with a gain modulation factor within1% of its ideal value the overall 1=f knee frequency will be relatively small (<0.1 Hz).

Full sky study of diffuse Galactic emission at decimeter wavelenghts

A detailed knowledge of the Galactic radio continuum is of high interest for studies of the dynamics and structure of the Galaxy as well as for the problem of foreground removal in Cosmic Microwave Background measurements. In this work we present a full-sky study of the diffuse Galactic emission at frequencies of few GHz, where synchrotron radiation is by far the dominant component. We perform a detailed combined analysis of the extended surveys at 408, 1420 and 2326 MHz (by Haslam et al. 1982; Reich 1982; Reich & Reich 1986; Jonas et al. 1998, respectively). Using the technique applied by Schlegel et al. (1998) to the IRAS data, we produce destriped versions of the three maps. This allows us to construct a nearly-full-sky map of the spectral index and of the normalization factor with sub-degree angular resolution. The resulting distribution of the spectral indices has an average of ¯ β = 2.695 and dispersion σβ = 0.120. This is representative for the Galactic diffuse synchrotron emission, with only minor effects from free-free emission and point sources. The maps produced in this work are available via ftp at cdsarc.u-strasbg.fr

Planck pre-launch status: The optical system

Planck is a scientific satellite that represents the next milestone in space-based research related to the cosmic microwave background, and in many other astrophysical fields. Planck was launched on 14 May of 2009 and is now operational. The uncertainty in the optical response of its detectors is a key factor allowing Planck to achieve its scientific objectives. More than a decade of analysis and measurements have gone into achieving the required performances. In this paper, we describe the main aspects of the Planck optics that are relevant to science, and the estimated in-flight performance, based on the knowledge available at the time of launch. We also briefly describe the impact of the major systematic effects of optical origin, and the concept of in-flight optical calibration. Detailed discussions of related areas are provided in accompanying papers.

The impact of Galactic synchrotron emission on CMB anisotropy measurements - I. Angular power spectrum analysis of total intensity all-sky surveys

Context. Galactic foreground emission fluctuations are a limiting factor for precise cosmic microwave background (CMB) anisotropy measurements. Aims. We intend to improve current estimates of the influence of Galactic synchrotron emission on the analysis of CMB anisotropies. Methods. We perform an angular power spectrum analysis (APS) of all-sky total intensity maps at 408 MHz and 1420 MHz, which are dominated by synchrotron emission out of the Galactic plane. We subtract the brighter sources from the maps, which turns out to be essential for the results obtained. We study the APS as a function of Galactic latitude by considering various cuts and as a function of sky position by dividing the sky into patches of ∼15 ◦ × 15 ◦ in size. Results. The APS of the Galactic radio diffuse synchrotron emission is best fitted by a power law, C� ∼ k� α , with α ∈ [−3.0, −2.6], where the lower values of α typically correspond to the higher latitudes. Nevertheless, the analysis of the patches reveals that strong local variations exist. A good correlation is found between the APS normalized amplitude, k100 = k×100 α , at 408 MHz and 1420 MHz. The mean APS for � ∈ [20, 40] is used to determine the mean spectral index between 408 MHz and 1420 MHz, β(0.408−1.4) GHz ∈ [−3.2, −2.9] (C� (ν) ∝ ν −2β ), which is then adopted to extrapolate the synchrotron APS results to the microwave range. Conclusions. We use the 408 MHz and 1420 MHz APS results to predict the Galactic synchrotron emission fluctuations at frequencies above 20 GHz. A simple extrapolation to 23 GHz of the synchrotron emission APS found at these radio frequencies does not explain all the power in the WMAP synchrotron component even at middle/high Galactic latitudes. This suggests a significant microwave contribution (of about 50% of the signal) by other components such as free-free or spinning dust emission. The comparison between the extrapolated synchrotron APS and the CMB APS shows that a mask excluding the regions with |bgal| < 5 ◦ would reduce the foreground fluctuations to about half of the cosmological ones at 70 GHz even at the lowest multipoles. The main implications of our analysis for the cosmological exploitation of microwave temperature anisotropy maps are discussed.

Power spectrum of the polarized diffuse Galactic radio emission

We have analyzed the available polarization surveys of the Galactic emission to estimate to what extent it may be a serious hindrance to forthcoming experiments aimed at detecting the polarized component of Cosmic Microwave Background (CMB) anisotropies. Regions were identified for which independent data consistently indicate that Faraday depolarization may be small. The power spectrum of the polarized emission, in terms of antenna temperature, was found to be described by

B-Pol: detecting primordial gravitational waves generated during inflation

C^{\rm P}_{\ell}\simeq (1.2\pm 0.8) 10^{-9}\cdot (\ell / 450)^{-1.8\pm 0.3}\cdot (\nu/ 2.4 {\rm GHz})^{-5.8}