WorldWideScience

Sample records for polarized cosmic microwave

  1. Cosmic Microwave Background Polarization and Inflation

    Science.gov (United States)

    Chuss, David T.

    2011-01-01

    Measurements of the cosmic microwave background (CMB) offer a means to explore the universe at a very early epoch. Specifically, if the universe went through a brief period of exponential expansion called inflation as current data suggest, gravitational waves from this period would polarize the CMB in a specific pattern. At GSFC, we are currently working towards two experiments that work in concert to measure this polarization pattern in search of evidence for inflation. The Cosmology Large Angular Scale Surveyor (CLASS) will measure the polarization at frequencies between 40 and 150 GHz from the Atacama Desert in Chile. The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne experiment that will make similar measurements at frequencies between 200 and 600 GHz.

  2. Precision Foreground Removal in Cosmic Microwave Background Polarization Maps

    Data.gov (United States)

    National Aeronautics and Space Administration — The most promising method for detecting primordial gravitational waves lies in the B-mode polarization of the cosmic microwave background, or CMB. A measurement of...

  3. Cosmic birefringence fluctuations and cosmic microwave background B-mode polarization

    Directory of Open Access Journals (Sweden)

    Seokcheon Lee

    2015-06-01

    Full Text Available Recently, BICEP2 measurements of the cosmic microwave background (CMB B-mode polarization has indicated the presence of primordial gravitational waves at degree angular scales, inferring the tensor-to-scalar ratio of r=0.2 and a running scalar spectral index, provided that dust contamination is low. In this Letter, we show that the existence of the fluctuations of cosmological birefringence can give rise to CMB B-mode polarization that fits BICEP2 data with r<0.11 and no running of the scalar spectral index. When dust contribution is taken into account, we derive an upper limit on the cosmological birefringence, Aβ2<0.0075, where A is the amplitude of birefringence fluctuations that couple to electromagnetism with a coupling strength β.

  4. Testing statistical isotropy in cosmic microwave background polarization maps

    Science.gov (United States)

    Rath, Pranati K.; Samal, Pramoda Kumar; Panda, Srikanta; Mishra, Debesh D.; Aluri, Pavan K.

    2018-04-01

    We apply our symmetry based Power tensor technique to test conformity of PLANCK Polarization maps with statistical isotropy. On a wide range of angular scales (l = 40 - 150), our preliminary analysis detects many statistically anisotropic multipoles in foreground cleaned full sky PLANCK polarization maps viz., COMMANDER and NILC. We also study the effect of residual foregrounds that may still be present in the Galactic plane using both common UPB77 polarization mask, as well as the individual component separation method specific polarization masks. However, some of the statistically anisotropic modes still persist, albeit significantly in NILC map. We further probed the data for any coherent alignments across multipoles in several bins from the chosen multipole range.

  5. Observing the Cosmic Microwave Background Polarization with Variable-delay Polarization Modulators for the Cosmology Large Angular Scale Surveyor

    Science.gov (United States)

    Harrington, Kathleen; CLASS Collaboration

    2018-01-01

    The search for inflationary primordial gravitational waves and the optical depth to reionization, both through their imprint on the large angular scale correlations in the polarization of the cosmic microwave background (CMB), has created the need for high sensitivity measurements of polarization across large fractions of the sky at millimeter wavelengths. These measurements are subjected to instrumental and atmospheric 1/f noise, which has motivated the development of polarization modulators to facilitate the rejection of these large systematic effects.Variable-delay polarization modulators (VPMs) are used in the Cosmology Large Angular Scale Surveyor (CLASS) telescopes as the first element in the optical chain to rapidly modulate the incoming polarization. VPMs consist of a linearly polarizing wire grid in front of a moveable flat mirror; varying the distance between the grid and the mirror produces a changing phase shift between polarization states parallel and perpendicular to the grid which modulates Stokes U (linear polarization at 45°) and Stokes V (circular polarization). The reflective and scalable nature of the VPM enables its placement as the first optical element in a reflecting telescope. This simultaneously allows a lock-in style polarization measurement and the separation of sky polarization from any instrumental polarization farther along in the optical chain.The Q-Band CLASS VPM was the first VPM to begin observing the CMB full time in 2016. I will be presenting its design and characterization as well as demonstrating how modulating polarization significantly rejects atmospheric and instrumental long time scale noise.

  6. Cosmic microwave background polarization as a probe of the anomalous nature of the cold spot

    Science.gov (United States)

    Vielva, P.; Martínez-González, E.; Cruz, M.; Barreiro, R. B.; Tucci, M.

    2011-01-01

    One of the most interesting explanations for the non-Gaussian cold spot detected in the Wilkinson Microwave Anisotropy Probe (WMAP) data by Vielva et al. is that it arises from the interaction of the cosmic microwave background radiation with a cosmic texture. In this case, a lack of polarization is expected in the region of the spot, as compared to the typical values associated to large fluctuations of a Gaussian and isotropic random field. In addition, other physical processes related to a non-linear evolution of the gravitational field could lead to a similar scenario. However, some of these alternative scenarios (e.g. a large void in the large-scale structure) have been shown to be very unlikely. In this work we characterize the polarization properties of the cold spot under both hypotheses: a large Gaussian fluctuation and an anomalous feature generated, for instance, by a cosmic texture. We also propose a methodology to distinguish between them, and we discuss its discrimination power as a function of the instrumental noise level. In particular, we address the cases of current experiments, like WMAP and Planck, and others in development as the Q, U and I Joint Tenerife Experiment (QUIJOTE). We find that for an ideal experiment with a high-polarization sensitivity, the Gaussian hypothesis could be rejected at a significance level better than 0.8 per cent. While WMAP is far from providing useful information in this respect, we find that Planck will be able to reach a significance level of around 7 per cent; in addition, we show that the ground-based experiment QUIJOTE could provide a significance level of around 1 per cent, close to the ideal case. If these results are combined with the significance level found for the cold spot in temperature, the capability of QUIJOTE and Planck to reject the alternative hypothesis becomes 0.025 and 0.124 per cent, respectively.

  7. Cosmic microwave background, where next?

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    Ground-based, balloon-borne and space-based experiments will observe the Cosmic Microwave Background in greater details to address open questions about the origin and the evolution of the Universe. In particular, detailed observations the polarization pattern of the Cosmic Microwave Background radiation have the potential to directly probe physics at the GUT scale and illuminate aspects of the physics of the very early Universe.

  8. Bayesian Analysis of Systematic Effects in Interferometric Observations of the Cosmic Microwave Background Polarization

    Science.gov (United States)

    Karakci, Ata; Zhang, L.; Sutter, P. M.; Bunn, E. F.; Korotkov, A.; Timbie, P. T.; Tucker, G. S.; Wandelt, B.

    2013-06-01

    The detection of the primordial B-mode spectrum of the polarized cosmic microwave background (CMB) signal may provide a probe of inflation. However, observation of such a faint signal requires excellent control of systematic errors. Interferometry proves to be a promising approach for overcoming such a challenge. In this thesis we present a complete simulation pipeline of interferometric observations of CMB polarization, including systematic errors. We employ a method for Bayesian inference of power spectra and signal reconstruction from interferometric data of the CMB polarization signal by using the technique of Gibbs sampling. Several categories of systematic errors are considered: instrumental errors, consisting of antenna gain and antenna coupling errors, and beam errors, consisting of antenna pointing errors, beam cross-polarization and beam shape (and size) errors. In order to recover the tensor-to-scalar ratio, r, within a 10% tolerance level, which ensures the experiment is sensitive enough to detect the B-signal at r=0.01 in the multipole range 28 QUBIC-like experiment, Gaussian-distributed systematic errors must be controlled with precisions of |g_rms| = 0.1 for antenna gain, |e_rms| = 5e-4 for antenna coupling, d_rms ~ 0.7 degrees for pointing, z_rms ~ 0.7 degrees for beam shape, and m_rms = 5e-4 for beam cross-polarization.

  9. Lensing reconstruction of cluster-mass cross correlation with cosmic microwave background polarization

    International Nuclear Information System (INIS)

    Yoo, Jaiyul; Hernquist, Lars; Zaldarriaga, Matias

    2010-01-01

    We extend our maximum likelihood method for reconstructing the cluster-mass cross correlation from cosmic microwave background (CMB) temperature anisotropies and develop new estimators that utilize six different quadratic combinations of CMB temperature and polarization fields. Our maximum likelihood estimators are constructed with delensed CMB temperature and polarization fields by using an assumed model of the convergence field, and they can be iteratively applied to a set of clusters, approaching the optimal condition for the lensing reconstruction as the assumed initial model is refined. Using smoothed particle hydrodynamics simulations, we create a catalog of realistic clusters obtainable from the current Sunyaev-Zel'dovich surveys, and we demonstrate the ability of the maximum likelihood estimators to reconstruct the cluster-mass cross correlation from the massive clusters. The iTT temperature estimator provides a signal-to-noise ratio of a factor of 3 larger than the iEB polarization estimator, unless the detector noise for measuring polarization anisotropies is controlled under 3 μK.

  10. Mitigating Complex Dust Foregrounds in Future Cosmic Microwave Background Polarization Experiments

    Science.gov (United States)

    Hensley, Brandon S.; Bull, Philip

    2018-02-01

    Polarized Galactic foregrounds are one of the primary sources of systematic error in measurements of the B-mode polarization of the cosmic microwave background (CMB). Experiments are becoming increasingly sensitive to complexities in the foreground frequency spectra that are not captured by standard parametric models, potentially affecting our ability to efficiently separate out these components. Employing a suite of dust models encompassing a variety of physical effects, we simulate observations of a future seven-band CMB experiment to assess the impact of these complexities on parametric component separation. We identify configurations of frequency bands that minimize the “model errors” caused by fitting simple parametric models to more complex “true” foreground spectra, which bias the inferred CMB signal. We find that: (a) fits employing a simple two-parameter modified blackbody (MBB) dust model tend to produce significant bias in the recovered polarized CMB signal in the presence of physically realistic dust foregrounds; (b) generalized MBB models with three additional parameters reduce this bias in most cases, but non-negligible biases can remain, and can be hard to detect; (c) line-of-sight effects, which give rise to frequency decorrelation, and the presence of iron grains are the most problematic complexities in the dust emission for recovering the true CMB signal. More sophisticated simulations will be needed to demonstrate that future CMB experiments can successfully mitigate these more physically realistic dust foregrounds.

  11. Systematic Effects in Interferometric Observations of the Cosmic Microwave Background Polarization

    Science.gov (United States)

    Karakci, Ata; Zhang, Le; Sutter, P. M.; Bunn, Emory F.; Korotkov, Andrei; Timbie, Peter; Tucker, Gregory S.; Wandelt, Benjamin D.

    2013-07-01

    The detection of the primordial B-mode spectrum of the polarized cosmic microwave background (CMB) signal may provide a probe of inflation. However, observation of such a faint signal requires excellent control of systematic errors. Interferometry proves to be a promising approach for overcoming such a challenge. In this paper we present a complete simulation pipeline of interferometric observations of CMB polarization, including systematic errors. We employ two different methods for obtaining the power spectra from mock data produced by simulated observations: the maximum likelihood method and the method of Gibbs sampling. We show that the results from both methods are consistent with each other as well as, within a factor of six, with analytical estimates. Several categories of systematic errors are considered: instrumental errors, consisting of antenna gain and antenna coupling errors; and beam errors, consisting of antenna pointing errors, beam cross-polarization, and beam shape (and size) errors. In order to recover the tensor-to-scalar ratio, r, within a 10% tolerance level, which ensures the experiment is sensitive enough to detect the B-signal at r = 0.01 in the multipole range 28 QUBIC-like experiment, Gaussian-distributed systematic errors must be controlled with precisions of |g rms| = 0.1 for antenna gain, |epsilonrms| = 5 × 10-4 for antenna coupling, δrms ≈ 0.°7 for pointing, ζrms ≈ 0.°7 for beam shape, and μrms = 5 × 10-4 for beam cross-polarization. Although the combined systematic effects produce a tolerance level on r twice as large for an experiment with linear polarizers, the resulting bias in r for a circular experiment is 15% which is still on the level of desirable sensitivity.

  12. SYSTEMATIC EFFECTS IN INTERFEROMETRIC OBSERVATIONS OF THE COSMIC MICROWAVE BACKGROUND POLARIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Karakci, Ata; Korotkov, Andrei; Tucker, Gregory S. [Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912 (United States); Zhang Le; Timbie, Peter [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Sutter, P. M.; Wandelt, Benjamin D. [Department of Physics, 1110 W. Green Street, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Bunn, Emory F., E-mail: ata_karakci@brown.edu [Physics Department, University of Richmond, Richmond, VA 23173 (United States)

    2013-07-15

    The detection of the primordial B-mode spectrum of the polarized cosmic microwave background (CMB) signal may provide a probe of inflation. However, observation of such a faint signal requires excellent control of systematic errors. Interferometry proves to be a promising approach for overcoming such a challenge. In this paper we present a complete simulation pipeline of interferometric observations of CMB polarization, including systematic errors. We employ two different methods for obtaining the power spectra from mock data produced by simulated observations: the maximum likelihood method and the method of Gibbs sampling. We show that the results from both methods are consistent with each other as well as, within a factor of six, with analytical estimates. Several categories of systematic errors are considered: instrumental errors, consisting of antenna gain and antenna coupling errors; and beam errors, consisting of antenna pointing errors, beam cross-polarization, and beam shape (and size) errors. In order to recover the tensor-to-scalar ratio, r, within a 10% tolerance level, which ensures the experiment is sensitive enough to detect the B-signal at r = 0.01 in the multipole range 28 < l < 384, we find that, for a QUBIC-like experiment, Gaussian-distributed systematic errors must be controlled with precisions of |g{sub rms}| = 0.1 for antenna gain, |{epsilon}{sub rms}| = 5 Multiplication-Sign 10{sup -4} for antenna coupling, {delta}{sub rms} Almost-Equal-To 0. Degree-Sign 7 for pointing, {zeta}{sub rms} Almost-Equal-To 0. Degree-Sign 7 for beam shape, and {mu}{sub rms} = 5 Multiplication-Sign 10{sup -4} for beam cross-polarization. Although the combined systematic effects produce a tolerance level on r twice as large for an experiment with linear polarizers, the resulting bias in r for a circular experiment is 15% which is still on the level of desirable sensitivity.

  13. Cosmic Microwave Background Polarization Detector with High Efficiency, Broad Bandwidth, and Highly Symmetric Coupling to Transition Edge Sensor Bolometers

    Science.gov (United States)

    Stevenson, T.; Benford, D.; Bennett, C.; Cao, N.; Chuss, D.; Denis, K.; Hsieh, W.; Kogut, A.; Moseley, S.; Panek, J.; Schneider, G.; Travers, D.; U-Yen, K.; Voellmer, G.; Wollack, E.

    2008-04-01

    We describe a prototype detector system designed for precise measurements of Cosmic Microwave Background polarization. The design combines a quasi-optical polarization modulator, a metal feedhorn, a superconducting planar microwave circuit, and a pair of transition-edge sensor (TES) bolometers operating at <100 mK. The circular feedhorn produces highly symmetric beams with very low cross-polarization. The planar circuit preserves symmetry in coupling to bolometers measuring orthogonal polarizations. We implement the circuit with superconducting niobium transmission lines. Three-dimensional interfaces between the planar circuit and waveguides leading to feedhorn and backshort have been carefully designed with electromagnetic simulations. Power is thermalized in resistors and conducted to bolometers via normal electrons. Our system is designed for a 29 43 GHz signal band. We have tested individual circuit elements in this frequency range. Fabrication of a full single-pixel system is underway.

  14. Robust Likelihoods for Inflationary Gravitational Waves from Maps of Cosmic Microwave Background Polarization

    Science.gov (United States)

    Switzer, Eric Ryan; Watts, Duncan J.

    2016-01-01

    The B-mode polarization of the cosmic microwave background provides a unique window into tensor perturbations from inflationary gravitational waves. Survey effects complicate the estimation and description of the power spectrum on the largest angular scales. The pixel-space likelihood yields parameter distributions without the power spectrum as an intermediate step, but it does not have the large suite of tests available to power spectral methods. Searches for primordial B-modes must rigorously reject and rule out contamination. Many forms of contamination vary or are uncorrelated across epochs, frequencies, surveys, or other data treatment subsets. The cross power and the power spectrum of the difference of subset maps provide approaches to reject and isolate excess variance. We develop an analogous joint pixel-space likelihood. Contamination not modeled in the likelihood produces parameter-dependent bias and complicates the interpretation of the difference map. We describe a null test that consistently weights the difference map. Excess variance should either be explicitly modeled in the covariance or be removed through reprocessing the data.

  15. Hierarchical Phased Array Antenna Focal Plane for Cosmic Microwave Background Polarization and Sub-mm Observations

    Science.gov (United States)

    Lee, Adrian

    -IDS and in space on the LiteBIRD CMB polarization mission. The deliverables for the proposed work include: *Fabrication and test of a sinuous-antenna-based pixel with a 5:1 total bandwidth. Separate pixels will be built that are sensitive down to 30 GHz and others that are sensitive up to 400 GHz to cover the full range required for CMB measurements and to push into the sub-mm wavelength range. The efficiency of these pixels will be maximized by introducing a low loss silicon nitride insulator layer in all of the transmission lines. *Hierarchical phased arrays that use up to five levels of arraying will be fabricated and tested. The hierarchical phased array approaches the optimal mapping speed (sensitivity) at all frequencies by adjusting the beam size of the array with frequency. *We will develop 3 and 5 layer anti-reflection coatings using a new ``thermal spray" technique that we have developed which heats ceramics and plastics to melting temperature an then sprays them on optical surfaces with excellent uniformity and thickness control. The dielectric constant of each layer can be adjusted by choosing mixing ratios of high and low dielectric constant materials. Prioritization committees including the Astro2010 decadal, Quarks to Cosmos, and Weiss Committee have strongly advocated for prioritizing Cosmic Microwave Background polarization measurements and other science goals in the mm and sub-mm wavelength regime. The technology we propose to develop has the potential to greatly increase the cost effectiveness of potential missions in this frequency range. We have assembled an experienced team that includes expertise in antenna design, RF superconducting circuits, microfabrication, and CMB observations. Our team includes detector and/or CMB observation experts Bill Holzapfel, Adrian Lee, Akito Kusaka, and Aritoki Suzuki.

  16. SECOND SEASON QUIET OBSERVATIONS: MEASUREMENTS OF THE COSMIC MICROWAVE BACKGROUND POLARIZATION POWER SPECTRUM AT 95 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, D.; Dumoulin, R. N.; Newburgh, L. B.; Zwart, J. T. L. [Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bischoff, C.; Brizius, A.; Buder, I.; Kusaka, A. [Kavli Institute for Cosmological Physics, Department of Physics, Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637 (United States); Chinone, Y. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Cleary, K.; Reeves, R. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Blvd M/C 249-17, Pasadena, CA 91125 (United States); Monsalve, R.; Bustos, R. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Naess, S. K.; Eriksen, H. K. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Wehus, I. K. [Department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Bronfman, L. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Church, S. E. [Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University, Varian Physics Building, 382 Via Pueblo Mall, Stanford, CA 94305 (United States); Dickinson, C. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Gaier, T., E-mail: ibuder@uchicago.edu [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Collaboration: QUIET Collaboration; and others

    2012-12-01

    The Q/U Imaging ExperimenT (QUIET) has observed the cosmic microwave background (CMB) at 43 and 95 GHz. The 43 GHz results have been published in a previous paper, and here we report the measurement of CMB polarization power spectra using the 95 GHz data. This data set comprises 5337 hr of observations recorded by an array of 84 polarized coherent receivers with a total array sensitivity of 87 {mu}K{radical}s. Four low-foreground fields were observed, covering a total of {approx}1000 deg{sup 2} with an effective angular resolution of 12.'8, allowing for constraints on primordial gravitational waves and high signal-to-noise measurements of the E-modes across three acoustic peaks. The data reduction was performed using two independent analysis pipelines, one based on a pseudo-C {sub l} (PCL) cross-correlation approach, and the other on a maximum-likelihood (ML) approach. All data selection criteria and filters were modified until a predefined set of null tests had been satisfied before inspecting any non-null power spectrum. The results derived by the two pipelines are in good agreement. We characterize the EE, EB, and BB power spectra between l = 25 and 975 and find that the EE spectrum is consistent with {Lambda}CDM, while the BB power spectrum is consistent with zero. Based on these measurements, we constrain the tensor-to-scalar ratio to r = 1.1{sup +0.9} {sub -0.8} (r < 2.8 at 95% C.L.) as derived by the ML pipeline, and r = 1.2{sup +0.9} {sub -0.8} (r < 2.7 at 95% C.L.) as derived by the PCL pipeline. In one of the fields, we find a correlation with the dust component of the Planck Sky Model, though the corresponding excess power is small compared to statistical errors. Finally, we derive limits on all known systematic errors, and demonstrate that these correspond to a tensor-to-scalar ratio smaller than r = 0.01, the lowest level yet reported in the literature.

  17. The Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Jones Aled

    1998-01-01

    Full Text Available We present a brief review of current theory and observations of the cosmic microwave background (CMB. New predictions for cosmological defect theories and an overview of the inflationary theory are discussed. Recent results from various observations of the anisotropies of the microwave background are described and a summary of the proposed experiments is presented. A new analysis technique based on Bayesian statistics that can be used to reconstruct the underlying sky fluctuations is summarised. Current CMB data is used to set some preliminary constraints on the values of fundamental cosmological parameters $Omega$ and $H_circ$ using the maximum likelihood technique. In addition, secondary anisotropies due to the Sunyaev-Zel'dovich effect are described.

  18. The origin of the universe as revealed through the polarization of the cosmic microwave background

    NARCIS (Netherlands)

    Dodelson, S.; et al., [Unknown; Meerburg, P.

    2009-01-01

    Modern cosmology has sharpened questions posed for millennia about the origin of our cosmic habitat. The age-old questions have been transformed into two pressing issues primed for attack in the coming decade: How did the Universe begin? and what physical laws govern the Universe at the highest

  19. BOOK REVIEW: The Cosmic Microwave Background The Cosmic Microwave Background

    Science.gov (United States)

    Coles, Peter

    2009-08-01

    With the successful launch of the European Space Agency's Planck satellite earlier this year the cosmic microwave background (CMB) is once again the centre of attention for cosmologists around the globe. Since its accidental discovery in 1964 by Arno Penzias and Robert Wilson, this relic of the Big Bang has been subjected to intense scrutiny by generation after generation of experiments and has gradually yielded up answers to the deepest questions about the origin of our Universe. Most recently, the Wilkinson Microwave Anisotropy Probe (WMAP) has made a full-sky analysis of the pattern of temperature and polarization variations that helped establish a new standard cosmological model, confirmed the existence of dark matter and dark energy, and provided strong evidence that there was an epoch of primordial inflation. Ruth Durrer's book reflects the importance of the CMB for future developments in this field. Aimed at graduate students and established researchers, it consists of a basic introduction to cosmology and the theory of primordial perturbations followed by a detailed explanation of how these manifest themselves as measurable variations in the present-day radiation field. It then focuses on the statistical methods needed to obtain accurate estimates of the parameters of the standard cosmological model, and finishes with a discussion of the effect of gravitational lensing on the CMB and on the evolution of its spectrum. The book apparently grew out of various lecture notes on CMB anisotropies for graduate courses given by the author. Its level and scope are well matched to the needs of such an audience and the presentation is clear and well-organized. I am sure that this book will be a useful reference for more senior scientists too. If I have a criticism, it is not about what is in the book but what is omitted. In my view, one of the most exciting possibilities for future CMB missions, including Planck, is the possibility that they might discover physics

  20. MEASUREMENTS OF E-MODE POLARIZATION AND TEMPERATURE-E-MODE CORRELATION IN THE COSMIC MICROWAVE BACKGROUND FROM 100 SQUARE DEGREES OF SPTPOL DATA

    Energy Technology Data Exchange (ETDEWEB)

    Crites, A. T.; Henning, J. W.; Ade, P. A. R.; Aird, K. A.; Austermann, J. E.; Beall, J. A.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Chiang, H. C.; Cho, H-M.; Citron, R.; Crawford, T. M.; Haan, T. de; Dobbs, M. A.; Everett, W.; Gallicchio, J.; Gao, J.; George, E. M.; Gilbert, A.; Halverson, N. W.; Hanson, D.; Harrington, N.; Hilton, G. C.; Holder, G. P.; Holzapfel, W. L.; Hoover, S.; Hou, Z.; Hrubes, J. D.; Huang, N.; Hubmayr, J.; Irwin, K. D.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Li, D.; Liang, C.; Luong-Van, D.; McMahon, J. J.; Mehl, J.; Meyer, S. S.; Mocanu, L.; Montroy, T. E.; Natoli, T.; Nibarger, J. P.; Novosad, V.; Padin, S.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Schaffer, K. K.; Smecher, G.; Stark, A. A.; Story, K. T.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Zahn, O.

    2015-05-18

    We present measurements of E-mode polarization and temperature-E-mode correlation in the cosmic microwave background using data from the first season of observations with SPTpol, the polarization-sensitive receiver currently installed on the South Pole Telescope (SPT). The observations used in this work cover 100 ${{{\\rm deg} }^{2}}$ of sky with arcminute resolution at 150 GHz. We report the E-mode angular auto-power spectrum (EE) and the temperature-E-mode angular cross-power spectrum (TE) over the multipole range 500 < ℓ ≤ 5000. These power spectra improve on previous measurements in the high-ℓ (small-scale) regime. We fit the combination of the SPTpol power spectra, data from Planck, and previous SPT measurements with a six-parameter ΛCDM cosmological model. We find that the best-fit parameters are consistent with previous results. The improvement in high-ℓ sensitivity over previous measurements leads to a significant improvement in the limit on polarized point-source power: after masking sources brighter than 50 mJy in unpolarized flux at 150 GHz, we find a 95% confidence upper limit on unclustered point-source power in the EE spectrum of ${{D}_{\\ell }}=\\ell (\\ell +1){{C}_{\\ell }}/2\\pi \\lt 0.40\\ \\mu {{{\\rm K}}^{2}}$ at $\\ell =3000$, indicating that future EE measurements will not be limited by power from unclustered point sources in the multipole range $\\ell \\lt 3600$, and possibly much higher in $\\ell .$

  1. Polarization of the cosmic background radiation

    International Nuclear Information System (INIS)

    Lubin, P.M.

    1980-03-01

    The results and technique of a measurement of the linear polarization of the Cosmic Background Radiation are discussed. The ground-based experiment utilizes a single horn (7 0 beam width) Dicke-type microwave polarimeter operating at 33 GHz (9.1 mm). Data taken between May 1978 and February 1980 from both the northern hemisphere (Berkeley Lat. = 38 0 N) and the southern hemisphere (Lima Lat. = 12 0 S) show the radiation to be essentially unpolarized over all areas surveyed. For the 38 0 declination data the 95% confidence level limit on a linearly polarized component is 0.3 mK for the average and 12 and 24 hour periods. Fitting all data gives the 95% confidence level limit on a linearly polarized component of 0.3 mK for spherical harmonics through third order. Constraints on various cosmological models are discussed in light of these limits

  2. Analysis of cosmic microwave background radiation in the presence of Lorentz violation

    OpenAIRE

    Mewes, Matthew

    2007-01-01

    We examine the effects Lorentz violation on observations of cosmic microwave background radiation. In particular, we focus on changes in polarization caused by vacuum birefringence. We place stringent constraints on previously untested violations.

  3. Primordial non-Gaussianity with μ-type and y-type spectral distortions: exploiting Cosmic Microwave Background polarization and dealing with secondary sources

    Science.gov (United States)

    Ravenni, Andrea; Liguori, Michele; Bartolo, Nicola; Shiraishi, Maresuke

    2017-09-01

    Cross-correlations between Cosmic Microwave Background (CMB) temperature and y-spectral distortion anisotropies have been previously proposed as a way to measure the local bispectrum parameter fNLloc. in a range of scales inaccessible to either CMB (T, E) bispectra or μ T correlations. This is useful e.g. to test scale dependence of primordial non-Gaussianity. Unfortunately, the primordial y T signal is strongly contaminated by the late-time correlation between the Integrated Sachs Wolfe and Sunyaev-Zel'dovich (SZ) effects. Moreover, SZ itself generates a large noise contribution in the y-parameter map. We consider two original ways to address these issues. In order to remove the bias due to the SZ-CMB temperature coupling, while also providing additional signal, we include in the analysis the cross-correlation between y-distortions and CMB polarization. In order to reduce the noise, we propose to clean the y-map by subtracting a SZ template, reconstructed via cross-correlation with external tracers (CMB and galaxy-lensing signals). We combine this SZ template subtraction with the previously suggested solution of directly masking detected clusters. Our final forecasts show that, using y-distortions, a PRISM-like survey can achieve 1σ(fNLloc.) = 300, while an ideal experiment will achieve 1σ(fNLloc.) = 130 with improvements of a factor between 2.1 and 3.8, depending on the considered survey, from adding the y E signal, and a further 20-30 % from template cleaning. These forecasts are much worse than current fNLloc. boundaries from Planck, but we stress that they refer to completely different scales.

  4. Primordial non-Gaussianity with μ-type and y -type spectral distortions: exploiting Cosmic Microwave Background polarization and dealing with secondary sources

    Energy Technology Data Exchange (ETDEWEB)

    Ravenni, Andrea; Liguori, Michele; Bartolo, Nicola [Dipartimento di Fisica e Astronomia ' G. Galilei' , Università degli Studi di Padova, via Marzolo 8, Padova, I-35131 Italy (Italy); Shiraishi, Maresuke, E-mail: ravenni@pd.infn.it, E-mail: liguori@pd.infn.it, E-mail: bartolo@pd.infn.it, E-mail: shiraishi-m@t.kagawa-nct.ac.jp [Department of General Education, National Institute of Technology, Kagawa College, 355 Chokushi-cho, Takamatsu, Kagawa, 761-8058 Japan (Japan)

    2017-09-01

    Cross-correlations between Cosmic Microwave Background (CMB) temperature and y -spectral distortion anisotropies have been previously proposed as a way to measure the local bispectrum parameter f {sub NL}{sup loc}. in a range of scales inaccessible to either CMB ( T , E ) bispectra or μ T correlations. This is useful e.g. to test scale dependence of primordial non-Gaussianity. Unfortunately, the primordial y T signal is strongly contaminated by the late-time correlation between the Integrated Sachs Wolfe and Sunyaev-Zel'dovich (SZ) effects. Moreover, SZ itself generates a large noise contribution in the y -parameter map. We consider two original ways to address these issues. In order to remove the bias due to the SZ-CMB temperature coupling, while also providing additional signal, we include in the analysis the cross-correlation between y -distortions and CMB polarization . In order to reduce the noise, we propose to clean the y -map by subtracting a SZ template, reconstructed via cross-correlation with external tracers (CMB and galaxy-lensing signals). We combine this SZ template subtraction with the previously suggested solution of directly masking detected clusters. Our final forecasts show that, using y -distortions, a PRISM-like survey can achieve 1σ( f {sub NL}{sup loc}.) = 300, while an ideal experiment will achieve 1σ( f {sub NL}{sup loc}.) = 130 with improvements of a factor between 2.1 and 3.8, depending on the considered survey, from adding the y E signal, and a further 20–30 % from template cleaning. These forecasts are much worse than current f {sub NL}{sup loc}. boundaries from Planck , but we stress that they refer to completely different scales.

  5. Anomalies of the Cosmic Microwave Background

    DEFF Research Database (Denmark)

    Hansen, Martin Anders Kirstejn

    The Cosmic Microwave Background (CMB) is the faint afterglow of the extreme conditions that existed shortly after Big Bang. The temperature of the CMB radiation across the sky is extremely uniform, yet tiny anisotropies are present, and have with recent satellite missions been mapped to very high...

  6. Cosmic microwave background science at commercial airline altitudes

    Science.gov (United States)

    Feeney, Stephen M.; Gudmundsson, Jon E.; Peiris, Hiranya V.; Verde, Licia; Errard, Josquin

    2017-07-01

    Obtaining high-sensitivity measurements of degree-scale cosmic microwave background (CMB) polarization is the most direct path to detecting primordial gravitational waves. Robustly recovering any primordial signal from the dominant foreground emission will require high-fidelity observations at multiple frequencies, with excellent control of systematics. We explore the potential for a new platform for CMB observations, the Airlander 10 hybrid air vehicle, to perform this task. We show that the Airlander 10 platform, operating at commercial airline altitudes, is well suited to mapping frequencies above 220 GHz, which are critical for cleaning CMB maps of dust emission. Optimizing the distribution of detectors across frequencies, we forecast the ability of Airlander 10 to clean foregrounds of varying complexity as a function of altitude, demonstrating its complementarity with both existing (Planck) and ongoing (C-BASS) foreground observations. This novel platform could play a key role in defining our ultimate view of the polarized microwave sky.

  7. Technology Development for Cosmic Microwave Background Cosmology

    Science.gov (United States)

    Munson, Charles D.

    2017-05-01

    The Cosmic Microwave Background (CMB) offers a unique window into the early universe by probing thermal radiation remaining from the big bang. Due to its low temperature and bright foregrounds, its thorough characterization requires technological advancement beyond the current state-of-the-art. In this thesis, I present the development and fabrication of novel metamaterial silicon optics to improve the sensitivity of current and future CMB telescopes. By machining subwavelength features into the silicon surfaces, traditional antireflection coatings can be replaced by all-silicon metamaterials that significantly reduce reflections over previous approaches. I discuss the design of these structured surfaces and the design and construction of a sophisticated fabrication facility necessary to implement this technology on large diameter (30+ cm) lenses for the Atacama Cosmology Telescope Polarization project (ACTPol). I then apply this metamaterial technology to the development of improved free-space filters for millimeter and sub-millimeter wavelength imaging (focusing specifically on blocking infrared radiation, necessary for current cryogenic detector systems). This produces a highly effective infrared-blocking filter, blocking over 99% of the incident power from a 300 K blackbody while maintaining transmission of better than 99% in a target CMB observing band (between 70 and 170 GHz). I conclude with a discussion of the development of a real-space simulation framework to assist in better understanding current CMB results and forecasting for future experiments. By taking a CMB realization and adding to it accurate real-space modeling of the Sunyaev-Zel'dovich effect and weak lensing distortions (introduced by galaxy clusters), a better understanding of the impacts of large scale structure on the CMB can be obtained.

  8. Anomalies of the Cosmic Microwave Background

    DEFF Research Database (Denmark)

    Hansen, Martin Anders Kirstejn

    The Cosmic Microwave Background (CMB) is the faint afterglow of the extreme conditions that existed shortly after Big Bang. The temperature of the CMB radiation across the sky is extremely uniform, yet tiny anisotropies are present, and have with recent satellite missions been mapped to very high...... accuracy. The information which the CMB provides has helped in creating the current standard cosmological model - the CDM model - and the theory of cosmic inflation as well as constrain a vast amount of cosmological parameters. The accuracy of observations of the CMB radiation is thus of extreme importance...... the observed CMB signal. We assume that emission from the Kuiper belt around the solar system in combination with a dipole modulation of the signal due to an unknown systematic effect may explain both the observed parity asymmetry, as well as the peculiar alignment of the quadrupole and octupole. We find...

  9. A Measurement of the Cosmic Microwave Background Temperature ...

    Indian Academy of Sciences (India)

    tribpo

    •calibrating the contributions from the feed assembly and receiver. The thermodynamic temperature of the CMB is estimated to be. 3.45 ± 0.78 K. Key words. Cosmic microwave background — cosmology: observations. 1. Introduction. The spectrum of the cosmic microwave background (CMB) has been measured by the.

  10. Academic Training: The cosmic microwave background - Lecture series

    CERN Multimedia

    Françoise Benz

    2004-01-01

    ACADEMIC TRAINING LECTURE REGULAR PROGRAMME 14, 15, 16, 17 and 18 June From 11:00 hrs to 12:00 hrs - Main Auditorium bldg. 500 The cosmic microwave background M. Zaldarriaga / Harvard University, USA The Cosmic Microwave Background has become an indispensable tool for cosmology. The measurement of its frequency spectrum firmly established the Hot Big Bang model of the Universe. Measurements of anisotropies in its temperature and its degree of polarization provide the earliest snapshot we have of the universe, giving us information about its state at the epoch of hydrogen recombination approximately 300,000 after the Big Bang. The anisotropies can be used to constrain many of the parameters in the cosmological model, such as the mean density of baryons and dark matter as well as the curvature of the Universe. In this lectures I will review the physics of the temperature and polarization anisotropies. I will discuss the mechanisms that lead to the anisotropies and how cosmological parameters can be inferr...

  11. The Physics of the Cosmic Microwave Background

    Energy Technology Data Exchange (ETDEWEB)

    Peacock, John [Royal Observatory, Edinburgh (United Kingdom)

    2007-04-07

    The award of the 2006 Nobel Prize for Physics is a reminder to non-specialists that the cosmic microwave background (CMB) has yielded astonishing advances in our understanding of cosmology. Mather and Smoot received their prize for work done with NASA's COBE satellite in the early 1990s, but the subject has if anything accelerated since then. The results from NASA's WMAP satellite, reported in 2003 and 2006, have proved COBE's equal in importance and have generated huge worldwide interest. There could therefore hardly be a better time to be writing a detailed textbook to explain what the fuss is all about to a new generation of research students. A comprehensive treatment of the physics of the CMB is not easy to achieve, because it is connected to so much else in cosmology. A student must have a background knowledge of the geometry and dynamics of an expanding universe, plus a deep exposure to the physics of quantum fields, in order to understand the modern 'inflationary' view in which the universe was set expanding by the tension of the vacuum, and was seeded with small inhomogeneities as a result of quantum fluctuations. Although the theory of inflation is not yet verified, the CMB has the potential to accomplish this; testing inflation is undoubtedly one of the principal aims of cosmology over the next decade. Even with this preparation, understanding the properties of the CMB is quite hard at the professional level, requiring the perturbation expansion of the relativistic Boltzmann equation. These technical difficulties are particularly strong in the frontier area of CMB polarization. Naselsky and his collaborators have allocated themselves a relatively brief 255 pages in which to meet these challenges, so some compromise is inevitable. Although the preface is not explicit about the assumed prior knowledge, no systematic material on background cosmology or on inflation is to be found. The former is reasonable in a graduate-level text

  12. Microwave SQUID multiplexer demonstration for cosmic microwave background imagers

    Science.gov (United States)

    Dober, B.; Becker, D. T.; Bennett, D. A.; Bryan, S. A.; Duff, S. M.; Gard, J. D.; Hays-Wehle, J. P.; Hilton, G. C.; Hubmayr, J.; Mates, J. A. B.; Reintsema, C. D.; Vale, L. R.; Ullom, J. N.

    2017-12-01

    Key performance characteristics are demonstrated for the microwave superconducting quantum interference device (SQUID) multiplexer (μmux) coupled to transition edge sensor (TES) bolometers that have been optimized for cosmic microwave background (CMB) observations. In a 64-channel demonstration, we show that the μmux produces a white, input referred current noise level of 29 pA/ √{H z } at a microwave probe tone power of -77 dB, which is well below the expected fundamental detector and photon noise sources for a ground-based CMB-optimized bolometer. Operated with negligible photon loading, we measure 98 pA/ √{H z } in the TES-coupled channels biased at 65% of the sensor normal resistance. This noise level is consistent with that predicted from bolometer thermal fluctuation (i.e., phonon) noise. Furthermore, the power spectral density is white over a range of frequencies down to ˜100 mHz, which enables CMB mapping on large angular scales that constrain the physics of inflation. Additionally, we report cross-talk measurements that indicate a level below 0.3%, which is less than the level of cross-talk from multiplexed readout systems in deployed CMB imagers. These measurements demonstrate the μmux as a viable readout technique for future CMB imaging instruments.

  13. Cosmic thermalization and the microwave background radiation

    International Nuclear Information System (INIS)

    Rana, N.C.

    1981-01-01

    A different origin of the microwave background radiation (MBR) is suggested in view of some of the difficulties associated with the standard interpretation. Extensive stellar-type nucleosynthesis could provide radiation with the requisite energy density of the MBR and its spectral features are guaranteed by adequate thermalization of the above radiation by an ambient intergalactic dust medium. This thermalization must have occurred in quite recent epochs, say around epochs of redshift z = 7. The model emerges with consistent limits on the cosmic abundance of helium, the general luminosity evolution of the extragalactic objects, the baryonic matter density in the Universe (or, equivalently the deceleration parameter) and the degree of isotropy of MBR. The model makes definite predictions on issues like the properties of the intergalactic thermalizers, the degree of isotropy of MBR at submillimetre wavelengths and cluster emission in the far infrared. (author)

  14. Anisotropies in the cosmic microwave background: Theory

    International Nuclear Information System (INIS)

    Dodelson, S.

    1998-02-01

    Anisotropies in the Cosmic Microwave Background (CMB) contain a wealth of information about the past history of the universe and the present values of cosmological parameters. I online some of the theoretical advances of the last few years. In particular, I emphasize that for a wide class of cosmological models, theorists can accurately calculate the spectrum to better than a percent. The spectrum of anisotropies today is directly related to the pattern of inhomogeneities present at the time of recombination. This recognition leads to a powerful argument that will enable us to distinguish inflationary models from other models of structure formation. If the inflationary models turn out to be correct, the free parameters in these models will be determined to unprecedented accuracy by the upcoming satellite missions

  15. On the cosmic microwave background radiation

    Directory of Open Access Journals (Sweden)

    José Maria Filardo Bassalo

    2017-12-01

    Full Text Available In this article we will try to give a pale idea to the reader of what could be the Cosmic Microwave Background (RCFM that, according to the traditional Big Bang model, was generated by a primordial explosion. With this purpose we find it very important to present a brief historical summary of how the Microcosm, based on the Standard Model of Elementary Particle Physics (MPPE, and the Macrocosm, based on the Standard Big Bang Model (MPBB, have evolved over time. In addition, in the final part of the article we will analyze the two physical processes presented in the literature that seek to explain the RCFM: Bariogenesis and Plasma Quark-Gluon.

  16. Spectral measurements of the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Kogut, A.J.

    1989-04-01

    Three experiments have measured the intensity of the Cosmic Microwave Background (CMB) at wavelengths 4.0, 3.0, and 0.21 cm. The measurement at 4.0 cm used a direct-gain total-power radiometer to measure the difference in power between the zenith sky and a large cryogenic reference target. Foreground signals are measured with the same instrument and subtracted from the zenith signal, leaving the CMB as the residual. The reference target consists of a large open-mouth cryostat with a microwave absorber submerged in liquid helium; thin windows block the radiative heat load and prevent condensation atmospheric gases within the cryostat. The thermodynamic temperature of the CMB at 4.0 cm is 2.59 +- 0.07 K. The measurement at 3.0 cm used a superheterodyne Dicke-switched radiometer with a similar reference target to measure the zenith sky temperature. A rotating mirror allowed one of the antenna beams to be redirected to a series of zenith angles, permitting automated atmospheric measurements without moving the radiometer. A weighted average of 5 years of data provided the thermodynamic temperature of the CMB at 3.0 cm of 2.62 +- 0.06 K. The measurement at 0.21 cm used Very Large Array observations of interstellar ortho-formaldehyde to determine the CMB intensity in molecular clouds toward the giant HII region W51A (G49.5-0.4). Solutions of the radiative transfer problem in the context of a large velocity gradient model provided estimates of the CMB temperature within the foreground clouds. Collisional excitation from neutral hydrogen molecules within the clouds limited the precision of the result. The thermodynamic temperature of the CMB at 0.21 cm is 3.2 +- 0.9 K. 72 refs., 27 figs., 38 tabs.

  17. Spectral measurements of the cosmic microwave background

    International Nuclear Information System (INIS)

    Kogut, A.J.

    1989-04-01

    Three experiments have measured the intensity of the Cosmic Microwave Background (CMB) at wavelengths 4.0, 3.0, and 0.21 cm. The measurement at 4.0 cm used a direct-gain total-power radiometer to measure the difference in power between the zenith sky and a large cryogenic reference target. Foreground signals are measured with the same instrument and subtracted from the zenith signal, leaving the CMB as the residual. The reference target consists of a large open-mouth cryostat with a microwave absorber submerged in liquid helium; thin windows block the radiative heat load and prevent condensation atmospheric gases within the cryostat. The thermodynamic temperature of the CMB at 4.0 cm is 2.59 +- 0.07 K. The measurement at 3.0 cm used a superheterodyne Dicke-switched radiometer with a similar reference target to measure the zenith sky temperature. A rotating mirror allowed one of the antenna beams to be redirected to a series of zenith angles, permitting automated atmospheric measurements without moving the radiometer. A weighted average of 5 years of data provided the thermodynamic temperature of the CMB at 3.0 cm of 2.62 +- 0.06 K. The measurement at 0.21 cm used Very Large Array observations of interstellar ortho-formaldehyde to determine the CMB intensity in molecular clouds toward the giant HII region W51A (G49.5-0.4). Solutions of the radiative transfer problem in the context of a large velocity gradient model provided estimates of the CMB temperature within the foreground clouds. Collisional excitation from neutral hydrogen molecules within the clouds limited the precision of the result. The thermodynamic temperature of the CMB at 0.21 cm is 3.2 +- 0.9 K. 72 refs., 27 figs., 38 tabs

  18. Fingerprints of Galactic Loop I on the Cosmic Microwave Background

    DEFF Research Database (Denmark)

    Liu, Hao; Mertsch, Philipp; Sarkar, Subir

    2014-01-01

    We investigate possible imprints of galactic foreground structures such as the "radio loops" in the derived maps of the cosmic microwave background. Surprisingly, there is evidence for these not only at radio frequencies through their synchrotron radiation, but also at microwave frequencies where...

  19. Cosmic ray access at polar heliographic latitudes

    International Nuclear Information System (INIS)

    Voelk, H.J.

    1976-01-01

    Based on a modified WKB analysis of the interplanetary irregularity spectra, a discussion of the radial dependence of the radial cosmic ray diffusion coefficient at polar heliographic latitudes is presented. At l-AU radial distance the parameters are taken to equal those observed in the ecliptic. In the sense of a present best estimate it is argued that relativistic nuclei should have significantly easier access to 1 AU at the pole than in the ecliptic. The reverse may very well be true for the direct access of very low rigidity particles

  20. Microwave dispersion of some polar liquids

    NARCIS (Netherlands)

    Poley, J.P.

    1955-01-01

    The chief purpose of the present investigation is the measurement and analysis of the microwave dispersion of some polar liquids. An outline of the problem and a historical survey of experimental work on the dielectric behaviour of polar liquids are given in Chapter I. A number of theoretical

  1. Electromagnetic Design of Feedhorn-Coupled Transition-Edge Sensors for Cosmic Microwave Background Polarimetery

    Science.gov (United States)

    Chuss, David T.

    2011-01-01

    Observations of the cosmic microwave background (CMB) provide a powerful tool for probing the evolution of the early universe. Specifically, precision measurement of the polarization of the CMB enables a direct test for cosmic inflation. A key technological element on the path to the measurement of this faint signal is the capability to produce large format arrays of background-limited detectors. We describe the electromagnetic design of feedhorn-coupled, TES-based sensors. Each linear orthogonal polarization from the feed horn is coupled to a superconducting microstrip line via a symmetric planar orthomode transducer (OMT). The symmetric OMT design allows for highly-symmetric beams with low cross-polarization over a wide bandwidth. In addition, this architecture enables a single microstrip filter to define the passband for each polarization. Care has been taken in the design to eliminate stray coupling paths to the absorbers. These detectors will be fielded in the Cosmology Large Angular Scale Surveyor (CLASS).

  2. Cosmic Microwave Background: cosmology from the Planck perspective

    Science.gov (United States)

    De Zotti, Gianfranco

    2017-08-01

    The Planck mission has measured the angular anisotropies in the temperature of the Cosmic Microwave Background (CMB) with an accuracy set by fundamental limits. These data have allowed the determination of the cosmological parameters with extraordinary precision. These lecture notes present an overview of the mission and of its cosmological results. After a short history of the project, the Planck instruments and their performances are introduced and compared with those of the WMAP satellite. Next the approach to data analysis adopted by the Planck collaboration is described. This includes the techniques for dealing with the contamination of the CMB signal by astrophysical foreground emissions and for determining cosmological parameters from the analysis of the CMB power spectrum. The power spectra measured by Planck were found to be very well described by the standard spatially flat six-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations. This is a remarkable result, considering that the six parameters account for the about 2500 independent power spectrum values measured by Planck (the power was measured for about 2500 multipoles), not to mention the about one trillion science samples produced. A large grid of cosmological models was also explored, using a range of additional astrophysical data sets in addition to Planck and high-resolution CMB data from ground-based experiments. On the whole, the Planck analysis of the CMB power spectrum allowed to vary and determined 16 parameters. Many other interesting parameters were derived from them. Although Planck was not initially designed to carry out high accuracy measurements of the CMB polarization anisotropies, its capabilities in this respect were significantly enhanced during its development. The quality of its polarization measurements have exceeded all original expectations. Planck's polarisation data confirmed and improved the understanding of the details of the cosmological

  3. Measurements of sub-degree B-mode polarization in the cosmic microwave background from 100 square degrees of SPTPOL data

    Energy Technology Data Exchange (ETDEWEB)

    Keisler, R.; Hoover, S.; Harrington, N.; Henning, J. W.; Ade, P. A. R.; Aird, K. A.; Austermann, J. E.; Beall, J. A.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Chiang, H. C.; Cho, H-M.; Citron, R.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Dobbs, M. A.; Everett, W.; Gallicchio, J.; Gao, J.; George, E. M.; Gilbert, A.; Halverson, N. W.; Hanson, D.; Hilton, G. C.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Huang, N.; Hubmayr, J.; Irwin, K. D.; Knox, L.; Lee, A. T.; Leitch, E. M.; Li, D.; Luong-Van, D.; Marrone, D. P.; McMahon, J. J.; Mehl, J.; Meyer, S. S.; Mocanu, L.; Natoli, T.; Nibarger, J. P.; Novosad, V.; Padin, S.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Schaffer, K. K.; Shirokoff, E.; Smecher, G.; Stark, A. A.; Story, K. T.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Zahn, O.

    2015-07-09

    We present a measurement of the B-mode polarization power spectrum (the BB spectrum) from 100 ${\\mathrm{deg}}^{2}$ of sky observed with SPTpol, a polarization-sensitive receiver currently installed on the South Pole Telescope. The observations used in this work were taken during 2012 and early 2013 and include data in spectral bands centered at 95 and 150 GHz. We report the BB spectrum in five bins in multipole space, spanning the range $300\\leqslant {\\ell }\\leqslant 2300$, and for three spectral combinations: 95 GHz × 95 GHz, 95 GHz × 150 GHz, and 150 GHz × 150 GHz. We subtract small (<0.5σ in units of statistical uncertainty) biases from these spectra and account for the uncertainty in those biases. The resulting power spectra are inconsistent with zero power but consistent with predictions for the BB spectrum arising from the gravitational lensing of E-mode polarization. If we assume no other source of BB power besides lensed B modes, we determine a preference for lensed B modes of 4.9σ. After marginalizing over tensor power and foregrounds, namely, polarized emission from galactic dust and extragalactic sources, this significance is 4.3σ. Fitting for a single parameter, ${A}_{\\mathrm{lens}}$, that multiplies the predicted lensed B-mode spectrum, and marginalizing over tensor power and foregrounds, we find ${A}_{\\mathrm{lens}}=1.08\\pm 0.26$, indicating that our measured spectra are consistent with the signal expected from gravitational lensing. The data presented here provide the best measurement to date of the B-mode power spectrum on these angular scales.

  4. Detectability of inflationary gravitational waves with microwave background polarization

    International Nuclear Information System (INIS)

    Kamionkowski, M.; Kosowsky, A.

    1998-01-01

    Inflation predicts specific relations between the amplitudes and spectral indices of the primordial spectrum of density (scalar metric) perturbations and gravitational waves (tensor metric perturbations). Detection of a stochastic gravitational-wave background is essential for identifying this unmistakable signature. Polarization of the cosmic microwave background can isolate these tensor modes in a model-independent way and thereby circumvent the cosmic-variance limit to detecting a small tensor signal with only a temperature map. Here we assess the detectability of a gravity-wave background with a temperature and polarization map. For detector sensitivities better than 10 endash 20μK√ (sec) , the sensitivity to a tensor signal is always dominated by the polarization map. With a detector sensitivity of order 1μK√ (sec) , polarization could improve on a temperature-map sensitivity to tensor modes by two to three orders of magnitude. Even a small amount of reionization substantially enhances tensor-mode detectability. We also argue that the sensitivity of the Planck Surveyor to tensor modes is significantly improved with polarization, even taking into account the resulting degradation of the intensity determination in the high-frequency channels. copyright 1997 The American Physical Society

  5. Angular anisotropy of the cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Silk, J.

    1982-01-01

    The theory of fluctuations in the cosmic microwave background radiation is reviewed. Anisotropy on large-scale (dipole and quadrupole) and on small scales is discussed. The smoothing effects of secondary ionization (fractional ionization x) are found to be unimportant over an angular scale greater than approx.= 5(OMEGAx)sup(1/3) degrees. (author)

  6. A Measurement of the Cosmic Microwave Background Temperature ...

    Indian Academy of Sciences (India)

    tribpo

    Cosmic Microwave Background Temperature at 1280 MHz. 5. Figure 3. Photograph of the 1280 MHz receiver with the aluminium shield lowered to the ground. 3. Noise reduction techniques. The circulator has been introduced at the input of the LNA in order to isolate the. LNA from reflections in the corrugated plate OMT ...

  7. Imprints of microcausality violation on the cosmic microwave background

    OpenAIRE

    Kobakhidze, Archil

    2008-01-01

    We consider a modification of the Heisenberg algebra with the non-vanishing commutator of scalar field operators. We then identify the scalar field with the second quantized inflaton fluctuation and calculate effects of microcausality violation on the temperature anisotropy of cosmic microwave background radiation.

  8. Academic Training: The cosmic microwave background - Lecture series

    CERN Multimedia

    Françoise Benz

    2004-01-01

    ACADEMIC TRAINING LECTURE REGULAR PROGRAMME 14, 15, 16, 17 and 18 June From 11:00 hrs to 12:00 hrs - Main Auditorium bldg. 500 The cosmic microwave background M. Zaldarriaga / Harvard University, USA ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch

  9. Feedhorn-Coupled Transition-Edge Superconducting Bolometer Arrays for Cosmic Microwave Background Polarimetry

    Science.gov (United States)

    Hubmayr, J.; Austermann, J.; Beall, J.; Becker, D.; Cho, H.-M.; Datta, R.; Duff, S. M.; Grace, E.; Halverson, N.; Henderson, S. W.; hide

    2015-01-01

    NIST produces large-format, dual-polarization-sensitive detector arrays for a broad range of frequencies (30-1400 GHz). Such arrays enable a host of astrophysical measurements. Detectors optimized for cosmic microwave background observations are monolithic, polarization-sensitive arrays based on feedhorn and planar Nb antenna-coupled transition-edge superconducting (TES) bolometers. Recent designs achieve multiband, polarimetric sensing within each spatial pixel. In this proceeding, we describe our multichroic, feedhorn-coupled design; demonstrate performance at 70-380 GHz; and comment on current developments for implementation of these detector arrays in the advanced Atacama Cosmology Telescope receiver

  10. Future cosmic microwave background delensing with galaxy surveys

    Science.gov (United States)

    Manzotti, A.

    2018-02-01

    The primordial B-modes component of the cosmic microwave background (CMB) polarization is a promising experimental data set to probe the inflationary paradigm. B modes are indeed a direct consequence of the presence of gravitational waves in the early Universe. However, several secondary effects in the low-redshift universe will produce nonprimordial B modes. In particular, the gravitational interactions of CMB photons with large-scale structures will distort the primordial E modes, adding a lensing B-mode component to the primordial signal. Removing the lensing component ("delensing") will then be necessary to constrain the amplitude of the primordial gravitational waves. Here, we examine the role of current and future large-scale structure surveys in a multitracers approach to CMB delensing. We find that, in general, galaxy surveys should be split into tomographic bins, as this can increase the reduction of lensing B modes by ˜25 % in power in the most futuristic case. Ongoing or recently completed CMB experiments will particularly benefit from large-scale structure tracers that, once properly combined, will have a better performance than a CMB internal reconstruction. With the decrease of instrumental noise, the lensing B-modes power removed using CMB internal reconstruction alone will rapidly increase. Nevertheless, optical galaxy surveys will still play an important role even for fourth-generation CMB experiments. In particular, an LSST-like survey can a achieve a delensing performance comparable to a third-generation CMB experiment but with entirely different systematics. This redundancy will be essential to demonstrate the robustness against systematics of an eventual detection of primordial B modes.

  11. Cosmology with cosmic microwave background anisotropy

    Indian Academy of Sciences (India)

    Measurements of CMB anisotropy and, more recently, polarization have played a very important role in allowing precise determination of various parameters of the `standard' cosmological model. The expectation of the paradigm of inflation and the generic prediction of the simplest realization of inflationary scenario in the ...

  12. First results from the microwave air yield beam experiment (MAYBE): Measurement of GHz radiation for ultra-high energy cosmic ray detection

    Energy Technology Data Exchange (ETDEWEB)

    Williams, C. [Chicago U., KICP; Bohacova, M. [Prague, Inst. Phys.; Bonifazi, C. [Rio de Janeiro Federal U.; Cataldi, G. [INFN, Lecce; Chemerisov, S. [Argonne (main); De Mello Neto, J. R.T. [INFN, Lecce; Facal San Luis, P. [Chicago U., KICP; Fox, B. [Hawaii U.; Gorham, P. W. [Hawaii U.; Hojvat, C. [Fermilab; Hollon, N. [Chicago U., KICP; Meyhandan, R. [Hawaii U.; Monasor, M. [Chicago U., KICP; D' Orfeuil, B. Rouille [Chicago U., KICP; Santos, E. M. [Rio de Janeiro Federal U.; Pochez, J. [Chicago U., KICP; Privitera, P. [Chicago U., KICP; Spinka, H. [Argonne (main); Verzi, V. [Rome U., Tor Vergata; Zhou, J. [Chicago U., KICP

    2013-01-01

    We present measurements of microwave emission from an electron-beam induced air plasma performed at the 3 MeV electron Van de Graaff facility of the Argonne National Laboratory. Results include the emission spectrum between 1 and 15 GHz, the polarization of the microwave radiation and the scaling of the emitted power with respect to beam intensity. MAYBE measurements provide further insight on microwave emission from extensive air showers as a novel detection technique for Ultra-High Energy Cosmic Rays.

  13. Probing large-scale magnetism with the cosmic microwave background

    Science.gov (United States)

    Giovannini, Massimo

    2018-04-01

    Prior to photon decoupling magnetic random fields of comoving intensity in the nano-Gauss range distort the temperature and the polarization anisotropies of the microwave background, potentially induce a peculiar B-mode power spectrum and may even generate a frequency-dependent circularly polarized V-mode. We critically analyze the theoretical foundations and the recent achievements of an interesting trialogue involving plasma physics, general relativity and astrophysics.

  14. Impact of stochastic primordial magnetic fields on the scalar contribution to cosmic microwave background anisotropies

    International Nuclear Information System (INIS)

    Finelli, Fabio; Paci, Francesco; Paoletti, Daniela

    2008-01-01

    We study the impact of a stochastic background of primordial magnetic fields on the scalar contribution of cosmic microwave background (CMB) anisotropies and on the matter power spectrum. We give the correct initial conditions for cosmological perturbations and the exact expressions for the energy density and Lorentz force associated to the stochastic background of primordial magnetic fields, given a power-law for their spectra cut at a damping scale. The dependence of the CMB temperature and polarization spectra on the relevant parameters of the primordial magnetic fields is illustrated.

  15. Exploring Cosmic Origins with CORE: Extragalactic sources in Cosmic Microwave Background maps

    OpenAIRE

    De Zotti, G.; Gonzalez-Nuevo, J.; Lopez-Caniego, M.; Negrello, M.; Greenslade, J.; Hernandez-Monteagudo, C.; Delabrouille, J.; Cai, Z. -Y.; Bonato, M.; Achucarro, A.; Ade, P.; Allison, R.; Ashdown, M.; Ballardini, M.; Banday, A. J.

    2016-01-01

    We discuss the potential of a next generation space-borne Cosmic Microwave Background (CMB) experiment for studies of extragalactic sources. Our analysis has particular bearing on the definition of the future space project, CORE, that has been submitted in response to ESA's call for a Medium-size mission opportunity as the successor of the Planck satellite. Even though the effective telescope size will be somewhat smaller than that of Planck, CORE will have a considerably better angular resol...

  16. Exploring cosmic origins with CORE: Extragalactic sources in cosmic microwave background maps

    Science.gov (United States)

    De Zotti, G.; González-Nuevo, J.; Lopez-Caniego, M.; Negrello, M.; Greenslade, J.; Hernández-Monteagudo, C.; Delabrouille, J.; Cai, Z.-Y.; Bonato, M.; Achúcarro, A.; Ade, P.; Allison, R.; Ashdown, M.; Ballardini, M.; Banday, A. J.; Banerji, R.; Bartlett, J. G.; Bartolo, N.; Basak, S.; Bersanelli, M.; Biesiada, M.; Bilicki, M.; Bonaldi, A.; Bonavera, L.; Borrill, J.; Bouchet, F.; Boulanger, F.; Brinckmann, T.; Bucher, M.; Burigana, C.; Buzzelli, A.; Calvo, M.; Carvalho, C. S.; Castellano, M. G.; Challinor, A.; Chluba, J.; Clements, D. L.; Clesse, S.; Colafrancesco, S.; Colantoni, I.; Coppolecchia, A.; Crook, M.; D'Alessandro, G.; de Bernardis, P.; de Gasperis, G.; Diego, J. M.; Di Valentino, E.; Errard, J.; Feeney, S. M.; Fernández-Cobos, R.; Ferraro, S.; Finelli, F.; Forastieri, F.; Galli, S.; Génova-Santos, R. T.; Gerbino, M.; Grandis, S.; Hagstotz, S.; Hanany, S.; Handley, W.; Hervias-Caimapo, C.; Hills, M.; Hivon, E.; Kiiveri, K.; Kisner, T.; Kitching, T.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamagna, L.; Lasenby, A.; Lattanzi, M.; Le Brun, A.; Lesgourgues, J.; Lewis, A.; Liguori, M.; Lindholm, V.; Luzzi, G.; Maffei, B.; Mandolesi, N.; Martinez-Gonzalez, E.; Martins, C. J. A. P.; Masi, S.; Massardi, M.; Matarrese, S.; McCarthy, D.; Melchiorri, A.; Melin, J.-B.; Molinari, D.; Monfardini, A.; Natoli, P.; Notari, A.; Paiella, A.; Paoletti, D.; Partridge, R. B.; Patanchon, G.; Piat, M.; Pisano, G.; Polastri, L.; Polenta, G.; Pollo, A.; Poulin, V.; Quartin, M.; Remazeilles, M.; Roman, M.; Rossi, G.; Roukema, B. F.; Rubiño-Martín, J.-A.; Salvati, L.; Scott, D.; Serjeant, S.; Tartari, A.; Toffolatti, L.; Tomasi, M.; Trappe, N.; Triqueneaux, S.; Trombetti, T.; Tucci, M.; Tucker, C.; Väliviita, J.; van de Weygaert, R.; Van Tent, B.; Vennin, V.; Vielva, P.; Vittorio, N.; Young, K.; Zannoni, M.

    2018-04-01

    We discuss the potential of a next generation space-borne Cosmic Microwave Background (CMB) experiment for studies of extragalactic sources. Our analysis has particular bearing on the definition of the future space project, CORE, that has been submitted in response to ESA's call for a Medium-size mission opportunity as the successor of the Planck satellite. Even though the effective telescope size will be somewhat smaller than that of Planck, CORE will have a considerably better angular resolution at its highest frequencies, since, in contrast with Planck, it will be diffraction limited at all frequencies. The improved resolution implies a considerable decrease of the source confusion, i.e. substantially fainter detection limits. In particular, CORE will detect thousands of strongly lensed high-z galaxies distributed over the full sky. The extreme brightness of these galaxies will make it possible to study them, via follow-up observations, in extraordinary detail. Also, the CORE resolution matches the typical sizes of high-z galaxy proto-clusters much better than the Planck resolution, resulting in a much higher detection efficiency; these objects will be caught in an evolutionary phase beyond the reach of surveys in other wavebands. Furthermore, CORE will provide unique information on the evolution of the star formation in virialized groups and clusters of galaxies up to the highest possible redshifts. Finally, thanks to its very high sensitivity, CORE will detect the polarized emission of thousands of radio sources and, for the first time, of dusty galaxies, at mm and sub-mm wavelengths, respectively.

  17. The absence of distortion in the cosmic microwave background spectrum and superconducting cosmic strings

    International Nuclear Information System (INIS)

    Sanchez, N.; Signore, M.

    1990-01-01

    From the results of recent measurements we place new constraints on superconducting cosmic strings (SCS) and on their cosmological evolution, independently of numerical simulation results. The absence of distortion in the cosmic microwave background radiation (MBR) spectrum recently reported from the preliminary data of the COBE (Cosmic background explorer) satellite, together with the available MBR angular temperature ΔT/T measurements and the latest fast pulsar timings, allow us to obtain (i) the electromagnetic-to-gravitational radiation ratio released by SCS loops, f -2 , (ii) the chemical potential due to SCS, μ 0SCS -3 , (iii) constraints on the loop evolution parameters which we confront to those given by numerical simulations, and (iv) limits on the string parameter Gμ: those obtained from COBE's data (Gμ -6 ) converge to those given by the latest PSR 1937+21 timing. Both limits on Gμ are reduced by an order of magnitude when taking into account numerical simulation results. (orig.)

  18. Cosmic microwave background radiation of black hole universe

    Science.gov (United States)

    Zhang, T. X.

    2010-11-01

    Modifying slightly the big bang theory, the author has recently developed a new cosmological model called black hole universe. This new cosmological model is consistent with the Mach principle, Einsteinian general theory of relativity, and observations of the universe. The origin, structure, evolution, and expansion of the black hole universe have been presented in the recent sequence of American Astronomical Society (AAS) meetings and published recently in a scientific journal: Progress in Physics. This paper explains the observed 2.725 K cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present universe with hundred billion-trillions of solar masses. According to the black hole universe model, the observed cosmic microwave background radiation can be explained as the black body radiation of the black hole universe, which can be considered as an ideal black body. When a hot and dense star-like black hole accretes its ambient materials and merges with other black holes, it expands and cools down. A governing equation that expresses the possible thermal history of the black hole universe is derived from the Planck law of black body radiation and radiation energy conservation. The result obtained by solving the governing equation indicates that the radiation temperature of the present universe can be ˜2.725 K if the universe originated from a hot star-like black hole, and is therefore consistent with the observation of the cosmic microwave background radiation. A smaller or younger black hole universe usually cools down faster. The characteristics of the original star-like or supermassive black hole are not critical to the physical properties of the black hole universe at present, because matter and radiation are mainly from the outside space, i.e., the mother universe.

  19. Simulating cosmic microwave background maps in multiconnected spaces

    International Nuclear Information System (INIS)

    Riazuelo, Alain; Uzan, Jean-Philippe; Lehoucq, Roland; Weeks, Jeffrey

    2004-01-01

    This paper describes the computation of cosmic microwave background (CMB) anisotropies in a universe with multiconnected spatial sections and focuses on the implementation of the topology in standard CMB computer codes. The key ingredient is the computation of the eigenmodes of the Laplacian with boundary conditions compatible with multiconnected space topology. The correlators of the coefficients of the decomposition of the temperature fluctuation in spherical harmonics are computed and examples are given for spatially flat spaces and one family of spherical spaces, namely, the lens spaces. Under the hypothesis of Gaussian initial conditions, these correlators encode all the topological information of the CMB and suffice to simulate CMB maps

  20. Deconvolution map-making for cosmic microwave background observations

    International Nuclear Information System (INIS)

    Armitage, Charmaine; Wandelt, Benjamin D.

    2004-01-01

    We describe a new map-making code for cosmic microwave background observations. It implements fast algorithms for convolution and transpose convolution of two functions on the sphere [B. Wandelt and K. Gorski, Phys. Rev. D 63, 123002 (2001)]. Our code can account for arbitrary beam asymmetries and can be applied to any scanning strategy. We demonstrate the method using simulated time-ordered data for three beam models and two scanning patterns, including a coarsened version of the WMAP strategy. We quantitatively compare our results with a standard map-making method and demonstrate that the true sky is recovered with high accuracy using deconvolution map-making

  1. Cosmic microwave background radiation in an inhomogeneous spherical space

    International Nuclear Information System (INIS)

    Aurich, R; Lustig, S; Kramer, P

    2011-01-01

    We analyse the cosmic microwave background (CMB) radiation in spherical three-spaces with nontrivial topology. The focus is on an inhomogeneous space which possesses observer-dependent CMB properties. The suppression of the CMB anisotropies on large angular scales is analysed with respect to the position of the CMB observer. The equivalence of a lens space to a Platonic cubic space is shown and used for the harmonic analysis. We give the transformation of the CMB multipole radiation amplitude as a function of the position of the observer. General sum rules are obtained in terms of the squares of the expansion coefficients for invariant polynomials on the three-sphere.

  2. Large Scale Anomalies of the Cosmic Microwave Background with Planck

    DEFF Research Database (Denmark)

    Frejsel, Anne Mette

    This thesis focuses on the large scale anomalies of the Cosmic Microwave Background (CMB) and their possible origins. The investigations consist of two main parts. The first part is on statistical tests of the CMB, and the consistency of both maps and power spectrum. We find that the Planck data....... Here we find evidence that the Planck CMB maps contain residual radiation in the loop areas, which can be linked to some of the large scale CMB anomalies: the point-parity asymmetry, the alignment of quadrupole and octupole and the dipolemodulation....

  3. Dark energy and the cosmic microwave background radiation

    Science.gov (United States)

    Dodelson, S.; Knox, L.

    2000-01-01

    We find that current cosmic microwave background anisotropy data strongly constrain the mean spatial curvature of the Universe to be near zero, or, equivalently, the total energy density to be near critical-as predicted by inflation. This result is robust to editing of data sets, and variation of other cosmological parameters (totaling seven, including a cosmological constant). Other lines of argument indicate that the energy density of nonrelativistic matter is much less than critical. Together, these results are evidence, independent of supernovae data, for dark energy in the Universe.

  4. Characteristic angular scales in cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Ghasemi, F.; Bahraminasab, A.; Movahed, M.S.; Rahvar, S.; Sreenivasan, K.R.; Tabar, M.R.R.

    2006-12-01

    We investigate the stochasticity in temperature fluctuations in the cosmic microwave background (CMB) radiation data from the Wilkinson Microwave Anisotropy Probe. We show that the angular fluctuation of the temperature is a Markov process with a Markov angular scale, Markov 1.01 -0.07 +0.09 . We characterize the complexity of the CMB fluctuations by means of a Fokker-Planck or Langevin equation and measure the associated Kramers-Moyal coefficients for the fluctuating temperature field T(n-circumflex) and its increment, ΔT = T(n-circumflex 1 ) - T(n-circumflex 2 ). Through this method we show that temperature fluctuations in the CMB have fat tails compared to a Gaussian distribution. (author)

  5. The Cosmic Microwave Background Radiation-A Unique Window on the Early Universe

    Science.gov (United States)

    Hinshaw, Gary

    2010-01-01

    The cosmic microwave background radiation is the remnant heat from the Big Bang. It provides us with a unique probe of conditions in the early universe, long before any organized structures had yet formed. The anisotropy in the radiation's brightness yields important clues about primordial structure and additionally provides a wealth of information about the physics of the early universe. Within the framework of inflationary dark matter models, observations of the anisotropy on sub-degree angular scales reveals the signatures of acoustic oscillations of the photon-baryon fluid at a redshift of 11 00. Data from the first seven years of operation of the Wilkinson Microwave Anisotropy Probe (WMAP) satellite provide detailed full-sky maps of the cosmic microwave background temperature and polarization anisotropy. Together, the data provide a wealth of cosmological information, including the age of the universe, the epoch when the first stars formed, and the overall composition of baryonic matter, dark matter, and dark energy. The results also provide constraints on the period of inflationary expansion in the very first moments of time. WMAP, part of NASA's Explorers program, was launched on June 30, 2001. The WMAP satellite was produced in a partnership between the Goddard Space Flight Center and Princeton University. The WMAP team also includes researchers at the Johns Hopkins University; the Canadian Institute of Theoretical Astrophysics; University of Texas; Oxford University; University of Chicago; Brown University; University of British Columbia; and University of California, Los Angeles.

  6. Extragalactic sources in Cosmic Microwave Background maps

    Energy Technology Data Exchange (ETDEWEB)

    Zotti, G. De; Castex, G. [SISSA, via Bonomea 265, 34136 Trieste (Italy); González-Nuevo, J. [Departamento de Física, Universidad de Oviedo, C. Calvo Sotelo s/n, 33007 Oviedo (Spain); Lopez-Caniego, M. [European Space Agency, ESAC, Planck Science Office, Camino bajo del Castillo, s/n, Urbanización Villafranca del Castillo, Villanueva de la Cañada, Madrid (Spain); Negrello, M.; Clemens, M. [INAF-Osservatorio Astronomico di Padova, vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Cai, Z.-Y. [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Delabrouille, J. [APC, 10, rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France); Herranz, D.; Bonavera, L. [Instituto de Física de Cantabria (CSIC-UC), avda. los Castros s/n, 39005 Santander (Spain); Melin, J.-B. [DSM/Irfu/SPP, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Tucci, M. [Département de Physique Théorique and Center for Astroparticle Physics, Université de Genève, 24 quai Ansermet, CH-1211 Genève 4 (Switzerland); Serjeant, S. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Bilicki, M. [Astrophysics, Cosmology and Gravity Centre, Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch (South Africa); Andreani, P., E-mail: gianfranco.dezotti@oapd.inaf.it, E-mail: gcastex@sissa.it, E-mail: gnuevo@uniovi.es, E-mail: marcos.lopez.caniego@sciops.esa.int [European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748, Garching (Germany); and others

    2015-06-01

    We discuss the potential of a next generation space-borne CMB experiment for studies of extragalactic sources with reference to COrE+, a project submitted to ESA in response to the call for a Medium-size mission (M4). We consider three possible options for the telescope size: 1 m, 1.5 m and 2 m (although the last option is probably impractical, given the M4 boundary conditions). The proposed instrument will be far more sensitive than Planck and will have a diffraction-limited angular resolution. These properties imply that even the 1 m telescope option will perform substantially better than Planck for studies of extragalactic sources. The source detection limits as a function of frequency have been estimated by means of realistic simulations taking into account all the relevant foregrounds. Predictions for the various classes of extragalactic sources are based on up-to-date models. The most significant improvements over Planck results are presented for each option. COrE+ will provide much larger samples of truly local star-forming galaxies (by about a factor of 8 for the 1 m telescope, of 17 for 1.5 m, of 30 for 2 m), making possible analyses of the properties of galaxies (luminosity functions, dust mass functions, star formation rate functions, dust temperature distributions, etc.) across the Hubble sequence. Even more interestingly, COrE+ will detect, at |b| > 30°, thousands of strongly gravitationally lensed galaxies (about 2,000, 6,000 and 13,000 for the 1 m, 1.5 m and 2 m options, respectively). Such large samples are of extraordinary astrophysical and cosmological value in many fields. Moreover, COrE+ high frequency maps will be optimally suited to pick up proto-clusters of dusty galaxies, i.e. to investigate the evolution of large scale structure at larger redshifts than can be reached by other means. Thanks to its high sensitivity COrE+ will also yield a spectacular advance in the blind detection of extragalactic sources in polarization: we expect that

  7. Evidence for Dark Energy from the Cosmic Microwave Background Alone Using the Atacama Cosmology Telescope Lensing Measurements

    Science.gov (United States)

    Sherwin, Blake D.; Dunkley, Joanna; Das, Sudeep; Appel, John W.; Bond, J. Richard; Carvalho, C. Sofia; Devlin, Mark J.; Duenner, Rolando; Essinger-Hileman, Thomas; Fowler, Joesph J.; hide

    2011-01-01

    For the first time, measurements of the cosmic microwave background radiation (CMB) alone favor cosmologies with w = -1 dark energy over models without dark energy at a 3.2-sigma level. We demonstrate this by combining the CMB lensing deflection power spectrum from the Atacama Cosmology Telescope with temperature and polarization power spectra from the "Wilkinson Microwave Anisotropy Probe. The lensing data break the geometric degeneracy of different cosmological models with similar CMB temperature power spectra. Our CMB-only measurement of the dark energy density Omega(delta) confirms other measurements from supernovae, galaxy clusters and baryon acoustic oscillations, and demonstrates the power of CMB lensing as a new cosmological tool.

  8. Effect of the early reionization on the cosmic microwave background and cosmological parameter estimates

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qing-Guo; Wang, Ke, E-mail: huangqg@itp.ac.cn, E-mail: wangke@itp.ac.cn [CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Zhong Guan Cun East Street 55 #, Beijing 100190 (China)

    2017-07-01

    The early reionization (ERE) is supposed to be a physical process which happens after recombination, but before the instantaneous reionization caused by the first generation of stars. We investigate the effect of the ERE on the temperature and polarization power spectra of cosmic microwave background (CMB), and adopt principal components analysis (PCA) to model-independently reconstruct the ionization history during the ERE. In addition, we also discuss how the ERE affects the cosmological parameter estimates, and find that the ERE does not impose any significant influences on the tensor-to-scalar ratio r and the neutrino mass at the sensitivities of current experiments. The better CMB polarization data can be used to give a tighter constraint on the ERE and might be important for more precisely constraining cosmological parameters in the future.

  9. An All Silicon Feedhorn-Coupled Focal Plane for Cosmic Microwave Background Polarimetry

    Science.gov (United States)

    Hubmayr, J.; Appel, J. W.; Austermann, J. E.; Beall, J. A.; Becker, D.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Cho, H. M.; hide

    2011-01-01

    Upcoming experiments aim to produce high fidelity polarization maps of the cosmic microwave background. To achieve the required sensitivity, we are developing monolithic, feedhorn-coupled transition edge sensor polarimeter arrays operating at 150 GHz. We describe this focal plane architecture and the current status of this technology, focusing on single-pixel polarimeters being deployed on the Atacama B-mode Search (ABS) and an 84-pixel demonstration feedhorn array backed by four 10-pixel polarimeter arrays. The feedhorn array exhibits symmetric beams, cross-polar response less than -23 dB and excellent uniformity across the array. Monolithic polarimeter arrays, including arrays of silicon feedhorns, will be used in the Atacama Cosmology Telescope Polarimeter (ACTPol) and the South Pole Telescope Polarimeter (SPTpol) and have been proposed for upcoming balloon-borne instruments.

  10. Large enhancement of deuteron polarization with frequency modulated microwaves

    CERN Document Server

    Adeva, B; Arik, S; Arvidson, A; Badelek, B; Ballintijn, M K; Bardin,; Baum, G; Berglund, P; Betev, L; Birda, I G; Birsa, R; Bjrkholm, P; Bonner, B E; de Botton, N; Boutemeur, M; Bradamante, Franco; Bressan, A; Brullc, A; Buchanan, J; Bültmann, S; Burtin, E; Cavata, C; Chen, J P; Clement, J; Clocchiatti, M; Corcoran, M D; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Deshpande, S; Dalla Torre, A; Van Dantzig, R; Dhawan, S; Dulya, C; Dyring, A; Eichblatt, S; Faivre, Jean-Claude; Fasching, D; Day, D; Feinstein, F; Fernández, C; Frois, B; Garabatos, C; Garzón, J A; Gaussiran, T; Giorgi, M; von Goeler, E; Goloutvin, Igor A; Gómez, A; Gracia, G; De Groot, N; Grosse-Perdekamp, M; Gülmez, E; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, D; von Harrach, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; De Jong, M; Kabu, E M; Kageya, T; Kaiser, R; Karev, A; Kessler, H J; Ketel, T J; Kiryushin, Yu T; Kishi, A; Kisselev, Yu; Klostermann, L; Krämer, Dietrich; Kukhtin, V; Kyynarinen, J; Lamanna, M; Landgraf, U; Lau, V; Krivokhijinea, K; Layda, T; Le Go, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Lindqvist, T; Litmaath, M; López-Ponte, S; Loewe, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B; McCarthy, J S; van Middelkoop, K; Medved, G; Miller, D; Mitchell, J; Mori, K; Moromisato, J; Mutchler, G S; Nagaitsev, A; Nassalski, J; Naumann, Lutz; Neganov, B; Niinikoski, T O; Oberski, J E J; Ogawa, A; Okumi, S; Ozben, C S; Penzo, Aldo L; Pérez, C A; Perrot-Kunne, F; Piegaia, R; Pinsky, L; Platchkov, S; Pló, M; Pose, D; Postma, D; Peshekhonov, H; Pretz, J; Pussieux, T; Pyrlik, J; Reyhancan, I; Rieubland, Jean Michel; Rijllart, A; Roberts, J B; Rock, S E; Rodríguez, M; Rondio, E; Rondon, O; Ropelewski, Leszek; Rosado, A; Sabo, I; Saborido, J; Salvato, G; Sandacz, A; Sanders, D; Savin, I; Schiavon, Paolo; Schüler, K P; Segel, R; Seitz, R; Semertzidis, Y; Sergeev, S; Sever, F; Shanahan, P; Sichtermann, E P; Smirnov, G; Staude, A; Steinmetz, A; Stuhrmann, H; Teichert, K M; Tessarotto, F; Thiel, W; Velasco, M; Vogt, J; Voss, R; Weinstein, R; Whitten, C; Willumeit, R; Windmolders, R; Wislicki, W; Witzmann, A; Yañez, A; Zanetti, A M; Zhao, J; Zamiatin, N I

    1996-01-01

    We report a large enhancement of 1.7 in deuteron polarization up to values of 0.6 due to frequency modulation of the polarizing microwaves in a two liters polarized target using the method of dynamic nuclear polarization. This target was used during a deep inelastic polarized muon-deuteron scattering experiment at CERN. Measurements of the electron paramagnetic resonance absorption spectra show that frequency modulation gives rise to additional microwave absorption in the spectral wings. Although these results are not understood theoretically, they may provide a useful testing ground for the deeper understanding of dynamic nuclear polarization.

  11. Is the Cosmic Microwave Background a Shell Around Us? or are the Microwaves Everywhere in the Universe?

    Science.gov (United States)

    Mather, John

    2015-01-01

    A: The cosmic microwave background (CMB) radiation fills the universe and travels in all directions. As we see it from here in satellite maps, it is about equally bright in all directions, and thats one of the main reasons we know its cosmic.

  12. Recent discoveries from the cosmic microwave background: a review of recent progress

    Science.gov (United States)

    Staggs, Suzanne; Dunkley, Jo; Page, Lyman

    2018-04-01

    Measurements of the anisotropies in the cosmic microwave background (CMB) radiation have provided a wealth of information about the cosmological model that describes the contents and evolution of the universe. These data have led to a standard model described by just six parameters. In this review we focus on discoveries made in the past decade from satellite and ground-based experiments, and look ahead to those anticipated in the coming decade. We provide an introduction to the key CMB observables including temperature and polarization anisotropies, and describe recent progress towards understanding the initial conditions of structure formation, and establishing the properties of the contents of the universe including neutrinos. Results are now being derived both from the primordial CMB signal that traces the behavior of the universe at 400 000 years of cosmic time, as well as from the signals imprinted at later times due to scattering from galaxy clusters, from the motion of electrons in the ionized universe, and from the gravitational lensing of the CMB photons. We describe current experimental methods to measure the CMB, particularly focusing on details relevant for ground and balloon-based instruments, and give an overview of the broad data analysis methods required to convert measurements of the microwave sky into cosmological parameters.

  13. Standard Clock in primordial density perturbations and cosmic microwave background

    International Nuclear Information System (INIS)

    Chen, Xingang; Namjoo, Mohammad Hossein

    2014-01-01

    Standard Clocks in the primordial epoch leave a special type of features in the primordial perturbations, which can be used to directly measure the scale factor of the primordial universe as a function of time a(t), thus discriminating between inflation and alternatives. We have started to search for such signals in the Planck 2013 data using the key predictions of the Standard Clock. In this Letter, we summarize the key predictions of the Standard Clock and present an interesting candidate example in Planck 2013 data. Motivated by this candidate, we construct and compute full Standard Clock models and use the more complete prediction to make more extensive comparison with data. Although this candidate is not yet statistically significant, we use it to illustrate how Standard Clocks appear in Cosmic Microwave Background (CMB) and how they can be further tested by future data. We also use it to motivate more detailed theoretical model building

  14. Interaction of ultrahigh energy cosmic rays with microwave background radiation

    International Nuclear Information System (INIS)

    Aharonyan, F.A.; Kanevskij, B.L.; Vardanyan, V.V.

    1989-01-01

    The formation of the bump and black-body cutoff in the cosmic-ray (CR) spectrum arising from the π-meson photoproduction reaction in collisions of CR protons with the microwave background radiation (MBR) photons is studied. A kinetic equation which describes CR proton propagation in MBR with account of a catastrophic of the π-meson photoproduction process is derived. The equilibrium CR proton spectrum obtained from the solution of the stationary kinetic equation is in general agreement with spectrum obtained under assumption of continuous energy loss approximation. However spectra from local sources especially for the times of propagation t>10 9 years differ noticeably from those obtained in the continuous loss approximation. 24 refs.; 5 figs

  15. Non-Gaussianity and the Cosmic Microwave Background Anisotropies

    CERN Document Server

    Bartolo, N; Riotto, A

    2010-01-01

    We review in a pedagogical way the present status of the impact of non-Gaussianity (NG) on the Cosmic Microwave Background (CMB) anisotropies. We first show how to set the initial conditions at second-order for the (gauge invariant) CMB anisotropies when some primordial NG is present. However, there are many sources of NG in CMB anisotropies, beyond the primordial one, which can contaminate the primordial signal. We mainly focus on the NG generated from the post-inflationary evolution of the CMB anisotropies at second-order in perturbation theory at large and small angular scales, such as the ones generated at the recombination epoch. We show how to derive the equations to study the second-order CMB anisotropies and provide analytical computations to evaluate their contamination to primordial NG (complemented with numerical examples). We also offer a brief summary of other secondary effects. This review requires basic knowledge of the theory of cosmological perturbations at the linear level.

  16. Cosmic microwave background anomalies in an open universe.

    Science.gov (United States)

    Liddle, Andrew R; Cortês, Marina

    2013-09-13

    We argue that the observed large-scale cosmic microwave anomalies, discovered by WMAP and confirmed by the Planck satellite, are most naturally explained in the context of a marginally open universe. Particular focus is placed on the dipole power asymmetry, via an open universe implementation of the large-scale gradient mechanism of Erickcek et al. Open inflation models, which are motivated by the string landscape and which can excite "supercurvature" perturbation modes, can explain the presence of a very-large-scale perturbation that leads to a dipole modulation of the power spectrum measured by a typical observer. We provide a specific implementation of the scenario which appears compatible with all existing constraints.

  17. Standard Clock in primordial density perturbations and cosmic microwave background

    Directory of Open Access Journals (Sweden)

    Xingang Chen

    2014-12-01

    Full Text Available Standard Clocks in the primordial epoch leave a special type of features in the primordial perturbations, which can be used to directly measure the scale factor of the primordial universe as a function of time a(t, thus discriminating between inflation and alternatives. We have started to search for such signals in the Planck 2013 data using the key predictions of the Standard Clock. In this Letter, we summarize the key predictions of the Standard Clock and present an interesting candidate example in Planck 2013 data. Motivated by this candidate, we construct and compute full Standard Clock models and use the more complete prediction to make more extensive comparison with data. Although this candidate is not yet statistically significant, we use it to illustrate how Standard Clocks appear in Cosmic Microwave Background (CMB and how they can be further tested by future data. We also use it to motivate more detailed theoretical model building.

  18. The Primordial Inflation Explorer (PIXIE): A Nulling Polarimeter for Cosmic Microwave Background Observations

    Science.gov (United States)

    Kogut, Alan J.; Fixsen, D. J.; Chuss, D. T.; Dotson, J.; Dwek, E.; Halpern, M.; Hinshaw, G. F.; Meyer, S. M.; Moseley, S. H.; Seiffert, M. D.; hide

    2011-01-01

    The Primordial Inflation Explorer (PIXIE) is a concept for an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. The instrument consists of a polarizing Michelson interferometer configured as a nulling polarimeter to measure the difference spectrum between orthogonal linear polarizations from two co-aligned beams. Either input can view the sky or a temperature-controlled absolute reference blackbody calibrator. Rhe proposed instrument can map the absolute intensity and linear polarization (Stokes I, Q, and U parameters) over the full sky in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). Multi-moded optics provide background-limited sensitivity using only 4 detectors, while the highly symmetric design and multiple signal modulations provide robust rejection of potential systematic errors. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r < 10..3 at 5 standard deviations. The rich PIXIE data set can also constrain physical processes ranging from Big Bang cosmology to the nature of the first stars to physical conditions within the interstellar medium of the Galaxy.

  19. Cosmic microwave background anisotropies in multiconnected flat spaces

    International Nuclear Information System (INIS)

    Riazuelo, Alain; Weeks, Jeffrey; Uzan, Jean-Philippe; Lehoucq, Roland; Luminet, Jean-Pierre

    2004-01-01

    This article investigates the signature of the seventeen multiconnected flat spaces in cosmic microwave background (CMB) maps. For each such space it recalls a fundamental domain and a set of generating matrices, and then goes on to find an orthonormal basis for the set of eigenmodes of the Laplace operator on that space. The basis eigenmodes are expressed as linear combinations of eigenmodes of the simply connected Euclidean space. A preceding work, which provides a general method for implementing multiconnected topologies in standard CMB codes, is then applied to simulate CMB maps and angular power spectra for each space. Unlike in the 3-torus, the results in most multiconnected flat spaces depend on the location of the observer. This effect is discussed in detail. In particular, it is shown that the correlated circles on a CMB map are generically not back to back, so that negative search of back-to-back circles in the Wilkinson Microwave Anisotropy Probe data does not exclude a vast majority of flat or nearly flat topologies

  20. Gravitational lensing effect and polarization of the cosmic microwave background in the PLANCK Experiment and post-planckian projects; Effet de lentilles gravitationnelles et polarisation du fond diffus cosmologique dans le cadre de l'experience PLANCK et de projets post-planckiens

    Energy Technology Data Exchange (ETDEWEB)

    Perotto, Laurence [Universite Paris 7 - Denis Diderot, UFR de Physique, 75205 Paris Cedex 13 (France)

    2006-01-15

    This thesis is motivated by the upcoming high-resolution, high-sensitivity microwave background experiments, which should be sensitive to the CMB polarization and lensing. The first chapter provides a review of the CMB polarization with emphasis on future related experiments. The PLANCK experiment is described in a second chapter, where I develop a fast simulation code of PLANCK time-ordered data optimized to ease elaboration and test of data analysis methods. The two last chapters deal with gravitational lensing of the cosmic background radiation. First, I evaluate the capability of the upcoming experiments mentioned above to measure the power spectrum of Large Scale Structure by means of the extraction of weak lensing. Then I derive their sensitivity to the total neutrino mass, using the suppression of power due to free-streaming of massive neutrinos. Finally, I develop a method to estimate the foreground effects in the gravitational lensing extraction process. This method uses the best linear estimator available in the literature and is validated by numerical simulations that include non-Gaussian CMB lensed maps and extra-galactic radio sources maps. I find that sources emission reduces the sensitivity of future experiments to the weak lensing and leads to an overestimate of the convergence power spectrum. (author)

  1. Broad Bandwidth Metamaterial Antireflection Coatings for Measurement of the Cosmic Microwave Background

    Data.gov (United States)

    National Aeronautics and Space Administration — The Cosmic Microwave Background (CMB) contains a number of faint signals that, if measured, could revolutionize our understandings of the Universe and fundamental...

  2. Photon-graviton conversion in a primordial magnetic field and the cosmic microwave background

    OpenAIRE

    Cillis, Analia N.; Harari, Diego D.

    1996-01-01

    We reconsider the effects of photon-graviton conversion in a primordial magnetic field upon the cosmic microwave background radiation. We argue that plasma effects make the photon-graviton conversion process negligible.

  3. Optimization of Transition Edge Sensor Arrays for Cosmic Microwave Background Observations With the South Pole Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Junjia; Ade, P. A. R.; Anderson, A. J.; Avva, J.; Ahmed, Z.; Arnold, K.; Austermann, J. E.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Byrum, K.; Carlstrom, J. E.; Carter, F. W.; Chang, C. L.; Cho, H. M.; Cliche, J. F.; Cukierman, A.; Czaplewski, D.; Divan, R.; de Haan, T.; Dobbs, M. A.; Dutcher, D.; Everett, W.; Gilbert, A.; Gannon, R.; Guyser, R.; Halverson, N. W.; Harrington, N. L.; Hattori, K.; Henning, J. W.; Hilton, G. C.; Holzapfel, W. L.; Hubmayr, J.; Huang, N.; Irwin, K. D.; Jeong, O.; Khaire, T.; Kubik, D.; Kuo, C. L.; Lee, A. T.; Leitch, E. M.; Meyer, S. S.; Miller, C. S.; Montgomery, J.; Nadolski, A.; Natoli, T.; Nguyen, H.; Novosad, V.; Padin, S.; Pan, Z.; Pearson, J.; Posada, C. M.; Rahlin, A.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Shariff, J. A.; Shirley, I.; Shirokoff, E.; Smecher, G.; Sobrin, J.; Stan, L.; Stark, A. A.; Story, K.; Suzuki, A.; Tang, Q. Y.; Thakur, R. B.; Thompson, K. L.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Wu, W. L. K.; Yefremenko, V.; Yoon, K. W.

    2017-06-01

    In this paper, we describe the optimization of transition-edge-sensor (TES) detector arrays for the third-generation camera for the South PoleTelescope. The camera, which contains similar to 16 000 detectors, will make high-angular-resolution maps of the temperature and polarization of the cosmic microwave background. Our key results are scatter in the transition temperature of Ti/Au TESs is reduced by fabricating the TESs on a thin Ti(5 nm)/Au(5 nm) buffer layer and the thermal conductivity of the legs that support our detector islands is dominated by the SiOx dielectric in the microstrip transmission lines that run along the legs.

  4. Cosmic sculpture: a new way to visualise the cosmic microwave background

    International Nuclear Information System (INIS)

    Clements, D L; Sato, S; Fonseca, A Portela

    2017-01-01

    3D printing presents an attractive alternative to visual representation of physical datasets such as astronomical images that can be used for research, outreach or teaching purposes, and is especially relevant to people with a visual disability. We here report the use of 3D printing technology to produce a representation of the all-sky cosmic microwave background (CMB) intensity anisotropy maps produced by the Planck mission. The success of this work in representing key features of the CMB is discussed as is the potential of this approach for representing other astrophysical data sets. 3D printing such datasets represents a highly complementary approach to the usual 2D projections used in teaching and outreach work, and can also form the basis of undergraduate projects. The CAD files used to produce the models discussed in this paper are made available. (paper)

  5. Cosmic microwave background constraints on secret interactions among sterile neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Forastieri, Francesco; Natoli, Paolo [Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Via Giuseppe Saragat 1, I-44122 Ferrara (Italy); Lattanzi, Massimiliano [Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara, Via Giuseppe Saragat 1, I-44122 Ferrara (Italy); Mangano, Gianpiero [Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Complesso Univ. Monte S.Angelo, I-80126 Napoli (Italy); Mirizzi, Alessandro [Dipartimento Interateneo di Fisica ' Michelangelo Merlin,' Via Amendola 173, 70126 Bari (Italy); Saviano, Ninetta, E-mail: francesco.forastieri@unife.it, E-mail: lattanzi@fe.infn.it, E-mail: mangano@na.infn.it, E-mail: alessandro.mirizzi@ba.infn.it, E-mail: natoli@fe.infn.it, E-mail: nsaviano@uni-mainz.de [PRISMA Cluster of Excellence and Mainz Institute for Theoretical Physics, JohannesGutenberg-Universität Mainz, 55099 Mainz (Germany)

    2017-07-01

    Secret contact interactions among eV sterile neutrinos, mediated by a massive gauge boson X (with M {sub X} || M {sub W} ), and characterized by a gauge coupling g {sub X} , have been proposed as a mean to reconcile cosmological observations and short-baseline laboratory anomalies. We constrain this scenario using the latest Planck data on Cosmic Microwave Background anisotropies, and measurements of baryon acoustic oscillations (BAO). We consistently include the effect of secret interactions on cosmological perturbations, namely the increased density and pressure fluctuations in the neutrino fluid, and still find a severe tension between the secret interaction framework and cosmology. In fact, taking into account neutrino scattering via secret interactions, we derive our own mass bound on sterile neutrinos and find (at 95 % CL) m {sub s} < 0.82 eV or m {sub s} < 0.29 eV from Planck alone or in combination with BAO, respectively. These limits confirm the discrepancy with the laboratory anomalies. Moreover, we constrain, in the limit of contact interaction, the effective strength G {sub X} to be < 2.8 (2.0) × 10{sup 10} G {sub F} from Planck (Planck+BAO). This result, together with the mass bound, strongly disfavours the region with M {sub X} ∼ 0.1 MeV and relatively large coupling g {sub X} {sub ∼} 10{sup −1}, previously indicated as a possible solution to the small scale dark matter problem.

  6. The Implications of Interstellar Dust for the Cosmic Microwave Background

    Science.gov (United States)

    Schmelz, Joan T.; Verschuur, Gerrit

    2018-01-01

    A detailed comparison of the full range of PLANCK and WMAP data for small (2 deg by 2 deg) areas of sky and the Cosmic Microwave Background (CMB) ILC maps reveals that the structure of foreground dust may be more complex than previously thought. If 857 and 353 GHz emission is dominated by galactic dust at a distance data also show that there is no single answer for the question, “To what extent does dust contaminate the cosmologically important 143 GHz data?” In some directions, the contamination appears to be quite strong, but in others, it is less of an issue. This complexity needs to be taken in account in order to derive an accurate foreground mask in the quest to understand the CMB small-scale structure. We hope that a continued investigation of these data will lead to a definitive answer to the question above and, possibly, to new scientific insights on interstellar matter, the CMB, or both.

  7. Making maps of the cosmic microwave background: The MAXIMA example

    Science.gov (United States)

    Stompor, Radek; Balbi, Amedeo; Borrill, Julian D.; Ferreira, Pedro G.; Hanany, Shaul; Jaffe, Andrew H.; Lee, Adrian T.; Oh, Sang; Rabii, Bahman; Richards, Paul L.; Smoot, George F.; Winant, Celeste D.; Wu, Jiun-Huei Proty

    2002-01-01

    This work describes cosmic microwave background (CMB) data analysis algorithms and their implementations, developed to produce a pixelized map of the sky and a corresponding pixel-pixel noise correlation matrix from time ordered data for a CMB mapping experiment. We discuss in turn algorithms for estimating noise properties from the time ordered data, techniques for manipulating the time ordered data, and a number of variants of the maximum likelihood map-making procedure. We pay particular attention to issues pertinent to real CMB data, and present ways of incorporating them within the framework of maximum likelihood map making. Making a map of the sky is shown to be not only an intermediate step rendering an image of the sky, but also an important diagnostic stage, when tests for and/or removal of systematic effects can efficiently be performed. The case under study is the MAXIMA-I data set. However, the methods discussed are expected to be applicable to the analysis of other current and forthcoming CMB experiments.

  8. Inflation Physics from the Cosmic Microwave Background and Large Scale Structure

    Science.gov (United States)

    Abazajian, K.N.; Arnold,K.; Austermann, J.; Benson, B.A.; Bischoff, C.; Bock, J.; Bond, J.R.; Borrill, J.; Buder, I.; Burke, D.L.; hide

    2013-01-01

    Fluctuations in the intensity and polarization of the cosmic microwave background (CMB) and the large-scale distribution of matter in the universe each contain clues about the nature of the earliest moments of time. The next generation of CMB and large-scale structure (LSS) experiments are poised to test the leading paradigm for these earliest moments---the theory of cosmic inflation---and to detect the imprints of the inflationary epoch, thereby dramatically increasing our understanding of fundamental physics and the early universe. A future CMB experiment with sufficient angular resolution and frequency coverage that surveys at least 1 of the sky to a depth of 1 uK-arcmin can deliver a constraint on the tensor-to-scalar ratio that will either result in a 5-sigma measurement of the energy scale of inflation or rule out all large-field inflation models, even in the presence of foregrounds and the gravitational lensing B-mode signal. LSS experiments, particularly spectroscopic surveys such as the Dark Energy Spectroscopic Instrument, will complement the CMB effort by improving current constraints on running of the spectral index by up to a factor of four, improving constraints on curvature by a factor of ten, and providing non-Gaussianity constraints that are competitive with the current CMB bounds.

  9. Microwave-gated dynamic nuclear polarization

    DEFF Research Database (Denmark)

    Bornet, Aurélien; Pinon, Arthur; Jhajharia, Aditya

    2016-01-01

    Dissolution dynamic nuclear polarization (D-DNP) has become a method of choice to enhance signals in nuclear magnetic resonance (NMR). Recently, we have proposed to combine cross-polarization (CP) with D-DNP to provide high polarization P((13)C) in short build-up times. In this paper, we show...

  10. A COSMIC MICROWAVE BACKGROUND LENSING MASS MAP AND ITS CORRELATION WITH THE COSMIC INFRARED BACKGROUND

    Energy Technology Data Exchange (ETDEWEB)

    Holder, G. P.; De Haan, T.; Dobbs, M. A.; Dudley, J. [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); Viero, M. P.; Bock, J. [California Institute of Technology, Pasadena, CA 91125 (United States); Zahn, O. [Berkeley Center for Cosmological Physics, Department of Physics, University of California, and Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Aird, K. A. [University of Chicago, Chicago, IL 60637 (United States); Benson, B. A.; Bhattacharya, S.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, Kansas City, MO 64110 (United States); Cho, H-M. [NIST Quantum Devices Group, Boulder, CO 80305 (United States); Conley, A. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); George, E. M. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Halverson, N. W. [Department of Astrophysical and Planetary Sciences and Department of Physics, University of Colorado, Boulder, CO 80309 (United States); and others

    2013-07-01

    We use a temperature map of the cosmic microwave background (CMB) obtained using the South Pole Telescope at 150 GHz to construct a map of the gravitational convergence to z {approx} 1100, revealing the fluctuations in the projected mass density. This map shows individual features that are significant at the {approx}4{sigma} level, providing the first image of CMB lensing convergence. We cross-correlate this map with Herschel/SPIRE maps covering 90 deg{sup 2} at wavelengths of 500, 350, and 250 {mu}m. We show that these submillimeter (submm) wavelength maps are strongly correlated with the lensing convergence map, with detection significances in each of the three submm bands ranging from 6.7{sigma} to 8.8{sigma}. We fit the measurement of the cross power spectrum assuming a simple constant bias model and infer bias factors of b = 1.3-1.8, with a statistical uncertainty of 15%, depending on the assumed model for the redshift distribution of the dusty galaxies that are contributing to the Herschel/SPIRE maps.

  11. Effect of a chameleon scalar field on the cosmic microwave background

    International Nuclear Information System (INIS)

    Davis, Anne-Christine; Schelpe, Camilla A. O.; Shaw, Douglas J.

    2009-01-01

    We show that a direct coupling between a chameleonlike scalar field and photons can give rise to a modified Sunyaev-Zel'dovich (SZ) effect in the cosmic microwave background (CMB). The coupling induces a mixing between chameleon particles and the CMB photons when they pass through the magnetic field of a galaxy cluster. Both the intensity and the polarization of the radiation are modified. The degree of modification depends strongly on the properties of the galaxy cluster such as magnetic field strength and electron number density. Existing SZ measurements of the Coma cluster enable us to place constraints on the photon-chameleon coupling. The constrained conversion probability in the cluster is P Coma (204 GHz) -5 at 95% confidence, corresponding to an upper bound on the coupling strength of g eff (cell) -8 GeV -1 or g eff (Kolmo) -10 GeV -1 , depending on the model that is assumed for the cluster magnetic field structure. We predict the radial profile of the chameleonic CMB intensity decrement. We find that the chameleon effect extends farther toward the edges of the cluster than the thermal SZ effect. Thus we might see a discrepancy between the x-ray emission data and the observed SZ intensity decrement. We further predict the expected change to the CMB polarization arising from the existence of a chameleonlike scalar field. These predictions could be verified or constrained by future CMB experiments.

  12. Photoinduced spin polarization and microwave technology

    International Nuclear Information System (INIS)

    Antipov, Sergey; Poluektov, Oleg; Schoessow, Paul; Kanareykin, Alexei; Jing, Chunguang

    2013-01-01

    We report here on studies of optically pumped active microwave media based on various fullerene derivatives, with an emphasis on the use of these materials in microwave electronics. We have investigated a class of optically excited paramagnetic materials that demonstrate activity in the X-band as candidate materials. We found that a particular fullerene derivative, Phenyl-C 61 -butyric acid methyl ester (PCBM), produced the largest electron paramagnetic resonance (EPR) emission signal compared to other organic compounds that have been suggested for use as microwave active materials. We also studied the effects of concentration, temperature, solvent etc. on the activity of the material. In these experiments, EPR studies using a commercial spectrometer were followed up by measurements of an RF signal reflected from a resonator loaded with the PCBM-based material. The activity was directly demonstrated through the change in the quality factor and RF coupling between the resonator and waveguide feed. At the inception of these experiments the primary interest was the development of a microwave PASER. The PASER (particle acceleration by stimulated emission of radiation [1]) is a novel acceleration concept that is based on the direct energy transfer from an active medium to a charged particle beam. While the previous work on the PASER has emphasized operations at infrared or visible wavelengths, operating in the microwave regime has significant advantages in terms of the less stringent quality requirements placed on the electron beam provided an appropriate microwave active medium can be found. This paper is focused on our investigation of the possibility of a PASER operating in the microwave frequency regime [2] using active paramagnetic materials. While a high level of gain for PCBM was demonstrated compared to other candidate materials, dielectric losses and quenching effects were found to negatively impact its performance for PASER applications. We present results on

  13. Testing theories of gravity and supergravity with inflation and observations of the cosmic microwave background

    Science.gov (United States)

    Chakravarty, G. K.; Mohanty, S.; Lambiase, G.

    theories when applied to inflation (a rapid expansion of early universe in which primordial gravitational waves might be generated and might still be detectable by the imprint they left or by the ripples that persist today) can have distinct signatures in the Cosmic Microwave Background radiation temperature and polarization anisotropies. We give a review of ΛCDM cosmology and survey the theories of gravity beyond Einstein’s General Relativity, specially which arise from SUGRA, and study the consequences of these theories in the context of inflation and put bounds on the theories and the parameters therein from the observational experiments like PLANCK, Keck/BICEP, etc. The possibility of testing these theories in the near future in CMB observations and new data coming from colliders like the LHC, provides an unique opportunity for constructing verifiable models of particle physics and General Relativity.

  14. Cosmic microwave background constraints for global strings and global monopoles

    International Nuclear Information System (INIS)

    Lopez-Eiguren, Asier; Lizarraga, Joanes; Urrestilla, Jon; Hindmarsh, Mark

    2017-01-01

    We present the first cosmic microwave background (CMB) power spectra from numerical simulations of the global O( N ) linear σ-model, with N =2,3, which have global strings and monopoles as topological defects. In order to compute the CMB power spectra we compute the unequal time correlators (UETCs) of the energy-momentum tensor, showing that they fall off at high wave number faster than naive estimates based on the geometry of the defects, indicating non-trivial (anti-)correlations between the defects and the surrounding Goldstone boson field. We obtain source functions for Einstein-Boltzmann solvers from the UETCs, using a recently developed method that improves the modelling at the radiation-matter transition. We show that the interpolation function that mimics the transition is similar to other defect models, but not identical, confirming the non-universality of the interpolation function. The CMB power spectra for global strings and global monopoles have the same overall shape as those obtained using the non-linear σ-model approximation, which is well captured by a large- N calculation. However, the amplitudes are larger than the large- N calculation would naively predict, and in the case of global strings much larger: a factor of 20 at the peak. Finally we compare the CMB power spectra with the latest CMB data in other to put limits on the allowed contribution to the temperature power spectrum at multipole l = 10 of 1.7% for global strings and 2.4% for global monopoles. These limits correspond to symmetry-breaking scales of 2.9× 10 15 GeV (6.3× 10 14 GeV with the expected logarithmic scaling of the effective string tension between the simulation time and decoupling) and 6.4× 10 15 GeV respectively. The bound on global strings is a significant one for the ultra-light axion scenario with axion masses m a ∼< 10 −28 eV . These upper limits indicate that gravitational waves from global topological defects will not be observable at the gravitational wave

  15. A Robust Algorithm to Determine the Topology of Space from the Cosmic Microwave Background Radiation

    OpenAIRE

    Weeks, Jeffrey R.

    2001-01-01

    Satellite measurements of the cosmic microwave back-ground radiation will soon provide an opportunity to test whether the universe is multiply connected. This paper presents a new algorithm for deducing the topology of the universe from the microwave background data. Unlike an older algorithm, the new algorithm gives the curvature of space and the radius of the last scattering surface as outputs, rather than requiring them as inputs. The new algorithm is also more tolerant of erro...

  16. Simulation and Automation of Microwave Frequency Control in Dynamic Nuclear Polarization for Solid Polarized Targets

    Science.gov (United States)

    Perera, Gonaduwage; Johnson, Ian; Keller, Dustin

    2017-09-01

    Dynamic Nuclear Polarization (DNP) is used in most of the solid polarized target scattering experiments. Those target materials must be irradiated using microwaves at a frequency determined by the difference in the nuclear Larmor and electron paramagnetic resonance (EPR) frequencies. But the resonance frequency changes with time as a result of radiation damage. Hence the microwave frequency should be adjusted accordingly. Manually adjusting the frequency can be difficult, and improper adjustments negatively impact the polarization. In order to overcome these difficulties, two controllers were developed which automate the process of seeking and maintaining the optimal frequency: one being a standalone controller for a traditional DC motor and the other a LabVIEW VI for a stepper motor configuration. Further a Monte-Carlo simulation was developed which can accurately model the polarization over time as a function of microwave frequency. In this talk, analysis of the simulated data and recent improvements to the automated system will be presented. DOE.

  17. Slow-roll inflation and the BB-mode correlation spectrum of the Cosmic Microwave Background

    Science.gov (United States)

    Malsawmtluangi, N.; Suresh, P. K.

    2017-08-01

    The BB-mode correlation angular spectrum of cosmic microwave background is studied for several inflation models. A comparative study of the resulting angular power spectrum with the recent joint analysis data of the BICEP2/Keck Array and Planck shows constraint to several slow-roll inflation models of cosmology.

  18. The MIDAS telescope for microwave detection of ultra-high energy cosmic rays

    Czech Academy of Sciences Publication Activity Database

    Alvarez-Muñiz, J.; Soares, E.A.; Berlin, A.; Bogdan, M.; Boháčová, Martina; Bonifazi, C.; Carvalho, W.R.; de Mello Neto, J.R.T.; San Luis, P.F.; Genat, J.F.; Hollon, N.; Mills, E.; Monasor, M.; Privitera, P.; Ramos de Castro, A.; Reyes, L.C.; Richardson, M.; Rouille D’Orfeuil, B.; Santos, E.M.; Wayne, S.; Williams, C.; Zas, E.; Zhou, J.

    2013-01-01

    Roč. 719, Aug (2013), s. 70-80 ISSN 0168-9002 Institutional support: RVO:68378271 Keywords : ultra high energy cosmic rays * radio-detection * microwave * GHz Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.316, year: 2013

  19. Maximum Likelihood Analysis of Systematic Errors in Interferometric Observations of the Cosmic Microwave Background

    Science.gov (United States)

    Zhang, Le; Karakci, Ata; Sutter, Paul M.; Bunn, Emory F.; Korotkov, Andrei; Timbie, Peter; Tucker, Gregory S.; Wandelt, Benjamin D.

    2013-06-01

    We investigate the impact of instrumental systematic errors in interferometric measurements of the cosmic microwave background (CMB) temperature and polarization power spectra. We simulate interferometric CMB observations to generate mock visibilities and estimate power spectra using the statistically optimal maximum likelihood technique. We define a quadratic error measure to determine allowable levels of systematic error that does not induce power spectrum errors beyond a given tolerance. As an example, in this study we focus on differential pointing errors. The effects of other systematics can be simulated by this pipeline in a straightforward manner. We find that, in order to accurately recover the underlying B-modes for r = 0.01 at 28 QUBIC, in agreement with analytical estimates. Only the statistical uncertainty for 28 < l < 88 would be changed at ~10% level. With the same instrumental configuration, we find that the pointing errors would slightly bias the 2σ upper limit of the tensor-to-scalar ratio r by ~10%. We also show that the impact of pointing errors on the TB and EB measurements is negligibly small.

  20. MAXIMUM LIKELIHOOD ANALYSIS OF SYSTEMATIC ERRORS IN INTERFEROMETRIC OBSERVATIONS OF THE COSMIC MICROWAVE BACKGROUND

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Le; Timbie, Peter [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Karakci, Ata; Korotkov, Andrei; Tucker, Gregory S. [Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912 (United States); Sutter, Paul M.; Wandelt, Benjamin D. [Department of Physics, 1110 W Green Street, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Bunn, Emory F., E-mail: lzhang263@wisc.edu [Physics Department, University of Richmond, Richmond, VA 23173 (United States)

    2013-06-01

    We investigate the impact of instrumental systematic errors in interferometric measurements of the cosmic microwave background (CMB) temperature and polarization power spectra. We simulate interferometric CMB observations to generate mock visibilities and estimate power spectra using the statistically optimal maximum likelihood technique. We define a quadratic error measure to determine allowable levels of systematic error that does not induce power spectrum errors beyond a given tolerance. As an example, in this study we focus on differential pointing errors. The effects of other systematics can be simulated by this pipeline in a straightforward manner. We find that, in order to accurately recover the underlying B-modes for r = 0.01 at 28 < l < 384, Gaussian-distributed pointing errors must be controlled to 0. Degree-Sign 7 root mean square for an interferometer with an antenna configuration similar to QUBIC, in agreement with analytical estimates. Only the statistical uncertainty for 28 < l < 88 would be changed at {approx}10% level. With the same instrumental configuration, we find that the pointing errors would slightly bias the 2{sigma} upper limit of the tensor-to-scalar ratio r by {approx}10%. We also show that the impact of pointing errors on the TB and EB measurements is negligibly small.

  1. Early-matter-like dark energy and the cosmic microwave background

    International Nuclear Information System (INIS)

    Aurich, R.; Lustig, S.

    2016-01-01

    Early-matter-like dark energy is defined as a dark energy component whose equation of state approaches that of cold dark matter (CDM) at early times. Such a component is an ingredient of unified dark matter (UDM) models, which unify the cold dark matter and the cosmological constant of the ΛCDM concordance model into a single dark fluid. Power series expansions in conformal time of the perturbations of the various components for a model with early-matter-like dark energy are provided. They allow the calculation of the cosmic microwave background (CMB) anisotropy from the primordial initial values of the perturbations. For a phenomenological UDM model, which agrees with the observations of the local Universe, the CMB anisotropy is computed and compared with the CMB data. It is found that a match to the CMB observations is possible if the so-called effective velocity of sound c eff of the early-matter-like dark energy component is very close to zero. The modifications on the CMB temperature and polarization power spectra caused by varying the effective velocity of sound are studied

  2. A Flat Universe from High-Resolution Maps of the Cosmic MicrowaveBackground Radiation

    Energy Technology Data Exchange (ETDEWEB)

    de Bernardis, P.; Ade, P.A.R.; Bock, J.J.; Bond, J.R.; Borrill,J.; Boscaleri, A.; Coble, K.; Crill, B.P.; De Gasperis, G.; Farese, P.C.; Ferreira, P.G.; Ganga, K.; Giacometti, M.; Hivon, E.; Hristov, V.V.; Iacoangeli, A.; Jaffe, A.H.; Lange, A.E.; Martinis, L.; Masi, S.; Mason,P.; Mauskopf, P.D.; Melchiorri, A.; Miglio, L.; Montroy, T.; Netterfield,C.B.; Pascale, E.; Piacentini, F.; Pogosyan, D.; Prunet, S.; Rao, S.; Romeo, G.; Ruhl, J.E.; Scaramuzzi, F.; Sforna, D.; Vittorio, N.

    2000-04-28

    The blackbody radiation left over from the Big Bang has been transformed by the expansion of the Universe into the nearly isotropic 2.73 K Cosmic Microwave Background. Tiny inhomogeneities in the early Universe left their imprint on the microwave background in the form of small anisotropies in its temperature. These anisotropies contain information about basic cosmological parameters, particularly the total energy density and curvature of the universe. Here we report the first images of resolved structure in the microwave background anisotropies over a significant part of the sky. Maps at four frequencies clearly distinguish the microwave background from foreground emission. We compute the angular power spectrum of the microwave background, and find a peak at Legendre multipole {ell}{sub peak} = (197 {+-} 6), with an amplitude DT{sub 200} = (69 {+-} 8){mu}K. This is consistent with that expected for cold dark matter models in a flat (euclidean) Universe, as favored by standard inflationary scenarios.

  3. A hunt for cosmic microwave background B-modes in the systematic contaminants jungle

    International Nuclear Information System (INIS)

    Errard, J.

    2012-01-01

    This thesis presents a study of selected instrumental and astrophysical systematics, which may affect the performance of new generation of future observations of the Cosmic Microwave Background (CMB) polarization. It elaborates on their impact on the science goals of those observations and discusses techniques and approaches for their removal. Its focus is on general issues typical of entire classes of experiments, but also on specific problems as encountered in the context of a CMB B-mode experiment, POLARBEAR. The main target of the CMB polarization effort undergoing currently in the field is a detection of the primordial B-modes anisotropies --- a so far undetected signature of the inflationary theories. This would have far-reaching impact on our understanding of the universe but also fundamental laws of physics. Understanding, modelling, and ultimately removal of the systematics are essential steps in any modern CMB analysis pipeline and their successful accomplishment, together with a high instrumental sensitivity, will decide of a final success of the entire effort. In this thesis I first describe optics of typical CMB experiments and introduce a parametrization of instrumental and cross-polarization effects particularly convenient for the analysis of their impact. Second, I present a model describing the atmospheric contamination and use it to provide some insights about the atmosphere's role and its impact on performance of ground-based experiments. I also outline how it could be used further to improve control of atmospheric effects in the CMB data analysis. Then, I discuss another source of sky systematics --- the polarized astrophysical foregrounds. In this context I present on the one hand a new approach to forecasting performance of the future experiments, which accounts for the presence of the foregrounds, while on the other I propose a framework for optimizing hardware of such experiments to let them achieve better performance. This part of thesis

  4. Lorentz invariance violation in the neutrino sector: a joint analysis from big bang nucleosynthesis and the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Wei-Ming; Cai, Rong-Gen [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Guo, Zong-Kuan [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China); University of Chinese Academy of Sciences, School of Astronomy and Space Science, Beijing (China); Zhang, Yuan-Zhong [Chinese Academy of Sciences, CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, P.O. Box 2735, Beijing (China)

    2017-06-15

    We investigate constraints on Lorentz invariance violation in the neutrino sector from a joint analysis of big bang nucleosynthesis and the cosmic microwave background. The effect of Lorentz invariance violation during the epoch of big bang nucleosynthesis changes the predicted helium-4 abundance, which influences the power spectrum of the cosmic microwave background at the recombination epoch. In combination with the latest measurement of the primordial helium-4 abundance, the Planck 2015 data of the cosmic microwave background anisotropies give a strong constraint on the deformation parameter since adding the primordial helium measurement breaks the degeneracy between the deformation parameter and the physical dark matter density. (orig.)

  5. Missing dust signature in the cosmic microwave background

    Czech Academy of Sciences Publication Activity Database

    Vavryčuk, Václav

    2017-01-01

    Roč. 470, č. 1 (2017), L44-L48 ISSN 0035-8711 Institutional support: RVO:67985530 Keywords : dust, extinction * galaxies: high redshift * galaxies: ISM * intergalactic medium * cosmic background radiation * early Universe Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 4.961, year: 2016

  6. Search for microwave emission from ultrahigh energy cosmic rays

    Czech Academy of Sciences Publication Activity Database

    Alvarez-Muñiz, J.; Berlin, A.; Bogdan, M.; Boháčová, Martina; Bonifazi, C.; Carvalho jr., W.R.; de Mello Neto, J.R.T.; Facal San Luis, P.; Genat, J.F.; Hollon, N.; Mills, E.; Monasor, M.; Privitera, P.; Reyes, L.C.; d´Orfeuil, B.R.; Santos, E.M.; Wayne, S.; Williams, C.; Zas, E.; Zhou, J.

    2012-01-01

    Roč. 86, č. 5 (2012), "051104-1"-"051104-5" ISSN 1550-7998 R&D Projects: GA MŠk(CZ) LA08016 Institutional research plan: CEZ:AV0Z10100502 Keywords : air showers * ultrahigh energy cosmic rays Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.691, year: 2012

  7. Developing Advanced Broadband Microwave Detectors for Next-Generation CMB Polarization Studies

    Data.gov (United States)

    National Aeronautics and Space Administration — The photons of the cosmic microwave background (CMB) stream toward us from the boundary of the observable universe and arrive with information about both their point...

  8. A large free-standing wire grid for microwave variable-delay polarization modulation

    Science.gov (United States)

    Voellmer, G. M.; Bennett, C.; Chuss, D. T.; Eimer, J.; Hui, H.; Moseley, S. H.; Novak, G.; Wollack, E. J.; Zeng, L.

    2008-07-01

    One technique for mapping the polarization signature of the cosmic microwave background uses large, polarizing grids in reflection. We present the system requirements, the fabrication, assembly, and alignment procedures, and the test results for the polarizing grid component of a 50 cm clear aperture, Variable-delay Polarization Modulator (VPM). This grid is being built and tested at the Goddard Space Flight Center as part of the Polarimeter for Observing Inflationary Cosmology at the Reionization Epoch (POINCARE). For the demonstration instrument, 64 μm diameter tungsten wires are being assembled into a 200 μm pitch, free-standing wire grid with a 50 cm clear aperture, and an expected overall flatness better than 30 μm. A rectangular, aluminum stretching frame holds the wires with sufficient tension to achieve a minimum resonant frequency of 185 Hz, allowing VPM mirror translation frequencies of several Hz. A lightly loaded, flattening ring with a 50 cm inside diameter rests against the wires and brings them into accurate planarity.

  9. Pre-big-bang cosmology and circles in the cosmic microwave background

    International Nuclear Information System (INIS)

    Nelson, William; Wilson-Ewing, Edward

    2011-01-01

    We examine the possibility that circles in the cosmic microwave background could be formed by the interaction of a gravitational wave pulse emitted in some pre-big-bang phase of the universe with the last scattering surface. We derive the expected size distribution of such circles, as well as their typical ring width and (for concentric circles) angular separation. We apply these results, in particular, to conformal cyclic cosmology, ekpyrotic cosmology as well as loop quantum cosmology with and without inflation in order to determine how the predicted geometric properties of these circles would vary from one model to the other, and thus, if detected, could allow us to differentiate between various pre-big-bang cosmological models. We also obtain a relation between the angular ring width and the angular radius of such circles that can be used in order to determine whether or not circles observed in the cosmic microwave background are due to energetic pre-big-bang events.

  10. Cosmic Strings and Their Induced Non-Gaussianities in the Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Christophe Ringeval

    2010-01-01

    small fraction of the CMB angular power spectrum, cosmic strings could actually be the main source of its non-Gaussianities. In this paper, after having reviewed the basic cosmological properties of a string network, we present the signatures Nambu-Goto cosmic strings would induce in various observables ranging from the one-point function of the temperature anisotropies to the bispectrum and trispectrum. It is shown that string imprints are significantly different than those expected from the primordial type of non-Gaussianity and could therefore be easily distinguished.

  11. PREFACE: Technology development for a cosmic microwave background probe of inflation

    Science.gov (United States)

    Hanany, S.; Irwin, K.

    2009-07-01

    In late 2007 NASA called for proposals to fund Astrophysics Strategic Mission Concept Studies. The goal was to generate concept studies for key future missions, which would be forwarded to the Astro2010 astrophysics decadal review committee for prioritization. Under the guidance and orchestration of the Primordial Polarization Program Definition Team, a NASA committee chartered to coordinate the activities of the cosmic microwave background (CMB) community, a CMB proposal aiming to represent the consensus of the entire community was submitted. A CMBPol Mission Concept Study grant was awarded in early 2008. Under the grant we reviewed the entire activities of the CMB community and proposed a path for the next decade. We also assessed the case and recommended a path for a future CMB polarization satellite. The grant funded three community-wide workshops that were held over the summer of 2008. The goal of the first workshop, held at Fermilab, was to discuss the theoretical foundation of inflation and its signature on the CMB, as well as the theoretical aspects of other polarimetric signatures observable at millimeter wavelengths. Volume 1141 of the American Institute of Physics conference proceedings summarizes the results of this workshop. The second workshop, held at Annapolis, Maryland, centered on expected systematic effects in polarimetric experiments and their potential mitigation. The third workshop, held at the NIST facility at Boulder, Colorado, focused on the technology requirements necessary to make incisive CMB polarization measurements and what was needed to advance the technology to the readiness level required for a start of a space-borne mission. The electronic proceedings presented here are the result of this third workshop. In preparing for the workshop the organizers assigned topical-editors for each technology topic. Each of them solicited white paper contributions from experts in their respective areas. The white papers were distributed to all

  12. Non-Gaussianity in the Cosmic Microwave Background Anisotropies at Recombination in the Squeezed limit

    CERN Document Server

    Bartolo, N; Riotto, A

    2012-01-01

    We estimate analytically the second-order cosmic microwave background temperature anisotropies at the recombination epoch in the squeezed limit and we deduce the contamination to the primordial local non-Gaussianity. We find that the level of contamination corresponds to f_NL^{con}=O(1) which is below the sensitivity of present experiments and smaller than the value O(5) recently claimed in the literature.

  13. Constraints on majoron dark matter from cosmic microwave background and astrophysical observations

    Energy Technology Data Exchange (ETDEWEB)

    Lattanzi, Massimiliano, E-mail: lattanzi@fe.infn.it [Dipartimento di Fisica e Science della Terra, Università di Ferrara and INFN, sezione di Ferrara, Polo Scientifico e Tecnologico - Edificio C Via Saragat, 1, I-44122 Ferrara Italy (Italy); Riemer-Sørensen, Signe [School of Mathematics and Physics, University of Queensland, St Lucia, Brisbane 4072, Queensland (Australia); Tórtola, Mariam; Valle, J.W.F. [AHEP Group, Instituto de Física Corpuscular – C.S.I.C./Universitat de València Campus de Paterna, Apt 22085, E-46071 València (Spain)

    2014-04-01

    The origin of dark matter and the generation of neutrino masses could be related if neutrino masses arise from the spontaneous violation of ungauged lepton number. In this case the associated Nambu–Goldstone boson, the majoron, could acquire a mass from non-perturbative gravitational effects and play the role of DM. Here we report our cosmological and astrophysical constraints on majoron dark matter coming from Cosmic Microwave Background (CMB) and a variety of X- and γ-ray observations.

  14. Using the full power of the cosmic microwave background to probe axion dark matter

    Science.gov (United States)

    Hložek, Renée; Marsh, David J. E.; Grin, Daniel

    2018-05-01

    The cosmic microwave background (CMB) places stringent constraints on models of dark matter (DM), and on the initial conditions of the Universe. The full Planck data set is used to test the possibility that some fraction of the DM is composed of ultralight axions (ULAs). This represents the first use of CMB lensing to test the ULA model. We find no evidence for a ULA component in the mass range 10-33 ≤ ma ≤ 10-24 eV. We put percent-level constraints on the ULA contribution to the DM, improving by up to a factor of two compared using temperature anisotropies alone. Axion DM also provides a low-energy window on to the physics of inflation through isocurvature perturbations. We perform the first systematic investigation into the parameter space of ULA isocurvature, using an accurate isocurvature transfer function at all ma values. We precisely identify a `window of co-existence' for 10-25 eV ≤ ma ≤ 10-24 eV where the data allow, simultaneously, a {˜ }10 {per cent} contribution of ULAs to the DM, and {˜ } 1 {per cent} contributions of isocurvature and tensor modes to the CMB power. ULAs in this window (and all lighter ULAs) are shown to be consistent with a large inflationary Hubble parameter, HI ˜ 1014 GeV. The window of co-existence will be fully probed by proposed CMB Stage-IV observations with increased accuracy in the high-ℓ lensing power and low-ℓ E- and B-mode polarizations. If ULAs in the window exist, this could allow for two independent measurements of HI in the CMB using isocurvature, and the tensor contribution to B modes.

  15. Detector Development for Polarization Studies of the Cosmic Microwave Background

    Data.gov (United States)

    National Aeronautics and Space Administration — Among the most pressing questions remaining in cosmology today are the issues of the true nature of dark energy and the mechanism of inflation. Studies of the...

  16. The music of the Big Bang the cosmic microwave background and the new cosmology

    CERN Document Server

    Balbi, Amedeo

    2008-01-01

    The cosmic microwave background radiation is the afterglow of the big bang: a tenuous signal, more than 13 billion years old, which carries the answers to many of the questions about the nature of our Universe. It was serendipitously discovered in 1964, and thoroughly investigated in the last four decades by a large number of experiments. Two Nobel Prizes in Physics have already been awarded for research on the cosmic background radiation: one in 1978 to Arno Penzias and Robert Wilson, who first discovered it, the other in 2006, to George Smoot and John Mather, for the results of the COBE satellite. Most cosmological information is encoded in the cosmic background radiation by acoustic oscillations in the dense plasma that filled the primordial Universe: a "music" of the big bang, which cosmologists have long been trying to reconstruct and analyze, in order to distinguish different cosmological models, much like one can distinguish different musical instruments by their timbre and overtones. Only lately, this...

  17. Remaining Problems in Interpretation of the Cosmic Microwave Background

    Directory of Open Access Journals (Sweden)

    Hans-Jörg Fahr

    2015-01-01

    Full Text Available By three independent hints it will be demonstrated that still at present there is a substantial lack of theoretical understanding of the CMB phenomenon. One point, as we show, is that at the phase of the recombination era one cannot assume complete thermodynamic equilibrium conditions but has to face both deviations in the velocity distributions of leptons and baryons from a Maxwell-Boltzmann distribution and automatically correlated deviations of photons from a Planck law. Another point is that at the conventional understanding of the CMB evolution in an expanding universe one has to face growing CMB temperatures with growing look-back times. We show, however, here that the expected CMB temperature increases would be prohibitive to star formation in galaxies at redshifts higher than z=2 where nevertheless the cosmologically most relevant supernovae have been observed. The third point in our present study has to do with the assumption of a constant vacuum energy density which is required by the present ΛCDM-cosmology. Our studies here rather lead to the conclusion that cosmic vacuum energy density scales with the inverse square of the cosmic expansion scale R=R(t. Thus we come to the conclusion that with the interpretation of the present-day high quality CMB data still needs to be considered carefully.

  18. Robustness of cosmic neutrino background detection in the cosmic microwave background

    CERN Document Server

    Audren, Benjamin; Cuesta, Antonio J; Gontcho, Satya Gontcho A; Lesgourgues, Julien; Niro, Viviana; Pellejero-Ibanez, Marcos; Pérez-Ràfols, Ignasi; Poulin, Vivian; Tram, Thomas; Tramonte, Denis; Verde, Licia

    2015-01-01

    The existence of a cosmic neutrino background can be probed indirectly by CMB experiments, not only by measuring the background density of radiation in the universe, but also by searching for the typical signatures of the fluctuations of free-streaming species in the temperature and polarisation power spectrum. Previous studies have already proposed a rather generic parametrisation of these fluctuations, that could help to discriminate between the signature of ordinary free-streaming neutrinos, or of more exotic dark radiation models. Current data are compatible with standard values of these parameters, which seems to bring further evidence for the existence of a cosmic neutrino background. In this work, we investigate the robustness of this conclusion under various assumptions. We generalise the definition of an effective sound speed and viscosity speed to the case of massive neutrinos or other dark radiation components experiencing a non-relativistic transition. We show that current bounds on these effectiv...

  19. Robustness of cosmic neutrino background detection in the cosmic microwave background

    Energy Technology Data Exchange (ETDEWEB)

    Audren, Benjamin [Institut de Théorie des Phénomènes Physiques, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne (Switzerland); Bellini, Emilio; Cuesta, Antonio J.; Verde, Licia [Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès 1, E08028 Barcelona (Spain); Gontcho, Satya Gontcho A; Pérez-Ràfols, Ignasi [Dept. d' Astronomia i Meteorologia, Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès 1, E08028 Barcelona (Spain); Lesgourgues, Julien [CERN, Theory Division, CH-1211 Geneva 23 (Switzerland); Niro, Viviana [Departamento de Física Teórica, Universidad Autónoma de Madrid and Instituto de Física Teórica UAM/CSIC, Calle Nicolás Cabrera 13-15, Cantoblanco, E-28049 Madrid (Spain); Pellejero-Ibanez, Marcos; Tramonte, Denis [Instituto de Astrofísica de Canarias (IAC), C/Vía Láctea s/n, E-38200, La Laguna, Tenerife (Spain); Poulin, Vivian [LAPTh, Université de Savoie, CNRS, B.P.110, Annecy-le-Vieux F-74941 (France); Tram, Thomas, E-mail: emilio.bellini@icc.ub.edu [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom)

    2015-03-01

    The existence of a cosmic neutrino background can be probed indirectly by CMB experiments, not only by measuring the background density of radiation in the universe, but also by searching for the typical signatures of the fluctuations of free-streaming species in the temperature and polarisation power spectrum. Previous studies have already proposed a rather generic parametrisation of these fluctuations, that could help to discriminate between the signature of ordinary free-streaming neutrinos, or of more exotic dark radiation models. Current data are compatible with standard values of these parameters, which seems to bring further evidence for the existence of a cosmic neutrino background. In this work, we investigate the robustness of this conclusion under various assumptions. We generalise the definition of an effective sound speed and viscosity speed to the case of massive neutrinos or other dark radiation components experiencing a non-relativistic transition. We show that current bounds on these effective parameters do not vary significantly when considering an arbitrary value of the particle mass, or extended cosmological models with a free effective neutrino number, dynamical dark energy or a running of the primordial spectrum tilt. We conclude that it is possible to make a robust statement about the detection of the cosmic neutrino background by CMB experiments.

  20. Development of Multi-chroic Millimeter-wave Polarization Sensitive Detector Arrays

    Data.gov (United States)

    National Aeronautics and Space Administration — Improved measurements of the polarization of the Cosmic Microwave Background (CMB) will improve our understanding of both cosmology and fundamental physics....

  1. arXiv Probing large-scale magnetism with the Cosmic Microwave Background

    CERN Document Server

    Giovannini, Massimo

    2018-03-19

    Prior to photon decoupling magnetic random fields of comoving intensity in the nano-Gauss range distort the temperature and the polarization anisotropies of the microwave background, potentially induce a peculiar B-mode power spectrum and may even generate a frequency-dependent circularly polarized V-mode. We critically analyze the theoretical foundations and the recent achievements of an interesting trialogue involving plasma physics, general relativity and astrophysics.

  2. Probing the properties of relic neutrinos using the cosmic microwave background, the Hubble Space Telescope and galaxy clusters

    Science.gov (United States)

    Nunes, Rafael C.; Bonilla, Alexander

    2018-02-01

    We investigate the observational constraints on the cosmic neutrino background (CNB) given by the extended ΛCDM scenario (ΛCDM + N_eff + \\sum m_{ν } + c^2_eff + c^2_vis + ξ _{ν }) using the latest observational data from the cosmic microwave background (CMB) as observed by Planck (i.e. temperature power spectrum, low-polarization and lensing reconstruction), baryon acoustic oscillations (BAOs), the new recent local value of the Hubble constant from the Hubble Space Telescope (HST) and information on the abundance of galaxy clusters (GCs). We study the constraints on the CNB background using CMB + BAO + HST data with and without the GC data. We find ΔNeff = 0.614 ± 0.26 at the 68 per cent confidence level when the GC data are added to the analysis. We do not find any significant deviation for sound speed in the CNB rest frame. We also analyse the particular case ΛCDM +Neff + ∑mν + ξν with the observational data. Within this scenario, we find ΔNeff = 0.60 ± 0.28 at the 68 per cent confidence level. In both scenarios, no mean deviations are found for the degeneracy parameter.

  3. A MEASUREMENT OF THE COSMIC MICROWAVE BACKGROUND GRAVITATIONAL LENSING POTENTIAL FROM 100 SQUARE DEGREES OF SPTPOL DATA

    Energy Technology Data Exchange (ETDEWEB)

    Story, K. T.; Hanson, D.; Ade, P. A. R.; Aird, K. A.; Austermann, J. E.; J. A. Beall,; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Chiang, H. C.; Cho, H-M.; Citron, R.; Crawford, T. M.; Crites, A. T.; Haan, T. de; Dobbs, M. A.; Everett, W.; Gallicchio, J.; Gao, J.; George, E. M.; Gilbert, A.; Halverson, N. W.; Harrington, N.; Henning, J. W.; Hilton, G. C.; Holder, G. P.; Holzapfel, W. L.; Hoover, S.; Hou, Z.; Hrubes, J. D.; Huang, N.; Hubmayr, J.; Irwin, K. D.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Li, D.; Liang, C.; Luong-Van, D.; McMahon, J. J.; Mehl, J.; Meyer, S. S.; Mocanu, L.; Montroy, T. E.; Natoli, T.; Nibarger, J. P.; Novosad, V.; Padin, S.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Saliwanchik, B. R.; Sayre, J. T.; Schaffer, K. K.; Smecher, G.; Stark, A. A.; Tucker, C.; Vanderlinde, K.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Yefremenko, V.; Zahn, O.

    2015-08-28

    We present a measurement of the cosmic microwave background (CMB) gravitational lensing potential using data from the first two seasons of observations with SPTpol, the polarization-sensitive receiver currently installed on the South Pole Telescope. The observations used in this work cover 100 deg(2) of sky with arcminute resolution at 150 GHz. Using a quadratic estimator, we make maps of the CMB lensing potential from combinations of CMB temperature and polarization maps. We combine these lensing potential maps to form a minimum-variance (MV) map. The lensing potential is measured with a signal-to-noise ratio of greater than one for angular multipoles between $100\\lt L\\lt 250$. This is the highest signal-to-noise mass map made from the CMB to date and will be powerful in cross-correlation with other tracers of large-scale structure. We calculate the power spectrum of the lensing potential for each estimator, and we report the value of the MV power spectrum between $100\\lt L\\lt 2000$ as our primary result. We constrain the ratio of the spectrum to a fiducial ΛCDM model to be A(MV) = 0.92 ± 0.14 (Stat.) ± 0.08 (Sys.). Restricting ourselves to polarized data only, we find A(POL) = 0.92 ± 0.24 (Stat.) ± 0.11 (Sys.). This measurement rejects the hypothesis of no lensing at $5.9\\sigma $ using polarization data alone, and at $14\\sigma $ using both temperature and polarization data.

  4. Microwave Kinetic Inductance Detector with Selective Polarization Coupling

    Science.gov (United States)

    Wollack, Edward; U-yen, Kongpop; Stevenson, Thomas; Brown, Ari; Moseley, Samuel; Hsieh, Wen-Ting

    2013-01-01

    A conventional low-noise detector requires a technique to both absorb incident power and convert it to an electrical signal at cryogenic temperatures. This innovation combines low-noise detector and readout functionality into one device while maintaining high absorption, controlled polarization sensitivity, and broadband detection capability. The resulting far-infrared detectors can be read out with a simple approach, which is compact and minimizes thermal loading. The proposed microwave kinetic inductance detector (MKID) consists of three basic elements. The first is the absorptive section in which the incident power is coupled to a superconducting resonator at far-infrared frequency above its superconducting critical frequency (where superconductor becomes normal conductor). This absorber's shape effectively absorbs signals in the desired polarization state and is resonant at the radio frequency (RF) used for readout of the device. Control over the metal film used in the absorber allows realization of structures with either a 50% broadband or 100% resonance absorptance over a 30% fractional bandwidth. The second element is a microwave resonator - which is realized from the thin metal films used to make the absorber as transmission lines - whose resonance frequency changes due to a variation in its kinetic inductance. The resonator's kinetic inductance is a function of the power absorbed by the device. A low-loss dielectric (mono-crystalline silicon) is used in a parallel-plate transmission line structure to realize the desired superconducting resonators. There is negligible coupling among the adjacent elements used to define the polarization sensitivity of each detector. The final component of the device is a microwave transmission line, which is coupled to the resonator, and allows detection of changes in resonance frequency for each detector in the focal plane array. The spiral shape of the detector's absorber allows incident power with two polarizations to

  5. Constraining neutrino physics with big bang nucleosynthesis and cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Hansen, S.H.; Melchiorri, A.; Mangano, G.; Miele, G.; Pisanti, O.

    2002-01-01

    We perform a likelihood analysis of the recent results on the anisotropy of cosmic microwave background radiation from the BOOMERanG and DASI experiments to show that they single out an effective number of neutrinos in good agreement with standard big bang nucleosynthesis. We also consider degenerate big bang nucleosynthesis to provide new bounds on effective relativistic degrees of freedom N ν and, in particular, on the neutrino chemical potential ξ α . When including supernova type Ia data we find, at 2σ, N ν ≤7 and -0.01≤ξ e ≤0.22, vertical bar ξ μ,τ vertical bar ≤2.6

  6. Natural Covariant Planck Scale Cutoffs and the Cosmic Microwave Background Spectrum

    Science.gov (United States)

    Chatwin-Davies, Aidan; Kempf, Achim; Martin, Robert T. W.

    2017-07-01

    We calculate the impact of quantum gravity-motivated ultraviolet cutoffs on inflationary predictions for the cosmic microwave background spectrum. We model the ultraviolet cutoffs fully covariantly to avoid possible artifacts of covariance breaking. Imposing these covariant cutoffs results in the production of small, characteristically k -dependent oscillations in the spectrum. The size of the effect scales linearly with the ratio of the Planck to Hubble lengths during inflation. Consequently, the relative size of the effect could be as large as one part in 1 05; i.e., eventual observability may not be ruled out.

  7. Quasi-Optical Design and Analysis of a Bolometric Interferometer for Cosmic Microwave Background Radiation Experiments

    OpenAIRE

    Scully, Stephen

    2016-01-01

    From humble beginnings in 2008, a group met to propose the idea of observing the Cosmic Microwave Background (CMB) in order to determine its polarisation properties, i.e. E- and B-modes. B-modes, a smoking gun for inflation theory, are a long sought after observation for cosmologists. From this the QUBIC collaboration was born. Here we explore the scientific justification for such a mission and the aims of the QUBIC telescope in furthering this knowledge with emphasis on the author’s contribu...

  8. Anisotropies of the cosmic microwave background in nonstandard cold dark matter models

    Science.gov (United States)

    Vittorio, Nicola; Silk, Joseph

    1992-01-01

    Small angular scale cosmic microwave anisotropies in flat, vacuum-dominated, cold dark matter cosmological models which fit large-scale structure observations and are consistent with a high value for the Hubble constant are reexamined. New predictions for CDM models in which the large-scale power is boosted via a high baryon content and low H(0) are presented. Both classes of models are consistent with current limits: an improvement in sensitivity by a factor of about 3 for experiments which probe angular scales between 7 arcmin and 1 deg is required, in the absence of very early reionization, to test boosted CDM models for large-scale structure formation.

  9. From primordial quantum fluctuations to the anisotropies of the cosmic microwave background radiation

    Energy Technology Data Exchange (ETDEWEB)

    Straumann, N. [Institute for Theoretical Physics University of Zurich, 8057 Zurich (Switzerland)

    2006-10-09

    These lecture notes cover mainly three connected topics. In the first part we give a detailed treatment of cosmological perturbation theory. The second part is devoted to cosmological inflation and the generation of primordial fluctuations. In part three it will be shown how these initial perturbation evolve and produce the temperature anisotropies of the cosmic microwave background radiation. Comparing the theoretical prediction for the angular power spectrum with the increasingly accurate observations provides important cosmological information (cosmological parameters, initial conditions). (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  10. From primordial quantum fluctuations to the anisotropies of the cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Straumann, N.

    2006-01-01

    These lecture notes cover mainly three connected topics. In the first part we give a detailed treatment of cosmological perturbation theory. The second part is devoted to cosmological inflation and the generation of primordial fluctuations. In part three it will be shown how these initial perturbation evolve and produce the temperature anisotropies of the cosmic microwave background radiation. Comparing the theoretical prediction for the angular power spectrum with the increasingly accurate observations provides important cosmological information (cosmological parameters, initial conditions). (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  11. Initial state effects on the cosmic microwave background and trans-Planckian physics

    International Nuclear Information System (INIS)

    Goldstein, Kevin; Lowe, David A.

    2003-01-01

    There exists a one complex parameter family of de Sitter invariant vacua, known as α vacua. In the context of slow roll inflation, we show that all but the Bunch-Davies vacuum generates unacceptable production of high energy particles at the end of inflation. As a simple model for the effects of trans-Planckian physics, we go on to consider non-de Sitter invariant vacua obtained by patching modes in the Bunch-Davies vacuum above some momentum scale M c , with modes in an α vacuum below M c . Choosing M c near the Planck scale M Pl , we find acceptable levels of hard particle production, and corrections to the cosmic microwave perturbations at the level of HM Pl /M c 2 , where H is the Hubble parameter during inflation. More general initial states of this type with H c Pl can give corrections to the spectrum of cosmic microwave background perturbations at order 1. The parameter characterizing the α vacuum during inflation is a new cosmological observable

  12. Circularly Polarized Microwave Antenna Element with Very Low Off-Axis Cross-Polarization

    Science.gov (United States)

    Greem. David; DuToit, Cornelis

    2013-01-01

    The goal of this work was to improve off-axis cross-polarization performance and ease of assembly of a circularly polarized microwave antenna element. To ease assembly, the initial design requirement of Hexweb support for the internal circuit part, as well as the radiating disks, was eliminated. There is a need for different plating techniques to improve soldering. It was also desirable to change the design to eliminate soldering as well as the need to use the Hexweb support. Thus, a technique was developed to build the feed without using solder, solving the lathing and soldering issue. Internal parts were strengthened by adding curvature to eliminate Hexweb support, and in the process, the new geometries of the internal parts opened the way for improving the off-axis cross-polarization performance as well. The radiating disks curvatures were increased for increased strength, but it was found that this also improved crosspolarization. Optimization of the curvatures leads to very low off-axis cross-polarization. The feed circuit was curved into a cylinder for improved strength, eliminating Hexweb support. An aperture coupling feed mechanism eliminated the need for feed pins to the disks, which would have required soldering. The aperture coupling technique also improves cross-polarization performance by effectively exciting the radiating disks very close to the antenna s central axis of symmetry. Because of the shape of the parts, it allowed for an all-aluminum design bolted together and assembled with no solder needed. The advantage of a solderless design is that the reliability is higher, with no single-point failure (solder), and no need for special plating techniques in order to solder the unit together. The shapes (curved or round) make for a more robust build without extra support materials, as well as improved offaxis cross-polarization.

  13. Southern Hemisphere Measurement of the Anisotropy in the CosmicMicrowave Background Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Smoot, George F.; Lubin, Phil M.

    1979-06-01

    A recent measurement of the anisotropy in the Cosmic Background Radiation from the southern hemisphere (Lima, Peru) is essentially in agreement with previous measurements from the northern hemisphere. The net anisotropy can be described as a first order spherical harmonic (Doppler) anisotropy of amplitude 3.1 {+-} 0.4 m{sup o}K with a quadrupole anisotropy of less than 1 m{sup o}K. In addition, measurements of the linear polarization yield an upper limit of 1 m{sup o}K, or one part in 3000, at 95% C.L. for the amplitudes of any spherical harmonic through third order.

  14. Characterization of a high-temperature superconducting bearing for use in a cosmic microwave background polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R [Energy Technology Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Hanany, Shaul [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Matsumura, Tomotake [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Johnson, Bradley [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Jones, Terry [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2005-02-01

    We have previously presented a design for a cosmic microwave background (CMB) polarimeter in which a cryogenically cooled half-wave plate rotates by means of a high-temperature superconducting (HTS) bearing. Here, a prototype bearing, consisting of a commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We measured its coefficient of friction and vibrational property as a function of several parameters, including temperature between 15 and 83 K, rotation frequency between 0.3 and 3.5 Hz, levitation distance between 6 and 10 mm and ambient pressure of {approx}10{sup -7} Torr. We concluded that the low rotational drag of the HTS bearing would allow rotations for long periods with minimal input power and negligible wear and tear, thus making this technology suitable for a future satellite mission.

  15. Autonomous low-noise system for broadband measurements of the cosmic microwave background radiation

    Science.gov (United States)

    Dekoulis, George

    2009-05-01

    This paper describes the digital side implementation of a new suborbital experiment for the measurement of broadband radiation emissions of the Cosmic Microwave Background (CMB) anisotropy. The system has been used in campaign mode for initial mapping of the galactic radiation power received at a single frequency. The recorded galactic sky map images are subsequently being used to forecast the emitted radiation at neighboring frequencies. A planned second campaign will verify the prediction algorithms efficiency in an autonomous manner. The system has reached an advanced stage in terms of hardware and software combined operation and intelligence, where other Space Physics measurements are performed autonomously depending on the burst event under investigation. The system has been built in a modular manner to expedite hardware and software upgrades. Such an upgrade has recently occurred mainly to expand the frequency range of space observations.

  16. The three-point correlation function of the cosmic microwave background in inflationary models

    CERN Document Server

    Gangui, Alejandro; Matarrese, Sabino; Mollerach, Silvia

    1994-01-01

    We analyze the temperature three-point correlation function and the skewness of the Cosmic Microwave Background (CMB), providing general relations in terms of multipole coefficients. We then focus on applications to large angular scale anisotropies, such as those measured by the {\\em COBE} DMR, calculating the contribution to these quantities from primordial, inflation generated, scalar perturbations, via the Sachs--Wolfe effect. Using the techniques of stochastic inflation we are able to provide a {\\it universal} expression for the ensemble averaged three-point function and for the corresponding skewness, which accounts for all primordial second-order effects. These general expressions would moreover apply to any situation where the bispectrum of the primordial gravitational potential has a {\\em hierarchical} form. Our results are then specialized to a number of relevant models: power-law inflation driven by an exponential potential, chaotic inflation with a quartic and quadratic potential and a particular c...

  17. Decoupling in an expanding universe: backreaction barely constrains short distance effects in the cosmic microwave background

    CERN Document Server

    Greene, B R; Shiu, G; Van der Schaar, J P; Greene, Brian R.; Schalm, Koenraad; Shiu, Gary; Schaar, Jan Pieter van der

    2005-01-01

    We clarify the status of transplanckian effects on the cosmic microwave background (CMB) anisotropy. We do so using the boundary effective action formalism of hep-th/0401164 which accounts quantitatively for the cosmological vacuum ambiguity. In this formalism we can clearly 1) delineate the validity of cosmological effective actions in an expanding universe. The corollary of the initial state ambiguity is the existence of an earliest time. The inability of an effective action to describe physics before this time demands that one sets initial conditions on the earliest time hypersurface. A calculation then shows that CMB anisotropy measurements are generically sensitive to high energy corrections to the initial conditions. 2) We compute the one-loop contribution to the stress-tensor due to high-energy physics corrections to an arbitrary cosmological initial state. We find that phenomenological bounds on the backreaction do not lead to strong constraints on the coefficient of the leading boundary irrelevant op...

  18. The cosmic microwave background how it changed our understanding of the universe

    CERN Document Server

    Evans, Rhodri

    2015-01-01

    Rhodri Evans tells the story of what we know about the universe, from Jacobus Kapteyn’s Island universe at the turn of the 20th Century, and the discovery by Hubble that the nebulae were external to our own galaxy, through Gamow’s early work on the cosmic microwave background (CMB) and its subsequent discovery by Penzias and Wilson, to modern day satellite-lead CMB research. Research results from the ground-based experiments DASI, BOOMERANG, and satellite missions COBE, WMAP and Planck are explained and interpreted to show how our current picture of the universe was arrived at, and the author looks at the future of CMB research and what we still need to learn. This account is enlivened by Dr Rhodri Evans' personal connections to the characters and places in the story.

  19. Testing the Interacting Dark Energy Model with Cosmic Microwave Background Anisotropy and Observational Hubble Data

    Directory of Open Access Journals (Sweden)

    Weiqiang Yang

    2017-07-01

    Full Text Available The coupling between dark energy and dark matter provides a possible approach to mitigate the coincidence problem of the cosmological standard model. In this paper, we assumed the interacting term was related to the Hubble parameter, energy density of dark energy, and equation of state of dark energy. The interaction rate between dark energy and dark matter was a constant parameter, which was, Q = 3 H ξ ( 1 + w x ρ x . Based on the Markov chain Monte Carlo method, we made a global fitting on the interacting dark energy model from Planck 2015 cosmic microwave background anisotropy and observational Hubble data. We found that the observational data sets slightly favored a small interaction rate between dark energy and dark matter; however, there was not obvious evidence of interaction at the 1 σ level.

  20. The cosmic microwave background radiation and the dog in the night

    Science.gov (United States)

    Partridge, R. B.

    The spectrum and angular distribution of the cosmic microwave background radiation (CMBR) are characterized, summarizing the results of recent observations. The emphasis is on null experiments which have established upper limits on anisotropies and spectral distortion. The benefits and pitfalls of null experiments are recalled; the generally observed isotropy of the CMBR and the possible ways anisotropy could be introduced are discussed; and data from searches for anisotropy on arcmin, degree, and arcsec scales are presented in tables and graphs and analyzed in detail. The observed CMBR spectrum is shown to be generally consistent with a black body at temperature 2.75 + or - 0.04 K at wavelengths from 0.1 to 12 cm, although some recent data (Kogut et al., 1988) seem to confirm the presence of distortion due to the Suniaev-Zel'dovich effect at wavelength 3.0 cm.

  1. Detection of the power spectrum of cosmic microwave background lensing by the Atacama Cosmology Telescope.

    Science.gov (United States)

    Das, Sudeep; Sherwin, Blake D; Aguirre, Paula; Appel, John W; Bond, J Richard; Carvalho, C Sofia; Devlin, Mark J; Dunkley, Joanna; Dünner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W; Hajian, Amir; Halpern, Mark; Hasselfield, Matthew; Hincks, Adam D; Hlozek, Renée; Huffenberger, Kevin M; Hughes, John P; Irwin, Kent D; Klein, Jeff; Kosowsky, Arthur; Lupton, Robert H; Marriage, Tobias A; Marsden, Danica; Menanteau, Felipe; Moodley, Kavilan; Niemack, Michael D; Nolta, Michael R; Page, Lyman A; Parker, Lucas; Reese, Erik D; Schmitt, Benjamin L; Sehgal, Neelima; Sievers, Jon; Spergel, David N; Staggs, Suzanne T; Swetz, Daniel S; Switzer, Eric R; Thornton, Robert; Visnjic, Katerina; Wollack, Ed

    2011-07-08

    We report the first detection of the gravitational lensing of the cosmic microwave background through a measurement of the four-point correlation function in the temperature maps made by the Atacama Cosmology Telescope. We verify our detection by calculating the levels of potential contaminants and performing a number of null tests. The resulting convergence power spectrum at 2° angular scales measures the amplitude of matter density fluctuations on comoving length scales of around 100 Mpc at redshifts around 0.5 to 3. The measured amplitude of the signal agrees with Lambda cold dark matter cosmology predictions. Since the amplitude of the convergence power spectrum scales as the square of the amplitude of the density fluctuations, the 4σ detection of the lensing signal measures the amplitude of density fluctuations to 12%.

  2. Cold dark matter and degree-scale cosmic microwave background anisotropy statistics after COBE

    Science.gov (United States)

    Gorski, Krzysztof M.; Stompor, Radoslaw; Juszkiewicz, Roman

    1993-01-01

    We conduct a Monte Carlo simulation of the cosmic microwave background (CMB) anisotropy in the UCSB South Pole 1991 degree-scale experiment. We examine cold dark matter cosmology with large-scale structure seeded by the Harrison-Zel'dovich hierarchy of Gaussian-distributed primordial inhomogeneities normalized to the COBE-DMR measurement of large-angle CMB anisotropy. We find it statistically implausible (in the sense of low cumulative probability F lower than 5 percent, of not measuring a cosmological delta-T/T signal) that the degree-scale cosmological CMB anisotropy predicted in such models could have escaped a detection at the level of sensitivity achieved in the South Pole 1991 experiment.

  3. The Cosmic Microwave Background: Detection and Interpretation of the First Light

    Science.gov (United States)

    Wollack, Edward J.

    2016-01-01

    A host of astrophysical observations suggest the early Universe was incredibly hot, dense, and homogeneous. A powerful and useful probe of this epoch is provided by the relic radiation, which we refer to today as the Cosmic Microwave Background (CMB). Precision maps of this light contain the earliest glimpse of the Universe after the Big Bang and signatures of the evolution of its contents. By exploiting these clues, constraints on the age, mass density, detailed composition, and geometry of the Universe can be made. A brief survey of the evolution of the radiometric and polarimetric imaging systems used in advancing our understanding of the early Universe will be reviewed. A survey of detector technologies, instrumentation techniques, and experimental challenges encountered in these efforts will be presented.

  4. Hot gas in clusters of galaxies, cosmic microwave background radiation and cosmology

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    Presence of the hot (kTe ~ 3 - 10 KeV) rarefied gas in the clusters of galaxies (most massive gravitationally bound objects in the Universe) leads to the appearance of  "shadows"  in the angular distribution of the Cosmic Microwave Background (CMB) Radiation and permits to measure the peculiar velocities of these clusters relative to the unique coordinate frame where CMB is isotropic. I plan to describe the physics leading to these observational effects. Planck spacecraft, ground based South Pole and Atacama Cosmology Telescopes discovered recently more than two thousand of unknown before Clusters of Galaxies at high redshifts detecting these "shadows" and traces of kinematic effect, demonstrating the correlation of the hot gas velocities with mass concentrations on large scales. Giant ALMA interferometer in Atacama desert resolved recently strong shocks between merging clusters of galaxies. Newly discovered clusters of galaxies permit to study the rate of growth of the large scale structur...

  5. Strong cosmic censorship for solutions of the Einstein-Maxwell field equations with polarized Gowdy symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Nungesser, Ernesto; Rendall, Alan D [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, 14476 Potsdam (Germany)

    2009-05-21

    A proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this, it is seen that the deep results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  6. Contamination cannot explain the lack of large-scale power in the cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Bunn, Emory F.; Bourdon, Austin

    2008-01-01

    Several anomalies appear to be present in the large-angle cosmic microwave background (CMB) anisotropy maps of the Wilkinson Microwave Anisotropy Probe. One of these is a lack of large-scale power. Because the data otherwise match standard models extremely well, it is natural to consider perturbations of the standard model as possible explanations. We show that, as long as the source of the perturbation is statistically independent of the source of the primary CMB anisotropy, no such model can explain this large-scale power deficit. On the contrary, any such perturbation always reduces the probability of obtaining any given low value of large-scale power. We rigorously prove this result when the lack of large-scale power is quantified with a quadratic statistic, such as the quadrupole moment. When a statistic based on the integrated square of the correlation function is used instead, we present strong numerical evidence in support of the result. The result applies to models in which the geometry of spacetime is perturbed (e.g., an ellipsoidal universe) as well as explanations involving local contaminants, undiagnosed foregrounds, or systematic errors. Because the large-scale power deficit is arguably the most significant of the observed anomalies, explanations that worsen this discrepancy should be regarded with great skepticism, even if they help in explaining other anomalies such as multipole alignments.

  7. Cosmic microwave background power spectrum estimation and map reconstruction with the expectation-maximization algorithm

    Science.gov (United States)

    Martínez-González, E.; Diego, J. M.; Vielva, P.; Silk, J.

    2003-11-01

    We apply the iterative expectation-maximization algorithm (EM) to estimate the power spectrum of the cosmic microwave background (CMB) from multifrequency microwave maps. In addition, we are also able to provide a reconstruction of the CMB map. By assuming that the combined emission of the foregrounds plus the instrumental noise is Gaussian distributed in Fourier space, we have simplified the EM procedure, finding an analytical expression for the maximization step. By using the simplified expression, the CPU time can be greatly reduced. We test the stability of our power spectrum estimator with realistic simulations of Planck data, including point sources and allowing for spatial variation of the frequency dependence of the Galactic emissions. Without prior information about any of the components, our new estimator can recover the CMB power spectrum up to scales l~ 1500 with less than 10 per cent error. This result is significantly improved if the brightest point sources are removed before applying our estimator. In this way, the CMB power spectrum can be recovered up to l~ 1700 with 10 per cent error and up to l~ 2100 with 50 per cent error. This result is very close to the one that would be obtained in the ideal case of only CMB plus white noise, for which all our assumptions are satisfied. Moreover, the EM algorithm also provides a straightforward mechanism for reconstructing the CMB map. The recovered cosmological signal shows a high degree of correlation (r= 0.98) with the input map and low residuals.

  8. The Complexities of Interstellar Dust and the Implications for the Small-scale Structure in the Cosmic Microwave Background

    Science.gov (United States)

    Verschuur, G. L.; Schmelz, J. T.

    2018-02-01

    A detailed comparison of the full range of PLANCK and Wilkinson Microwave Anisotropy Probe data for small (2° × 2°) areas of sky and the Cosmic Microwave Background Internal Linear Combination (ILC) maps reveals that the structure of foreground dust may be more complex than previously thought. If 857 and 353 GHz emission is dominated by galactic dust at a distance data also show that there is no single answer for the question: “to what extent does dust contaminate the cosmologically important 143 GHz data?” In some directions, the contamination appears to be quite strong, but in others, it is less of an issue. This complexity needs to be taken in account in order to derive an accurate foreground mask in the quest to understand the Cosmic Microwave Background small-scale structure. We hope that a continued investigation of these data will lead to a definitive answer to the question above and, possibly, to new scientific insights on interstellar matter, the Cosmic Microwave Background, or both.

  9. Multiscale multichroic focal planes for measurements of the cosmic microwave background

    Science.gov (United States)

    Cukierman, Ari; Lee, Adrian T.; Raum, Christopher; Suzuki, Aritoki; Westbrook, Benjamin

    2018-01-01

    We report on the development of multiscale multichroic focal planes for measurements of the cosmic microwave background (CMB). A multichroic focal plane, i.e., one that consists of pixels that are simultaneously sensitive in multiple frequency bands, is an efficient architecture for increasing the sensitivity of an experiment as well as for disentangling the contamination due to galactic foregrounds, which is increasingly becoming the limiting factor in extracting cosmological information from CMB measurements. To achieve these goals, it is necessary to observe across a broad frequency range spanning roughly 30-350 GHz. For this purpose, the Berkeley CMB group has been developing multichroic pixels consisting of planar superconducting sinuous antennas coupled to extended hemispherical lenslets, which operate at sub-Kelvin temperatures. The sinuous antennas, microwave circuitry and the transition-edge-sensor (TES) bolometers to which they are coupled are integrated in a single lithographed wafer.We describe the design, fabrication, testing and performance of multichroic pixels with bandwidths of 3:1 and 4:1 across the entire frequency range of interest. Additionally, we report on a demonstration of multiscale pixels, i.e., pixels whose effective size changes as a function of frequency. This property keeps the beam width approximately constant across all frequencies, which in turn allows the sensitivity of the experiment to be optimal in every frequency band. We achieve this by creating phased arrays from neighboring lenslet-coupled sinuous antennas, where the size of each phased array is chosen independently for each frequency band. We describe the microwave circuitry in detail as well as the benefits of a multiscale architecture, e.g., mitigation of beam non-idealities, reduced readout requirements, etc. Finally, we discuss the design and fabrication of the detector modules and focal-plane structures including cryogenic readout components, which enable the

  10. Relieving the tension between weak lensing and cosmic microwave background with interacting dark matter and dark energy models

    Science.gov (United States)

    An, Rui; Feng, Chang; Wang, Bin

    2018-02-01

    We constrain interacting dark matter and dark energy (IDMDE) models using a 450-degree-square cosmic shear data from the Kilo Degree Survey (KiDS) and the angular power spectra from Planck's latest cosmic microwave background measurements. We revisit the discordance problem in the standard Lambda cold dark matter (ΛCDM) model between weak lensing and Planck datasets and extend the discussion by introducing interacting dark sectors. The IDMDE models are found to be able to alleviate the discordance between KiDS and Planck as previously inferred from the ΛCDM model, and moderately favored by a combination of the two datasets.

  11. The cosmic microwave background radiation power spectrum as a random bit generator for symmetric- and asymmetric-key cryptography.

    Science.gov (United States)

    Lee, Jeffrey S; Cleaver, Gerald B

    2017-10-01

    In this note, the Cosmic Microwave Background (CMB) Radiation is shown to be capable of functioning as a Random Bit Generator, and constitutes an effectively infinite supply of truly random one-time pad values of arbitrary length. It is further argued that the CMB power spectrum potentially conforms to the FIPS 140-2 standard. Additionally, its applicability to the generation of a (n × n) random key matrix for a Vernam cipher is established.

  12. The detection of the imprint of filaments on cosmic microwave background lensing

    Science.gov (United States)

    He, Siyu; Alam, Shadab; Ferraro, Simone; Chen, Yen-Chi; Ho, Shirley

    2018-04-01

    Galaxy redshift surveys, such as the 2-Degree-Field Survey (2dF)1, Sloan Digital Sky Survey (SDSS)2, 6-Degree-Field Survey (6dF)3, Galaxy And Mass Assembly survey (GAMA)4 and VIMOS Public Extragalactic Redshift Survey (VIPERS)5, have shown that the spatial distribution of matter forms a rich web, known as the cosmic web6. Most galaxy survey analyses measure the amplitude of galaxy clustering as a function of scale, ignoring information beyond a small number of summary statistics. Because the matter density field becomes highly non-Gaussian as structure evolves under gravity, we expect other statistical descriptions of the field to provide us with additional information. One way to study the non-Gaussianity is to study filaments, which evolve non-linearly from the initial density fluctuations produced in the primordial Universe. In our study, we report the detection of lensing of the cosmic microwave background (CMB) by filaments, and we apply a null test to confirm our detection. Furthermore, we propose a phenomenological model to interpret the detected signal, and we measure how filaments trace the matter distribution on large scales through filament bias, which we measure to be around 1.5. Our study provides new scope to understand the environmental dependence of galaxy formation. In the future, the joint analysis of lensing and Sunyaev-Zel'dovich observations might reveal the properties of `missing baryons', the vast majority of the gas that resides in the intergalactic medium, which has so far evaded most observations.

  13. A measurement of the low frequency spectrum of the cosmic microwave background radiation

    International Nuclear Information System (INIS)

    Levin, S.M.

    1987-04-01

    As part of a larger effort to measure the spectrum of the Cosmic Background Radiation (CBR) at low frequencies, the intensity of the CBR has been measured at a frequency of 1.410 GHz. The measurement was made by comparing the power received from the sky with the power received from a specially designed cooled calibration target with known properties. Sources of radiation other than the CBR were then identified and subtracted to calculate the antenna temperature of the CBR at 1.410 GHz. The instrument used to measure the CBR was a total-power microwave radiometer with a 25 MHz bandwidth centered at 1.410 GHz. The radiometer had a noise temperature of 80 K, and sufficient data were taken that radiometer noise did not contribute significantly to the total measurement error. The sources of error were predominantly systematic in nature, and the largest error was due to uncertainty in the reflection characteristics of the cold-load calibrator. Identification and subtraction of signals from the Galaxy (0.7 K) and the Earth's atmosphere (0.8 K) were also significant parts of the data reduction and error analysis. The brightness temperature of the Cosmic Background Radiation at 1.410 GHz is 222. +- 0.55 Kelvin. The spectrum of the CBR, as determined by this measurement and other published results, is consistent with a blackbody spectrum of temperature 2.741 +- 0.016. Constraints on the amount by which the CBR spectrum deviates from Planck spectrum are used to place limits on energy releases early in the history of the universe. 55 refs., 25 figs., 8 tabs

  14. Variations in Solar Parameters and Cosmic Rays with Solar Magnetic Polarity

    Energy Technology Data Exchange (ETDEWEB)

    Oh, S. [Department of Earth Science Education, Chonnam National University, Gwangju, 61186 (Korea, Republic of); Yi, Y., E-mail: suyeonoh@jnu.ac.kr [Department of Astronomy, Space Science and Geology, Chungnam National University, Daejeon, 34134 (Korea, Republic of)

    2017-05-01

    The sunspot number varies with the 11-year Schwabe cycle, and the solar magnetic polarity reverses every 11 years approximately at the solar maximum. Because of polarity reversal, the difference between odd and even solar cycles is seen in solar activity. In this study, we create the mean solar cycle expressed by phase using the monthly sunspot number for all solar cycles 1–23. We also generate the mean solar cycle for sunspot area, solar radio flux, and cosmic ray flux within the allowance of observational range. The mean solar cycle has one large peak at solar maximum for odd solar cycles and two small peaks for most even solar cycles. The odd and even solar cycles have the statistical difference in value and shape at a confidence level of at least 98%. For solar cycles 19–23, the second peak in the even solar cycle is larger than the first peak. This result is consistent with the frequent solar events during the declining phase after the solar maximum. The difference between odd and even solar cycles can be explained by a combined model of polarity reversal and solar rotation. In the positive/negative polarity, the polar magnetic field introduces angular momentum in the same/opposite direction as/to the solar rotation. Thus the addition/subtraction of angular momentum can increase/decrease the motion of plasma to support the formation of sunspots. Since the polarity reverses at the solar maximum, the opposite phenomenon occurs in the declining phase.

  15. ArtDeco: a beam-deconvolution code for absolute cosmic microwave background measurements

    Science.gov (United States)

    Keihänen, E.; Reinecke, M.

    2012-12-01

    We present a method for beam-deconvolving cosmic microwave background (CMB) anisotropy measurements. The code takes as input the time-ordered data along with the corresponding detector pointings and known beam shapes, and produces as output the harmonic aTlm, aElm, and aBlm coefficients of the observed sky. From these one can derive temperature and Q and U polarisation maps. The method is applicable to absolute CMB measurements with wide sky coverage, and is independent of the scanning strategy. We tested the code with extensive simulations, mimicking the resolution and data volume of Planck 30 GHz and 70 GHz channels, but with exaggerated beam asymmetry. We applied it to multipoles up to l = 1700 and examined the results in both pixel space and harmonic space. We also tested the method in presence of white noise. The code is released under the terms of the GNU General Public License and can be obtained from http://sourceforge.net/projects/art-deco/

  16. Detecting Gravitational Lensing of the Cosmic Microwave Background by Galaxy Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Eric Jones [Univ. of Chicago, IL (United States)

    2014-08-01

    Clusters of galaxies gravitationally lens the Cosmic Microwave Background (CMB) leading to a distinct signal in the CMB on arcminute scales. Measurement of the cluster lensing effect offers the exciting possibility of constraining the masses of galaxy clusters using CMB data alone. Improved constraints on cluster masses are in turn essential to the use of clusters as cosmological probes: uncertainties in cluster masses are currently the dominant systematic affecting cluster abundance constraints on cosmology. To date, however, the CMB cluster lensing signal remains undetected because of its small magnitude and angular size. In this thesis, we develop a maximum likelihood approach to extracting the signal from CMB temperature data. We validate the technique by applying it to mock data designed to replicate as closely as possible real data from the South Pole Telescope’s (SPT) Sunyaev-Zel’dovich (SZ) survey: the effects of the SPT beam, transfer function, instrumental noise and cluster selection are incorporated. We consider the effects of foreground emission on the analysis and show that uncertainty in amount of foreground lensing results in a small systematic error on the lensing constraints. Additionally, we show that if unaccounted for, the SZ effect leads to unacceptably large biases on the lensing constraints and develop an approach for removing SZ contamination. The results of the mock analysis presented here suggest that a 4σ first detection of the cluster lensing effect can be achieved with current SPT-SZ data.

  17. Bayesian Noise Estimation for Non-ideal Cosmic Microwave Background Experiments

    Science.gov (United States)

    Wehus, I. K.; Næss, S. K.; Eriksen, H. K.

    2012-03-01

    We describe a Bayesian framework for estimating the time-domain noise covariance of cosmic microwave background (CMB) observations, typically parameterized in terms of a 1/f frequency profile. This framework is based on the Gibbs sampling algorithm, which allows for exact marginalization over nuisance parameters through conditional probability distributions. In this paper, we implement support for gaps in the data streams and marginalization over fixed time-domain templates, and also outline how to marginalize over confusion from CMB fluctuations, which may be important for high signal-to-noise experiments. As a by-product of the method, we obtain proper constrained realizations, which themselves can be useful for map making. To validate the algorithm, we demonstrate that the reconstructed noise parameters and corresponding uncertainties are unbiased using simulated data. The CPU time required to process a single data stream of 100,000 samples with 1000 samples removed by gaps is 3 s if only the maximum posterior parameters are required, and 21 s if one also wants to obtain the corresponding uncertainties by Gibbs sampling.

  18. BAYESIAN NOISE ESTIMATION FOR NON-IDEAL COSMIC MICROWAVE BACKGROUND EXPERIMENTS

    International Nuclear Information System (INIS)

    Wehus, I. K.; Næss, S. K.; Eriksen, H. K.

    2012-01-01

    We describe a Bayesian framework for estimating the time-domain noise covariance of cosmic microwave background (CMB) observations, typically parameterized in terms of a 1/f frequency profile. This framework is based on the Gibbs sampling algorithm, which allows for exact marginalization over nuisance parameters through conditional probability distributions. In this paper, we implement support for gaps in the data streams and marginalization over fixed time-domain templates, and also outline how to marginalize over confusion from CMB fluctuations, which may be important for high signal-to-noise experiments. As a by-product of the method, we obtain proper constrained realizations, which themselves can be useful for map making. To validate the algorithm, we demonstrate that the reconstructed noise parameters and corresponding uncertainties are unbiased using simulated data. The CPU time required to process a single data stream of 100,000 samples with 1000 samples removed by gaps is 3 s if only the maximum posterior parameters are required, and 21 s if one also wants to obtain the corresponding uncertainties by Gibbs sampling.

  19. Evidence of a truncated spectrum in the angular correlation function of the cosmic microwave background

    Science.gov (United States)

    Melia, F.; López-Corredoira, M.

    2018-03-01

    Aim. The lack of large-angle correlations in the fluctuations of the cosmic microwave background (CMB) conflicts with predictions of slow-roll inflation. But while probabilities (≲0.24%) for the missing correlations disfavour the conventional picture at ≳3σ, factors not associated with the model itself may be contributing to the tension. Here we aim to show that the absence of large-angle correlations is best explained with the introduction of a non-zero minimum wave number kmin for the fluctuation power spectrum P(k). Methods: We assumed that quantum fluctuations were generated in the early Universe with a well-defined power spectrum P(k), although with a cut-off kmin ≠ 0. We then re-calculated the angular correlation function of the CMB and compared it with Planck observations. Results: The Planck 2013 data rule out a zero kmin at a confidence level exceeding 8σ. Whereas purely slow-roll inflation would have stretched all fluctuations beyond the horizon, producing a P(k) with kmin = 0 - and therefore strong correlations at all angles - a kmin ≠ 0 would signal the presence of a maximum wavelength at the time (tdec) of decoupling. This argues against the basic inflationary paradigm, and perhaps even suggests non-inflationary alternatives, for the origin and growth of perturbations in the early Universe. In at least one competing cosmology, the Rh = ct universe, the inferred kmin corresponds to the gravitational radius at tdec.

  20. The Atacama Cosmology Telescope: Cross-Correlation of Cosmic Microwave Background Lensing and Quasars

    Science.gov (United States)

    Sherwin, Blake D; Das, Sudeep; Haijian, Amir; Addison, Graeme; Bond, Richard; Crichton, Devin; Devlin, Mark J.; Dunkley, Joanna; Gralla, Megan B.; Halpern, Mark; hide

    2012-01-01

    We measure the cross-correlation of Atacama cosmology telescope cosmic microwave background (CMB) lensing convergence maps with quasar maps made from the Sloan Digital Sky Survey DR8 SDSS-XDQSO photometric catalog. The CMB lensing quasar cross-power spectrum is detected for the first time at a significance of 3.8 sigma, which directly confirms that the quasar distribution traces the mass distribution at high redshifts z > 1. Our detection passes a number of null tests and systematic checks. Using this cross-power spectrum, we measure the amplitude of the linear quasar bias assuming a template for its redshift dependence, and find the amplitude to be consistent with an earlier measurement from clustering; at redshift z ap 1.4, the peak of the distribution of quasars in our maps, our measurement corresponds to a bias of b = 2.5 +/- 0.6. With the signal-to-noise ratio on CMB lensing measurements likely to improve by an order of magnitude over the next few years, our results demonstrate the potential of CMB lensing crosscorrelations to probe astrophysics at high redshifts.

  1. Effect of the Great Attractor on the cosmic microwave background radiation

    Science.gov (United States)

    Bertschinger, Edmund; Gorski, Krzysztof M.; Dekel, Avishai

    1990-01-01

    A map is presented of the anisotropy Delta T/T in cosmic microwave background (CMB) temperature of our region of the universe as viewed by a distant observer, predicted on the basis of the gravitational potential field. This field is calculated in the vicinity of the Local Group of galaxies from the observed peculiar velocities of galaxies under the assumption that the peculiar motions are induced by gravity. If the cosmological density parameter Omega is one, the gravitational potential field of the Great Attractor and surrounding regions produces a maximum Sachs-Wolfe anisotropy of Delta T/T = (1.7 + or - 0.3) x 10 to the -5th on an angular scale of 1 deg. Doppler and adiabatic contributions to this anisotropy are expected to be somewhat larger. If similar fluctuations in the gravitational potential are present elsewhere in the universe, the anisotropy present when the CMB was last scattered should be visible from the earth and should be detectable in current experiments.

  2. Sterile neutrinos with non-standard secret interactions imprints on Cosmic Microwave Background anisotropies

    Science.gov (United States)

    Forastieri, F.

    2017-05-01

    Short baseline laboratory (SBL) anomalies have shown preference for light sterile neutrinos with eV masses. These particles, if confirmed, would be produced in the early universe and would add their contribution to the relativistic energy density basically increasing the effective number of extra relativistic species (N eff). It has been shown that when the matter potential produced by the sterile interactions becomes smaller than the vacuum oscillation frequency, sterile neutrinos are plentifully produced by the scattering effects in the sterile neutrino sector. This behaviour, however, leads to a ΔN eff ≃ 1 which is in tension at 3 - 5σ with the actual constraints given by the latest Cosmic Microwave Background radiation (CMB) observations. In order to avoid the thermalization of eV sterile neutrinos in the early universe, secret interactions between the sterile and active sectors mediated by a massive vector boson (MX 0.1 eV and seem to save the cosmological constraints coming from big-bang nucleosynthesis (BBN) and mass bounds. In this framework, cosmological observations represent a powerful tool to constrain neutrino physics complementary to laboratory experiments. In particular, observations of the CMB have the potential to constrain the properties of relic neutrinos, as well as of additional light relic particles in the universe. In this work we present the effects of the strength of the interaction on the neutrino fluid perturbations and on the CMB anisotropies power spectrum.

  3. Analysis of identification of digital images from a map of cosmic microwaves

    Science.gov (United States)

    Skeivalas, J.; Turla, V.; Jurevicius, M.; Viselga, G.

    2018-04-01

    This paper discusses identification of digital images from the cosmic microwave background radiation map formed according to the data of the European Space Agency "Planck" telescope by applying covariance functions and wavelet theory. The estimates of covariance functions of two digital images or single images are calculated according to the random functions formed of the digital images in the form of pixel vectors. The estimates of pixel vectors are formed on expansion of the pixel arrays of the digital images by a single vector. When the scale of a digital image is varied, the frequencies of single-pixel color waves remain constant and the procedure for calculation of covariance functions is not affected. For identification of the images, the RGB format spectrum has been applied. The impact of RGB spectrum components and the color tensor on the estimates of covariance functions was analyzed. The identity of digital images is assessed according to the changes in the values of the correlation coefficients in a certain range of values by applying the developed computer program.

  4. Polarized microwave forward model simulations for tropical storm ...

    Indian Academy of Sciences (India)

    microwave remote sensing of precipitation sys- tems largely depends on the forward radiative transfer model (Petty 2001), which are themselves based on some assumptions and hence are never perfect. The Tropical Rainfall Measuring Mission. (TRMM) satellite was designed to measure preci- pitation with high resolution ...

  5. Effects of differently polarized microwave radiation on the microscopic structure of the nuclei in human fibroblasts.

    Science.gov (United States)

    Shckorbatov, Yuriy G; Pasiuga, Vladimir N; Goncharuk, Elena I; Petrenko, Tatiana Ph; Grabina, Valentin A; Kolchigin, Nicolay N; Ivanchenko, Dmitry D; Bykov, Victor N; Dumin, Oleksandr M

    2010-10-01

    To investigate the influence of microwave radiation on the human fibroblast nuclei, the effects of three variants of electromagnetic wave polarization, linear and left-handed and right-handed elliptically polarized, were examined. Experimental conditions were: frequency (f) 36.65 GHz, power density (P) at the surface of exposed object 1, 10, 30, and 100 µW/cm(2), exposure time 10 s. Human fibroblasts growing in a monolayer on a cover slide were exposed to microwave electromagnetic radiation. The layer of medium that covered cells during microwave exposure was about 1 mm thick. Cells were stained immediately after irradiation by 2% (w/v) orcein solution in 45% (w/v) acetic acid. Experiments were made at room temperature (25 °C), and control cell samples were processed in the same conditions. We assessed heterochromatin granule quantity (HGQ) at 600× magnification. Microwave irradiation at the intensity of 1 µW/cm(2) produced no effect, and irradiation at the intensities of 10 and 100 µW/cm(2) induced an increase in HGQ. More intense irradiation induced more chromatin condensation. The right-handed elliptically polarized radiation revealed more biological activity than the left-handed polarized one.

  6. Using the Full Power of the Cosmic Microwave Background to Probe Axion Dark Matter

    Science.gov (United States)

    Hložek, Renée; Marsh, David J. E.; Grin, Daniel

    2018-02-01

    The cosmic microwave background (CMB) places stringent constraints on models of dark matter (DM), and on the initial conditions of the Universe. The full Planck data set is used to test the possibility that some fraction of the DM is composed of ultralight axions (ULAs). This represents the first use of CMB lensing to test the ULA model. We find no evidence for a ULA component in the mass range 10-33 ≤ ma ≤ 10-24eV. We put percent-level constraints on the ULA contribution to the DM, improving by up to a factor of two compared using temperature anisotropies alone. Axion DM also provides a low-energy window onto the physics of inflation through isocurvature perturbations. We perform the first systematic investigation into the parameter space of ULA isocurvature, using an accurate isocurvature transfer function at all ma values. We precisely identify a "window of co-existence" for 10-25eV ≤ ma ≤ 10-24eV where the data allow, simultaneously, a ˜10% contribution of ULAs to the DM, and ˜1% contributions of isocurvature and tensor modes to the CMB power. ULAs in this window (and all lighter ULAs) are shown to be consistent with a large inflationary Hubble parameter, HI ˜ 1014GeV. The window of co-existence will be fully probed by proposed CMB Stage-IV observations with increased accuracy in the high-ℓ lensing power and low-ℓ E and B-mode polarisation. If ULAs in the window exist, this could allow for two independent measurements of HI in the CMB using isocurvature, and the tensor contribution to B-modes.

  7. Measuring the Redshift Dependence of The Cosmic Microwave Background Monopole Temperature With Planck Data

    Science.gov (United States)

    De Martino, I.; Atrio-Barandela, F.; Da Silva, A.; Ebling, H.; Kashlinsky, A.; Kocevski, D.; Martins, C. J. A. P.

    2012-01-01

    We study the capability of Planck data to constrain deviations of the cosmic microwave background (CMB) blackbody temperature from adiabatic evolution using the thermal Sunyaev-Zeldovich anisotropy induced by clusters of galaxies. We consider two types of data sets depending on how the cosmological signal is removed: using a CMB template or using the 217 GHz map. We apply two different statistical estimators, based on the ratio of temperature anisotropies at two different frequencies and on a fit to the spectral variation of the cluster signal with frequency. The ratio method is biased if CMB residuals with amplitude approximately 1 microK or larger are present in the data, while residuals are not so critical for the fit method. To test for systematics, we construct a template from clusters drawn from a hydro-simulation included in the pre-launch Planck Sky Model. We demonstrate that, using a proprietary catalog of X-ray-selected clusters with measured redshifts, electron densities, and X-ray temperatures, we can constrain deviations of adiabatic evolution, measured by the parameter a in the redshift scaling T (z) = T0(1 + z)(sup 1-alpha), with an accuracy of sigma(sub alpha) = 0.011 in the most optimal case and with sigma alpha = 0.018 for a less optimal case. These results represent a factor of 2-3 improvement over similar measurements carried out using quasar spectral lines and a factor 6-20 with respect to earlier results using smaller cluster samples.

  8. Accelerating the cosmic microwave background map-making procedure through preconditioning

    Science.gov (United States)

    Szydlarski, M.; Grigori, L.; Stompor, R.

    2014-12-01

    Estimation of the sky signal from sequences of time ordered data is one of the key steps in cosmic microwave background (CMB) data analysis, commonly referred to as the map-making problem. Some of the most popular and general methods proposed for this problem involve solving generalised least-squares (GLS) equations with non-diagonal noise weights given by a block-diagonal matrix with Toeplitz blocks. In this work, we study new map-making solvers potentially suitable for applications to the largest anticipated data sets. They are based on iterative conjugate gradient (CG) approaches enhanced with novel, parallel, two-level preconditioners. We apply the proposed solvers to examples of simulated non-polarised and polarised CMB observations and a set of idealised scanning strategies with sky coverage ranging from a nearly full sky down to small sky patches. We discuss their implementation for massively parallel computational platforms and their performance for a broad range of parameters that characterise the simulated data sets in detail. We find that our best new solver can outperform carefully optimised standard solvers used today by a factor of as much as five in terms of the convergence rate and a factor of up to four in terms of the time to solution, without significantly increasing the memory consumption and the volume of inter-processor communication. The performance of the new algorithms is also found to be more stable and robust and less dependent on specific characteristics of the analysed data set. We therefore conclude that the proposed approaches are well suited to address successfully challenges posed by new and forthcoming CMB data sets.

  9. Neutrino Physics from the Cosmic Microwave Background and Large Scale Structure

    International Nuclear Information System (INIS)

    Abazajian, K. N.; Bischoff, C.; Bock, J.; Carvalho, C. S.; Chiang, H. C.; Dawson, K. S.; Halverson, N. W.; Hubmayr, J.; Knox, L.; Kuo, C.-L.; Linder, E.; Lubin, P.; Smith, K. M.; Spergel, D.; Stompor, R.; Vieregg, A. G.; Wang, G.; Wu, W.; Yoon, K. W.; Zahn, O.

    2014-01-01

    This is a report on the status and prospects of the quantification of neutrino properties through the cosmological neutrino background for the Cosmic Frontier of the Division of Particles and Fields Community Summer Study long-term planning exercise. Experiments planned and underway are prepared to study the cosmological neutrino background in detail via its influence on distance-redshift relations and the growth of structure. The program for the next decade described in this document, including upcoming spectroscopic galaxy surveys eBOSS and DESI and a new Stage-IV CMB polarization experiment CMB-S4, will achieve σ(σmν) = 16 meV and σ(N eff ) = 0.020. Such a mass measurement will produce a high significance detection of non-zero σmν, whose lower bound derived from atmospheric and solar neutrino oscillation data is about 58 meV. If neutrinos have a minimal normal mass hierarchy, this measurement will definitively rule out the inverted neutrino mass hierarchy, shedding light on one of the most puzzling aspects of the Standard Model of particle physics - the origin of mass. This precise a measurement of N eff will allow for high sensitivity to any light and dark degrees of freedom produced in the big bang and a precision test of the standard cosmological model prediction that N eff = 3.046

  10. Cold dark matter confronts the cosmic microwave background - Large-angular-scale anisotropies in Omega sub 0 + lambda 1 models

    Science.gov (United States)

    Gorski, Krzysztof M.; Silk, Joseph; Vittorio, Nicola

    1992-01-01

    A new technique is used to compute the correlation function for large-angle cosmic microwave background anisotropies resulting from both the space and time variations in the gravitational potential in flat, vacuum-dominated, cold dark matter cosmological models. Such models with Omega sub 0 of about 0.2, fit the excess power, relative to the standard cold dark matter model, observed in the large-scale galaxy distribution and allow a high value for the Hubble constant. The low order multipoles and quadrupole anisotropy that are potentially observable by COBE and other ongoing experiments should definitively test these models.

  11. Seasonal variation of secondary cosmic rays in the low polar atmosphere

    Science.gov (United States)

    Germanenko, Alexey; Balabin, Yury

    Monitoring of different kind of secondary cosmic rays in the low atmosphere is carried out for some years in the Polar Geophysical Institute. At the present moment two monitoring stations (Apatity, Murmansk region and Barentsburg, Spitzbergen) are in operation. Additionally to conventional 18-NM-64 neutron monitor (NM) there are leadless 4-NM-64 section (LLNM), thermal neutron detector (TND) and scintillation detector of gamma-ray (SDG) of 20-400 keV energy range. SDG has 5 cm lead shield at bottom and sides, accepts radiation only from the atmosphere. In a row of neutron detectors from NM to TND seasonal variation grows up from 0 to ˜ 10 %. The distinct and big seasonal variation (˜ 30 %) is on SDG detector. Low energy gamma-rays are caused of pion and muon decay, first of all low energy muons. It was suggested muon seasonal variation, depending on atmosphere temperature and seasonal condition, determines the SDG-variation.

  12. LiteBIRD: a small satellite for the study of B-mode polarization and inflation from cosmic background radiation detection

    Science.gov (United States)

    Hazumi, M.; Borrill, J.; Chinone, Y.; Dobbs, M. A.; Fuke, H.; Ghribi, A.; Hasegawa, M.; Hattori, K.; Hattori, M.; Holzapfel, W. L.; Inoue, Y.; Ishidoshiro, K.; Ishino, H.; Karatsu, K.; Katayama, N.; Kawano, I.; Kibayashi, A.; Kibe, Y.; Kimura, N.; Koga, K.; Komatsu, E.; Lee, A. T.; Matsuhara, H.; Matsumura, T.; Mima, S.; Mitsuda, K.; Morii, H.; Murayama, S.; Nagai, M.; Nagata, R.; Nakamura, S.; Natsume, K.; Nishino, H.; Noda, A.; Noguchi, T.; Ohta, I.; Otani, C.; Richards, P. L.; Sakai, S.; Sato, N.; Sato, Y.; Sekimoto, Y.; Shimizu, A.; Shinozaki, K.; Sugita, H.; Suzuki, A.; Suzuki, T.; Tajima, O.; Takada, S.; Takagi, Y.; Takei, Y.; Tomaru, T.; Uzawa, Y.; Watanabe, H.; Yamasaki, N.; Yoshida, M.; Yoshida, T.; Yotsumoto, K.

    2012-09-01

    LiteBIRD [Lite (Light) satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection] is a small satellite to map the polarization of the cosmic microwave background (CMB) radiation over the full sky at large angular scales with unprecedented precision. Cosmological inflation, which is the leading hypothesis to resolve the problems in the Big Bang theory, predicts that primordial gravitational waves were created during the inflationary era. Measurements of polarization of the CMB radiation are known as the best probe to detect the primordial gravitational waves. The LiteBIRD working group is authorized by the Japanese Steering Committee for Space Science (SCSS) and is supported by JAXA. It has more than 50 members from Japan, USA and Canada. The scientific objective of LiteBIRD is to test all the representative inflation models that satisfy single-field slow-roll conditions and lie in the large-field regime. To this end, the requirement on the precision of the tensor-to-scalar ratio, r, at LiteBIRD is equal to or less than 0.001. Our baseline design adopts an array of multi-chroic superconducting polarimeters that are read out with high multiplexing factors in the frequency domain for a compact focal plane. The required sensitivity of 1.8μKarcmin is achieved with 2000 TES bolometers at 100mK. The cryogenic system is based on the Stirling/JT technology developed for SPICA, and the continuous ADR system shares the design with future X-ray satellites.

  13. Constraining Dark Energy with X-ray Galaxy Clusters, Supernovae and the Cosmic Microwave Background

    International Nuclear Information System (INIS)

    Rapetti, D

    2005-01-01

    We present new constraints on the evolution of dark energy from an analysis of Cosmic Microwave Background, supernova and X-ray galaxy cluster data. Our analysis employs a minimum of priors and exploits the complementary nature of these data sets. We examine a series of dark energy models with up to three free parameters: the current dark energy equation of state w 0 , the early time equation of state w et and the scale factor at transition, a t . From a combined analysis of all three data sets, assuming a constant equation of state and that the Universe is flat, we measure w 0 = 1.05 -0.12 +0.10 . Including w et as a free parameter and allowing the transition scale factor to vary over the range 0.5 t 0 = -1.27 -0.39 +0.33 and w et = -0.66 -0.62 +0.44 . We find no significant evidence for evolution in the dark energy equation of state parameter with redshift. Marginal hints of evolution in the supernovae data become less significant when the cluster constraints are also included in the analysis. The complementary nature of the data sets leads to a tight constraint on the mean matter density, (Omega) m and alleviates a number of other parameter degeneracies, including that between the scalar spectral index n s , the physical baryon density (Omega) b h 2 and the optical depth τ. This complementary nature also allows us to examine models in which we drop the prior on the curvature. For non-flat models with a constant equation of state, we measure w 0 = -1.09 -0.15 +0.12 and obtain a tight constraint on the current dark energy density, (Omega) de = 0.70 ± 0.03. For dark energy models other than a cosmological constant, energy-momentum conservation requires the inclusion of spatial perturbations in the dark energy component. Our analysis includes such perturbations, assuming a sound speed c s 2 = 1 in the dark energy fluid as expected for Quintessence scenarios. For our most general dark energy model, not including such perturbations would lead to spurious constraints

  14. microwave satellite water vapour column retrieval for polar winter conditions

    Energy Technology Data Exchange (ETDEWEB)

    Perro, Christopher; Lesins, Glen; Duck, Thomas J.; Cadeddu, Maria

    2016-01-01

    A new microwave satellite water vapour retrieval for the polar winter atmosphere is presented. The retrieval builds on the work of Miao et al. (2001) and Melsheimer and Heygster (2008), employing auxiliary information for atmospheric conditions and numerical optimization. It was tested using simulated and actual measurements from the Microwave Humidity Sounder (MHS) satellite instruments. Ground truth was provided by the G-band vapour radiometer (GVR) at Barrow, Alaska. For water vapour columns less than 6 kg m-2, comparisons between the retrieval and GVR result in a root mean square (RMS) deviation of 0.39 kg m-2 and a systematic bias of 0.08 kg m-2. These results are compared with RMS deviations and biases at Barrow for the retrieval of Melsheimer and Heygster (2008), the AIRS and MIRS satellite data products, and the ERA-Interim, NCEP, JRA-55, and ASR reanalyses. When applied to MHS measurements, the new retrieval produces a smaller RMS deviation and bias than for the earlier retrieval and satellite data products. The RMS deviations for the new retrieval were comparable to those for the ERA-Interim, JRA-55, and ASR reanalyses; however, the MHS retrievals have much finer horizontal resolution (15 km at nadir) and reveal more structure. The new retrieval can be used to obtain pan-Arctic maps of water vapour columns of unprecedented quality. It may also be applied to measurements from the Special Sensor Microwave/Temperature 2 (SSM/T2), Advanced Microwave Sounding Unit B (AMSU-B), Special Sensor Microwave Imager/Sounder (SSMIS), Advanced Technology Microwave Sounder (ATMS), and Chinese MicroWave Humidity Sounder (MWHS) instruments.

  15. Cosmic polarimetry in magnetoactive plasmas

    CERN Document Server

    Giovannini, Massimo

    2009-01-01

    Polarimetry of the Cosmic Microwave Background (CMB) represents one of the possible diagnostics aimed at testing large-scale magnetism at the epoch of the photon decoupling. The propagation of electromagnetic disturbances in a magnetized plasma leads naturally to a B-mode polarization whose angular power spectrum is hereby computed both analytically and numerically. Combined analyses of all the publicly available data on the B-mode polarization are presented, for the first time, in the light of the magnetized $\\Lambda$CDM scenario. Novel constraints on pre-equality magnetism are also derived in view of the current and expected sensitivities to the B-mode polarization.

  16. Microwave field distribution in a magic angle spinning dynamic nuclear polarization NMR probe.

    Science.gov (United States)

    Nanni, Emilio A; Barnes, Alexander B; Matsuki, Yoh; Woskov, Paul P; Corzilius, Björn; Griffin, Robert G; Temkin, Richard J

    2011-05-01

    We present a calculation of the microwave field distribution in a magic angle spinning (MAS) probe utilized in dynamic nuclear polarization (DNP) experiments. The microwave magnetic field (B(1S)) profile was obtained from simulations performed with the High Frequency Structure Simulator (HFSS) software suite, using a model that includes the launching antenna, the outer Kel-F stator housing coated with Ag, the RF coil, and the 4mm diameter sapphire rotor containing the sample. The predicted average B(1S) field is 13μT/W(1/2), where S denotes the electron spin. For a routinely achievable input power of 5W the corresponding value is γ(S)B(1S)=0.84MHz. The calculations provide insights into the coupling of the microwave power to the sample, including reflections from the RF coil and diffraction of the power transmitted through the coil. The variation of enhancement with rotor wall thickness was also successfully simulated. A second, simplified calculation was performed using a single pass model based on Gaussian beam propagation and Fresnel diffraction. This model provided additional physical insight and was in good agreement with the full HFSS simulation. These calculations indicate approaches to increasing the coupling of the microwave power to the sample, including the use of a converging lens and fine adjustment of the spacing of the windings of the RF coil. The present results should prove useful in optimizing the coupling of microwave power to the sample in future DNP experiments. Finally, the results of the simulation were used to predict the cross effect DNP enhancement (ϵ) vs. ω(1S)/(2π) for a sample of (13)C-urea dissolved in a 60:40 glycerol/water mixture containing the polarizing agent TOTAPOL; very good agreement was obtained between theory and experiment. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. The EUMETSAT Polar System - Second Generation (EPS-SG) micro-wave imaging (MWI) mission

    Science.gov (United States)

    Bojkov, B. R.; Accadia, C.; Klaes, D.; Canestri, A.; Cohen, M.

    2017-12-01

    The EUMETSAT Polar System (EPS) will be followed by a second generation system called EPS-SG. This new family of missions will contribute to the Joint Polar System being jointly set up with NOAA in the timeframe 2020-2040. These satellites will fly, like Metop (EPS), in a sun synchronous, low earth orbit at 830 km altitude and 09:30 local time descending node, providing observations over the full globe with revisit times of 12 hours. EPS-SG consists of two different satellites configurations, the EPS-SGa series dedicated to IR and MW sounding, and the EPS-SGb series dedicated to microwave imaging and scatterometry. The EPS-SG family will consist of three successive launches of each satellite-type. The Microwave Imager (MWI) will be hosted on Metop-SGb series of satellites, with the primary objective of supporting Numerical Weather Prediction (NWP) at regional and global scales. Other applications will be observation of surface parameters such as sea ice concentration and hydrology applications. The 18 MWI instrument frequencies range from 18.7 GHz to 183 GHz. All MWI channels up to 89 GHz will measure V- and H polarizations. The MWI was also designed to provide continuity of measurements for select heritage microwave imager channels (e.g. SSM/I, AMSR-E). The additional sounding channels such as the 50-55 and 118 GHz bands will provide additional cloud and precipitation information over sea and land. This combination of channels was successfully tested on the NPOESS Aircraft Sounder Testbed - Microwave Sounder (NAST-M) airborne radiometer, and it is the first time that will be implemented in a conical scanning configuration in a single instrument. An overview of the EPS-SG programme and the MWI instrument will be presented.

  18. A map of the cosmic microwave background radiation from the Wilkinson Microwave Anisotropy Probe (WMAP), showing the large-scale fluctuations (the quadrupole and octopole) isolated by an analysis done partly by theorists at CERN.

    CERN Multimedia

    2004-01-01

    A recent analysis, in part by theorists working at CERN, suggests a new view of the cosmic microwave background radiation. It seems the solar system, rather than the universe, causes the radiation's large-scale fluctuations, similar to the bass in a song.

  19. A MEASUREMENT OF ARCMINUTE ANISOTROPY IN THE COSMIC MICROWAVE BACKGROUND WITH THE SUNYAEV-ZEL'DOVICH ARRAY

    International Nuclear Information System (INIS)

    Sharp, Matthew K.; Marrone, Daniel P.; Carlstrom, John E.; Culverhouse, Thomas; Greer, Christopher; Hennessy, Ryan; Leitch, Erik M.; Loh, Michael; Pryke, Clem; Hawkins, David; Lamb, James W.; Muchovej, Stephen; Woody, David; Joy, Marshall; Miller, Amber; Mroczkowski, Tony

    2010-01-01

    We present 30 GHz measurements of the angular power spectrum of the cosmic microwave background (CMB) obtained with the Sunyaev-Zel'dovich Array. The measurements are sensitive to arcminute angular scales, where secondary anisotropy from the Sunyaev-Zel'dovich effect (SZE) is expected to dominate. For a broad bin centered at multipole 4066, we find 67 +77 -50 μK 2 ; of which 26 ± 5 μK 2 is the expected contribution from primary CMB anisotropy and 80 ± 54 μK 2 is the expected contribution from undetected radio sources. These results imply an upper limit of 155 μK 2 (95% CL) on the secondary contribution to the anisotropy in our maps. This level of SZE anisotropy power is consistent with expectations based on recent determinations of the normalization of the matter power spectrum, i.e., σ 8 ∼ 0.8.

  20. Geodesic curve-of-sight formulae for the cosmic microwave background: a unified treatment of redshift, time delay, and lensing

    International Nuclear Information System (INIS)

    Saito, Ryo; Naruko, Atsushi; Hiramatsu, Takashi; Sasaki, Misao

    2014-01-01

    In this paper, we introduce a new approach to a treatment of the gravitational effects (redshift, time delay and lensing) on the observed cosmic microwave background (CMB) anisotropies based on the Boltzmann equation. From the Liouville's theorem in curved spacetime, the intensity of photons is conserved along a photon geodesic when non-gravitational scatterings are absent. Motivated by this fact, we derive a second-order line-of-sight formula by integrating the Boltzmann equation along a perturbed geodesic (curve) instead of a background geodesic (line). In this approach, the separation of the gravitational and intrinsic effects are manifest. This approach can be considered as a generalization of the remapping approach of CMB lensing, where all the gravitational effects can be treated on the same footing

  1. Circularly polarized microwaves for magnetic resonance study in the GHz range: Application to nitrogen-vacancy in diamonds

    Energy Technology Data Exchange (ETDEWEB)

    Mrózek, M., E-mail: mariusz.mrozek@uj.edu.pl; Rudnicki, D. S.; Gawlik, W. [Institute of Physics, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow (Poland); Mlynarczyk, J. [Department of Electronics, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow (Poland)

    2015-07-06

    The ability to create time-dependent magnetic fields of controlled polarization is essential for many experiments with magnetic resonance. We describe a microstrip circuit that allows us to generate strong magnetic field at microwave frequencies with arbitrary adjusted polarization. The circuit performance is demonstrated by applying it to an optically detected magnetic resonance and Rabi nutation experiments in nitrogen-vacancy color centers in diamond. Thanks to high efficiency of the proposed microstrip circuit and degree of circular polarization of 85%; it is possible to address the specific spin states of a diamond sample using a low power microwave generator. The circuit may be applied to a wide range of magnetic resonance experiments with a well-controlled polarization of microwaves.

  2. CMB polarization at large angular scales: Data analysis of the POLAR experiment

    International Nuclear Information System (INIS)

    O'Dell, Christopher W.; Keating, Brian G.; Oliveira-Costa, Angelica de; Tegmark, Max; Timbie, Peter T.

    2003-01-01

    The coming flood of cosmic microwave background (CMB) polarization experiments, spurred by the recent detection of CMB polarization by the DASI and WMAP instruments, will be confronted by many new analysis tasks specific to polarization. For the analysis of CMB polarization data sets, the devil is truly in the details. With this in mind, we present details of the data analysis for the POLAR experiment, which recently led to the tightest upper limits on the polarization of the cosmic microwave background radiation at large angular scales. We discuss the data selection process, map-making algorithms, offset removal, and likelihood analysis which were used to find upper limits on the polarization. Stated using the modern convention for reporting CMB Stokes parameters, these limits are 5.0 μK on both E- and B-type polarization at 95% confidence. Finally, we discuss simulations used to test our analysis techniques and to probe the fundamental limitations of the experiment

  3. Low-temperature dynamic nuclear polarization at 9.4 T with a 30 mW microwave source.

    Science.gov (United States)

    Thurber, Kent R; Yau, Wai-Ming; Tycko, Robert

    2010-06-01

    Dynamic nuclear polarization (DNP) can provide large signal enhancements in nuclear magnetic resonance (NMR) by transfer of polarization from electron spins to nuclear spins. We discuss several aspects of DNP experiments at 9.4 T (400 MHz resonant frequency for (1)H, 264 GHz for electron spins in organic radicals) in the 7-80K temperature range, using a 30 mW, frequency-tunable microwave source and a quasi-optical microwave bridge for polarization control and low-loss microwave transmission. In experiments on frozen glycerol/water doped with nitroxide radicals, DNP signal enhancements up to a factor of 80 are observed (relative to (1)H NMR signals with thermal equilibrium spin polarization). The largest sensitivity enhancements are observed with a new triradical dopant, DOTOPA-TEMPO. Field modulation with a 10 G root-mean-squared amplitude during DNP increases the nuclear spin polarizations by up to 135%. Dependencies of (1)H NMR signal amplitudes, nuclear spin relaxation times, and DNP build-up times on the dopant and its concentration, temperature, microwave power, and modulation frequency are reported and discussed. The benefits of low-temperature DNP can be dramatic: the (1)H spin polarization is increased approximately 1000-fold at 7 K with DNP, relative to thermal polarization at 80K. (c) 2010 Elsevier Inc. All rights reserved.

  4. Constraints on direction-dependent cosmic birefringence from Planck polarization data

    Science.gov (United States)

    Contreras, Dagoberto; Boubel, Paula; Scott, Douglas

    2017-12-01

    Cosmic birefringence is the process that rotates the plane of polarization by an amount, α, as photons propagate through free space. Such an effect arises in parity-violating extensions to the electromagnetic sector, such as the Chern-Simons term common in axion models, quintessence models, or Lorentz-violating extensions to the standard model. Most studies consider the monopole of this rotation, but it is also possible for the effect to have spatial anisotropies. Paying particular attention to large scales, we implement a novel pixel-based method to extract the spherical harmonics for L 30. Our results are consistent with no detection and we set 95 % upper limits on the amplitude of a scale-invariant power spectrum of L(L+1)CL/2π<[2.2 (stat.)±0.7 (syst.)]×10-5=[0.07 (stat.)±0.02 (syst.)] deg2, on par with previous constraints. This implies specific limits on the dipole and quadrupole amplitudes to be √C1/4π lesssim 0.o2 and √C2/4π lesssim 0.o1, at 95 % CL, respectively, improving previous constraints by an order of magnitude. We further constrain a model independent M=0 quadrupole in an arbitrary direction to be α20 = 0.o02 ± 0.o21, with an unconstrained direction. However, we find an excess of dipolar power with an amplitude √3C1/4π = 0.o32±0.o10 (stat.)±0.o08 (syst.)], in the direction (l,b)=(295o,17o)±(22o,17o) (stat.)±(5o,16o) (syst.), larger than 1.4 % of simulations with no birefringence. We attribute part of this signal to the contamination of residual foregrounds not accounted for in our simulations, although this should be further investigated.

  5. A MEASUREMENT OF SECONDARY COSMIC MICROWAVE BACKGROUND ANISOTROPIES FROM THE 2500 SQUARE-DEGREE SPT-SZ SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    George, E. M.; Reichardt, C. L.; Aird, K. A.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Cho, H-M.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Dobbs, M. A.; Dudley, J.; Halverson, N. W.; Harrington, N. L.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Lueker, M.; Luong-Van, D.; McMahon, J. J.; Mehl, J.; Meyer, S. S.; Millea, M.; Mocanu, L. M.; Mohr, J. J.; Montroy, T. E.; Padin, S.; Plagge, T.; Pryke, C.; Ruhl, J. E.; Schaffer, K. K.; Shaw, L.; Shirokoff, E.; Spieler, H. G.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; van Engelen, A.; Vanderlinde, K.; Vieira, J. D.; Williamson, R.; Zahn, O.

    2015-01-28

    We present measurements of secondary cosmic microwave background (CMB) anisotropies and cosmic infrared background (CIB) fluctuations using data from the South Pole Telescope (SPT) covering the complete 2540 deg(2) SPT-SZ survey area. Data in the three SPT-SZ frequency bands centered at 95, 150, and 220 GHz, are used to produce six angular power spectra (three single-frequency auto-spectra and three cross-spectra) covering the multipole range 2000 < ℓ < 11, 000 (angular scales 5' gsim θ gsim 1'). These are the most precise measurements of the angular power spectra at ℓ > 2500 at these frequencies. The main contributors to the power spectra at these angular scales and frequencies are the primary CMB, CIB, thermal and kinematic Sunyaev-Zel'dovich effects (tSZ and kSZ), and radio galaxies. We include a constraint on the tSZ power from a measurement of the tSZ bispectrum from 800 deg(2) of the SPT-SZ survey. We measure the tSZ power at 143  GHz to be $D^{\\rm tSZ}_{3000} = 4.08^{+0.58}_{-0.67}\\,\\mu {\\rm K}^2{}$ and the kSZ power to be $D^{\\rm kSZ}_{3000} = 2.9 \\pm 1.3\\, \\mu {\\rm K}^2{}$. The data prefer positive kSZ power at 98.1% CL. We measure a correlation coefficient of $\\xi = 0.113^{+0.057}_{-0.054}$ between sources of tSZ and CIB power, with ξ < 0 disfavored at a confidence level of 99.0%. The constraint on kSZ power can be interpreted as an upper limit on the duration of reionization. When the post-reionization homogeneous kSZ signal is accounted for, we find an upper limit on the duration Δz < 5.4  at 95% CL.

  6. Improved Constraints on Cosmology and Foregrounds from BICEP2 and Keck Array Cosmic Microwave Background Data with Inclusion of 95 GHz Band.

    Science.gov (United States)

    Ade, P A R; Ahmed, Z; Aikin, R W; Alexander, K D; Barkats, D; Benton, S J; Bischoff, C A; Bock, J J; Bowens-Rubin, R; Brevik, J A; Buder, I; Bullock, E; Buza, V; Connors, J; Crill, B P; Duband, L; Dvorkin, C; Filippini, J P; Fliescher, S; Grayson, J; Halpern, M; Harrison, S; Hilton, G C; Hui, H; Irwin, K D; Karkare, K S; Karpel, E; Kaufman, J P; Keating, B G; Kefeli, S; Kernasovskiy, S A; Kovac, J M; Kuo, C L; Leitch, E M; Lueker, M; Megerian, K G; Netterfield, C B; Nguyen, H T; O'Brient, R; Ogburn, R W; Orlando, A; Pryke, C; Richter, S; Schwarz, R; Sheehy, C D; Staniszewski, Z K; Steinbach, B; Sudiwala, R V; Teply, G P; Thompson, K L; Tolan, J E; Tucker, C; Turner, A D; Vieregg, A G; Weber, A C; Wiebe, D V; Willmert, J; Wong, C L; Wu, W L K; Yoon, K W

    2016-01-22

    We present results from an analysis of all data taken by the BICEP2 and Keck Array cosmic microwave background (CMB) polarization experiments up to and including the 2014 observing season. This includes the first Keck Array observations at 95 GHz. The maps reach a depth of 50 nK deg in Stokes Q and U in the 150 GHz band and 127 nK deg in the 95 GHz band. We take auto- and cross-spectra between these maps and publicly available maps from WMAP and Planck at frequencies from 23 to 353 GHz. An excess over lensed ΛCDM is detected at modest significance in the 95×150 BB spectrum, and is consistent with the dust contribution expected from our previous work. No significant evidence for synchrotron emission is found in spectra such as 23×95, or for correlation between the dust and synchrotron sky patterns in spectra such as 23×353. We take the likelihood of all the spectra for a multicomponent model including lensed ΛCDM, dust, synchrotron, and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r) using priors on the frequency spectral behaviors of dust and synchrotron emission from previous analyses of WMAP and Planck data in other regions of the sky. This analysis yields an upper limit r_{0.05}<0.09 at 95% confidence, which is robust to variations explored in analysis and priors. Combining these B-mode results with the (more model-dependent) constraints from Planck analysis of CMB temperature plus baryon acoustic oscillations and other data yields a combined limit r_{0.05}<0.07 at 95% confidence. These are the strongest constraints to date on inflationary gravitational waves.

  7. Primordial Inflation Polarization Explorer: Status and Plans

    Science.gov (United States)

    Kogut, Alan

    2009-01-01

    The Primordial Inflation Polarization Explorer is a balloon-borne instrument to measure the polarization of the cosmic microwave background in order to detect the characteristic signature of gravity waves created during an inflationary epoch in the early universe. PIPER combines cold /I.G K\\ optics, 5120 bolometric detectors, and rapid polarization modulation using VPM grids to achieve both high sensitivity and excellent control of systematic errors. I will discuss the current status and plans for the PIPER instrument.

  8. The Primordial Inflation Polarization Explorer (PIPER): Instrument Description.

    Science.gov (United States)

    Eimer, Joseph; Bennett, C.; McCullagh, N.; Zeng, L.; Benford, D.; Chuss, D.; Fixsen, D.; Hinderks, J.; Jhabvala, C.; Kogut, A.; Mirel, P.; Moseley, S.; Staguhn, J.; Voellmer, G.; Wollack, E.; Irwin, K.; Hilton, G.; Halpern, M.; Ade, P.; Tucker, C.; Dotson, J.

    2010-01-01

    We describe the PIPER balloon born instrument for observing the polarization of the cosmic microwave background. The experiment uses two co-aligned cold optic telescopes with variable-delay polarization modulators as their first optical element. Each telescope has two 32 x 40 arrays of backshort-under-grid(BUG) TES bolometers.

  9. Response of the polar atmosphere of the earth to variations of cosmic-ray intensity in the stratosphere

    Science.gov (United States)

    Ulianov, V. P.; Rudnev, Iu. F.; Novikov, A. M.

    The effect of cosmic-ray intensity variations in the polar stratosphere on the circulation in this region is investigated on the basis of data from the Tiksi and Murmansk stations. It is shown that an increase in solar activity manifested in Forbush effects at the end of February and the beginning of March leads in general to an earlier-than-usual spring reversal of stratospheric circulation. The reversal mechanism evidently has a complex character: a decrease in the intensity of the circumpolar vortex is observed three to five days after the Forbush effect; this decrease is succeeded by a significant increase eight to ten days after the effect.

  10. The advanced cosmic microwave explorer - A millimeter-wave telescope and stabilized platform

    Science.gov (United States)

    Meinhold, P. R.; Chingcuanco, A. O.; Gundersen, J. O.; Schuster, J. A.; Seiffert, M. D.; Lubin, P. M.; Morris, D.; Villela, T.

    1993-01-01

    We have developed and flown a 1 m diameter Gregorian telescope system for measurements of anisotropy in the Cosmic Background Radiation (CBR). The telescope is incorporated in a balloon-borne stabilized platform with arcminute stabilization capability. To date, the system has flown four times and observed from the ground at the South Pole twice. The telescope has used both coherent and incoherent detectors. We describe the development of the telescope, pointing platform, and one of the receivers employed in making measurements of the CBR. Performance of the system during the first flight and operation on the ground at the South Pole are described, and the quality of the South Pole as a millimeter wave observing site is discussed.

  11. A measurement of gravitational lensing of the cosmic microwave background by galaxy clusters using data from the south pole telescope

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, E. J.; Keisler, R.; Dodelson, S.; Aird, K. A.; Allen, S. W.; Ashby, M. L. N.; Bautz, M.; Bayliss, M.; Benson, B. A.; Bleem, L. E.; Bocquet, S.; Brodwin, M.; Carlstrom, J. E.; Chang, C. L.; Chiu, I.; Cho, H-M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; Desai, S.; Dietrich, J. P.; de Haan, T.; Dobbs, M. A.; Foley, R. J.; Forman, W. R.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Halverson, N. W.; Harrington, N. L.; Hennig, C.; Hoekstra, H.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Jones, C.; Knox, L.; Lee, A. T.; Leitch, E. M.; Liu, J.; Lueker, M.; Luong-Van, D.; Mantz, A.; Marrone, D. P.; McDonald, M.; McMahon, J. J.; Meyer, S. S.; Millea, M.; Mocanu, L. M.; Murray, S. S.; Padin, S.; Pryke, C.; Reichardt, C. L.; Rest, A.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Shirokoff, E.; Song, J.; Spieler, H. G.; Stalder, B.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; van Engelen, A.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zahn, O.; Zenteno, A.

    2015-06-20

    Clusters of galaxies are expected to gravitationally lens the cosmic microwave background (CMB) and thereby generate a distinct signal in the CMB on arcminute scales. Measurements of this effect can be used to constrain the masses of galaxy clusters with CMB data alone. Here we present a measurement of lensing of the CMB by galaxy clusters using data from the South Pole Telescope (SPT). We develop a maximum likelihood approach to extract the CMB cluster lensing signal and validate the method on mock data. We quantify the effects on our analysis of several potential sources of systematic error and find that they generally act to reduce the best-fit cluster mass. It is estimated that this bias to lower cluster mass is roughly 0.85σ in units of the statistical error bar, although this estimate should be viewed as an upper limit. We apply our maximum likelihood technique to 513 clusters selected via their Sunyaev–Zeldovich (SZ) signatures in SPT data, and rule out the null hypothesis of no lensing at 3.1σ. The lensing-derived mass estimate for the full cluster sample is consistent with that inferred from the SZ flux: ${M}_{200,\\mathrm{lens}}={0.83}_{-0.37}^{+0.38}\\;{M}_{200,\\mathrm{SZ}}$ (68% C.L., statistical error only).

  12. An array of lens-coupled antennas for cosmic microwave background measurements in the 30 Ghz band

    Science.gov (United States)

    Colin, Angel; Ortiz, David; Villa, Enrique; Artal, Edurado; Martínez-González, Enrique

    2012-03-01

    An array of bow-tie slot antennas coupled through an extended hemispherical lens is proposed to operate in the 30 GHz frequency band. The design includes a combination of three microstrip Wilkinson power dividers (WPD) and transitions to coplanar wave guides (CPW) to form the feeding antenna network. This configuration is suitable for the integration with heterodyne imaging detectors commonly used in radioastronomy. Measurements and simulation results exhibit a frequency range of operation from 20 to 40 GHz with a bandwidth of 24% achieved for -10 dB return loss at the central frequency. The measured radiation patterns show a maximum peak gain of around 13 dB with HPBW of 10° for the E-plane, and whose first side lobes are lower than 13 dB below the main lobe in both angular shift sides. The presented results will be considered as preliminary feasibility studies in the 30 GHz QUIJOTE-CMB Instrument, which is designed to study the anisotropies of the Cosmic Microwave Background (CMB).

  13. Flat tree-level inflationary potentials in the light of cosmic microwave background and large scale structure data

    CERN Document Server

    Ballesteros, G; Espinosa, J R; de Austri, R Ruiz; Trotta, R

    2008-01-01

    We use cosmic microwave background and large scale structure data to test a broad and physically well-motivated class of inflationary models: those with flat tree-level potentials (typical in supersymmetry). The non-trivial features of the potential arise from radiative corrections which give a simple logarithmic dependence on the inflaton field, making the models very predictive. We also consider a modified scenario with new physics beyond a certain high-energy cut-off showing up as non-renormalizable operators (NRO) in the inflaton field. We find that both kinds of models fit remarkably well CMB and LSS data, with very few free parameters. Besides, a large part of these models naturally predict a reasonable number of e-folds. A robust feature of these scenarios is the smallness of tensor perturbations (r < 10^{-3}). The NRO case can give a sizeable running of the spectral index while achieving a sufficient number of e-folds. We use Bayesian model comparison tools to assess the relative performance of the...

  14. Synthesis of polymer-derived ceramic Si(B)CN-carbon nanotube composite by microwave-induced interfacial polarization.

    Science.gov (United States)

    Bhandavat, R; Kuhn, W; Mansfield, E; Lehman, J; Singh, G

    2012-01-01

    We demonstrate synthesis of a polymer-derived ceramic (PDC)-multiwall carbon nanotube (MWCNT) composite using microwave irradiation at 2.45 GHz. The process takes about 10 min of microwave irradiation for the polymer-to-ceramic conversion. The successful conversion of polymer coated carbon nanotubes to ceramic composite is chemically ascertained by Fourier transform-infrared and X-ray photoelectron spectroscopy and physically by thermogravimetric analysis and transmission electron microscopy characterization. Frequency dependent dielectric measurements in the S-Band (300 MHz to 3 GHz) were studied to quantify the extent of microwave-CNT interaction and the degree of selective heating available at the MWCNT-polymer interface. Experimentally obtained return loss of the incident microwaves in the specimen explains the reason for heat generation. The temperature-dependent permittivity of polar molecules further strengthens the argument of internal heat generation. © 2011 American Chemical Society

  15. L-Band H Polarized Microwave Emission During the Corn Growth Cycle

    Science.gov (United States)

    Joseph, A. T.; va der Velde, R.; O'Neill, P. E.; Kim, E.; Lang, R. H.; Gish, T.

    2012-01-01

    Hourly L-band (1.4 GHz) horizontally (H) polarized brightness temperatures (T(sub B))'s measured during five episodes (more than two days of continuous measurements) of the 2002 corn growth cycle are analyzed. These T(sub B)'s measurements were acquired as a part of a combined active/passive microwave field campaign, and were obtained at five incidence and three azimuth angles relative to the row direction. In support of this microwave data collection, intensive ground sampling took place once a week. Moreover, the interpretation of the hourly T(sub B)'s could also rely on the data obtained using the various automated instruments installed in the same field. In this paper, the soil moisture and temperature measured at fixed time intervals have been employed as input for the tau-omega model to reproduce the hourly T(sub B). Through the calibration of the vegetation and surface roughness parameterizations, the impact of the vegetation morphological changes on the microwave emission and the dependence of the soil surface roughness parameter, h(sub r), on soil moisture are investigated. This analysis demonstrates that the b parameter, appearing in the representation of the canopy opacity, has an angular dependence that varies throughout the growing period and also that the parameter hr increases as the soil dries in a portion of the dry-down cycle. The angular dependence of the b parameter imposes the largest uncertainty on T(sub B) simulations near senescence as the response of b to the incidence is also affected by the crop row orientation. On the other hand, the incorporation of a soil moisture dependent h(sub r) parameterization was responsible for the largest error reduction of T(sub B) simulations in the early growth cycle.

  16. The effect of soil moisture on the 37 GHz microwave polarization difference index (MPDI)

    International Nuclear Information System (INIS)

    Felde, G.W.

    1998-01-01

    Previous studies have shown that the 37 GHz microwave polarization difference index (MPDI) has an inverse nonlinear relationship to the normalized difference vegetation index (NDVI) with the MPDI (NDVI) being more sensitive to vegetation density under sparse (moderate) vegetation conditions. It has also been noted that soil moisture can have a significant influence on the MPDI. This study quantifies the effect of soil moisture on the MPDI using the RADTRAN model and comparison with measurements from a few geographically restricted (eastern USA) study sites. Model results show the MPDI increases with soil moisture but its sensitivity approaches zero when soil moisture values or vegetation densities are large. Results based on special sensor microwave/imager (SSM/I) measured values of MPDI, using the NDVI as a surrogate for vegetation density and an antecedent precipitation index (API) as a surrogate for soil moisture, were consistent with those based on the model. Linear equations, one for each of three categories of vegetation density, expressing MPDI as a function of API were derived based on SSM/I measurements. These equations demonstrate that soil moisture information can be extracted from the MPDI when the NDVI is used to account for the effect of vegetation and that the effect of soil moisture on the MPDI should be taken into account if it is to be used as a vegetation index. The potential to normalize MPDI values for variations in soil moisture is discussed. (author)

  17. Polarization entanglement purification of nonlocal microwave photons based on the cross-Kerr effect in circuit QED

    Science.gov (United States)

    Zhang, Hao; Liu, Qian; Xu, Xu-Sheng; Xiong, Jun; Alsaedi, Ahmed; Hayat, Tasawar; Deng, Fu-Guo

    2017-11-01

    Microwave photons have become very important qubits in quantum communication, as the first quantum satellite has been launched successfully. Therefore, it is a necessary and meaningful task for ensuring the high security and efficiency of microwave-based quantum communication in practice. Here, we present an original polarization entanglement purification protocol for nonlocal microwave photons based on the cross-Kerr effect in circuit quantum electrodynamics (QED). Our protocol can solve the problem that the purity of maximally entangled states used for constructing quantum channels will decrease due to decoherence from environment noise. This task is accomplished by means of the polarization parity-check quantum nondemolition (QND) detector, the bit-flipping operation, and the linear microwave elements. The QND detector is composed of several cross-Kerr effect systems which can be realized by coupling two superconducting transmission line resonators to a superconducting molecule with the N -type level structure. We give the applicable experimental parameters of QND measurement system in circuit QED and analyze the fidelities. Our protocol has good applications in long-distance quantum communication assisted by microwave photons in the future, such as satellite quantum communication.

  18. Measuring the polarisation anisotropy of the Cosmic Microwave Background with the QUBIC bolometric interferometer

    International Nuclear Information System (INIS)

    Bigot-Sazy, Marie-Anne

    2013-01-01

    The quest of B-mode polarisation of the cosmic background is one of the scientific priorities of the observational cosmology today. Observing the B-mode would be the most direct way to constrain the period of inflation. The detection of such a weak signal is however a real experimental challenge. In addition to a high statistical sensitivity (huge number of horns and bolometers required), future experiments will need an excellent quality of foreground removal and an unprecedented control of systematics. An important experimental effort aiming at the detection of the B-mode is in progress. The QUBIC instrument is one of the many experiments dedicated to the search of B-mode, it is based on a novel technology: bolometric interferometry. In this thesis, we explain the design of this instrument and we describe the different components. We will focus on the optical beam combiner, we will present a method which allows to study the effects of optical aberrations and of misalignments of the components of the combiner on the global sensitivity of the instrument. We will develop a new specific procedure of calibration: the self-calibration, specific to bolometric interferometry, which is based on the redundancy of baselines. The self-calibration relies on comparing all the redundant baselines with each others and permits to calibrate parameters that characterize completely the instrument at the same time for each channel. Finally, we will present the latest results of the simulation for the map-making with the instrument QUBIC and the estimation of the power spectra from the resulting maps. (author)

  19. Evolution of microwave limb sounder ozone and the polar vortex during winter

    Science.gov (United States)

    Manney, G. L.; Froidevaux, L.; Waters, J. W.; Zurek, R. W.

    1995-01-01

    The evolution of polar ozone observed by the Upper Atmosphere Research Satellite (UARS) Microwave Limb Sounder (MLS) is described for the northern hemisphere (NH) winters of 1991/1992, 1992/1993, and 1993/1994 and the southern hemisphere (SH) winters of 1992 and 1993. Imterannual and interhemispheric variability in polar ozone evolution are closely related to differences in the polar vortex and to the frequency, duration and strength of stratospheric sudden warmings. Ozone in the midstratospheric vortices increases during the winter, with largest increases associated with stratospheric warmings and a much larger increase in the NH than in the SH. A smaller NH increase was observed in 1993/1994, when the middle stratospheric vortex was stronger. During strong stratospheric warmings in the NH, the upper stratospheric vortex may be so much eroded that it presents little barrier to poleward transport; in contrast, the SH vortex remains strong throughout the stratosphere during wintertime warmings, and ozone increases only below the mixing ratio peak, due to enhanced diabatic descent. Ozone mixing ratios decrease rapidly in the lower stratosphere in both SH late winters, as expected from chemical destruction due to enhanced reactive chlorine. The interplay between dynamics and chemistry is more complex in the NH lower stratosphere and interannual variability is greater. Evidence has previously been shown for chemical ozone destruction in the 1991/1992 and 1992/1993 winters. We show here evidence suggesting some chemical destruction in late February and early March 1994. In the NH late winter lower stratosphere the pattern of high-ozone values (typical of the vortex) seen in mid-latitudes is related to the strength of the lower-stratospheric vortex, with the largest areal extent of high ozone outside the vortex in 1994, when the lower stratospheric vortex is relatively weak, and the least extent in 1993 when the lower stratospheric vortex is strongest.

  20. ASSOCIATIONS BETWEEN SMALL-SCALE STRUCTURE IN LOCAL GALACTIC NEUTRAL HYDROGEN AND IN THE COSMIC MICROWAVE BACKGROUND OBSERVED BY PLANCK

    International Nuclear Information System (INIS)

    Verschuur, Gerrit L.

    2015-01-01

    High-resolution galactic neutral hydrogen (HI) data obtained with the Green Bank Telescope (GBT) over 56 square degrees of sky around l = 132°, b = 25° are compared with small-scale structure in the Cosmic Microwave Background observed by PLANCK, specifically at 143 and 857 GHz, as well as with 100 μm observations from the IRIS survey. The analysis uses data in 13 2° × 2° sub-areas found in the IRSA database at IPAC. The results confirm what has been reported previously; nearby galactic HI features and high-frequency continuum sources believed to be cosmological are in fact clearly associated. While several attempts strongly suggest that the associations are statistically significant, the key to understanding the phenomenon lies in the fact that in any given area HI is associated with cirrus dust at certain HI velocities and with 143 GHz features at different velocities. At the same time, for the 13 sub-areas studied, there is very little overlap between the dust and 143 GHz features. The data do not imply that the HI itself gives rise to the high-frequency continuum emission. Rather, they appear to indicate undiagnosed brightness enhancements indirectly associated with the HI. If low density interstellar electrons concentrated into clumps, or observed in directions where their integrated line-of-sight column densities are greater than the background in a manner similar to the phenomena that give rise to structure in diffuse HI structure, they will profoundly affect attempts to create a foreground electron mask used for processing PLANCK as well as WMAP data

  1. PROBING THE INFLATON: SMALL-SCALE POWER SPECTRUM CONSTRAINTS FROM MEASUREMENTS OF THE COSMIC MICROWAVE BACKGROUND ENERGY SPECTRUM

    International Nuclear Information System (INIS)

    Chluba, Jens; Erickcek, Adrienne L.; Ben-Dayan, Ido

    2012-01-01

    In the early universe, energy stored in small-scale density perturbations is quickly dissipated by Silk damping, a process that inevitably generates μ- and y-type spectral distortions of the cosmic microwave background (CMB). These spectral distortions depend on the shape and amplitude of the primordial power spectrum at wavenumbers k ∼ 4 Mpc –1 . Here, we study constraints on the primordial power spectrum derived from COBE/FIRAS and forecasted for PIXIE. We show that measurements of μ and y impose strong bounds on the integrated small-scale power, and we demonstrate how to compute these constraints using k-space window functions that account for the effects of thermalization and dissipation physics. We show that COBE/FIRAS places a robust upper limit on the amplitude of the small-scale power spectrum. This limit is about three orders of magnitude stronger than the one derived from primordial black holes in the same scale range. Furthermore, this limit could be improved by another three orders of magnitude with PIXIE, potentially opening up a new window to early universe physics. To illustrate the power of these constraints, we consider several generic models for the small-scale power spectrum predicted by different inflation scenarios, including running-mass inflation models and inflation scenarios with episodes of particle production. PIXIE could place very tight constraints on these scenarios, potentially even ruling out running-mass inflation models if no distortion is detected. We also show that inflation models with sub-Planckian field excursion that generate detectable tensor perturbations should simultaneously produce a large CMB spectral distortion, a link that could potentially be established with PIXIE.

  2. Widely tunable single-bandpass microwave photonic filter based on polarization processing of a nonsliced broadband optical source.

    Science.gov (United States)

    Wang, Hui; Zheng, Jian Yu; Li, Wei; Wang, Li Xian; Li, Ming; Xie, Liang; Zhu, Ning Hua

    2013-11-15

    We propose a new scheme of microwave photonic filter (MPF) based on the polarization processing of a broadband optical source (BOS), which features single-bandpass response and a wide span of operation bandwidth. The BOS is orthogonally polarized by a polarization division multiplexing emulator (PDME) with a tunable time delay between the two polarization states and incident at ± 45° to one principle axis of a polarization modulator (PolM). The PDME cascades a PolM, and a polarizer realizes a microwave modulation making the phase of the carrier able to be tuned while ± 1st sidebands remain unchanged, which after propagating in a dispersive medium results in a tunable single-bandpass response in the RF domain. We experimentally verify the MPF. By adjusting the time delay and the optical spectrum bandwidth, the passband center frequency is continuously tuned from DC to 20 GHz and the 3 dB passband bandwidth changes while the optical spectrum bandwidth ranges from 1 to 4 nm.

  3. [Review] Polarization and Polarimetry

    Science.gov (United States)

    Trippe, Sascha

    2014-02-01

    Polarization is a basic property of light and is fundamentally linked to the internal geometry of a source of radiation. Polarimetry complements photometric, spectroscopic, and imaging analyses of sources of radiation and has made possible multiple astrophysical discoveries. In this article I review (i) the physical basics of polarization: electromagnetic waves, photons, and parameterizations; (ii) astrophysical sources of polarization: scattering, synchrotron radiation, active media, and the Zeeman, Goldreich-Kylafis, and Hanle effects, as well as interactions between polarization and matter (like birefringence, Faraday rotation, or the Chandrasekhar-Fermi effect); (iii) observational methodology: on-sky geometry, influence of atmosphere and instrumental polarization, polarization statistics, and observational techniques for radio, optical, and X/γ wavelengths; and (iv) science cases for astronomical polarimetry: solar and stellar physics, planetary system bodies, interstellar matter, astrobiology, astronomical masers, pulsars, galactic magnetic fields, gamma-ray bursts, active galactic nuclei, and cosmic microwave background radiation.

  4. Demonstration of polarization sensitivity of emulsion-based pair conversion telescope for cosmic gamma-ray polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Ozaki, Keita, E-mail: ozaki@radix.h.kobe-u.ac.jp [Kobe University, 3-11, Tsurukabuto, Nada-ku, Kobe 657-8501 (Japan); Takahashi, Satoru, E-mail: satoru@radix.h.kobe-u.ac.jp [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Aoki, Shigeki; Kamada, Keiki; Kaneyama, Taichi; Nakagawa, Ryo; Rokujo, Hiroki [Kobe University, 3-11, Tsurukabuto, Nada-ku, Kobe 657-8501 (Japan)

    2016-10-11

    Linear polarization of high-energy gamma-rays (10MeV–100 GeV) can be detected by measuring the azimuthal angle of electron–positron pairs and observing the modulation of the azimuthal distribution. To demonstrate the gamma-ray polarization sensitivity of emulsion, we conducted a test using a polarized gamma-ray beam (0.8–2.4 GeV) at SPring-8/LEPS. Emulsion tracks were reconstructed using scanning data, and gamma-ray events were selected automatically. Using an optical microscope, out of the 2381 gamma-ray conversions that were observed, 1372 remained after event selection, on the azimuthal angle distribution of which we measured the modulation. From the distribution of the azimuthal angles of the selected events, a modulation factor of 0.21+0.11−0.09 was measured, from which the detection of a non-zero modulation was established with a significance of 3.06σ. This attractive polarimeter will be applied to the GRAINE project, a balloon-borne experiment that observes 10–100 GeV cosmic gamma-rays with an emulsion-based pair conversion telescope.

  5. The small satellite NINA-MITA to study galactic and solar cosmic rays in low-altitude polar orbit

    Science.gov (United States)

    Furano, G.; Bidoli, V.; Casolino, M.; de Pascale, M. P.; Iannucci, A.; Morselli, A.; Picozza, P.; Reali, E.; Sparvoli, R.; Bakaldin, A.; Galper, A.; Koldashov, M.; Korotkov, M.; Leonov, A.; Mikhailov, V.; Murashov, A.; Voronov, S.; Mazzenga, G.; Ricci, M.; Castellini, G.; Barbiellini, M.; Boezio, M.; Bonvicini, V.; Cirami, R.; Vacchi, A.; Zampa, N.; Ambriola, M.; Bellotti, R.; Cafagna, F.; Ciacio, F.; Circella, M.; de Marzo, C.; Adriani, O.; Papini, P.; Piccardi, S.; Spillantini, P.

    The satellite MITA, carrying on board the scientific payload NINA-2, was launched on July the 15th, 2000 from the cosmodrome of Plesetsk (Russia) with a Cosmos-3M rocket. The satellite and the payload are currently operating within nominal parameters. NINA-2 is the first scientific payload for the technological flight of the Italian small satellite MITA. The detector used in this mission is identical to the one already flying on the Russian satellite Resurs-O1 n.4 in a 840-km sun-synchronous orbit, but makes use of the extensive computer and telemetry capabilities of MITA bus to improve the active data acquisition time. NINA physics objectives are to study cosmic nuclei from hydrogen to iron in the energy range between 10 MeV/n and 1 GeV/n during the years 2000-2003, that is the solar maximum period. The device is capable of charge identification up to iron with isotope sensitivity up to oxigen. The 87.3 degrees, 460 km altitude polar orbit allows investigations of cosmic rays of solar and galactic origin, so to study long and short term solar transient phenomena, and the study of the trapped radiation at higher geomagnetic cutoff.

  6. What have we learnt from Wilkinson microwave anisotropy probe?

    Indian Academy of Sciences (India)

    data: the temperature-polarization correlation, correlations with large scale structure, the large-scale power deficit and its implications, and the search for non-Gaussianity. Keywords. Cosmology; cosmic microwave background. PACS Nos 95.85.Bh; 98.80.Es. 1. What makes the WMAP data so special? Just over a year ago, ...

  7. Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds

    Science.gov (United States)

    Schlegel, David J.; Finkbeiner, Douglas P.; Davis, Marc

    1998-06-01

    standard reddening law and use the colors of elliptical galaxies to measure the reddening per unit flux density of 100 μm emission. We find consistent calibration using the B-R color distribution of a sample of the 106 brightest cluster ellipticals, as well as a sample of 384 ellipticals with B-V and Mg line strength measurements. For the latter sample, we use the correlation of intrinsic B-V versus Mg2 index to tighten the power of the test greatly. We demonstrate that the new maps are twice as accurate as the older Burstein-Heiles reddening estimates in regions of low and moderate reddening. The maps are expected to be significantly more accurate in regions of high reddening. These dust maps will also be useful for estimating millimeter emission that contaminates cosmic microwave background radiation experiments and for estimating soft X-ray absorption. We describe how to access our maps readily for general use.

  8. Comparison of global observations and trends of total precipitable water derived from microwave radiometers and COSMIC radio occultation from 2006 to 2013

    Science.gov (United States)

    Ho, Shu-Peng; Peng, Liang; Mears, Carl; Anthes, Richard A.

    2018-01-01

    We compare atmospheric total precipitable water (TPW) derived from the SSM/I (Special Sensor Microwave Imager) and SSMIS (Special Sensor Microwave Imager/Sounder) radiometers and WindSat to collocated TPW estimates derived from COSMIC (Constellation System for Meteorology, Ionosphere, and Climate) radio occultation (RO) under clear and cloudy conditions over the oceans from June 2006 to December 2013. Results show that the mean microwave (MW) radiometer - COSMIC TPW differences range from 0.06 to 0.18 mm for clear skies, from 0.79 to 0.96 mm for cloudy skies, from 0.46 to 0.49 mm for cloudy but non-precipitating conditions, and from 1.64 to 1.88 mm for precipitating conditions. Because RO measurements are not significantly affected by clouds and precipitation, the biases mainly result from MW retrieval uncertainties under cloudy and precipitating conditions. All COSMIC and MW radiometers detect a positive TPW trend over these 8 years. The trend using all COSMIC observations collocated with MW pixels for this data set is 1.79 mm decade-1, with a 95 % confidence interval of (0.96, 2.63), which is in close agreement with the trend estimated by the collocated MW observations (1.78 mm decade-1 with a 95 % confidence interval of 0.94, 2.62). The sample of MW and RO pairs used in this study is highly biased toward middle latitudes (40-60° N and 40-65° S), and thus these trends are not representative of global average trends. However, they are representative of the latitudes of extratropical storm tracks and the trend values are approximately 4 to 6 times the global average trends, which are approximately 0.3 mm decade-1. In addition, the close agreement of these two trends from independent observations, which represent an increase in TPW in our data set of about 6.9 %, are a strong indication of the positive water vapor-temperature feedback on a warming planet in regions where precipitation from extratropical storms is already large.

  9. On the performance of telemedicine system using 17-GHz orthogonally polarized microwave links under the influence of heavy rainfall.

    Science.gov (United States)

    Fong, Bernard; Fong, A C M; Hong, G Y

    2005-09-01

    This paper describes the design of a telemedicine system based on next-generation wireless local area networks (WLANs) operating at 17 GHz. Seventeen gigahertz is proposed for next-generation WLAN services offering numerous advantages over traditional IEEE 802.11 networks that operate in the range of 2.4-5 GHz. Orthogonal polarization is often used to increase spectrum efficiency by utilizing signal paths of horizontal and vertical polarization. Radio waves exceeding 10 GHz are particularly vulnerable to signal degradation under the influence of rain which causes an effective reduction in isolation between polarized signal paths. This paper investigates the influence of heavy rain in a tropical region on wide-band microwave signals at 17 GHz using two links provided by a fixed broad-band wireless access system for two-way data exchange between paramedics attending an accident scene and the hospital via microwave equipment installed in the ambulance. We also study the effects of cross polarization and phase rotation due to persistent heavy rainfall in tropical regions.

  10. Testing Cosmic Inflation

    Science.gov (United States)

    Chuss, David

    2010-01-01

    The Cosmic Microwave Background (CMB) has provided a wealth of information about the history and physics of the early Universe. Much progress has been made on uncovering the emerging Standard Model of Cosmology by such experiments as COBE and WMAP, and ESA's Planck Surveyor will likely increase our knowledge even more. Despite the success of this model, mysteries remain. Currently understood physics does not offer a compelling explanation for the homogeneity, flatness, and the origin of structure in the Universe. Cosmic Inflation, a brief epoch of exponential expansion, has been posted to explain these observations. If inflation is a reality, it is expected to produce a background spectrum of gravitational waves that will leave a small polarized imprint on the CMB. Discovery of this signal would give the first direct evidence for inflation and provide a window into physics at scales beyond those accessible to terrestrial particle accelerators. I will briefly review aspects of the Standard Model of Cosmology and discuss our current efforts to design and deploy experiments to measure the polarization of the CMB with the precision required to test inflation.

  11. The Probe of Inflation and Cosmic Origins

    Science.gov (United States)

    Hanany, Shaul; Inflation Probe Mission Study Team

    2018-01-01

    The Probe of Inflation and Cosmic Origins will map the polarization of the cosmic microwave background over the entire sky with unprecedented sensitivity. It will search for gravity wave signals from the inflationary epoch, thus probing quantum gravity and constraining the energy scale of inflation; it will test the standard model of particle physics by measuring the number of light particles in the Universe and the mass of the neutrino; it will elucidate the nature of dark matter and search for new forms of matter in the early Universe; it will constrain star formation history over cosmic time; and it will determine the mechanisms of structure formation from galaxy cluster to stellar scales. I will review the status of design of this probe-scale mission.

  12. The Atacama Cosmology Telescope: A Measurement of the Cosmic Microwave Background Power Spectrum at 148 AND 218 GHz from the 2008 Southern Survey

    Science.gov (United States)

    Das, Sudeep; Marriage, Tobias A.; Ade, Peter A. R.; Aguirre, Paula; Amiri, Mandana; Appel, John W.; Barrientos, L. Felipe; Battistelli, Elia A.; Bond, J. Richard; Brown, Ben; hide

    2010-01-01

    We present measurements of the cosmic microwave background (CMB) power spectrum made by the Atacama Cosmology Telescope at 148 GHz and 218 GHz, as well as the cross-frequency spectrum between the two channels. Our results dearly show the second through the seventh acoustic peaks in the CMB power spectrum. The measurements of these higher-order peaks provide an additional test of the ACDM cosmological model. At l > 3000, we detect power in excess of the primary anisotropy spectrum of the CMB. At lower multipoles 500 < l < 3000, we find evidence for gravitational lensing of the CMB in the power spectrum at the 2.8(sigma) level. We also detect a low level of Galactic dust in our maps, which demonstrates that we can recover known faint, diffuse signals.

  13. Observational constraints on cosmic string production during brane inflation

    International Nuclear Information System (INIS)

    Pogosian, Levon; Tye, S.-H. Henry; Wasserman, Ira; Wyman, Mark

    2003-01-01

    Overall, brane inflation is compatible with the recent analysis of the Wilkinson microwave anisotropy probe (WMAP) data. Here we explore the constraints of WMAP and the 2dF Galaxy Redshift Survey (2dFGRS) data on the various brane inflationary scenarios. Brane inflation naturally ends with the production of cosmic strings, which may provide a way to distinguish these models observationally. We argue that currently available data cannot exclude a non-negligible contribution from cosmic strings definitively. We perform a partial statistical analysis of mixed models that include a subdominant contribution from cosmic strings. Although the data favor models without cosmic strings, we conclude that they cannot definitively rule out a cosmic-string-induced contribution of ∼10% to the observed temperature, polarization and galaxy density fluctuations. These results imply that Gμ(less-or-similar sign)1.3x10 -6 √(Bλ/0.1), where λ≤1 is a measure of the intercommutation probability of the cosmic string networks and B measures the importance of perturbations induced by cosmic strings. We argue that, conservatively, the data available currently still permit B(less-or-similar sign)0.1. Precision measurements sensitive to the B-mode polarization produced by vector density perturbation modes driven by the string network could provide evidence for these models. Accurate determinations of n s (k), the scalar fluctuation index, could also distinguish among various brane inflation models

  14. Recent results and perspectives on cosmology and fundamental physics from microwave surveys

    DEFF Research Database (Denmark)

    Burigana, Carlo; Battistelli, Elia Stefano; Benetti, Micol

    2016-01-01

    Recent cosmic microwave background (CMB) data in temperature and polarization have reached high precision in estimating all the parameters that describe the current so-called standard cosmological model. Recent results about the integrated Sachs-Wolfe (ISW) effect from CMB anisotropies, galaxy su...

  15. Planck intermediate results XXXVIII. E- and B-modes of dust polarization from the magnetized filamentary structure of the interstellar medium

    DEFF Research Database (Denmark)

    Ade, P. A. R.; Aghanim, N.; Arnaud, M.

    2016-01-01

    The quest for a B-mode imprint from primordial gravity waves on the polarization of the cosmic microwave background (CMB) requires the characterization of foreground polarization from Galactic dust. We present a statistical study of the filamentary structure of the 353 GHz Planck Stokes maps at h...

  16. Accuracy and precision of polar lower stratospheric temperatures from reanalyses evaluated from A-Train CALIOP and MLS, COSMIC GPS RO, and the equilibrium thermodynamics of supercooled ternary solutions and ice clouds

    Science.gov (United States)

    Lambert, Alyn; Santee, Michelle L.

    2018-02-01

    We investigate the accuracy and precision of polar lower stratospheric temperatures (100-10 hPa during 2008-2013) reported in several contemporary reanalysis datasets comprising two versions of the Modern-Era Retrospective analysis for Research and Applications (MERRA and MERRA-2), the Japanese 55-year Reanalysis (JRA-55), the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-I), and the National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (NCEP-CFSR). We also include the Goddard Earth Observing System model version 5.9.1 near-real-time analysis (GEOS-5.9.1). Comparisons of these datasets are made with respect to retrieved temperatures from the Aura Microwave Limb Sounder (MLS), Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) Global Positioning System (GPS) radio occultation (RO) temperatures, and independent absolute temperature references defined by the equilibrium thermodynamics of supercooled ternary solutions (STSs) and ice clouds. Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations of polar stratospheric clouds are used to determine the cloud particle types within the Aura MLS geometric field of view. The thermodynamic calculations for STS and the ice frost point use the colocated MLS gas-phase measurements of HNO3 and H2O. The estimated bias and precision for the STS temperature reference, over the 68 to 21 hPa pressure range, are 0.6-1.5 and 0.3-0.6 K, respectively; for the ice temperature reference, they are 0.4 and 0.3 K, respectively. These uncertainties are smaller than those estimated for the retrieved MLS temperatures and also comparable to GPS RO uncertainties (bias 0.7 K) in the same pressure range. We examine a case study of the time-varying temperature structure associated with layered ice clouds formed by orographic gravity waves forced by flow over the Palmer Peninsula and

  17. Optical and microwave control of resonance fluorescence and squeezing spectra in a polar molecule

    Science.gov (United States)

    Antón, M. A.; Maede-Razavi, S.; Carreño, F.; Thanopulos, I.; Paspalakis, E.

    2017-12-01

    A two-level quantum emitter with broken inversion symmetry simultaneously driven by an optical field and a microwave field that couples to the permanent dipole's moment is presented. We focus to a situation where the angular frequency of the microwave field is chosen such that it closely matches the Rabi frequency of the optical field, the so-called Rabi resonance condition. Using a series of unitary transformations we obtain an effective Hamiltonian in the double-dressed basis which results in easily solvable Bloch equations which allow us to derive analytical expressions for the spectrum of the scattered photons. We analyze the steady-state population inversion of the system which shows a distinctive behavior at the Rabi resonance with regard to an ordinary two-level nonpolar system. We show that saturation can be produced even in the case that the optical field is far detuned from the transition frequency, and we demonstrate that this behavior can be controlled through the intensity and the angular frequency of the microwave field. The spectral properties of the scattered photons are analyzed and manifest the emergence of a series of Mollow-like triplets which may be spectrally broadened or narrowed for proper values of the amplitude and/or frequency of the low-frequency field. We also analyze the phase-dependent spectrum which reveals that a significant enhancement or suppression of the squeezing at certain sidebands can be produced. These quantum phenomena are illustrated in a recently synthesized molecular complex with high nonlinear optical response although they can also occur in other quantum systems with broken inversion symmetry.

  18. Cosmic Microwave Background as a Thermal Gas of SU(2 Photons: Implications for the High-z Cosmological Model and the Value of H0

    Directory of Open Access Journals (Sweden)

    Steffen Hahn

    2017-01-01

    Full Text Available Presently, we are facing a 3σ tension in the most basic cosmological parameter, the Hubble constant H0. This tension arises when fitting the Lambda-cold-dark-matter model (ΛCDM to the high-precision temperature-temperature (TT power spectrum of the Cosmic Microwave Background (CMB and to local cosmological observations. We propose a resolution of this problem by postulating that the thermal photon gas of the CMB obeys an SU(2 rather than U(1 gauge principle, suggesting a high-z cosmological model which is void of dark-matter. Observationally, we rely on precise low-frequency intensity measurements in the CMB spectrum and on a recent model independent (low-z extraction of the relation between the comoving sound horizon rs at the end of the baryon drag epoch and H0 (rsH0=const. We point out that the commonly employed condition for baryon-velocity freeze-out is imprecise, judged by a careful inspection of the formal solution to the associated Euler equation. As a consequence, the above-mentioned 3σ tension actually transforms into a 5σ discrepancy. To make contact with successful low-z  ΛCDM cosmology we propose an interpolation based on percolated/depercolated vortices of a Planck-scale axion condensate. For a first consistency test of such an all-z model we compute the angular scale of the sound horizon at photon decoupling.

  19. A DIRECT MEASUREMENT OF THE LINEAR BIAS OF MID-INFRARED-SELECTED QUASARS AT z ≈ 1 USING COSMIC MICROWAVE BACKGROUND LENSING

    Energy Technology Data Exchange (ETDEWEB)

    Geach, J. E. [Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield, AL10 9AB (United Kingdom); Hickox, R. C.; Hainline, K. N. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); Bleem, L. E.; Benson, B. A.; Bhattacharya, S.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Brodwin, M. [Department of Physics and Astronomy, University of Missouri, Kansas City, MO 64110 (United States); Holder, G. P.; De Haan, T.; Dobbs, M. A.; Dudley, J. [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); Aird, K. A. [University of Chicago, Chicago, IL 60637 (United States); Cho, H.-M. [NIST Quantum Devices Group, Boulder, CO 80305 (United States); George, E. M.; Holzapfel, W. L. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Halverson, N. W., E-mail: j.geach@herts.ac.uk [Department of Astrophysical and Planetary Sciences and Department of Physics, University of Colorado, Boulder, CO 80309 (United States); and others

    2013-10-20

    We measure the cross-power spectrum of the projected mass density as traced by the convergence of the cosmic microwave background lensing field from the South Pole Telescope (SPT) and a sample of Type 1 and 2 (unobscured and obscured) quasars at (z) ∼ 1 selected with the Wide-field Infrared Survey Explorer, over 2500 deg{sup 2}. The cross-power spectrum is detected at ≈7σ, and we measure a linear bias b = 1.61 ± 0.22, consistent with clustering analyses. Using an independent lensing map, derived from Planck observations, to measure the cross-spectrum, we find excellent agreement with the SPT analysis. The bias of the combined sample of Type 1 and 2 quasars determined in this work is similar to that previously determined for Type 1 quasars alone; we conclude that obscured and unobscured quasars trace the matter field in a similar way. This result has implications for our understanding of quasar unification and evolution schemes.

  20. The Role of Quasi-Transverse Propagation in Observed Polarization of Flare Loop Microwave Radiation

    Science.gov (United States)

    Shain, A. V.; Melnikov, V. F.; Morgachev, A. S.

    2017-12-01

    The ordinary mode of gyrosynchrotron radiation was identified to be predominant in some segments of flare loops in solar flares of July 19, 2012, and October 22, 2014. These events were studied by investigation of the quasi-transverse propagation effect on the observed polarization. The analysis involved reconstruction of the magnetic field topology at the linear force-free approximation based on the data of the SDO HMI space telescope and the subsequent simulation of radio emission of flare loops with the GX Simulator software package. The quasi-transverse propagation effect was established to be characteristic for both events, but its influence on the radio emission polarization at a frequency of 17 GHz was observed only in the October 22, 2014 flare.

  1. Three-dimensional inhomogeneous rain fields: implications for the distribution of intensity and polarization of the microwave thermal radiation.

    Science.gov (United States)

    Ilyushin, Yaroslaw; Kutuza, Boris

    Observations and mapping of the upwelling thermal radiation of the Earth is the very promising remote sensing technique for the global monitoring of the weather and precipitations. For reliable interpretation of the observation data, numerical model of the microwave radiative transfer in the precipitating atmosphere is necessary. In the present work, numerical simulations of thermal microwave radiation in the rain have been performed at three wavelengths (3, 8 and 22 mm). Radiative properties of the rain have been simulated using public accessible T-matrix codes (Mishchenko, Moroz) for non-spherical particles of fixed orientation and realistic raindrop size distributions (Marshall-Palmer) within the range of rain intensity 1-100 mm/h. Thermal radiation of infinite flat slab medium and isolated rain cell of kilometer size has been simulated with finite difference scheme for the vectorial radiative transfer equation (VRTE) in dichroic scattering medium. Principal role of cell structure of the rain field in the formation of angular and spatial distribution of the intensity and polarization of the upwelling thermal radiation has been established. Possible approaches to interpretation of satellite data are also discussed. It is necessary that spatial resolution of microwave radiometers be less than rain cell size. At the present time the resolution is approximately 15 km. It can be considerably improved, for example by two-dimensional synthetic aperture millimeter-wave radiometric interferometer for measuring full-component Stokes vector of emission from hydrometeors. The estimates show that in millimeter band it is possible to develop such equipment with spatial resolution of the order of 1-2 km, which is significantly less than the size of rain cell, with sensitivity 0.3-0.5 K. Under this condition the second Stokes parameter may by successfully measured and may be used for investigation of precipitation regions. Y-shaped phased array antenna is the most promising to

  2. Microwave Radiometers from 0.6 to 22 GHz for Juno, A Polar Orbiter Around Jupiter

    Science.gov (United States)

    Pingree, P.; Janssen, M.; Oswald, J.; Brown, S.; Chen, J.; Hurst, K.; Kitiyakara, A.; Maiwald, F.; Smith, S.

    2008-01-01

    A compact instrument called the MWR (MicroWave Radiometer) is under development at JPL for Juno, the next NASA New Frontiers mission, scheduled to launch in 2011. It's purpose is to measure the thermal emission from Jupiter's atmosphere at six selected frequencies from 0.6 to 22 GHz, operating in direct detection mode, in order to quantify the distributions and abundances of water and ammonia in Jupiter's atmosphere. The goal is to understand the previously unobserved dynamics of the sub-cloud atmosphere, and to discriminate among models for planetary formation in our solar system. As part of a deep space mission aboard a solar-powered spacecraft, MWR is designed to be compact, lightweight, and low power. The receivers and control electronics are protected by a radiation-shielding enclosure on the Juno spacecraft that would provide a benign and stable operating temperature environment. All antennas and RF transmission lines outside the vault must withstand low temperatures and the harsh radiation environment surrounding Jupiter. This paper describes the concept of the MWR instrument and presents results of one breadboard receiver channel.

  3. Cumulative-Phase-Alteration of Galactic-Light Passing Through the Cosmic-Microwave-Background: A New Mechanism for Some Observed Spectral-Shifts

    Directory of Open Access Journals (Sweden)

    Tank H. K.

    2012-07-01

    Full Text Available Currently, whole of the measured “cosmological-red-shift ” is interpreted as due to the “metric-expansion-of-space”; so for the required “closer -density” of the universe, we need twenty times more mass-energy than the visible baryonic-matter contained in the universe. This paper proposes a new mechanism, which can account for good per- centage of the red-shift in the extra-galactic-light, greatly reducing the requirement of dark matter-energy. Also, this mechanism can cause a new kin d of blue-shift reported here, and their observational evidences. These spectral-s hifts are proposed to result due to cumulative phase-alteration of extra-galactic-light b ecause of vector-addition of: (i electric-field of extra-galactic-light and (ii that of the cosmic-microwave-background (CMB. Since the center-frequency of CMB is much lower than extra-galactic-light, the cumulative-phase-alteration results in red -shift, observed as an additional contribu- tor to the measured “cosmological red-shift”; and since the center-frequency of CMB is higher than the radio-frequency-signals used to measure velocity of space-probes like: Pioneer-10, Pioneer-11, Galileo and Ulysses, the cum ulative-phase-alteration re- sulted in blue-shift, leading to the interpretation of deceleration of these space-probes. While the galactic-light experiences the red-shift, and th e ranging-signals of the space- probes experience blue -shift, they are comparable in magnitude, providing a supportive- evidence for the new mechanism proposed here. More confirmative-experiments for this new mechanism are also proposed.

  4. FROM WMAP TO PLANCK: EXACT RECONSTRUCTION OF FOUR- AND FIVE-DIMENSIONAL INFLATIONARY POTENTIAL FROM HIGH-PRECISION COSMIC MICROWAVE BACKGROUND MEASUREMENTS

    International Nuclear Information System (INIS)

    Popa, L. A.; Caramete, A.; Mandolesi, N.; Burigana, C.

    2009-01-01

    We make a more general determination of the inflationary observables in the standard four-dimensional (4D) and five-dimensional (5D) single-field inflationary scenarios by the exact reconstruction of the dynamics of the inflation potential during the observable inflation with a minimal number of assumptions: the computation does not assume the slow-roll approximation and is valid in all regimes if the field is monotonically rolling down its potential. We address higher order effects in the standard and braneworld single-field inflation scenarios by fitting the Hubbble expansion rate and subsequently the inflationary potential directly to WMAP5+SN+BAO and Planck-like simulated data sets. Making use of the Hamilton-Jacobi formalism developed for the 5D single-field inflation model, we compute the scale dependence of the amplitudes of the scalar and tensor perturbations by integrating the exact mode equation. The solutions in 4D and 5D inflation scenarios differ through the dynamics of the background scalar field and the number of e-folds assumed to be compatible with the observational window of inflation. We analyze the implications of the theoretical uncertainty in the determination of the reheating temperature after inflation on the observable predictions of inflation and evaluate its impact on the degeneracy of the standard inflation consistency relation. We find that the detection of tensor perturbations and the theoretical uncertainties in the inflationary observable represents a significant challenge for the future Planck cosmic microwave background measurements: distinguishing between the observational signatures of the standard and braneworld single-field inflation scenarios. This work has been done in the frame of Planck Core Team activities.

  5. The Atacama Cosmology Telescope: A Measurement of the 600 less than l less than 8000 Cosmic Microwave Background Power Spectrum at 148 GHz

    Science.gov (United States)

    Fowler, J. W.; Acquaviva, V.; Ade, P. A. R.; Aguirre, P.; Amiri, M.; Appel, J. W.; Barrientos, L. F.; Bassistelli, E. S.; Bond, J. R.; Brown, B.; hide

    2010-01-01

    We present a measurement of the angular power spectrum of the cosmic microwave background (CMB) radiation observed at 148 GHz. The measurement uses maps with 1.4' angular resolution made with data from the Atacama Cosmology Telescope (ACT). The observations cover 228 deg(sup 2) of the southern sky, in a 4 deg. 2-wide strip centered on declination 53 deg. South. The CMB at arc minute angular scales is particularly sensitive to the Silk damping scale, to the Sunyaev-Zel'dovich (SZ) effect from galaxy dusters, and to emission by radio sources and dusty galaxies. After masking the 108 brightest point sources in our maps, we estimate the power spectrum between 600 less than l less than 8000 using the adaptive multi-taper method to minimize spectral leakage and maximize use of the full data set. Our absolute calibration is based on observations of Uranus. To verify the calibration and test the fidelity of our map at large angular scales, we cross-correlate the ACT map to the WMAP map and recover the WMAP power spectrum from 250 less than l less than 1150. The power beyond the Silk damping tail of the CMB (l approximately 5000) is consistent with models of the emission from point sources. We quantify the contribution of SZ clusters to the power spectrum by fitting to a model normalized to sigma 8 = 0.8. We constrain the model's amplitude A(sub sz) less than 1.63 (95% CL). If interpreted as a measurement of as, this implies sigma (sup SZ) (sub 8) less than 0.86 (95% CL) given our SZ model. A fit of ACT and WMAP five-year data jointly to a 6-parameter ACDM model plus point sources and the SZ effect is consistent with these results.

  6. Infrared and millimeter wave techniques for the Cosmic Background Explorer Satellite

    Science.gov (United States)

    Mather, J. C.

    1977-01-01

    The Cosmic Background Explorer Satellite will employ infrared and microwave techniques to gain information about the very early universe. Three instruments will cover the spectral range from 8 microns to 13 mm, determining both the spectrum and angular distribution of the large scale background radiation fields. A cryogenic polarizing Michelson interferometric spectrometer will measure the spectrum of the 3 deg K relic radiation from the big bang with precision. Four differential microwave radiometers will map the sky from 23 to 90 GHz in a search for anisotropy of the universe. A broadband cryogenic IR photometer will map zodiacal dust emission, galactic dust, and an extragalactic residual component.

  7. COBE Differential Microwave Radiometers - Instrument design and implementation

    Science.gov (United States)

    Smoot, G.; Bennett, C.; Weber, R.; Maruschak, J.; Ratliff, R.; Janssen, M.; Chitwood, J.; Hilliard, L.; Lecha, M.; Mills, R.; Patschke, R.; Richards, C.; Backus, C.; Mather, J.; Hauser, M.; Weiss, R.; Wilkinson, D.; Gulkis, S.; Boggess, N.; Cheng, E.; Kelsall, T.; Lubin, P.; Meyer, S.; Moseley, H.; Murdock, T.; Shafer, R.; Silverberg, R.; Wright, E.

    1990-09-01

    Differential Microwave Radiometers (DMRs) at frequencies of 31.5, 53, and 90 GHz have been designed and built to map the large angular scale variations in the brightness temperature of the cosmic microwave background radiation. The instrument is being flown aboard NASA's Cosmic Background Explorer (COBE) satellite, launched on November 18, 1989. Each receiver input is switched between two antennas pointing 60 deg apart on the sky. The satellite is in near-polar orbit with the orbital plane precessing at 1 deg per day, causing the beams to scan the entire sky in 6 months. In 1 year of observation, the instruments are capable of mapping the sky to an rms sensitivity of 0.1 mK per 7 deg field of view. The mission and the instrument have been carefully designed to minimize the need for systematic corrections to the data.

  8. A quasi-optical and corrugated waveguide microwave transmission system for simultaneous dynamic nuclear polarization NMR on two separate 14.1 T spectrometers

    Science.gov (United States)

    Dubroca, Thierry; Smith, Adam N.; Pike, Kevin J.; Froud, Stuart; Wylde, Richard; Trociewitz, Bianca; McKay, Johannes; Mentink-Vigier, Frederic; van Tol, Johan; Wi, Sungsool; Brey, William; Long, Joanna R.; Frydman, Lucio; Hill, Stephen

    2018-04-01

    Nuclear magnetic resonance (NMR) is an intrinsically insensitive technique, with Boltzmann distributions of nuclear spin states on the order of parts per million in conventional magnetic fields. To overcome this limitation, dynamic nuclear polarization (DNP) can be used to gain up to three orders of magnitude in signal enhancement, which can decrease experimental time by up to six orders of magnitude. In DNP experiments, nuclear spin polarization is enhanced by transferring the relatively larger electron polarization to NMR active nuclei via microwave irradiation. Here, we describe the design and performance of a quasi-optical system enabling the use of a single 395 GHz gyrotron microwave source to simultaneously perform DNP experiments on two different 14.1 T (1H 600 MHz) NMR spectrometers: one configured for magic angle spinning (MAS) solid state NMR; the other configured for solution state NMR experiments. In particular, we describe how the high power microwave beam is split, transmitted, and manipulated between the two spectrometers. A 13C enhancement of 128 is achieved via the cross effect for alanine, using the nitroxide biradical AMUPol, under MAS-DNP conditions at 110 K, while a 31P enhancement of 160 is achieved via the Overhauser effect for triphenylphosphine using the monoradical BDPA under solution NMR conditions at room temperature. The latter result is the first demonstration of Overhauser DNP in the solution state at a field of 14.1 T (1H 600 MHz). Moreover these results have been produced with large sample volumes (∼100 μL, i.e. 3 mm diameter NMR tubes).

  9. VESPA-22: a ground-based microwave spectrometer for long-term measurements of polar stratospheric water vapor

    Science.gov (United States)

    Mevi, Gabriele; Muscari, Giovanni; Bertagnolio, Pietro Paolo; Fiorucci, Irene; Pace, Giandomenico

    2018-02-01

    The new ground-based 22 GHz spectrometer, VESPA-22 (water Vapor Emission Spectrometer for Polar Atmosphere at 22 GHz) measures the 22.23 GHz water vapor emission line with a bandwidth of 500 MHz and a frequency resolution of 31 kHz. The integration time for a measurement ranges from 6 to 24 h, depending on season and weather conditions. Water vapor spectra are collected using the beam-switching technique. VESPA-22 is designed to operate automatically with little maintenance; it employs an uncooled front-end characterized by a receiver temperature of about 180 K and its quasi-optical system presents a full width at half maximum of 3.5°. Every 30 min VESPA-22 measures also the sky opacity using the tipping curve technique. The instrument calibration is performed automatically by a noise diode; the emission temperature of this element is estimated twice an hour by observing alternatively a black body at ambient temperature and the sky at an elevation of 60°. The retrieved profiles obtained inverting 24 h integration spectra present a sensitivity larger than 0.8 from about 25 to 75 km of altitude during winter and from about 30 to 65 km during summer, a vertical resolution from about 12 to 23 km (depending on altitude), and an overall 1σ uncertainty lower than 7 % up to 60 km altitude and rapidly increasing to 20 % at 75 km. In July 2016, VESPA-22 was installed at the Thule High Arctic Atmospheric Observatory located at Thule Air Base (76.5° N, 68.8° W), Greenland, and it has been operating almost continuously since then. The VESPA-22 water vapor mixing ratio vertical profiles discussed in this work are obtained from 24 h averaged spectra and are compared with version 4.2 of concurrent Aura/Microwave Limb Sounder (MLS) water vapor vertical profiles. In the sensitivity range of VESPA-22 retrievals, the intercomparison from July 2016 to July 2017 between VESPA-22 dataset and Aura/MLS dataset convolved with VESPA-22 averaging kernels shows an average difference

  10. The Cosmic Background Explorer

    Science.gov (United States)

    Gulkis, Samuel; Lubin, Philip M.; Meyer, Stephan S.; Silverberg, Robert F.

    1990-01-01

    The Cosmic Background Explorer (CBE), NASA's cosmological satellite which will observe a radiative relic of the big bang, is discussed. The major questions connected to the big bang theory which may be clarified using the CBE are reviewed. The satellite instruments and experiments are described, including the Differential Microwave Radiometer, which measures the difference between microwave radiation emitted from two points on the sky, the Far-Infrared Absolute Spectrophotometer, which compares the spectrum of radiation from the sky at wavelengths from 100 microns to one cm with that from an internal blackbody, and the Diffuse Infrared Background Experiment, which searches for the radiation from the earliest generation of stars.

  11. The Early Universe: Searching for Evidence of Cosmic Inflation

    Science.gov (United States)

    Chuss, David T.

    2012-01-01

    In the past two decades, our understanding of the evolution and fate of the universe has increased dramatically. This "Age of Precision Cosmology" has been ushered in by measurements that have both elucidated the details of the Big Bang cosmology and set the direction for future lines of inquiry. Our universe appears to consist of 5% baryonic matter; 23% of the universe's energy content is dark matter which is responsible for the observed structure in the universe; and 72% of the energy density is so-called "dark energy" that is currently accelerating the expansion of the universe. In addition, our universe has been measured to be geometrically flat to 1 %. These observations and related details of the Big Bang paradigm have hinted that the universe underwent an epoch of accelerated expansion known as "inflation" early in its history. In this talk, I will review the highlights of modern cosmology, focusing on the contributions made by measurements of the cosmic microwave background, the faint afterglow of the Big Bang. I will also describe new instruments designed to measure the polarization of the cosmic microwave background in order to search for evidence of cosmic inflation.

  12. The Python Sky Model: software for simulating the Galactic microwave sky

    Science.gov (United States)

    Thorne, B.; Dunkley, J.; Alonso, D.; Næss, S.

    2017-08-01

    We present a numerical code to simulate maps of Galactic emission in intensity and polarization at microwave frequencies, aiding in the design of cosmic microwave background experiments. This python code builds on existing efforts to simulate the sky by providing an easy-to-use interface and is based on publicly available data from the WMAP (Wilkinson Microwave Anisotropy Probe) and Planck satellite missions. We simulate synchrotron, thermal dust, free-free and anomalous microwave emission over the whole sky, in addition to the cosmic microwave background, and include a set of alternative prescriptions for the frequency dependence of each component, for example, polarized dust with multiple temperatures and a decorrelation of the signals with frequency, which introduce complexity that is consistent with current data. We also present a new prescription for adding small-scale realizations of these components at resolutions greater than current all-sky measurements. The usefulness of the code is demonstrated by forecasting the impact of varying foreground complexity on the recovered tensor-to-scalar ratio for the LiteBIRD satellite. The code is available at: https://github.com/bthorne93/PySM_public.

  13. Spherical Orbifolds for Cosmic Topology

    International Nuclear Information System (INIS)

    Kramer, Peter

    2012-01-01

    Harmonic analysis is a tool to infer cosmic topology from the measured astrophysical cosmic microwave background CMB radiation. For overall positive curvature, Platonic spherical manifolds are candidates for this analysis. We combine the specific point symmetry of the Platonic manifolds with their deck transformations. This analysis in topology leads from manifolds to orbifolds. We discuss the deck transformations of the orbifolds and give eigenmodes for the harmonic analysis as linear combinations of Wigner polynomials on the 3-sphere. These provide new tools for detecting cosmic topology from the CMB radiation.

  14. Cosmic rays and climate

    CERN Multimedia

    2009-01-01

    Inside the new chamber the CLOUD team will be able to recreate the conditions of any part of the atmosphere, from the polar stratosphere to the low level tropics (top). The new chamber safely in position in the East hall. Once carefully cleaned the chamber will be turned sideways onto its legs ready for the beam of 'cosmic rays' (bottom).

  15. Existence of dark matter with observed properties of cosmic microwave background radiation substantiates three conservation laws of classical physics and all principles of quantum mechanics as creates the value of Planck’s constant

    Science.gov (United States)

    Boriev, I. A.

    2018-03-01

    Astronomical data indicate a presence of dark matter (DM) in the space, what is necessary for explanation of observed dynamics of the galaxies within Newtonian mechanics. DM, at its very low density (∼10-26kg/m3), constitutes main part of the matter in the Universe, 10 times the mass of all visible cosmic bodies. No doubt, namely properties of DM, which fills space, must determine its physical properties and fundamental physical laws. Taking into account observed properties of cosmic microwave background radiation (CMBR), whose energy is ∼90% of all cosmic radiation, and understanding that this radiation is produced by DM motion, conservation laws of classical physics and principles of quantum mechanics receive their materialistic substantiation. Thus, CMBR high homogeneity and isotropy (∼10-4), and hence the same properties of DM (and space) justify momentum and angular momentum conservation laws, respectively, according to E. Noether's theorems. CMBR has black body spectrum at ∼2.7K with maximum wavelength ∼1.9·10-3m, what allows calculate the value of mechanical action produced by DM thermal motion (∼7·10-34 J·s). This value corresponds well to the Planck’s constant, which is the mechanical action too, what gives materialistic basis for all principles of quantum mechanics. Obtained results directly confirm the reality of DM existence, and show that CMBR is an observed display of DM thermal motion. Understanding that namely from DM occur known creation of electron-positron pairs as contrarily rotating material vortexes (according to their spins) let substantiate positron nature of ball lightning what first explains all its observed specific properties.

  16. Particle physics implications of Wilkinson microwave anisotropy ...

    Indian Academy of Sciences (India)

    ... Journals; Pramana – Journal of Physics; Volume 63; Issue 6. Particle physics implications of Wilkinson microwave anisotropy project measurements. U A Yajnik. Volume 63 Issue 6 December 2004 pp 1317-1330 ... Keywords. Cosmic microwave background radiation; inflation; Wilkinson microwave anisotropy project.

  17. Gold Nanoparticle Microwave Synthesis

    International Nuclear Information System (INIS)

    Krantz, Kelsie E.; Christian, Jonathan H.; Coopersmith, Kaitlin; Washington II, Aaron L.; Murph, Simona H.

    2016-01-01

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  18. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  19. PIPER: Primordial Inflation Polarization Explorer

    Science.gov (United States)

    Lazear, Justin; Benford, D.; Chuss, D.; Fixsen, D.; Hinderks, J.; Hinshaw, G.; Jhabvala, C.; Johnson, B.; Kogut, A.; Mirel, P.; Mosely, H.; Staguhn, J.; Wollack, E.; Weston, A.; Vlahacos, K.; Bennett, C.; Eimer, J.; Halpern, M.; Irwin, K.; Dotson, J.; Ade, P.; Tucker, C.

    2011-05-01

    The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne instrument to measure the polarization of the cosmic microwave background in search of the expected signature of primordial gravity waves excited during an inflationary epoch shortly after the Big Bang. PIPER consists of two co-aligned telescopes, one sensitive to the Q Stokes parameter and the other to U. Sky signals will be detected with 5120 transition edge sensor (TES) bolometers distributed in four rectangular close-packed arrays maintained at 100 mK. To maximize the sensitivity of the instrument, both telescopes are mounted within a single open bucket dewar and are maintained at 1.5 K throughout flight, with no ambient-temperature windows between the sky and the detectors. To mitigate the effects of systematic errors, the polarized sky signals will be modulated using a variable-delay polarization modulator. PIPER will observe at frequencies 200, 270, 350, and 600 GHz to separate the CMB from polarized dust emission within the Galaxy. A series of flights alternating between northern and southern hemisphere launch sites will produce nearly full-sky maps in Stokes I, Q, U, and V. I will discuss the current status and potential science returns from the PIPER project.

  20. Cosmic strings and cosmic structure

    International Nuclear Information System (INIS)

    Albrecht, A.; Brandenberger, R.; Turok, N.

    1987-01-01

    The paper concerns the application of the theory of cosmic strings to explain the structure of the Universe. The formation of cosmic strings in the early Universe is outlined, along with the Big Bang theory, Grand Unified theories, and the first three minutes after the Big Bang. A description is given of the shaping of the Universe by cosmic strings, including the evolution of the string. The possibility for direct observation of cosmic strings is discussed. (U.K.)

  1. Cosmic rays in space

    International Nuclear Information System (INIS)

    Fujitaka, Kazunobu

    2005-01-01

    Cosmos is a mysterious space by which many researchers are fascinated for many years. But, going into space means that we will receive extra exposure due to existence of cosmic rays. Cosmic rays are mainly composed of highly energetic protons. It was born in the last stage of stellar life. Understanding of cosmos will certainly bring right understanding of radiation energy, or energy itself. As no one could see the very early stage of cosmic rays, there is only a speculation. But it is better to speculate something based on certain side evidences, than to give up the whole. Such attitude shall be welcomed in the space researches. Anyway, cosmic rays were born in the last explosion of a star, which is called as Super Nova. After cosmic rays are emitted from the Super Nova, it will reach to the human surroundings. To indicate its intensity, special unit of ''dose rate'' is used. When a man climbs a mountain, cosmic ray intensity surely increases. It doubles as he goes up every 1500m elevation. It was ascertained by our own measurements. Then what happens when the goes up more? At aviation altitude, where airplanes fly, the dose rate will be increased up to 100times the high mountain cases. And what is expected when he goes up further more, up to space orbit altitude? In this case, the dose rate increases up to 10times the airplane cases. Geomagnetism affects the dose rate very much. As primary cosmic ray particles are charged particles, they cannot do well with existence of the magnetic field. In effect, cosmic rays can penetrate into the polar atmosphere along geomagnetic lines of forces which stand almost vertical, but penetration of low energy cosmic rays will be banned when they intend to penetrate crossing the geomagnetic lines of forces in equatorial region. Therefore, exposure due to cosmic rays will become large in polar region, while it remains small in equatorial region. In effect, airplanes which fly over the equator. Only, we have to know that the cosmos

  2. The Thirty Gigahertz Instrument Receiver for the QUIJOTE Experiment: Preliminary Polarization Measurements and Systematic-Error Analysis.

    Science.gov (United States)

    Casas, Francisco J; Ortiz, David; Villa, Enrique; Cano, Juan L; Cagigas, Jaime; Pérez, Ana R; Aja, Beatriz; Terán, J Vicente; de la Fuente, Luisa; Artal, Eduardo; Hoyland, Roger; Génova-Santos, Ricardo

    2015-08-05

    This paper presents preliminary polarization measurements and systematic-error characterization of the Thirty Gigahertz Instrument receiver developed for the QUIJOTE experiment. The instrument has been designed to measure the polarization of Cosmic Microwave Background radiation from the sky, obtaining the Q, U, and I Stokes parameters of the incoming signal simultaneously. Two kinds of linearly polarized input signals have been used as excitations in the polarimeter measurement tests in the laboratory; these show consistent results in terms of the Stokes parameters obtained. A measurement-based systematic-error characterization technique has been used in order to determine the possible sources of instrumental errors and to assist in the polarimeter calibration process.

  3. Microwave hydrology: A trilogy

    Science.gov (United States)

    Stacey, J. M.; Johnston, E. J.; Girard, M. A.; Regusters, H. A.

    1985-01-01

    Microwave hydrology, as the term in construed in this trilogy, deals with the investigation of important hydrological features on the Earth's surface as they are remotely, and passively, sensed by orbiting microwave receivers. Microwave wavelengths penetrate clouds, foliage, ground cover, and soil, in varying degrees, and reveal the occurrence of standing liquid water on and beneath the surface. The manifestation of liquid water appearing on or near the surface is reported by a microwave receiver as a signal with a low flux level, or, equivalently, a cold temperature. Actually, the surface of the liquid water reflects the low flux level from the cosmic background into the input terminals of the receiver. This trilogy describes and shows by microwave flux images: the hydrological features that sustain Lake Baykal as an extraordinary freshwater resource; manifestations of subsurface water in Iran; and the major water features of the Congo Basin, a rain forest.

  4. CMB polarization from secondary vector and tensor modes

    International Nuclear Information System (INIS)

    Mollerach, Silvia; Harari, Diego; Matarrese, Sabino

    2004-01-01

    We consider a novel contribution to the polarization of the cosmic microwave background induced by vector and tensor modes generated by the nonlinear evolution of primordial scalar perturbations. Our calculation is based on relativistic second-order perturbation theory and allows us to estimate the effects of these secondary modes on the polarization angular power spectra. We show that a nonvanishing B-mode polarization unavoidably arises from pure scalar initial perturbations, thus limiting our ability to detect the signature of primordial gravitational waves generated during inflation. This secondary effect dominates over that of primordial tensors for an inflationary tensor-to-scalar ratio r -6 . The magnitude of the effect is smaller than the contamination produced by the conversion of polarization of type E into type B, by weak gravitational lensing. However, the lensing signal can be cleaned, making the secondary modes discussed here the actual background limiting the detection of small amplitude primordial gravitational waves

  5. B polarization of the CMB from Faraday rotation

    International Nuclear Information System (INIS)

    Scoccola, Claudia; Harari, Diego; Mollerach, Silvia

    2004-01-01

    We study the effect of Faraday rotation due to a uniform magnetic field on the polarization of the cosmic microwave background. Scalar fluctuations give rise only to parity-even E-type polarization of the cosmic microwave background. However in the presence of a magnetic field, a nonvanishing parity-odd B-type polarization component is produced through Faraday rotation. We derive the exact solution for the E and B modes generated by scalar perturbations including the Faraday rotation effect of a uniform magnetic field, and evaluate their cross correlations with temperature anisotropies. We compute the angular autocorrelation function of the B-modes in the limit that the Faraday rotation is small. We find that uniform primordial magnetic fields of present strength around B 0 =10 -9 G rotate E-modes into B-modes with amplitude comparable to those due to the weak gravitational lensing effect at frequencies around ν=30 GHz. The strength of B-modes produced by Faraday rotation scales as B 0 /ν 2 . We evaluate also the depolarizing effect of Faraday rotation upon the cross correlation between temperature anisotropy and E-type polarization

  6. Multi-polarized Radarsat-2 SAR Data for Retrieving Rice Ear Parameters by Integrating a Microwave Scattering Model with a Genetic Algorithm Optimization Tool

    Science.gov (United States)

    Zhang, Y.

    2017-12-01

    Accurately mapping rice ear parameters with microwave synthetic aperture radar (SAR) data plays a role in estimation of rice yield for ensuring food security at regional or national scales. In this study, the backscatter of rice canopy was first simulated by a parameterized rice canopy scattering model (RCSM). An inversion scheme by integrating RCSM and genetic algorithm optimization tool (GAOT) was then proposed for retrieving three key physical parameters of rice ear from a C-band, quad-polarized (HH, HV, VH and VV) Radarsat-2 SAR data. Results show that RCSM can effectively simulate backscattering coefficients of rice canopy at fully polarimetric mode with a root-mean-square error (RMSE) of diameter and number density, are retrieved by the RCSM-GAOT inversion scheme with better accuracy. They are estimated with RMSE of < 1.2 cm, < 0.6 mm and < 30 #/m2 for ear length, ear radius and number density, respectively. The distribution map of three ear parameters explicitly represents the spatial variations over the entire study area. This study demonstrates the potential of Radarsat-2 multi-polarized SAR data in operational estimation of ear parameters closely relating to rice yield.

  7. Development of microwave kinetic inductance detectors and their readout system for LiteBIRD

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, K.; Hazumi, M. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Ishino, H.; Kibayashi, A. [Okayama University, Okayama 700-8530 (Japan); Kibe, Y., E-mail: kibe@fphy.hep.okayama-u.ac.jp [Okayama University, Okayama 700-8530 (Japan); Mima, S. [Terahertz-wave Research Group, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Okamura, T.; Sato, N.; Tomaru, T. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Yamada, Y. [Okayama University, Okayama 700-8530 (Japan); Yoshida, M. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Yuasa, T. [Okayama University, Okayama 700-8530 (Japan); Watanabe, H. [SOKENDAI, Tsukuba, Ibaraki 305-0801 (Japan)

    2013-12-21

    Primordial gravitational waves generated by inflation have produced an odd-parity pattern B-mode in the cosmic microwave background (CMB) polarization. LiteBIRD (Light satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection) aims at detecting this B-mode polarization precisely. It requires about 2000 detectors capable of detecting a frequency range from 50 GHz to 250 GHz with ultra low noise. Superconducting detectors are suitable for this requirement. We have fabricated and tested microwave kinetic inductance detectors (MKIDs) and developed a new readout system. We have designed antenna-coupled MKIDs. Quasi-particles are created by incident radiation and are detected as a change of the surface impedance of a superconductor strip. This change of the surface impedance is translated into the change of the resonant frequency of a microwave signal transmitted through the resonator. We also have developed a new readout system for MKIDs. The newly developed readout system is not only able to read out the amplitude and the phase data with the homodyne detection for multi-channels, but also provides a unique feature of tracking the resonant frequency of the target resonator. This mechanism enables us to detect signals with a large dynamic range. We report on the recent R and D status of the developing MKIDs and on the read-out system for LiteBIRD.

  8. Microwave-assisted ADMET polymerization

    OpenAIRE

    Rojas Jiménez, Giovanni

    2015-01-01

    Microwave-assisted ADMET polymerization is reported on a series of α,ω-diene monomers, both polar and non-polar. Investigations indicate that of the multiple microwave modes possible, constant power is the most advantageous, providing polymers up to M‾w=31,000g/mol. Molecular weight values are nearly triple in comparison with conventional oil bath heating. Polymers are characterized by NMR, GPC, TGA, and DSC. Microwave irradiation provides a highly controllable and energy efficient ADMET poly...

  9. TRMM MICROWAVE IMAGER (TMI) WENTZ OCEAN PRODUCTS V3

    Data.gov (United States)

    National Aeronautics and Space Administration — The TRMM Microwave Imager (TMI) is a 5-channel, dual-polarized, passive microwave radiometer. Microwave radiation is emitted by the Earth's surface and by water...

  10. Cosmic particles

    International Nuclear Information System (INIS)

    Fritszh, Harald; Max-Planck-Institut fuer Physik und Astrophysik, Muenchen

    1986-01-01

    The paper on 'Cosmic particles' was presented at the conference on 'The early universe and its evolution', Erice, Italy 1986. The link between ideas in cosmology and in elementary particle physics is examined. The subject is discussed under the following topic headings: cosmic kinetics, cosmic dynamics and general relativity, dynamics of the dust universe, particle physics, unity of quarks and leptons, the hot universe and standard particle physics, creation of matter, and the inflation of the universe. (U.K.)

  11. The Optical Design and Characterization of the Microwave Anisotropy Probe

    Science.gov (United States)

    Page, L.; Jackson, C.; Barnes, C.; Bennett, C.; Halpern, M.; Hinshaw, G.; Jarosik, N.; Kogut, A.; Limon, M.; Meyer, S. S.; Spergel, D. N.; Tucker, G. S.; Wilkinson, D. T.; Wollack, E.; Wright, E. L.

    2003-03-01

    The primary goal of the MAP satellite, now in orbit, is to make high-fidelity polarization-sensitive maps of the full sky in five frequency bands between 20 and 100 GHz. From these maps we will characterize the properties of the cosmic microwave background (CMB) anisotropy and Galactic and extragalactic emission on angular scales ranging from the effective beam size, less than 0.23d, to the full sky. MAP is a differential microwave radiometer. Two back-to-back shaped offset Gregorian telescopes feed two mirror symmetric arrays of 10 corrugated feeds. We describe the prelaunch design and characterization of the optical system, compare the optical models to the measurements, and consider multiple possible sources of systematic error.

  12. Planck intermediate results. XXII. Frequency dependence of thermal emission from Galactic dust in intensity and polarization

    DEFF Research Database (Denmark)

    Cardoso, J. F.; Delabrouille, J.; Ganga, K.

    2015-01-01

    of the cosmic microwave background. We use a mask that focuses our analysis on the diffuse interstellar medium at intermediate Galactic latitudes. We determine the spectral indices of dust emission in intensity and polarization between 100 and 353 GHz, for each sky patch. Both indices are found to be remarkably......)% from 353 to 70 GHz. We discuss this result within the context of existing dust models. The decrease in p could indicate differences in polarization efficiency among components of interstellar dust (e.g., carbon versus silicate grains). Our observational results provide inputs to quantify and optimize...

  13. THE EFFECTS OF DARK MATTER ANNIHILATION ON COSMIC REIONIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Kaurov, Alexander A.; Hooper, Dan; Gnedin, Nickolay Y., E-mail: kaurov@uchicago.edu [Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 (United States)

    2016-12-20

    We revisit the possibility of constraining the properties of dark matter (DM) by studying the epoch of cosmic reionization. Previous studies have shown that DM annihilation was unlikely to have provided a large fraction of the photons which ionized the universe, but instead played a subdominant role relative to stars and quasars. The DM might, however, have begun to efficiently annihilate with the formation of primordial microhalos at z  ∼ 100–200, much earlier than the formation of the first stars. Therefore, if DM annihilation ionized the universe at even the percent level over the interval z  ∼ 20–100, it could leave a significant imprint on the global optical depth, τ . Moreover, we show that cosmic microwave background polarization data and future 21 cm measurements will enable us to more directly probe the DM contribution to the optical depth. In order to compute the annihilation rate throughout the epoch of reionization, we adopt the latest results from structure formation studies and explore the impact of various free parameters on our results. We show that future measurements could make it possible to place constraints on the DM’s annihilation cross-sections, which are at a level comparable to those obtained from the observations of dwarf galaxies, cosmic-ray measurements, and studies of recombination.

  14. Exploring cosmic origins with CORE: B-mode component separation

    Science.gov (United States)

    Remazeilles, M.; Banday, A. J.; Baccigalupi, C.; Basak, S.; Bonaldi, A.; De Zotti, G.; Delabrouille, J.; Dickinson, C.; Eriksen, H. K.; Errard, J.; Fernandez-Cobos, R.; Fuskeland, U.; Hervías-Caimapo, C.; López-Caniego, M.; Martinez-González, E.; Roman, M.; Vielva, P.; Wehus, I.; Achucarro, A.; Ade, P.; Allison, R.; Ashdown, M.; Ballardini, M.; Banerji, R.; Bartlett, J.; Bartolo, N.; Baumann, D.; Bersanelli, M.; Bonato, M.; Borrill, J.; Bouchet, F.; Boulanger, F.; Brinckmann, T.; Bucher, M.; Burigana, C.; Buzzelli, A.; Cai, Z.-Y.; Calvo, M.; Carvalho, C.-S.; Castellano, G.; Challinor, A.; Chluba, J.; Clesse, S.; Colantoni, I.; Coppolecchia, A.; Crook, M.; D'Alessandro, G.; de Bernardis, P.; de Gasperis, G.; Diego, J.-M.; Di Valentino, E.; Feeney, S.; Ferraro, S.; Finelli, F.; Forastieri, F.; Galli, S.; Genova-Santos, R.; Gerbino, M.; González-Nuevo, J.; Grandis, S.; Greenslade, J.; Hagstotz, S.; Hanany, S.; Handley, W.; Hernandez-Monteagudo, C.; Hills, M.; Hivon, E.; Kiiveri, K.; Kisner, T.; Kitching, T.; Kunz, M.; Kurki-Suonio, H.; Lamagna, L.; Lasenby, A.; Lattanzi, M.; Lesgourgues, J.; Lewis, A.; Liguori, M.; Lindholm, V.; Luzzi, G.; Maffei, B.; Martins, C. J. A. P.; Masi, S.; Matarrese, S.; McCarthy, D.; Melin, J.-B.; Melchiorri, A.; Molinari, D.; Monfardini, A.; Natoli, P.; Negrello, M.; Notari, A.; Paiella, A.; Paoletti, D.; Patanchon, G.; Piat, M.; Pisano, G.; Polastri, L.; Polenta, G.; Pollo, A.; Poulin, V.; Quartin, M.; Rubino-Martin, J.-A.; Salvati, L.; Tartari, A.; Tomasi, M.; Tramonte, D.; Trappe, N.; Trombetti, T.; Tucker, C.; Valiviita, J.; Van de Weijgaert, R.; van Tent, B.; Vennin, V.; Vittorio, N.; Young, K.; Zannoni, M.

    2018-04-01

    We demonstrate that, for the baseline design of the CORE satellite mission, the polarized foregrounds can be controlled at the level required to allow the detection of the primordial cosmic microwave background (CMB) B-mode polarization with the desired accuracy at both reionization and recombination scales, for tensor-to-scalar ratio values of rgtrsim 5× 10‑3. We consider detailed sky simulations based on state-of-the-art CMB observations that consist of CMB polarization with τ=0.055 and tensor-to-scalar values ranging from r=10‑2 to 10‑3, Galactic synchrotron, and thermal dust polarization with variable spectral indices over the sky, polarized anomalous microwave emission, polarized infrared and radio sources, and gravitational lensing effects. Using both parametric and blind approaches, we perform full component separation and likelihood analysis of the simulations, allowing us to quantify both uncertainties and biases on the reconstructed primordial B-modes. Under the assumption of perfect control of lensing effects, CORE would measure an unbiased estimate of r=(5 ± 0.4)× 10‑3 after foreground cleaning. In the presence of both gravitational lensing effects and astrophysical foregrounds, the significance of the detection is lowered, with CORE achieving a 4σ-measurement of r=5× 10‑3 after foreground cleaning and 60% delensing. For lower tensor-to-scalar ratios (r=10‑3) the overall uncertainty on r is dominated by foreground residuals, not by the 40% residual of lensing cosmic variance. Moreover, the residual contribution of unprocessed polarized point-sources can be the dominant foreground contamination to primordial B-modes at this r level, even on relatively large angular scales, l ~ 50. Finally, we report two sources of potential bias for the detection of the primordial B-modes by future CMB experiments: (i) the use of incorrect foreground models, e.g. a modelling error of Δβs = 0.02 on the synchrotron spectral indices may result in an

  15. Development of Optics and Detectors for Advanced CMB Polarization Measurements

    Data.gov (United States)

    National Aeronautics and Space Administration — Measurements of the cosmic microwave background (CMB) have been essential to the development of modern cosmology. Future observations will provide cosmological...

  16. DMSP SSM/I- Microwave Imager

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SSM/I is a seven-channel, four frequency, linearly-polarized, passive microwave radiometric system which measures atmospheric, ocean and terrain microwave...

  17. Excess B‐modes extracted from the Planck polarization maps

    DEFF Research Database (Denmark)

    Nørgaard-Nielsen, Hans Ulrik

    2016-01-01

    One of the main obstacles for extracting the Cosmic Microwave Background (CMB) from mm/submm observations is the pollution from the main Galactic components: synchrotron, free‐free and thermal dust emission. The feasibility of using simple neural networks to extract CMB has been demonstrated...... a mask covering about 63 % of the sky have been used together with a “high pass filter” in order to minimize the influence of the remaining systematic errors in the Planck Q and U maps. Using the Planck 2015 released polarization maps, a BB power spectrum have been extracted by Multilayer Perceptron...

  18. An Ultra-Wideband, Microwave Radar for Measuring Snow Thickness on Sea Ice and Mapping Near-Surface Internal Layers in Polar Firn

    Science.gov (United States)

    Panzer, Ben; Gomez-Garcia, Daniel; Leuschen, Carl; Paden, John; Rodriguez-Morales, Fernando; Patel, Azsa; Markus, Thorsten; Holt, Benjamin; Gogineni, Prasad

    2013-01-01

    Sea ice is generally covered with snow, which can vary in thickness from a few centimeters to >1 m. Snow cover acts as a thermal insulator modulating the heat exchange between the ocean and the atmosphere, and it impacts sea-ice growth rates and overall thickness, a key indicator of climate change in polar regions. Snow depth is required to estimate sea-ice thickness using freeboard measurements made with satellite altimeters. The snow cover also acts as a mechanical load that depresses ice freeboard (snow and ice above sea level). Freeboard depression can result in flooding of the snow/ice interface and the formation of a thick slush layer, particularly in the Antarctic sea-ice cover. The Center for Remote Sensing of Ice Sheets (CReSIS) has developed an ultra-wideband, microwave radar capable of operation on long-endurance aircraft to characterize the thickness of snow over sea ice. The low-power, 100mW signal is swept from 2 to 8GHz allowing the air/snow and snow/ ice interfaces to be mapped with 5 c range resolution in snow; this is an improvement over the original system that worked from 2 to 6.5 GHz. From 2009 to 2012, CReSIS successfully operated the radar on the NASA P-3B and DC-8 aircraft to collect data on snow-covered sea ice in the Arctic and Antarctic for NASA Operation IceBridge. The radar was found capable of snow depth retrievals ranging from 10cm to >1 m. We also demonstrated that this radar can be used to map near-surface internal layers in polar firn with fine range resolution. Here we describe the instrument design, characteristics and performance of the radar.

  19. Balloon-Borne Observations of the Anisotropy of the Cosmic Microwave'Background on Angular Scales of 0.2 to 40 Degrees'

    Science.gov (United States)

    2000-01-01

    During this final period, BOOMERANG was deployed to McMurdo Mtn., Antarctica in late 1998 and successfully flew a 10.5 day long duration flight. The experiment returned excellent data, and produced the first resolved images of the early universe. These results, as well as those produced during a test flight over North America in August, 1997, are given in the references below. Analysis of the data from the 1998 flight is continuing. In parallel, we have begun to prepare the payload for a long-duration flight from McMurdo in December 2001. For this flight, the focal plane is being outfitted with polarization sensitive detectors, with the goal of detecting the polarization of the CMB that is predicted to exist at degree angular scales.

  20. Cosmic impacts, cosmic catastrophes. I

    Science.gov (United States)

    Chapman, Clark R.; Morrison, David

    1989-01-01

    The discovery of cosmic impacts and their effects on the earth's surface are discussed. The manner in which the object impacts with the earth is described. The formation of crytovolcanic structures by craters is examined. Examples of cosmic debris collisions with earth, in particular the Tunguska explosion of 1908 and the Meteor Crater in Arizona, are provided.

  1. High time resolution observations of the polar stratosphere and mesosphere using a ground-based 230-250 GHz microwave radiometer

    Science.gov (United States)

    Newnham, D. A.; Espy, P. J.; Clilverd, M. A.; Maxfield, D. J.; Hartogh, P.; Holmén, K.; Blindheim, S.; Horne, R. B.

    2012-04-01

    Microwave radiometry is used to measure thermal emission by the Doppler- and pressure-broadened molecular rotational lines of atmospheric gases, from which vertical abundance profiles can be determined. Since solar radiation is not required for the measurement, the technique has the advantage that continuous observations are possible including throughout the polar winter. We describe the development of a passive microwave radiometer [Espy, P. J., P. Hartogh, and K. Holmen (2006), Proc. SPIE, 6362, 63620P, doi:10.1117/12.688953] for ground-based remote sensing of the polar middle atmosphere. The instrument measures nitric oxide (NO), ozone (O3), and carbon monoxide (CO) vertical profiles over the altitude range 35-90 km with time resolution as high as 15 minutes, allowing the diurnal variability of trace chemical species to be investigated. Heterodyne detection of atmospheric emission at 230 GHz and 250 GHz (wavelength ~1.25 mm) with a receiver noise temperature of 300 K is achieved using a superconductor-insulator-superconductor (SIS) mixer cooled to 4 K. The down-converted signals at 1.35 GHz and 2.10 GHz are analysed using both a moderate-resolution (28 kHz, 220 MHz bandwidth) and a high-resolution (14 kHz, 40 MHz bandwidth) chirp-transform spectrometer (CTS). The instrument was operated semi-autonomously at Troll station (72° 01'S 02° 32'E, 1270 m above sea level), Antarctica during 2008-10 and at the Arctic LIDAR Observatory for Middle Atmosphere Research (ALOMAR, 69° 16'N, 16° 00'E, 380 m above sea level), northern Norway during 2011-12. NO volume mixing ratio (VMR) profiles have been inverted from calibrated brightness temperature spectra of the NO line centred at 250.796 GHz, observed above Troll station, using the Microwave Observation Line Estimation and Retrieval (MOLIERE) version 5 code. A priori pressure, temperature, ozone, water vapour, and NO profiles above 30 km were calculated using the Sodankylä Ion and Neutral Chemistry (SIC, version 6

  2. Lethality in mice and rats exposed to 2450 MHz circularly polarized microwaves as a function of exposure duration and environmental factors

    Energy Technology Data Exchange (ETDEWEB)

    Berman, E.; Kinn, J.B.; Ali, J.; Carter, H.B.; Rehnberg, B.; Stead, A.G.

    1985-02-01

    Adult male CD-1 mice and CD rats were used to determine LD50/24 h lethality rates from exposure to 2450-MHz circularly polarized microwaves. Groups of 16 mice or six rats were exposed in each of 32 combinations of nominal power density, exposure duration, and environmental temperature and relative humidity. An analysis of variance probit model was used to determine the influence each variable had on the probability of death. Significant factors in lethality were nominal power density, exposure duration and environmental temperature, but not environmental relative humidity. The estimated power density (mW cm-2) required to kill 50% of the animals in 24 h is halved when the environmental temperature is increased from 20 to 30 degrees C. Similarly, only 20-25% of the power density is required when the exposure duration is increased from 1 to 4 h. The use of nominal power density as a predictor of the probability of death was more efficient than specific absorption rate estimated experimentally by twin-well calorimetry. The exposure of one mouse at a time, instead of 16, did not alter the predicted death rate.

  3. Geometry and groups for cosmic topology

    International Nuclear Information System (INIS)

    Kramer, Peter

    2011-01-01

    The Cosmic Microwave Background is measured by satellite observation with great precision. It offers insight into its origin in early states of the universe. Unexpected low multipole amplitudes of the incoming CMB radiation may be due to a multiply connected topology of cosmic 3-space. We present and analyze the geometry and homotopy for the family of Platonic spherical 3-manifolds, provide their harmonic analysis, and formulate topological selection rules.

  4. Magnetized $\\Lambda$CDM inhomogeneities and the cosmic dark ages

    CERN Document Server

    Giovannini, Massimo

    2011-01-01

    Exact solutions of the perturbations equations in the magnetized LambdaCDM scenario are presented. They apply during the dark ages and, more specifically, after the baryons are freed from the drag of the photons. The magnetized growth rate of matter perturbations is compared with the growth index obtained in the concordance paradigm and under the assumption that dark energy does not cluster for a redshift window ranging from the epoch of reionization to the stage of dark-energy dominance. The constraints derived from this analysis are shown to be qualitatively complementary and quantitatively competitive with the bounds stemming from the analysis of the distortion patterns induced by the magnetized adiabatic mode on the temperature and polarization anisotropies of the Cosmic Microwave Background.

  5. First Observation of the Submillimeter Polarization Spectrum in a Translucent Molecular Cloud

    Science.gov (United States)

    Ashton, Peter C.; Ade, Peter A. R.; Angilè, Francesco E.; Benton, Steven J.; Devlin, Mark J.; Dober, Bradley; Fissel, Laura M.; Fukui, Yasuo; Galitzki, Nicholas; Gandilo, Natalie N.; Klein, Jeffrey; Korotkov, Andrei L.; Li, Zhi-Yun; Martin, Peter G.; Matthews, Tristan G.; Moncelsi, Lorenzo; Nakamura, Fumitaka; Netterfield, Calvin B.; Novak, Giles; Pascale, Enzo; Poidevin, Frédérick; Santos, Fabio P.; Savini, Giorgio; Scott, Douglas; Shariff, Jamil A.; Soler, Juan D.; Thomas, Nicholas E.; Tucker, Carole E.; Tucker, Gregory S.; Ward-Thompson, Derek

    2018-04-01

    Polarized emission from aligned dust is a crucial tool for studies of magnetism in the ISM, but a troublesome contaminant for studies of cosmic microwave background polarization. In each case, an understanding of the significance of the polarization signal requires well-calibrated physical models of dust grains. Despite decades of progress in theory and observation, polarized dust models remain largely underconstrained. During its 2012 flight, the balloon-borne telescope BLASTPol obtained simultaneous broadband polarimetric maps of a translucent molecular cloud at 250, 350, and 500 μm. Combining these data with polarimetry from the Planck 850 μm band, we have produced a submillimeter polarization spectrum, the first for a cloud of this type. We find the polarization degree to be largely constant across the four bands. This result introduces a new observable with the potential to place strong empirical constraints on ISM dust polarization models in a previously inaccessible density regime. Compared to models by Draine & Fraisse, our result disfavors two of their models for which all polarization arises due only to aligned silicate grains. By creating simple models for polarized emission in a translucent cloud, we verify that extinction within the cloud should have only a small effect on the polarization spectrum shape, compared to the diffuse ISM. Thus, we expect the measured polarization spectrum to be a valid check on diffuse ISM dust models. The general flatness of the observed polarization spectrum suggests a challenge to models where temperature and alignment degree are strongly correlated across major dust components.

  6. Measuring CMB polarization from ISS: the SPOrt experiment

    International Nuclear Information System (INIS)

    Colombo, L.P.L.

    2004-01-01

    The SPOrt (Sky Polarization Observatory) experiment aims to measure CMBP (cosmic microwave background polarization) on about 80% of the sky from space. Selected by ESA to fly on board the ISS in 2006, it is funded by the Italian Space Agency (ASI). As shown also by the recent WMAP release, CMBP data, besides of removing various degeneracies among cosmological parameters, provided new and important information on the cosmic opacity τ and, therefore, on very early cosmic objects which reionized the world at z ∼ 15. Most such information is obtained from low-l spectral components, that SPOrt, with its HPBW resolution of 7 degrees will explore with a high level of sensitivity. The 4 polarimeters of SPOrt work at 22, 32 and (2x) 90 GHz. At lower frequencies they will provide a (nearly) all-sky survey of Galactic synchrotron polarized emission, while data at the higher frequency will measure the CMBP signal. Correlating SPOrt with anisotropy data, by other experiments, shall therefore provide significant cosmological information. We performed a number of simulations of SPOrt performance, aimed to determine how far τ and/or other parameter(s) concerning reionization are constrained by the expected data. We also considered a possible interplay between reionization histories and Dark Energy nature. Besides of information on technological developments for systematics reduction, long term stability and observing time efficiency, we report here recent outputs on the expected SPOrt performance in constraining cosmological models

  7. Cosmic transparency and acceleration

    Science.gov (United States)

    Holanda, R. F. L.; Pereira, S. H.; Jain, Deepak

    2018-01-01

    In this paper, by considering an absorption probability independent of photon wavelength, we show that current type Ia supernovae (SNe Ia) and gamma-ray burst (GRB) observations plus high-redshift measurements of the cosmic microwave background (CMB) radiation temperature support cosmic acceleration regardless of the transparent-universe assumption. Two flat scenarios are considered in our analyses: the Λ CDM model and a kinematic model. We consider τ (z )=2 ln (1 +z )ɛ, where τ (z ) denotes the opacity between an observer at z =0 and a source at z . This choice is equivalent to deforming the cosmic distance duality relation as DLDA-1=(1 +z )2+ɛ and, if the absorption probability is independent of photon wavelength, the CMB temperature evolution law is TCMB(z )=T0(1 +z )1+2 ɛ /3. By marginalizing on the ɛ parameter, our analyses rule out a decelerating universe at 99.99% C.L. for all scenarios considered. Interestingly, by considering only SNe Ia and GRBs observations, we obtain that a decelerated universe—indicated by ΩΛ≤0.33 and q0>0 —is ruled out around 1.5 σ C.L. and 2 σ C.L., respectively, regardless of the transparent-universe assumption.

  8. Particle physics implications of Wilkinson microwave anisotropy ...

    Indian Academy of Sciences (India)

    1016 GeV) inflation. Keywords. Cosmic microwave background radiation; inflation; Wilkinson microwave anisotropy project. PACS Nos 98.80.-k; 98.80.Cq; 98.80.Es; 95.30.Cq; 12.10.Dm; 12.60.Jv. 1. Introduction. This review [1] is divided into ...

  9. Consistency relation for cosmic magnetic fields

    DEFF Research Database (Denmark)

    Jain, R. K.; Sloth, M. S.

    2012-01-01

    If cosmic magnetic fields are indeed produced during inflation, they are likely to be correlated with the scalar metric perturbations that are responsible for the cosmic microwave background anisotropies and large scale structure. Within an archetypical model of inflationary magnetogenesis, we show...... to be extremely useful to test some recent calculations in the literature. Apart from primordial non-Gaussianity induced by the curvature perturbations, such a cross correlation might provide a new observational probe of inflation and can in principle reveal the primordial nature of cosmic magnetic fields. DOI...

  10. A HIGH SENSITIVE MICROWAVE MEASURING DEVICE OF THE MOISTURE CONTENT IN THE NON-POLAR DIELECTRIC LIQUIDS BASED ON AN INHOMOGENEOUS STEP COAXIAL RESONATOR

    Directory of Open Access Journals (Sweden)

    V. V. Rudakov

    2016-11-01

    Full Text Available Purpose. Objective is to create a moisture meter for non-polar liquid dielectrics with low volumetric moisture content of more than 10‑3 %. Methodology. Moisture measuring is based on dielcometric method. It is implemented as a resonant method of determining a capacitance measuring transducer. Measuring transducer capacitive type has a working and parasitic capacitance. It was suggested the definition of moisture on four of resonance frequencies: when the measuring transducer is turned off, one by one filled with air, «dry» and investigated liquid, to determine the parasitic capacitance of the measuring generator, and the parasitic capacitance of the measuring transducer and humidity. Measurement frequency was increased up to microwave range to increase the sensitivity. Measuring transducer with distributed parameters representing a step heterogeneous coaxial resonator is used by. This measuring transducer has a zero stray capacitance, because the potential electrode has a galvanic connection with an external coaxial electrode. Inductive ties loop is used to neglect parasitic capacitance of the measuring generator, and to increase the quality factor of the system. Measuring moisture is reduced to measuring the two frequencies of resonance frequency and «dry» and investigated liquid. Resonant characteristics transducer in a step inhomogeneous coaxial resonator have been investigated to determine the quality factor of filled with air and transformer oil, and experiments to measure the moisture content in transformer oil have been conducted. Results. Measuring transducer of distributed type is developed and researched – it is step inhomogeneous coaxial resonator. It has a smaller geometric length and larger scatter of the first and second resonant frequencies. Expression is obtained for determination of moisture on the basis of two resonant frequencies. The formula of the two frequencies to determine the moisture is correct. Resonant

  11. Diagnostics method of interplanetary disturbances according to investigation of cosmic ray fluctuations and its realization in an automation system of science studies at the polar geocosmophysical Tiksi observatory

    International Nuclear Information System (INIS)

    Kozlov, V.I.; Borisov, D.Z.; Tugolukov, N.N.

    1984-01-01

    Diagnostics method of interplanetary disturbances (ID) according to investigation of galactic cosmic ray (GCR) fluctuations is under discussion. Experimental results on early ID diagnostics on April 1984 obtained under real time conditions are presented. Hourly magnitudes of GCR intensity from 20.04 up to 2.05 1984 and, respectively, indexes of GCR scintillations are presented. Short-term increases of indexes with the same decay are observed before the beginning of the main forbush decrease on 26.04 1984, this means the early ID diagnostics

  12. Microwave Ovens

    Science.gov (United States)

    ... Products and Procedures Home, Business, and Entertainment Products Microwave Ovens Share Tweet Linkedin Pin it More sharing ... 1030.10 - Microwave Ovens Required Reports for the Microwave Oven Manufacturers or Industry Exemption from Certain Reporting ...

  13. Microwave engineering

    CERN Document Server

    Pozar, David M

    2012-01-01

    The 4th edition of this classic text provides a thorough coverage of RF and microwave engineering concepts, starting from fundamental principles of electrical engineering, with applications to microwave circuits and devices of practical importance.  Coverage includes microwave network analysis, impedance matching, directional couplers and hybrids, microwave filters, ferrite devices, noise, nonlinear effects, and the design of microwave oscillators, amplifiers, and mixers. Material on microwave and RF systems includes wireless communications, radar, radiometry, and radiation hazards. A large

  14. Cosmic archeology with the Cosmic Microwave Background Radiation

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Wuensche de Souza

    2010-03-01

    how the Universe "started" and evolved to what we see today. We will discuss in this article some challenges faced by modern cosmology to be able to describe our Universe and how CMBR observations can help in this task.

  15. Measuring anisotropies in the cosmic neutrino background

    Science.gov (United States)

    Lisanti, Mariangela; Safdi, Benjamin R.; Tully, Christopher G.

    2014-10-01

    Neutrino capture on tritium has emerged as a promising method for detecting the cosmic neutrino background (C ν B ). We show that relic neutrinos are captured most readily when their spin vectors are antialigned with the polarization axis of the tritium nuclei and when they approach along the direction of polarization. As a result, C ν B observatories may measure anisotropies in the cosmic neutrino velocity and spin distributions by polarizing the tritium targets. A small dipole anisotropy in the C ν B is expected due to the peculiar velocity of the lab frame with respect to the cosmic frame and due to late-time gravitational effects. The PTOLEMY experiment, a tritium observatory currently under construction, should observe a nearly isotropic background. This would serve as a strong test of the cosmological origin of a potential signal. The polarized-target measurements may also constrain nonstandard neutrino interactions that would induce larger anisotropies and help discriminate between Majorana versus Dirac neutrinos.

  16. Evading the pulsar constraints on the cosmic string tension in supergravity inflation

    International Nuclear Information System (INIS)

    Kamada, Kohei; Miyamoto, Yuhei; Yokoyama, Jun'ichi

    2012-04-01

    The cosmic string is a useful probe of the early Universe and may give us a clue to physics at high energy scales where any artificial particle accelerators cannot reach. Although one of the most promising tools is the cosmic microwave background, the constraint from gravitational waves is becoming so stringent that one may not hope to detect its signatures in the cosmic microwave background. In this paper, we construct a scenario that contains cosmic strings observable in the cosmic microwave background while evading the constraint imposed by the recent pulsar timing data. We argue that cosmic strings with relatively large tension are allowed by delaying the onset of the scaling regime. We also show that this scenario is naturally realized in the context of chaotic inflation in supergravity, where the phase transition is governed by the Hubble induced mass.

  17. Novel calibration system with sparse wires for CMB polarization receivers

    Energy Technology Data Exchange (ETDEWEB)

    Tajima, O.; /KEK, Tsukuba /Chicago U., KICP; Nguyen, H.; /Fermilab; Bischoff, C.; /Chicago U., KICP /Harvard-Smithsonian Ctr. Astrophys.; Brizius, A.; Buder, I.; Kusaka, A. /Chicago U., KICP

    2011-07-01

    B-modes in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate 'simultaneously' all detectors on the large focal plane. We developed a novel calibration system that rotates a large 'sparse' grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature from the wire surface. Since the detector has a finite beam size, the observed signal is smeared according to the beam property. The resulting smeared polarized radiation has a reasonable intensity (a few Kelvin or less) compared to the sky temperature ({approx}10 K observing condition). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.

  18. Cosmic impacts, cosmic catastrophes. II

    Science.gov (United States)

    Chapman, Clark R.; Morrison, David

    1990-01-01

    The role of extraterrestrial impacts in shaping the earth's history is discussed, arguing that cosmic impacts represent just one example of a general shift in thinking that has made the idea of catastrophes respectable in science. The origins of this view are presented and current catastrophic theory is discussed in the context of modern debate on the geological formation of the earth. Various conflicting theories are reviewed and prominent participants in the ongoing scientific controversy concerning catastrophism are introduced.

  19. Cosmology with cosmic microwave background anisotropy

    Indian Academy of Sciences (India)

    high precision on large angular scales (l < 800) by the WMAP experiment [2], while smaller angular scales have been probed by ground and balloon-based CMB experiments [3–7]. These data are broadly consistent with a ΛCDM model in which the Universe is spatially flat and is composed of radiation, baryons, neutrinos ...

  20. Cosmology with cosmic microwave background anisotropy

    Indian Academy of Sciences (India)

    The currently existing experimental constraints shown are due to: Big Bang nucleosynthesis (BBN), binary pulsars, and WMAP-1 (first year) with SDSS. Also shown are the projections for LIGO (both LIGO-I, after one year running, and LIGO-II), LISA, and BBO (both initial sensitivity, BBO-I, and after cross-correlating receivers, ...

  1. Microwave imaging

    CERN Document Server

    Pastorino, Matteo

    2010-01-01

    An introduction to the most relevant theoretical and algorithmic aspects of modern microwave imaging approaches Microwave imaging-a technique used in sensing a given scene by means of interrogating microwaves-has recently proven its usefulness in providing excellent diagnostic capabilities in several areas, including civil and industrial engineering, nondestructive testing and evaluation, geophysical prospecting, and biomedical engineering. Microwave Imaging offers comprehensive descriptions of the most important techniques so far proposed for short-range microwave imaging-in

  2. Lensing bias to CMB polarization measurements of compensated isocurvature perturbations

    Science.gov (United States)

    Heinrich, Chen

    2018-01-01

    Compensated isocurvature perturbations (CIPs) are opposite spatial fluctuations in the baryon and dark matter (DM) densities. They arise in the curvaton model and some models of baryogenesis. While the gravitational effects of baryon fluctuations are compensated by those of DM, leaving no observable impacts on the cosmic microwave background (CMB) at first order, they modulate the sound horizon at recombination, thereby correlating CMB anisotropies at different multipoles. As a result, CIPs can be reconstructed using quadratic estimators similarly to CMB detection of gravitational lensing. Because of these similarities, however, the CIP estimators are biased with lensing contributions that must be subtracted. These lensing contributions for CMB polarization measurement of CIPs are found to roughly triple the noise power of the total CIP estimator on large scales. In addition, the cross power with temperature and E -mode polarization are contaminated by lensing-ISW (integrated Sachs-Wolfe) correlations and reionization-lensing correlations respectively. For a cosmic-variance-limited temperature and polarization experiment measuring out to multipoles lmax=2500 , the lensing noise raises the detection threshold by a factor of 1.5, leaving a 2.7 σ detection possible for the maximal CIP signal in the curvaton model.

  3. Thermal analysis of a prototype cryogenic polarization modulator for use in a space-borne CMB polarization experiment

    Science.gov (United States)

    Iida, T.; Sakurai, Y.; Matsumura, T.; Sugai, H.; Imada, H.; Kataza, H.; Ohsaki, H.; Hazumi, M.; Katayama, N.; Yamamoto, R.; Utsunomiya, S.; Terao, Y.

    2017-12-01

    We report a thermal analysis of a polarization modulator unit (PMU) for use in a space-borne cosmic microwave background (CMB) project. A measurement of the CMB polarization allows us to probe the physics of early universe, and that is the best method to test the cosmic inflation experimentally. One of the key instruments for this science is to use a halfwave plate (HWP) based polarization modulator. The HWP is required to rotate continuously at about 1 Hz below 10 K to minimize its own thermal emission to a detector system. The rotating HWP system at the cryogenic environment can be realized by using a superconducting magnetic bearing (SMB) without significant heat dissipation by mechanical friction. While the SMB achieves the smooth rotation due to the contactless bearing, an estimation of a levitating HWP temperature becomes a challenge. We manufactured a one-eighth scale prototype model of PMU and built a thermal model. We verified our thermal model with the experimental data. We forecasted the projected thermal performance of PMU for a full-scale model based on the thermal model. From this analysis, we discuss the design requirement toward constructing the full-scale model for use in a space environment such as a future CMB satellite mission, LiteBIRD.

  4. Effects of microwave on spin tunneling in single-molecule magnets

    Science.gov (United States)

    Kim, Gwang-Hee; Kim, Tae-Suk

    2005-03-01

    We study theoretically the effects of the irradiated microwave on the magnetization in single-molecule magnets (SMMs) like V15 and Fe8. We find that the shape of magnetization depends on the microwave intensity as well as the microwave polarization. The applied microwave field enhances the tunneling probability. The linearly polarized microwaves induce the suppression of magnetization at both positive and negative magnetic fields. The circularly polarized microwaves are absorbed either at one direction of magnetic field or at both directions of magnetic fields, depending on the polarization directions with respect to the direction of longitudinal magnetic field. The generic features we found will be compared with the recent experimental results.

  5. The Primordial Inflation Polarization ExploreR (PIPER)

    Science.gov (United States)

    Gandilo, Natalie; Ade, Peter; Benford, Dominic; Bennett, Charles; Chuss, David; Datta, Rahul; Dotson, Jessie; Essinger-Hileman, Thomas; Fixsen, Dale; Halpern, Mark; Hilton, Gene; Hinshaw, Gary; Irwin, Kent; Jhabvala, Christine; Kimball, Mark; Kogut, Al; Lowe, Luke; McMahon, Jeff; Miller, Timothy; Mirel, Paul; Moseley, Samuel Harvey; Pawlyk, Samuel; Rodriguez, Samelys; Sharp, Elmer; Shirron, Peter; Staguhn, Johannes G.; Sullivan, Dan; Switzer, Eric; Taraschi, Peter; Tucker, Carole; Walts, Alexander; Wollack, Edward

    2018-01-01

    The Primordial Inflation Polarization ExploreR (PIPER) is a balloon-borne telescope designed to map the large scale polarization of the Cosmic Microwave Background as well as the polarized emission from galactic dust at 200, 270, 350, and 600 GHz, with 21, 15, 14, and 14 arcminutes of angular resolution respectively. PIPER uses twin telescopes with Variable-delay Polarization Modulators to simultaneously map Stokes I, Q, U and V. Cold optics and the lack of a warm window allow the instrument to achieve background limited sensitivity, with mapping speed approximately 10 times faster than a similar instrument with a single ambient-temperature mirror. Over the course of 8 conventional balloon flights from the Northern and Southern hemisphere, PIPER will map 85% of the sky, measuring the B-mode polarization spectrum from the reionization bump to l~300, and placing an upper limit on the tensor-to-scalar ratio of rMexico, and the first science flight is planned for June 2018 from Palestine, Texas.

  6. Impact of polarized foregrounds on LSPE-SWIPE observations

    Science.gov (United States)

    Buzzelli, A.; Migliaccio, M.; de Gasperis, G.; de Bernardis, P.; Masi, S.; Vittorio, N.

    2018-01-01

    A first measurement of Cosmic Microwave Background B-mode polarization on large scales could provide a convincing confirmation of the existence of a primordial background of gravitational waves as predicted in the inflation scenario. A major obstacle to observe B-modes is represented by polarized foreground contamination from our Galaxy. In particular, thermal dust and synchrotron emission dominate over the primordial signal at high and low frequencies, respectively. Several experiments have been designed to observe B-mode polarization. Here, we focus on the forthcoming LSPE-SWIPE balloon experiment, devoted to the accurate observation of large scale CMB polarization, and present preliminary forecasts on the impact of foreground contamination on LSPE-SWIPE observations. Using the last release of Planck foreground maps as templates, we estimate the amplitude of dust and synchrotron emission in the sky region and at the frequency channels of interest for LSPE-SWIPE. Furthermore, we investigate the generation of polarization-optimized Galactic masks and we give preliminary indications on the requirements of component separation methods.

  7. Cosmology from CMB Polarization with POLARBEAR and the Simons Array

    Science.gov (United States)

    Barron, Darcy; POLARBEAR Collaboration

    2018-01-01

    POLARBEAR is a cosmic microwave background (CMB) polarization experiment located in the Atacama desert in Chile. The science goals of the POLARBEAR project are to do a deep search for CMB B-mode polarization created by inflationary gravitational waves, as well as characterize the CMB B-mode signal from gravitational lensing. POLARBEAR-1 started observations in 2012, and the POLARBEAR team has published a series of results from its first season of observations, including the first measurement of a non-zero B-mode polarization angular power spectrum, measured at sub-degree scales where the dominant signal is gravitational lensing of the CMB. Recently, we released an improved measurement of the B-mode polarization power spectrum, improving our band-power uncertainties by a factor of two, by adding new data from our second observing season and re-analyzing the combined data set.To further improve on these measurements, POLARBEAR is expanding to include an additional two telescopes with multi-chroic receivers observing at 95, 150, 220, and 270 GHz, known as the Simons Array. With high sensitivity and large sky coverage, the Simons Array will create a detailed survey of B-mode polarization, and its spectral information will be used to extract the CMB signal from astrophysical foregrounds. We will present the latest POLARBEAR results, as well as the status of development of the Simons Array and its expected capabilities.

  8. Microwave Irradiation

    Indian Academy of Sciences (India)

    Microwave Irradiation. Way to Eco-friendly, Green Chemistry. Rashmi Sanghi. This article highlights with examples, the usefulness of microwaves for carrying out a'variety of organic transfor- mations. Introduction and Background. The rapid heating of food in the kitchen using microwave ovens prompted a number of ...

  9. The Determination of the Muon Magnetic Moment from Cosmic Rays

    Science.gov (United States)

    Amsler, C.

    1974-01-01

    Describes an experiment suited for use in an advanced laboratory course in particle physics. The magnetic moment of cosmic ray muons which have some polarization is determined with an error of about five percent. (Author/GS)

  10. Gravitational Waves from Abelian Gauge Fields and Cosmic Strings at Preheating

    CERN Document Server

    Dufaux, Jean-Francois; Garcia-Bellido, Juan

    2010-01-01

    Primordial gravitational waves provide a very important stochastic background that could be detected soon with interferometric gravitational wave antennas or indirectly via the induced patterns in the polarization anisotropies of the cosmic microwave background. The detection of these waves will open a new window into the early Universe, and therefore it is important to characterize in detail all possible sources of primordial gravitational waves. In this paper we develop theoretical and numerical methods to study the production of gravitational waves from out-of-equilibrium gauge fields at preheating. We then consider models of preheating after hybrid inflation, where the symmetry breaking field is charged under a local U(1) symmetry. We analyze in detail the dynamics of the system in both momentum and configuration space, and show that gauge fields leave specific imprints in the resulting gravitational wave spectra, mainly through the appearence of new peaks at characteristic frequencies that are related to...

  11. The Primordial Inflation Polarization Explorer (PIPER)

    Science.gov (United States)

    Lazear, Justin Scott; Ade, Peter A.; Benford, Dominic J.; Bennett, Charles L.; Chuss, David T.; Dotson, Jessie L.; Eimer, Joseph R.; Fixsen, Dale J.; Halpern, Mark; Hinderks, James; hide

    2014-01-01

    The Primordial Inflation Polarization ExploreR (Piper) is a balloon-borne cosmic microwave background (CMB) polarimeter designed to search for evidence of inflation by measuring the large-angular scale CMB polarization signal. Bicep2 recently reported a detection of B-mode power corresponding to the tensor-to-scalar ratio r = 0.2 on approximately 2 degree scales. If the Bicep2 signal is caused by inflationary gravitational waves (IGWs), then there should be a corresponding increase in B-mode power on angular scales larger than 18 degrees. Piper is currently the only suborbital instrument capable of fully testing and extending the Bicep2 results by measuring the B-mode power spectrum on angular scales theta ? = approximately 0.6 deg to 90 deg, covering both the reionization bump and recombination peak, with sensitivity to measure the tensor-to-scalar ratio down to r = 0.007, and four frequency bands to distinguish foregrounds. Piper will accomplish this by mapping 85% of the sky in four frequency bands (200, 270, 350, 600 GHz) over a series of 8 conventional balloon flights from the northern and southern hemispheres. The instrument has background-limited sensitivity provided by fully cryogenic (1.5 K) optics focusing the sky signal onto four 32×40-pixel arrays of time-domain multiplexed Transition-Edge Sensor (TES) bolometers held at 140 milli-Kelvin. Polarization sensitivity and systematic control are provided by front-end Variabledelay Polarization Modulators (VPMs), which rapidly modulate only the polarized sky signal at 3 Hz and allow Piper to instantaneously measure the full Stokes vector (I,Q,U,0V) for each pointing. We describe the Piper instrument and progress towards its first flight.

  12. Exploring cosmic origins with CORE: Gravitational lensing of the CMB

    Science.gov (United States)

    Challinor, A.; Allison, R.; Carron, J.; Errard, J.; Feeney, S.; Kitching, T.; Lesgourgues, J.; Lewis, A.; Zubeldía, Í.; Achucarro, A.; Ade, P.; Ashdown, M.; Ballardini, M.; Banday, A. J.; Banerji, R.; Bartlett, J.; Bartolo, N.; Basak, S.; Baumann, D.; Bersanelli, M.; Bonaldi, A.; Bonato, M.; Borrill, J.; Bouchet, F.; Boulanger, F.; Brinckmann, T.; Bucher, M.; Burigana, C.; Buzzelli, A.; Cai, Z.-Y.; Calvo, M.; Carvalho, C.-S.; Castellano, G.; Chluba, J.; Clesse, S.; Colantoni, I.; Coppolecchia, A.; Crook, M.; d'Alessandro, G.; de Bernardis, P.; de Gasperis, G.; De Zotti, G.; Delabrouille, J.; Di Valentino, E.; Diego, J.-M.; Fernandez-Cobos, R.; Ferraro, S.; Finelli, F.; Forastieri, F.; Galli, S.; Genova-Santos, R.; Gerbino, M.; González-Nuevo, J.; Grandis, S.; Greenslade, J.; Hagstotz, S.; Hanany, S.; Handley, W.; Hernandez-Monteagudo, C.; Hervías-Caimapo, C.; Hills, M.; Hivon, E.; Kiiveri, K.; Kisner, T.; Kunz, M.; Kurki-Suonio, H.; Lamagna, L.; Lasenby, A.; Lattanzi, M.; Liguori, M.; Lindholm, V.; López-Caniego, M.; Luzzi, G.; Maffei, B.; Martinez-González, E.; Martins, C. J. A. P.; Masi, S.; Matarrese, S.; McCarthy, D.; Melchiorri, A.; Melin, J.-B.; Molinari, D.; Monfardini, A.; Natoli, P.; Negrello, M.; Notari, A.; Paiella, A.; Paoletti, D.; Patanchon, G.; Piat, M.; Pisano, G.; Polastri, L.; Polenta, G.; Pollo, A.; Poulin, V.; Quartin, M.; Remazeilles, M.; Roman, M.; Rubino-Martin, J.-A.; Salvati, L.; Tartari, A.; Tomasi, M.; Tramonte, D.; Trappe, N.; Trombetti, T.; Tucker, C.; Valiviita, J.; Van de Weijgaert, R.; van Tent, B.; Vennin, V.; Vielva, P.; Vittorio, N.; Young, K.; Zannoni, M.

    2018-04-01

    Lensing of the cosmic microwave background (CMB) is now a well-developed probe of the clustering of the large-scale mass distribution over a broad range of redshifts. By exploiting the non-Gaussian imprints of lensing in the polarization of the CMB, the CORE mission will allow production of a clean map of the lensing deflections over nearly the full-sky. The number of high-S/N modes in this map will exceed current CMB lensing maps by a factor of 40, and the measurement will be sample-variance limited on all scales where linear theory is valid. Here, we summarise this mission product and discuss the science that will follow from its power spectrum and the cross-correlation with other clustering data. For example, the summed mass of neutrinos will be determined to an accuracy of 17 meV combining CORE lensing and CMB two-point information with contemporaneous measurements of the baryon acoustic oscillation feature in the clustering of galaxies, three times smaller than the minimum total mass allowed by neutrino oscillation measurements. Lensing has applications across many other science goals of CORE, including the search for B-mode polarization from primordial gravitational waves. Here, lens-induced B-modes will dominate over instrument noise, limiting constraints on the power spectrum amplitude of primordial gravitational waves. With lensing reconstructed by CORE, one can "delens" the observed polarization internally, reducing the lensing B-mode power by 60 %. This can be improved to 70 % by combining lensing and measurements of the cosmic infrared background from CORE, leading to an improvement of a factor of 2.5 in the error on the amplitude of primordial gravitational waves compared to no delensing (in the null hypothesis of no primordial B-modes). Lensing measurements from CORE will allow calibration of the halo masses of the tens of thousands of galaxy clusters that it will find, with constraints dominated by the clean polarization-based estimators. The 19

  13. Inflation Fossils in Cosmic Structure

    Science.gov (United States)

    Kamionkowski, Marc

    The agreement of the predictions of inflation with increasingly precise cosmic microwave background (CMB) and large-scale-structure (LSS) data is remarkable. The notion that such a simple early-Universe scenario, based on still-mysterious ultra-high-energy physics, can explain such a wealth of precise data is simply amazing. An active ongoing program of research is afoot to seek the CMB polarization signatures of inflationary gravitational waves and measure the primordial bispectrum in order to learn about inflation. Still, there is far more that can be done to probe inflationary physics, and no stone should be left unturned in this quest. Here we propose a multi-component program of theoretical research that includes model building, new CMB/LSS tests, a potentially powerful new survey strategy, and the investigation of a new observational avenue for large-scale structure. We propose to broaden the circle of ideas to empirically probe inflation. To begin, the hemispherical power asymmetry seen in WMAP and Planck is truly striking. While it may simply be an unusual statistical fluke, a more tantalizing possibility is that it is a remnant of the pre-inflationary Universe. We propose to develop and study several physical models for this asymmetry and work out other testable predictions of these models. Only by pursuing other signatures of whatever new physics may be responsible for this asymmetry will we be able to infer if it is truly a window to new physics. We also plan to develop departures from statistical isotropy (SI) as a test of inflationary models. We have recently shown that single-field slow-roll inflation generically predicts a quadrupolar departure from SI in primordial perturbations, albeit a very small one. The power quadrupole is expected, however, to be significantly larger in more general inflationary models. We propose to calculate these power quadrupoles so that new constraints to the power quadrupole from CMB and LSS data can be applied to test

  14. Consistency relation for cosmic magnetic fields

    Science.gov (United States)

    Jain, Rajeev Kumar; Sloth, Martin S.

    2012-12-01

    If cosmic magnetic fields are indeed produced during inflation, they are likely to be correlated with the scalar metric perturbations that are responsible for the cosmic microwave background anisotropies and large scale structure. Within an archetypical model of inflationary magnetogenesis, we show that there exists a new simple consistency relation for the non-Gaussian cross correlation function of the scalar metric perturbation with two powers of the magnetic field in the squeezed limit where the momentum of the metric perturbation vanishes. We emphasize that such a consistency relation turns out to be extremely useful to test some recent calculations in the literature. Apart from primordial non-Gaussianity induced by the curvature perturbations, such a cross correlation might provide a new observational probe of inflation and can in principle reveal the primordial nature of cosmic magnetic fields.

  15. Recovery of Large Angular Scale CMB Polarization for Instruments Employing Variable-Delay Polarization Modulators

    Science.gov (United States)

    Miller, N. J.; Chuss, D. T.; Marriage, T. A.; Wollack, E. J.; Appel, J. W.; Bennett, C. L.; Eimer, J.; Essinger-Hileman, T.; Fixsen, D. J.; Harrington, K.; hide

    2016-01-01

    Variable-delay Polarization Modulators (VPMs) are currently being implemented in experiments designed to measure the polarization of the cosmic microwave background on large angular scales because of their capability for providing rapid, front-end polarization modulation and control over systematic errors. Despite the advantages provided by the VPM, it is important to identify and mitigate any time-varying effects that leak into the synchronously modulated component of the signal. In this paper, the effect of emission from a 300 K VPM on the system performance is considered and addressed. Though instrument design can greatly reduce the influence of modulated VPM emission, some residual modulated signal is expected. VPM emission is treated in the presence of rotational misalignments and temperature variation. Simulations of time-ordered data are used to evaluate the effect of these residual errors on the power spectrum. The analysis and modeling in this paper guides experimentalists on the critical aspects of observations using VPMs as front-end modulators. By implementing the characterizations and controls as described, front-end VPM modulation can be very powerful for mitigating 1/ f noise in large angular scale polarimetric surveys. None of the systematic errors studied fundamentally limit the detection and characterization of B-modes on large scales for a tensor-to-scalar ratio of r= 0.01. Indeed, r less than 0.01 is achievable with commensurately improved characterizations and controls.

  16. RECOVERY OF LARGE ANGULAR SCALE CMB POLARIZATION FOR INSTRUMENTS EMPLOYING VARIABLE-DELAY POLARIZATION MODULATORS

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N. J.; Marriage, T. A.; Appel, J. W.; Bennett, C. L.; Eimer, J.; Essinger-Hileman, T.; Harrington, K.; Rostem, K.; Watts, D. J. [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218 (United States); Chuss, D. T. [Department of Physics, Villanova University, 800 E Lancaster, Villanova, PA 19085 (United States); Wollack, E. J.; Fixsen, D. J.; Moseley, S. H.; Switzer, E. R., E-mail: Nathan.J.Miller@nasa.gov [Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-02-20

    Variable-delay Polarization Modulators (VPMs) are currently being implemented in experiments designed to measure the polarization of the cosmic microwave background on large angular scales because of their capability for providing rapid, front-end polarization modulation and control over systematic errors. Despite the advantages provided by the VPM, it is important to identify and mitigate any time-varying effects that leak into the synchronously modulated component of the signal. In this paper, the effect of emission from a 300 K VPM on the system performance is considered and addressed. Though instrument design can greatly reduce the influence of modulated VPM emission, some residual modulated signal is expected. VPM emission is treated in the presence of rotational misalignments and temperature variation. Simulations of time-ordered data are used to evaluate the effect of these residual errors on the power spectrum. The analysis and modeling in this paper guides experimentalists on the critical aspects of observations using VPMs as front-end modulators. By implementing the characterizations and controls as described, front-end VPM modulation can be very powerful for mitigating 1/f noise in large angular scale polarimetric surveys. None of the systematic errors studied fundamentally limit the detection and characterization of B-modes on large scales for a tensor-to-scalar ratio of r = 0.01. Indeed, r < 0.01 is achievable with commensurately improved characterizations and controls.

  17. Cosmic odyssey

    International Nuclear Information System (INIS)

    Heidmann, J.

    1989-01-01

    The immensity of the cosmos, the richness of the universe, the limits of space and time: these are the themes of Cosmic Odyssey, which takes the reader on imaginary journeys through the past, present and future of our universe. After a first look at the starry night sky, the enigmas posed since ancient times by the universe are reviewed. There then follows a broadbrush view of the universe as we understand it today. Following this, a trio of chapters take us to ultimate questions about its nature. The author explores in turn the relativistic universe, the quantum universe and the inflationary universe. Finally the journey returns to questions that touch on our own presence in the universe. Cosmology, the science of understanding the nature of the universe as a whole, has gone through an extraordinary revolution in its approach. This book explains in detail the link between particle physics and cosmology, the very early universe, the significance of Grand Unified Theory and superstrings, the magical qualities of the inflationary universe, and the seemingly bleak scenarios for the farthest future. (author)

  18. Cosmic Discovery

    Science.gov (United States)

    Harwit, Martin

    1984-04-01

    In the remarkable opening section of this book, a well-known Cornell astronomer gives precise thumbnail histories of the 43 basic cosmic discoveries - stars, planets, novae, pulsars, comets, gamma-ray bursts, and the like - that form the core of our knowledge of the universe. Many of them, he points out, were made accidentally and outside the mainstream of astronomical research and funding. This observation leads him to speculate on how many more major phenomena there might be and how they might be most effectively sought out in afield now dominated by large instruments and complex investigative modes and observational conditions. The book also examines discovery in terms of its political, financial, and sociological context - the role of new technologies and of industry and the military in revealing new knowledge; and methods of funding, of peer review, and of allotting time on our largest telescopes. It concludes with specific recommendations for organizing astronomy in ways that will best lead to the discovery of the many - at least sixty - phenomena that Harwit estimates are still waiting to be found.

  19. Constraints on Cosmological Models from Cosmic Flows

    Science.gov (United States)

    Hudson, M. J.; Smith, R. J.; Lucey, J. R.; Schlegel, D. J.; Davies, R. L.

    Cosmic flows are the only probe of the large-scale mass power spectrum available at low redshift. An important statistic is the bulk flow of a peculiar velocity sample with respect to the Cosmic Microwave background. We compare the bulk flow of the SMAC cluster sample to the predictions of popular cosmological models and to other recent large-scale peculiar velocity surveys. Both analyses account for aliasing of small-scale power due to the sparse and non-uniform sampling of the surveys. We conclude that the SMAC bulk flow is in marginal conflict with flat COBE-normalized ΛCDM models which fit the cluster abundance constraint. However, power spectra which are steeper shortward of the peak are consistent with all of the above constraints. When recent large-scale peculiar velocity surveys are compared, we conclude that all measured bulk flows (with the possible exception of that of Lauer & Postman) are consistent with each other given the errors, provided the latter allow for ``cosmic covariance''. A rough estimate of the mean bulk flow of all surveys (except Lauer & Postman) is ˜400 km/s with respect to the Cosmic Microwave Background.

  20. The Thirty Gigahertz Instrument Receiver for the QUIJOTE Experiment: Preliminary Polarization Measurements and Systematic-Error Analysis

    Directory of Open Access Journals (Sweden)

    Francisco J. Casas

    2015-08-01

    Full Text Available This paper presents preliminary polarization measurements and systematic-error characterization of the Thirty Gigahertz Instrument receiver developed for the QUIJOTE experiment. The instrument has been designed to measure the polarization of Cosmic Microwave Background radiation from the sky, obtaining the Q, U, and I Stokes parameters of the incoming signal simultaneously. Two kinds of linearly polarized input signals have been used as excitations in the polarimeter measurement tests in the laboratory; these show consistent results in terms of the Stokes parameters obtained. A measurement-based systematic-error characterization technique has been used in order to determine the possible sources of instrumental errors and to assist in the polarimeter calibration process.

  1. Gravitational-wave stochastic background from cosmic strings.

    Science.gov (United States)

    Siemens, Xavier; Mandic, Vuk; Creighton, Jolien

    2007-03-16

    We consider the stochastic background of gravitational waves produced by a network of cosmic strings and assess their accessibility to current and planned gravitational wave detectors, as well as to big bang nucleosynthesis (BBN), cosmic microwave background (CMB), and pulsar timing constraints. We find that current data from interferometric gravitational wave detectors, such as Laser Interferometer Gravitational Wave Observatory (LIGO), are sensitive to areas of parameter space of cosmic string models complementary to those accessible to pulsar, BBN, and CMB bounds. Future more sensitive LIGO runs and interferometers such as Advanced LIGO and Laser Interferometer Space Antenna (LISA) will be able to explore substantial parts of the parameter space.

  2. Gravitational-Wave Stochastic Background from Cosmic Strings

    International Nuclear Information System (INIS)

    Siemens, Xavier; Creighton, Jolien; Mandic, Vuk

    2007-01-01

    We consider the stochastic background of gravitational waves produced by a network of cosmic strings and assess their accessibility to current and planned gravitational wave detectors, as well as to big bang nucleosynthesis (BBN), cosmic microwave background (CMB), and pulsar timing constraints. We find that current data from interferometric gravitational wave detectors, such as Laser Interferometer Gravitational Wave Observatory (LIGO), are sensitive to areas of parameter space of cosmic string models complementary to those accessible to pulsar, BBN, and CMB bounds. Future more sensitive LIGO runs and interferometers such as Advanced LIGO and Laser Interferometer Space Antenna (LISA) will be able to explore substantial parts of the parameter space

  3. Excess B-modes extracted from the Planck polarization maps

    Science.gov (United States)

    Nørgaard-Nielsen, H. U.

    2016-06-01

    One of the main obstacles for extracting the Cosmic Microwave Background (CMB) from mm/submm observations is the pollution from the main Galactic components: synchrotron, free-free and thermal dust emission. The feasibility of using simple neural networks to extract CMB has been demonstrated on both temperature and polarization data obtained by the WMAP satellite. The main goal of this paper is to demonstrate the feasibility of neural networks for extracting the CMB signal from the Planck polarization data with high precision. Both auto-correlation and cross-correlation power spectra within a mask covering about 63 % of the sky have been used together with a ``high pass filter'' in order to minimize the influence of the remaining systematic errors in the Planck Q and U maps. Using the Planck 2015 released polarization maps, a BB power spectrum have been extracted by Multilayer Perceptron neural networks. This spectrum contains a bright feature with signal to noise ratios ≃ 4.5 within 200 ≤ l ≤ 250. The spectrum is significantly brighter than the BICEP2 2015 spectrum, with a spectral behaviour quite different from the ``canonical'' models (weak lensing plus B-modes spectra with different tensor to scalar ratios). The feasibility of the neural network to remove the residual systematics from the available Planck polarization data to a high level has been demonstrated.

  4. Microwave undulator

    International Nuclear Information System (INIS)

    Batchelor, K.

    1986-03-01

    The theory of a microwave undulator utilizing a plane rectangular waveguide operating in the TE/sub 10n/ mode and other higher order modes is presented. Based on this, a possible undulator configuration is analyzed, leading to the conclusion that the microwave undulator represents a viable option for undulator wavelength down to about 1 cm where peak voltage and available microwave power considerations limit effectiveness. 4 refs., 4 figs

  5. Mapping the CMB with the Wilkinson Microwave Anisotropy Probe

    Science.gov (United States)

    Hinshaw, Gary F.

    2007-01-01

    The data from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite provide detailed full-sky maps of the cosmic microwave background temperature anisotropy and new full-sky maps of the polarization. Together, the data provide a wealth of cosmological information, including the age of the universe, the epoch when the first stars formed, and the overall composition of baryonic matter, dark matter, and dark energy. The results also provide constraints on the period of inflationary expansion in the very first moments of time. These and other aspects of the mission results will be discussed and commented on. WMAP, part of NASA's Explorers program, was launched on June 30,200 1. The WMAP satellite was produced in a partnership between the Goddard Space Flight Center and Princeton University. The WMAP team also includes researchers at the Johns Hopkins University; the Canadian Institute of Theoretical Astrophysics; University of Texas; University of Chicago; Brown University; University of British Columbia; and University of California, Los Angeles.

  6. Cosmic Interactions

    Science.gov (United States)

    2008-01-01

    An image based on data taken with ESO's Very Large Telescope reveals a triplet of galaxies intertwined in a cosmic dance. ESO PR Photo 02/08 ESO PR Photo 02/08 NGC 7173, 7174, and 7176 The three galaxies, catalogued as NGC 7173 (top), 7174 (bottom right) and 7176 (bottom left), are located 106 million light-years away towards the constellation of Piscis Austrinus (the 'Southern Fish'). NGC 7173 and 7176 are elliptical galaxies, while NGC 7174 is a spiral galaxy with quite disturbed dust lanes and a long, twisted tail. This seems to indicate that the two bottom galaxies - whose combined shape bears some resemblance to that of a sleeping baby - are currently interacting, with NGC 7176 providing fresh material to NGC 7174. Matter present in great quantity around the triplet's members also points to the fact that NGC 7176 and NGC 7173 have interacted in the past. Astronomers have suggested that the three galaxies will finally merge into a giant 'island universe', tens to hundreds of times as massive as our own Milky Way. ESO PR Photo 02/08 ESO PR Photo 02b/08 NGC 7173, 7174, and 7176 The triplet is part of a so-called 'Compact Group', as compiled by Canadian astronomer Paul Hickson in the early 1980s. The group, which is the 90th entry in the catalogue and is therefore known as HCG 90, actually contains four major members. One of them - NGC 7192 - lies above the trio, outside of this image, and is another peculiar spiral galaxy. Compact groups are small, relatively isolated, systems of typically four to ten galaxies in close proximity to one another. Another striking example is Robert's Quartet. Compact groups are excellent laboratories for the study of galaxy interactions and their effects, in particular the formation of stars. As the striking image reveals, there are many other galaxies in the field. Some are distant ones, while others seem to be part of the family. Studies made with other telescopes have indeed revealed that the HCG 90 group contains 16 members

  7. ALICE Cosmic Ray Detector

    CERN Multimedia

    Fernandez Tellez, A; Martinez Hernandez, M; Rodriguez Cahuantzi, M

    2013-01-01

    The ALICE underground cavern provides an ideal place for the detection of high energy atmospheric muons coming from cosmic ray showers. ACORDE detects cosmic ray showers by triggering the arrival of muons to the top of the ALICE magnet.

  8. Microwave Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Makes ultra-high-resolution field measurements. The Microwave Microscope (MWM) has been used in support of several NRL experimental programs involving sea...

  9. Microwave detector

    Science.gov (United States)

    Meldner, H.W.; Cusson, R.Y.; Johnson, R.M.

    1985-02-08

    A microwave detector is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite produces a magnetization field flux that links a B-dot loop. The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means are provided for measuring electric voltage or current induced in the B-dot loop. The recorded output of the detector is proportional to the time derivative of the square of the envelope shape of the microwave pulse.

  10. Improved constraint on the primordial gravitational-wave density using recent cosmological data and its impact on cosmic string models

    International Nuclear Information System (INIS)

    Henrot-Versillé, Sophie; Robinet, Florent; Leroy, Nicolas; Plaszczynski, Stéphane; Arnaud, Nicolas; Bizouard, Marie-Anne; Cavalier, Fabien; Christensen, Nelson; Couchot, François; Franco, Samuel; Hello, Patrice; Huet, Dominique; Kasprzack, Marie; Perdereau, Olivier; Spinelli, Marta; Tristram, Matthieu

    2015-01-01

    The production of a primordial stochastic gravitational-wave (GW) background by processes occuring in the early Universe is expected in a broad range of models. Observing this background would open a unique window onto the Universe's evolutionary history. Probes like the cosmic microwave background (CMB) or the baryon acoustic oscillations (BAO) can be used to set upper limits on the stochastic GW background energy density Ω GW for frequencies above 10 −15 Hz. We perform a profile likelihood analysis of the Planck CMB temperature anisotropies and gravitational lensing data combined with WMAP low-ℓ polarization, BAO, South Pole Telescope and Atacama Cosmology Telescope data. We find that Ω GW h 0 2 <3.8×10 −6 at a 95% confidence level for adiabatic initial conditions, which improves over the previous limit by a factor 2.3. Assuming that the primordial GW has been produced by a network of cosmic strings, we have derived exclusion limits in the cosmic string parameter space. If the size of the loops is determined by gravitational back-reaction, string tension values greater than ∼4 × 10 −9 are excluded for a reconnection probability of 10 −3 . (paper)

  11. Current constraints on the cosmic growth history

    International Nuclear Information System (INIS)

    Bean, Rachel; Tangmatitham, Matipon

    2010-01-01

    We present constraints on the cosmic growth history with recent cosmological data, allowing for deviations from ΛCDM as might arise if cosmic acceleration is due to modifications to general relativity or inhomogeneous dark energy. We combine measures of the cosmic expansion history, from Type 1a supernovae, baryon acoustic oscillations, and the cosmic microwave background (CMB), with constraints on the growth of structure from recent galaxy, CMB, and weak lensing surveys along with integated Sachs Wolfe-galaxy cross correlations. Deviations from ΛCDM are parameterized by phenomenological modifications to the Poisson equation and the relationship between the two Newtonian potentials. We find modifications that are present at the time the CMB is formed are tightly constrained through their impact on the well-measured CMB acoustic peaks. By contrast, constraints on late-time modifications to the growth history, as might arise if modifications are related to the onset of cosmic acceleration, are far weaker, but remain consistent with ΛCDM at the 95% confidence level. For these late-time modifications we find that differences in the evolution on large and small scales could provide an interesting signature by which to search for modified growth histories with future wide angular coverage, large scale structure surveys.

  12. Polarization of Sunyaev-Zel'dovich signal due to electron pressure anisotropy in galaxy clusters

    Science.gov (United States)

    Khabibullin, I.; Komarov, S.; Churazov, E.; Schekochihin, A.

    2018-02-01

    We describe polarization of the Sunyaev-Zel'dovich (SZ) effect associated with electron pressure anisotropy likely present in the intracluster medium (ICM). The ICM is an astrophysical example of a weakly collisional plasma where the Larmor frequencies of charged particles greatly exceed their collision frequencies. This permits formation of pressure anisotropies, driven by evolving magnetic fields via adiabatic invariance, or by heat fluxes. SZ polarization arises in the process of Compton scattering of the cosmic microwave background (CMB) photons off the thermal ICM electrons due to the difference in the characteristic thermal velocities of the electrons along two mutually orthogonal directions in the sky plane. The signal scales linearly with the optical depth of the region containing large-scale correlated anisotropy, and with the degree of anisotropy itself. It has the same spectral dependence as the polarization induced by cluster motion with respect to the CMB frame (kinematic SZ effect polarization), but can be distinguished by its spatial pattern. For the illustrative case of a galaxy cluster with a cold front, where electron transport is mediated by Coulomb collisions, we estimate the CMB polarization degree at the level of 10-8 (˜10 nK). An increase of the effective electron collisionality due to plasma instabilities will reduce the effect. Such polarization, therefore, may be an independent probe of the electron collisionality in the ICM, which is one of the key properties of a high-β weakly collisional plasma from the point of view of both astrophysics and plasma theory.

  13. Statistical Physics for Cosmic Structures

    CERN Document Server

    Gabrielli, Andrea

    2004-01-01

    The physics of scale-invariant and complex systems is a novel interdisciplinary field. Its ideas allow us to look at natural phenomena in a radically new and original way, eventually leading to unifying concepts independent of the detailed structure of the systems. The objective is the study of complex, scale-invariant, and more general stochastic structures that appear both in space and time in a vast variety of natural phenomena, which exhibit new types of collective behaviors, and the fostering of their understanding. This book has been conceived as a methodological monograph in which the main methods of modern statistical physics for cosmological structures and density fields (galaxies, Cosmic Microwave Background Radiation, etc.) are presented in detail. The main purpose is to present clearly, to a workable level, these methods, with a certain mathematical accuracy, providing also some paradigmatic examples of applications. This should result in a new and more general framework for the statistical analys...

  14. Primordial gravitational waves measurements and anisotropies of CMB polarization rotation

    Directory of Open Access Journals (Sweden)

    Si-Yu Li

    2015-12-01

    Full Text Available Searching for the signal of primordial gravitational waves in the B-modes (BB power spectrum is one of the key scientific aims of the cosmic microwave background (CMB polarization experiments. However, this could be easily contaminated by several foreground issues, such as the interstellar dust grains and the galactic cyclotron electrons. In this paper we study another mechanism, the cosmic birefringence, which can be introduced by a CPT-violating interaction between CMB photons and an external scalar field. Such kind of interaction could give rise to the rotation of the linear polarization state of CMB photons, and consequently induce the CMB BB power spectrum, which could mimic the signal of primordial gravitational waves at large scales. With the recently released polarization data of BICEP2 and the joint analysis data of BICEP2/Keck Array and Planck, we perform a global fitting analysis on constraining the tensor-to-scalar ratio r by considering the polarization rotation angle [α(nˆ] which can be separated into a background isotropic part [α¯] and a small anisotropic part [Δα(nˆ]. Since the data of BICEP2 and Keck Array experiments have already been corrected by using the “self-calibration” method, here we mainly focus on the effects from the anisotropies of CMB polarization rotation angle. We find that including Δα(nˆ in the analysis could slightly weaken the constraints on the tensor-to-scalar ratio r, when using current CMB polarization measurements. We also simulate the mock CMB data with the BICEP3-like sensitivity. Very interestingly, we find that if the effects of the anisotropic polarization rotation angle could not be taken into account properly in the analysis, the constraints on r will be dramatically biased. This implies that we need to break the degeneracy between the anisotropies of the CMB polarization rotation angle and the CMB primordial tensor perturbations, in order to measure the signal of primordial

  15. Cosmic Complexity

    Science.gov (United States)

    Mather, John C.

    2012-01-01

    neutrons, liberating a little energy and creating complexity. Then, the expanding universe cooled some more, and neutrons and protons, no longer kept apart by immense temperatures, found themselves unstable and formed helium nuclei. Then, a little more cooling, and atomic nuclei and electrons were no longer kept apart, and the universe became transparent. Then a little more cooling, and the next instability began: gravitation pulled matter together across cosmic distances to form stars and galaxies. This instability is described as a "negative heat capadty" in which extracting energy from a gravitating system makes it hotter -- clearly the 2nd law of thermodynamics does not apply here! (This is the physicist's part of the answer to e e cummings' question: what is the wonder that's keeping the stars apart?) Then, the next instability is that hydrogen and helium nuclei can fuse together to release energy and make stars burn for billions of years. And then at the end of the fuel source, stars become unstable and explode and liberate the chemical elements back into space. And because of that, on planets like Earth, sustained energy flows support the development of additional instabilities and all kinds of complex patterns. Gravitational instability pulls the densest materials into the core of the Earth, leaving a thin skin of water and air, and makes the interior churn incessantly as heat flows outwards. And the heat from the sun, received mostly near the equator and flowing towards the poles, supports the complex atmospheric and oceanic circulations. And because or that, the physical Earth is full of natural chemical laboratories, concentrating elements here, mixing them there, raising and lowering temperatures, ceaselessly experimenting with uncountable events where new instabilities can arise. At least one of them was the new experiment called life. Now that we know that there are at least as many planets as there are stars, it is hard to imagine that nature's ceasess

  16. On the large COMPASS polarized deuteron target

    CERN Document Server

    Finger, M; Baum, G; Doshita, N; Finger, M Jr; Gautheron, F; Goertz, St; Hasegawa, T; Heckmann, J; Hess, Ch; Horikawa, N; Ishimoto, S; Iwata, T; Kisselev, Y; Koivuniemi, J; Kondo, K; Le Goff, J-M; Magnon, A; Marchand, C; Matsuda, T; Meyer, W; Reicherz, G; Srnka, A

    2006-01-01

    The spin structure of the nucleons is investigated in deep inelastic scattering of a polarized muon beam and a polarized nucleon target in the COMPASS experiment at CERN since 2001. To achieve high luminosities a large solid polarized target is used. The COMPASS polarized target consists of a high cooling power $^{3}$He/$^{4}$He dilution refrigerator capable to maintain working temperature of the target material at about 50mK, a superconducting solenoid and dipole magnet system for longitudinal and transversal magnetic field on the target material, respectively, target cells containing polarizable material, microwave cavities and high power microwave radiation systems for dynamic nuclear polarization and the nuclear magnetic resonance system for nuclear spin polarization measurements. During 2001–2004 experiments superconducting magnet system with opening angle $\\pm$69 mrad, polarized target holder with two target cells and corresponding microwave and NMR systems have been used. For the data taking from 200...

  17. Extended Special Sensor Microwave Imager (SSM/I) Sensor Data Record (SDR) in netCDF

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Special Sensor Microwave Imager (SSM/I) is a seven-channel linearly polarized passive microwave radiometer that operates at frequencies of 19.36 (vertically and...

  18. Extended Special Sensor Microwave Imager (SSM/I) Temperature Data Record (TDR) in netCDF

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Special Sensor Microwave Imager (SSM/I) is a seven-channel linearly polarized passive microwave radiometer that operates at frequencies of 19.36 (vertically and...

  19. Microwave Measurements

    CERN Document Server

    Skinner, A D

    2007-01-01

    The IET has organised training courses on microwave measurements since 1983, at which experts have lectured on modern developments. Their lecture notes were first published in book form in 1985 and then again in 1989, and they have proved popular for many years with a readership beyond those who attended the courses. The purpose of this third edition of the lecture notes is to bring the latest techniques in microwave measurements to this wider audience. The book begins with a survey of the theory of current microwave circuits and continues with a description of the techniques for the measureme

  20. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  1. Collisions of cosmic F- and D-strings

    International Nuclear Information System (INIS)

    Jones, N.

    2004-01-01

    Recent theoretical advances and upcoming experimental measurements make the testing of generic predictions of string theory models of cosmology feasible. Brane anti-brane models of inflation within superstring theory are promising as string theory descriptions of the physics of the early universe. While varied in their construction, these models can have the generic and observable consequence that cosmic strings will be abundant in the early universe. This leads to possible detectable effects in the cosmic microwave background, gravitational wave physics and gravitational lensing. Detailed calculations of cosmic string interactions within string theory are presented, in order to distinguish these cosmic strings from those in more conventional theories; these interaction probabilities can be very different from conventional 4-dimension strings, providing the possibility of experimental tests of string theory. (authors)

  2. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2013-01-01

    Microwave photonics continues to see rapid growth. The integration of optical fiber and wireless networks has become a commercial reality and is becoming increasingly pervasive. Such hybrid technology will lead to many innovative applications, including backhaul solutions for mobile networks and ultrabroadband wireless networks that can provide users with very high bandwidth services. Microwave Photonics, Second Edition systematically introduces important technologies and applications in this emerging field. It also reviews recent advances in micro- and millimeter-wavelength and terahertz-freq

  3. Polarized electrogowdy spacetimes censored

    Energy Technology Data Exchange (ETDEWEB)

    Nungesser, Ernesto, E-mail: ernesto.nungesser@aei.mpg.d [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, 14476 Potsdam (Germany)

    2010-05-01

    A sketch of the proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  4. High energy cosmic rays

    CERN Document Server

    Stanev, Todor

    2010-01-01

    Offers an accessible text and reference (a cosmic-ray manual) for graduate students entering the field and high-energy astrophysicists will find this an accessible cosmic-ray manual Easy to read for the general astronomer, the first part describes the standard model of cosmic rays based on our understanding of modern particle physics. Presents the acceleration scenario in some detail in supernovae explosions as well as in the passage of cosmic rays through the Galaxy. Compares experimental data in the atmosphere as well as underground are compared with theoretical models

  5. Cosmic Accelerators: An Introduction

    International Nuclear Information System (INIS)

    Kanbach, Gottfried

    2005-01-01

    High energy, relativistic, particles are an essential component of the Universe and play a major role in astrophysics. In a few years we will reach the centennial of the discovery of cosmic rays; all through this century the properties, origin, and effects of this radiation have intrigued researchers in astrophysics and elementary particles alike. We briefly review the history, current status, and future perspectives of cosmic ray research. Emphasis will be placed on the multitude of cosmic accelerators, direct observations of these objects, and the effects of cosmic rays in the Galaxy and beyond

  6. Optical Modeling and Polarization Calibration for CMB Measurements with Actpol and Advanced Actpol

    Science.gov (United States)

    Koopman, Brian; Austermann, Jason; Cho, Hsiao-Mei; Coughlin, Kevin P.; Duff, Shannon M.; Gallardo, Patricio A.; Hasselfield, Matthew; Henderson, Shawn W.; Ho, Shuay-Pwu Patty; Hubmayr, Johannes; hide

    2016-01-01

    The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive upgrade to the Atacama Cosmology Telescope, located at an elevation of 5190 m on Cerro Toco in Chile. ACTPol uses transition edge sensor bolometers coupled to orthomode transducers to measure both the temperature and polarization of the Cosmic Microwave Background (CMB). Calibration of the detector angles is a critical step in producing polarization maps of the CMB. Polarization angle offsets in the detector calibration can cause leakage in polarization from E to B modes and induce a spurious signal in the EB and TB cross correlations, which eliminates our ability to measure potential cosmological sources of EB and TB signals, such as cosmic birefringence. We calibrate the ACTPol detector angles by ray tracing the designed detector angle through the entire optical chain to determine the projection of each detector angle on the sky. The distribution of calibrated detector polarization angles are consistent with a global offset angle from zero when compared to the EB-nulling offset angle, the angle required to null the EB cross-correlation power spectrum. We present the optical modeling process. The detector angles can be cross checked through observations of known polarized sources, whether this be a galactic source or a laboratory reference standard. To cross check the ACTPol detector angles, we use a thin film polarization grid placed in front of the receiver of the telescope, between the receiver and the secondary reflector. Making use of a rapidly rotating half-wave plate (HWP) mount we spin the polarizing grid at a constant speed, polarizing and rotating the incoming atmospheric signal. The resulting sinusoidal signal is used to determine the detector angles. The optical modeling calibration was shown to be consistent with a global offset angle of zero when compared to EB nulling in the first ACTPol results and will continue to be a part of our calibration implementation. The first

  7. Recent Developments in Astrophysical and Cosmological Exploitation of Microwave Surveys

    DEFF Research Database (Denmark)

    Burigana, Carlo; Davies, Rodney D.; De Bernardis, Paolo

    2013-01-01

    In this paper, we focus on the astrophysical results and the related cosmological implications derived from recent microwave surveys, with emphasis to those coming from the Planck mission. We critically discuss the impact of systematic effects and the role of methods to separate the cosmic...... microwave background (CMB) signal from the astrophysical emissions and each different astrophysical component from the others. We then review the state-of-the-art diffuse emissions, extragalactic sources, cosmic infrared background and galaxy clusters, addressing the information they provide to our global...

  8. Maria Montessori's Cosmic Vision, Cosmic Plan, and Cosmic Education

    Science.gov (United States)

    Grazzini, Camillo

    2013-01-01

    This classic position of the breadth of Cosmic Education begins with a way of seeing the human's interaction with the world, continues on to the grandeur in scale of time and space of that vision, then brings the interdependency of life where each growing human becomes a participating adult. Mr. Grazzini confronts the laws of human nature in…

  9. Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes

    CERN Document Server

    Adam, R.; Aghanim, N.; Arnaud, M.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartlett, J.G.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoit-Levy, A.; Bernard, J.P.; Bersanelli, M.; Bielewicz, P.; Bonaldi, A.; Bonavera, L.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bracco, A.; Bucher, M.; Burigana, C.; Butler, R.C.; Calabrese, E.; Cardoso, J.F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.R.; Chiang, H.C.; Christensen, P.R.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Combet, C.; Couchot, F.; Coulais, A.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Zotti, G.; Delabrouille, J.; Delouis, J.M.; Desert, F.X.; Dickinson, C.; Diego, J.M.; Dolag, K.; Dole, H.; Donzelli, S.; Dore, O.; Douspis, M.; Ducout, A.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Elsner, F.; Ensslin, T.A.; Eriksen, H.K.; Falgarone, E.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A.A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Ghosh, T.; Giard, M.; Giraud-Heraud, Y.; Gjerlow, E.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Guillet, V.; Hansen, F.K.; Hanson, D.; Harrison, D.L.; Helou, G.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hivon, E.; Holmes, W.A.; Huffenberger, K.M.; Hurier, G.; Jaffe, A.H.; Jaffe, T.R.; Jewell, J.; Jones, W.C.; Juvela, M.; Keihanen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Knox, L.; Krachmalnicoff, N.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.M.; Lasenby, A.; Lattanzi, M.; Lawrence, C.R.; Leahy, J.P.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Macias-Perez, J.F.; Maffei, B.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschenes, M.A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J.A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Pearson, T.J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Pratt, G.W.; Prunet, S.; Puget, J.L.; Rachen, J.P.; Reach, W.T.; Rebolo, R.; Remazeilles, M.; Renault, C.; Renzi, A.; Ricciardi, S.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; d'Orfeuil, B.Rouille; Rubino-Martin, J.A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Soler, J.D.; Spencer, L.D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.S.; Sygnet, J.F.; Tauber, J.A.; Terenzi, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vibert, L.; Vielva, P.; Villa, F.; Wade, L.A.; Wandelt, B.D.; Watson, R.; Wehus, I.K.; White, M.; White, S.D.M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2016-02-09

    The polarized thermal emission from Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100GHz. We exploit the Planck HFI polarization data from 100 to 353GHz to measure the dust angular power spectra $C_\\ell^{EE,BB}$ over the range $40<\\ell<600$. These will bring new insights into interstellar dust physics and a precise determination of the level of contamination for CMB polarization experiments. We show that statistical properties of the emission can be characterized over large fractions of the sky using $C_\\ell$. For the dust, they are well described by power laws in $\\ell$ with exponents $\\alpha^{EE,BB}=-2.42\\pm0.02$. The amplitudes of the polarization $C_\\ell$ vary with the average brightness in a way similar to the intensity ones. The dust polarization frequency dependence is consistent with modified blackbody emission with $\\beta_d=1.59$ and $T_d=19.6$K. We find a systematic ratio between the amplitudes of ...

  10. Interactions of cosmic superstrings

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Mark G.; /Fermilab

    2007-06-01

    We develop methods by which cosmic superstring interactions can be studied in detail. These include the reconnection probability and emission of radiation such as gravitons or small string loops. Loop corrections to these are discussed, as well as relationships to (p; q)-strings. These tools should allow a phenomenological study of string models in anticipation of upcoming experiments sensitive to cosmic string radiation.

  11. Deepening Cosmic Education

    Science.gov (United States)

    Leonard, Gerard

    2013-01-01

    This article is a special blend of research, theory, and practice, with clear insight into the origins of Cosmic Education and cosmic task, while recalling memories of student explorations in botany, in particular, episodes from Mr. Leonard's teaching. Mr. Leonard speaks of a storytelling curriculum that eloquently puts perspective into dimensions…

  12. Constraints on Cosmic Strings from the LIGO-Virgo Gravitational-Wave Detectors

    Science.gov (United States)

    Aasi, J.; Abadie, J.; Abbott, B.P.; Abbott, R.; Abbott, T.; Abernathy, M.R.; Accadia, T.; Adams, C.; Adams, T.; Adhikari, R.X.; hide

    2014-01-01

    Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs from cosmic microwave background measurements and pulsar timing data. In particular, if the size of loops is given by the gravitational backreaction scale, we place upper limits on the string tension (Newton's Constant x mass per unit length) below 10(exp -8) in some regions of the cosmic string parameter space.

  13. Our Cosmic Insignificance

    Science.gov (United States)

    Kahane, Guy

    2014-01-01

    The universe that surrounds us is vast, and we are so very small. When we reflect on the vastness of the universe, our humdrum cosmic location, and the inevitable future demise of humanity, our lives can seem utterly insignificant. Many philosophers assume that such worries about our significance reflect a banal metaethical confusion. They dismiss the very idea of cosmic significance. This, I argue, is a mistake. Worries about cosmic insignificance do not express metaethical worries about objectivity or nihilism, and we can make good sense of the idea of cosmic significance and its absence. It is also possible to explain why the vastness of the universe can make us feel insignificant. This impression does turn out to be mistaken, but not for the reasons typically assumed. In fact, we might be of immense cosmic significance—though we cannot, at this point, tell whether this is the case. PMID:25729095

  14. Cosmic ray decreases affect atmospheric aerosols and clouds

    DEFF Research Database (Denmark)

    Svensmark, Henrik; Bondo, Torsten; Svensmark, J.

    2009-01-01

    Close passages of coronal mass ejections from the sun are signaled at the Earth's surface by Forbush decreases in cosmic ray counts. We find that low clouds contain less liquid water following Forbush decreases, and for the most influential events the liquid water in the oceanic atmosphere can...... diminish by as much as 7%. Cloud water content as gauged by the Special Sensor Microwave/Imager (SSM/I) reaches a minimum ≈7 days after the Forbush minimum in cosmic rays, and so does the fraction of low clouds seen by the Moderate Resolution Imaging Spectroradiometer (MODIS) and in the International...

  15. Angular and Polarization Response of Multimode Sensors with Resistive-Grid Absorbers

    Science.gov (United States)

    Kusaka, Akito; Wollack, Edward J.; Stevenson, Thomas R.

    2014-01-01

    High sensitivity receiver systems with near ideal polarization sensitivity are highly desirable for development of millimeter and sub-millimeter radio astronomy. Multimoded bolometers provide a unique solution to achieve such sensitivity, for which hundreds of single-mode sensors would otherwise be required. The primary concern in employing such multimoded sensors for polarimetery is the control of the polarization systematics. In this paper, we examine the angular- and polarization- dependent absorption pattern of a thin resistive grid or membrane, which models an absorber used for a multimoded bolometer. The result shows that a freestanding thin resistive absorber with a surface resistivity of eta/2, where eta is the impedance of free space, attains a beam pattern with equal E- and H-plane responses, leading to zero cross polarization. For a resistive-grid absorber, the condition is met when a pair of grids is positioned orthogonal to each other and both have a resistivity of eta/2. When a reflective backshort termination is employed to improve absorption efficiency, the cross-polar level can be suppressed below -30 dB if acceptance angle of the sensor is limited to < or approx. 60deg. The small cross-polar systematics have even-parity patterns and do not contaminate the measurements of odd-parity polarization patterns, for which many of recent instruments for cosmic microwave background are designed. Underlying symmetry that suppresses these cross-polar systematics is discussed in detail. The estimates and formalism provided in this paper offer key tools in the design consideration of the instruments using the multimoded polarimeters.

  16. Understanding the microwave annealing of silicon

    Directory of Open Access Journals (Sweden)

    Chaochao Fu

    2017-03-01

    Full Text Available Though microwave annealing appears to be very appealing due to its unique features, lacking an in-depth understanding and accurate model hinder its application in semiconductor processing. In this paper, the physics-based model and accurate calculation for the microwave annealing of silicon are presented. Both thermal effects, including ohmic conduction loss and dielectric polarization loss, and non-thermal effects are thoroughly analyzed. We designed unique experiments to verify the mechanism and extract relevant parameters. We also explicitly illustrate the dynamic interaction processes of the microwave annealing of silicon. This work provides an in-depth understanding that can expedite the application of microwave annealing in semiconductor processing and open the door to implementing microwave annealing for future research and applications.

  17. Polar low monitoring

    Science.gov (United States)

    Bobylev, Leonid; Zabolotskikh, Elizaveta; Mitnik, Leonid

    2010-05-01

    Polar lows are intense mesoscale atmospheric low pressure weather systems, developing poleward of the main baroclinic zone and associated with high surface wind speeds. Small size and short lifetime, sparse in-situ observations in the regions of their development complicate polar low study. Our knowledge of polar lows and mesocyclones has come almost entirely during the period of satellite remote sensing since, by virtue of their small horizontal scale, it was rarely possible to analyse these lows on conventional weather charts using only the data from the synoptic observing network. However, the effects of intense polar lows have been felt by coastal communities and seafarers since the earliest times. These weather systems are thought to be responsible for the loss of many small vessels over the centuries, although the nature of the storms was not understood and their arrival could not be predicted. The actuality of the polar low research is stipulated by their high destructive power: they are a threat to such businesses as oil and gas exploration, fisheries and shipping. They could worsen because of global warming: a shrinking of sea ice around the North Pole, which thawed to its record minimum in the summer of 2007, is likely to give rise to more powerful storms that form only over open water and can cause hurricane-strength winds. Therefore, study of polar lows, their timely detection, tracking and forecasting represents a challenge for today meteorology. Satellite passive microwave data, starting from Special Sensor Microwave Imager (SSM/I) onboard Defense Meteorological Satellite Program (DMSP) satellite, remain invaluable source of regularly available remotely sensed data to study polar lows. The sounding in this spectral range has several advantages in comparison with observations in visible and infrared ranges and Synthetic Aperture Radar (SAR) data: independence on day time and clouds, regularity and high temporal resolution in Polar Regions. Satellite

  18. Cosmic statistics on linear scales

    Science.gov (United States)

    Papai, Peter

    We use the formalism of Szapudi (2004) to derive full explicit expressions for the linear two-point correlation function, including redshift space distortions and large angle effects. We take into account a non-perturbative geometric term in the Jacobian, which is still linear in terms of the dynamics. This term had been identified previously (Kaiser, 1987; Hamilton and Culhane, 1996), but has been neglected in all subsequent explicit calculations of the linear redshift space two-point correlation function. Our results represent a significant correction to previous explicit expressions and608are in excellent agreement with our measurements in the Hubble Volume Simulation. We measure the matter probability distribution function (PDF) via counts in cells in a volume limited subsample of the Sloan Digital Sky Survey (SDSS) Luminous Red Galaxy Catalog on scales from 30 h-1 Mpc to 150 h-1Mpc and estimate the linear integrated Sachs-Wolfe (ISW) effect produced by supervoids and superclusters in the tail of the PDF. We characterize the PDF by the variance, S3, and S4, and study in simulations the systematic effects due to finite volume, survey shape and redshift distortion. We compare our measurement to the prediction of ΛCDM with linear bias and find a good agreement. We use the moments to approximate the tail of the PDF with analytic functions. A simple Gaussian model for the superstructures appears to be consistent with the claim by Granett et al. (2008) that density fluctuations on 100 h-1Mpc scales produce hot and cold spots with DeltaT ≈ 10mu K on the cosmic microwave background. We calculate the full density and ISW profiles of spherical superstructures. We find that the Gaussian assumptions capable of describing N-body simulations and simulated ISW maps remarkably well on large scales. We construct an ISW map based on locations of superstructures identified previously in the SDSS Luminous Red Galaxy sample. A matched filter analysis of the cosmic microwave

  19. Implications of cosmic strings with time-varying tension on the CMB and large scale structure

    International Nuclear Information System (INIS)

    Ichikawa, Kazuhide; Takahashi, Tomo; Yamaguchi, Masahide

    2006-01-01

    We investigate cosmological evolution and implications of cosmic strings with time-dependent tension. We derive basic equations of time development of the correlation length and the velocity of such strings, based on the one-scale model. Then, we find that, in the case where the tension depends on some power of the cosmic time, cosmic strings with time-dependent tension goes into the scaling solution if the power is lower than a critical value. We also discuss cosmic microwave background anisotropy and matter power spectra produced by these strings. The constraints on their tensions from the Wilkinson microwave anisotropy probe (WMAP) 3 yr data and Sloan digital sky survey (SDSS) data are also given

  20. Microwave Irradiation

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 3. Microwave Irradiation - Way to Eco-friendly, Green Chemistry. Rashmi Sanghi. General Article Volume 5 Issue 3 March 2000 pp 77-81. Fulltext. Click here to view fulltext PDF. Permanent link:

  1. 11. European cosmic ray symposium

    International Nuclear Information System (INIS)

    1989-03-01

    The biannual Symposium includes all aspects of cosmic ray research. The scientific programme was organized under three main headings: Cosmic rays in the heliosphere, Cosmic rays in the interstellar and extragalactic space, Properties of high-energy interactions as studied by cosmic rays. Seven invited talks were indexed seprately for the INIS database. (R.P.)

  2. Light scattering by cosmic particles

    NARCIS (Netherlands)

    Hovenier, J.W.; Min, M.

    2008-01-01

    We define cosmic particles as particles outside the Earth. Two types of cosmic particles can be distinguished, namely liquid and solid particles. The solid particles are often called grains or cosmic dust particles. Cosmic particles occur in a great variety of astronomical objects and environments.

  3. CMB polarization systematics due to beam asymmetry: Impact on inflationary science

    International Nuclear Information System (INIS)

    Shimon, Meir; Keating, Brian; Ponthieu, Nicolas; Hivon, Eric

    2008-01-01

    Cosmic microwave background (CMB) polarization provides a unique window into cosmological inflation; the amplitude of the B-mode polarization from last scattering is uniquely sensitive to the energetics of inflation. However, numerous systematic effects arising from optical imperfections can contaminate the observed B-mode power spectrum. In particular, systematic effects due to the coupling of the underlying temperature and polarization fields with elliptical or otherwise asymmetric beams yield spurious systematic signals. This paper presents a nonperturbative analytic calculation of some of these signals. We show that results previously derived in real space can be generalized, formally, by including infinitely many higher-order corrections to the leading order effects. These corrections can be summed and represented as analytic functions when a fully Fourier-space approach is adopted from the outset. The formalism and results presented in this paper were created to determine the susceptibility of CMB polarization probes of the primary gravitational wave signal but can be easily extended to the analysis of gravitational lensing of the CMB.

  4. Cosmic x ray physics

    Science.gov (United States)

    Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

    1991-01-01

    The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

  5. Cosmic Dust Catalog

    Data.gov (United States)

    National Aeronautics and Space Administration — Since May 1981, the National Aeronautics and Space Administration (NASA) has used aircraft to collect cosmic dust (CD) particles from Earth's stratosphere. Specially...

  6. A COSMIC VARIANCE COOKBOOK

    International Nuclear Information System (INIS)

    Moster, Benjamin P.; Rix, Hans-Walter; Somerville, Rachel S.; Newman, Jeffrey A.

    2011-01-01

    Deep pencil beam surveys ( 2 ) are of fundamental importance for studying the high-redshift universe. However, inferences about galaxy population properties (e.g., the abundance of objects) are in practice limited by 'cosmic variance'. This is the uncertainty in observational estimates of the number density of galaxies arising from the underlying large-scale density fluctuations. This source of uncertainty can be significant, especially for surveys which cover only small areas and for massive high-redshift galaxies. Cosmic variance for a given galaxy population can be determined using predictions from cold dark matter theory and the galaxy bias. In this paper, we provide tools for experiment design and interpretation. For a given survey geometry, we present the cosmic variance of dark matter as a function of mean redshift z-bar and redshift bin size Δz. Using a halo occupation model to predict galaxy clustering, we derive the galaxy bias as a function of mean redshift for galaxy samples of a given stellar mass range. In the linear regime, the cosmic variance of these galaxy samples is the product of the galaxy bias and the dark matter cosmic variance. We present a simple recipe using a fitting function to compute cosmic variance as a function of the angular dimensions of the field, z-bar , Δz, and stellar mass m * . We also provide tabulated values and a software tool. The accuracy of the resulting cosmic variance estimates (δσ v /σ v ) is shown to be better than 20%. We find that for GOODS at z-bar =2 and with Δz = 0.5, the relative cosmic variance of galaxies with m * >10 11 M sun is ∼38%, while it is ∼27% for GEMS and ∼12% for COSMOS. For galaxies of m * ∼ 10 10 M sun , the relative cosmic variance is ∼19% for GOODS, ∼13% for GEMS, and ∼6% for COSMOS. This implies that cosmic variance is a significant source of uncertainty at z-bar =2 for small fields and massive galaxies, while for larger fields and intermediate mass galaxies, cosmic

  7. Polarization Optics

    OpenAIRE

    Fressengeas, Nicolas

    2010-01-01

    The physics of polarization optics *Polarized light propagation *Partially polarized light; DEA; After a brief introduction to polarization optics, this lecture reviews the basic formalisms for dealing with it: Jones Calculus for totally polarized light and Stokes parameters associated to Mueller Calculus for partially polarized light.

  8. Microwave quantum logic spectroscopy and control of molecular ions

    DEFF Research Database (Denmark)

    Shi, M.; F. Herskind, P.; Drewsen, M.

    2013-01-01

    A general method for rotational microwave spectroscopy and control of polar molecular ions via direct microwave addressing is considered. Our method makes use of spatially varying AC Stark shifts, induced by far off-resonant, focused laser beams to achieve an effective coupling between...

  9. Strong Cosmic Censorship

    Science.gov (United States)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  10. Line-of-sight extrapolation noise in dust polarization

    Science.gov (United States)

    Poh, Jason; Dodelson, Scott

    2017-05-01

    The B-modes of polarization at frequencies ranging from 50-1000 GHz are produced by Galactic dust, lensing of primordial E-modes in the cosmic microwave background (CMB) by intervening large scale structure, and possibly by primordial B-modes in the CMB imprinted by gravitational waves produced during inflation. The conventional method used to separate the dust component of the signal is to assume that the signal at high frequencies (e.g. 350 GHz) is due solely to dust and then extrapolate the signal down to a lower frequency (e.g. 150 GHz) using the measured scaling of the polarized dust signal amplitude with frequency. For typical Galactic thermal dust temperatures of ˜20 K , these frequencies are not fully in the Rayleigh-Jeans limit. Therefore, deviations in the dust cloud temperatures from cloud to cloud will lead to different scaling factors for clouds of different temperatures. Hence, when multiple clouds of different temperatures and polarization angles contribute to the integrated line-of-sight polarization signal, the relative contribution of individual clouds to the integrated signal can change between frequencies. This can cause the integrated signal to be decorrelated in both amplitude and direction when extrapolating in frequency. Here we carry out a Monte Carlo analysis on the impact of this line-of-sight extrapolation noise on a greybody dust model consistent with Planck and Pan-STARRS observations, enabling us to quantify its effect. Using results from the Planck experiment, we find that this effect is small, more than an order of magnitude smaller than the current uncertainties. However, line-of-sight extrapolation noise may be a significant source of uncertainty in future low-noise primordial B-mode experiments. Scaling from Planck results, we find that accounting for this uncertainty becomes potentially important when experiments are sensitive to primordial B-mode signals with amplitude r ≲0.0015 in the greybody dust models considered in this

  11. Line-of-sight extrapolation noise in dust polarization

    Energy Technology Data Exchange (ETDEWEB)

    Poh, Jason; Dodelson, Scott

    2017-05-19

    The B-modes of polarization at frequencies ranging from 50-1000 GHz are produced by Galactic dust, lensing of primordial E-modes in the cosmic microwave background (CMB) by intervening large scale structure, and possibly by primordial B-modes in the CMB imprinted by gravitational waves produced during inflation. The conventional method used to separate the dust component of the signal is to assume that the signal at high frequencies (e.g., 350 GHz) is due solely to dust and then extrapolate the signal down to lower frequency (e.g., 150 GHz) using the measured scaling of the polarized dust signal amplitude with frequency. For typical Galactic thermal dust temperatures of about 20K, these frequencies are not fully in the Rayleigh-Jeans limit. Therefore, deviations in the dust cloud temperatures from cloud to cloud will lead to different scaling factors for clouds of different temperatures. Hence, when multiple clouds of different temperatures and polarization angles contribute to the integrated line-of-sight polarization signal, the relative contribution of individual clouds to the integrated signal can change between frequencies. This can cause the integrated signal to be decorrelated in both amplitude and direction when extrapolating in frequency. Here we carry out a Monte Carlo analysis on the impact of this line-of-sight extrapolation noise, enabling us to quantify its effect. Using results from the Planck experiment, we find that this effect is small, more than an order of magnitude smaller than the current uncertainties. However, line-of-sight extrapolation noise may be a significant source of uncertainty in future low-noise primordial B-mode experiments. Scaling from Planck results, we find that accounting for this uncertainty becomes potentially important when experiments are sensitive to primordial B-mode signals with amplitude r < 0.0015 .

  12. Cosmic Dark Radiation and Neutrinos

    Directory of Open Access Journals (Sweden)

    Maria Archidiacono

    2013-01-01

    Full Text Available New measurements of the cosmic microwave background (CMB by the Planck mission have greatly increased our knowledge about the universe. Dark radiation, a weakly interacting component of radiation, is one of the important ingredients in our cosmological model which is testable by Planck and other observational probes. At the moment, the possible existence of dark radiation is an unsolved question. For instance, the discrepancy between the value of the Hubble constant, H0, inferred from the Planck data and local measurements of H0 can to some extent be alleviated by enlarging the minimal ΛCDM model to include additional relativistic degrees of freedom. From a fundamental physics point of view, dark radiation is no less interesting. Indeed, it could well be one of the most accessible windows to physics beyond the standard model, for example, sterile neutrinos. Here, we review the most recent cosmological results including a complete investigation of the dark radiation sector in order to provide an overview of models that are still compatible with new cosmological observations. Furthermore, we update the cosmological constraints on neutrino physics and dark radiation properties focusing on tensions between data sets and degeneracies among parameters that can degrade our information or mimic the existence of extra species.

  13. Polarized proton target-IV. Operations manual

    International Nuclear Information System (INIS)

    Hill, D.; Fletcher, O.; Moretti, A.; Onesto, F.

    1976-01-01

    Standard operating procedures are presented for the vacuum, cryogenic, and electronic systems of a polarized proton target. The systems are comprised of (1) a target cryostat; (2) a 4 He pumping system; (3) a 3 He pumping system; (4) a microwave system; (5) a magnet and power supply; (6) a computerized polarization monitor; and (7) miscellaneous auxiliary equipment

  14. Microwave power engineering applications

    CERN Document Server

    Okress, Ernest C

    2013-01-01

    Microwave Power Engineering, Volume 2: Applications introduces the electronics technology of microwave power and its applications. This technology emphasizes microwave electronics for direct power utilization and transmission purposes. This volume presents the accomplishments with respect to components, systems, and applications and their prevailing limitations in the light of knowledge of the microwave power technology. The applications discussed include the microwave heating and other processes of materials, which utilize the magnetron predominantly. Other applications include microwave ioni

  15. Advances in microwaves 8

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 8 covers the developments in the study of microwaves. The book discusses the circuit forms for microwave integrated circuits; the analysis of microstrip transmission lines; and the use of lumped elements in microwave integrated circuits. The text also describes the microwave properties of ferrimagnetic materials, as well as their interaction with electromagnetic waves propagating in bounded waveguiding structures. The integration techniques useful at high frequencies; material technology for microwave integrated circuits; specific requirements on technology for d

  16. Nuclear Physics Meets the Sources of the Ultra-High Energy Cosmic Rays.

    Science.gov (United States)

    Boncioli, Denise; Fedynitch, Anatoli; Winter, Walter

    2017-07-07

    The determination of the injection composition of cosmic ray nuclei within astrophysical sources requires sufficiently accurate descriptions of the source physics and the propagation - apart from controlling astrophysical uncertainties. We therefore study the implications of nuclear data and models for cosmic ray astrophysics, which involves the photo-disintegration of nuclei up to iron in astrophysical environments. We demonstrate that the impact of nuclear model uncertainties is potentially larger in environments with non-thermal radiation fields than in the cosmic microwave background. We also study the impact of nuclear models on the nuclear cascade in a gamma-ray burst radiation field, simulated at a level of complexity comparable to the most precise cosmic ray propagation code. We conclude with an isotope chart describing which information is in principle necessary to describe nuclear interactions in cosmic ray sources and propagation.

  17. Cosmic questions: an introduction.

    Science.gov (United States)

    Primack, J R; Abrams, N E

    2001-12-01

    This introductory talk at the Cosmic Questions conference sponsored by the AAAS summarizes some earlier pictures of the universe and some pictures based on modern physics and cosmology. The uroboros (snake swallowing its tail) is an example of a traditional picture. The Biblical flat-earth picture was very different from the Greek spherical earth-centered picture, which was the standard view until the end of the Middle Ages. Many people incorrectly assume that the Newtonian picture of stars scattered through otherwise empty space is still the prevailing view. Seeing Earth from space shows the power of a new picture. The Hubble Space Telescope can see all the bright galaxies, all the way to the cosmic Dark Ages. We are at the center of cosmic spheres of time: looking outward is looking backward in time. All the matter and energy in the universe can be represented as a cosmic density pyramid. The laws of physics only allow the material objects in the universe to occupy a wedge-shaped region on a diagram of mass versus size. All sizes--from the smallest size scale, the Planck scale, to the entire visible universe--can be represented on the Cosmic Uroboros. There are interesting connections across this diagram, and the human scale lies in the middle.

  18. Cosmic Rays and Climate

    CERN Document Server

    Kirkby, Jasper

    2007-01-01

    Among the most puzzling questions in climate change is that of solar-climate variability, which has attracted the attention of scientists for more than two centuries. Until recently, even the existence of solar-climate variability has been controversial—perhaps because the observations had largely involved correlations between climate and the sunspot cycle that had persisted for only a few decades. Over the last few years, however, diverse reconstructions of past climate change have revealed clear associations with cosmic ray variations recorded in cosmogenic isotope archives, providing persuasive evidence for solar or cosmic ray forcing of the climate. However, despite the increasing evidence of its importance, solar-climate variability is likely to remain controversial until a physical mechanism is established. Although this remains a mystery, observations suggest that cloud cover may be influenced by cosmic rays, which are modulated by the solar wind and, on longer time scales, by the geomagnetic fiel...

  19. Heterotic cosmic strings

    International Nuclear Information System (INIS)

    Becker, Katrin; Becker, Melanie; Krause, Axel

    2006-01-01

    We show that all three conditions for the cosmological relevance of heterotic cosmic strings, the right tension, stability and a production mechanism at the end of inflation, can be met in the strongly coupled M-theory regime. Whereas cosmic strings generated from weakly coupled heterotic strings have the well-known problems posed by Witten in 1985, we show that strings arising from M5-branes wrapped around 4-cycles (divisors) of a Calabi-Yau in heterotic M-theory compactifications solve these problems in an elegant fashion

  20. Cosmic Sum Rules

    DEFF Research Database (Denmark)

    T. Frandsen, Mads; Masina, Isabella; Sannino, Francesco

    2011-01-01

    We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays and show how it can be used to predict the positron fraction at energies not yet explored by current experiments and to constrain specific models.......We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays and show how it can be used to predict the positron fraction at energies not yet explored by current experiments and to constrain specific models....

  1. Cosmic ray: Studying the origin

    International Nuclear Information System (INIS)

    Szabelski, J.

    1997-01-01

    Investigations of the origin of cosmic rays are presented. Different methods are discussed: studies of cosmic gamma rays of energy from 30 MeV to about 10 15 eV (since photons point to their places of origin), studies of the mass composition of cosmic rays (because it reflects source morphology), and studies of cosmic rays with energy above 1O 19 eV (for these are the highest energies observed in nature). (author)

  2. Galactic propagation of cosmic rays

    International Nuclear Information System (INIS)

    Cesarsky, C.J.

    1982-09-01

    After introducing various phenomenological models of cosmic ray propagation in the galaxy, we examine how some of them fare when compared to the data. We show that a model based on resonant diffusion of cosmic rays off an interstellar spectrum of hydromagnetic waves can account for the presently available evidence on cosmic rays and the interstellar medium

  3. Probing physics at extreme energies with cosmic ultra-high energy ...

    Indian Academy of Sciences (India)

    beyond the standard model (SM) and processes taking place at the earliest moments of our universe. Furthermore ... cleons above ~70 EeV lose energy drastically due to photo-pion production on the cosmic microwave ... age of the universe or could be released from topological defects that were produced in the early ...

  4. Cosmic rays and the search for a Lorentz Invariance Violation

    International Nuclear Information System (INIS)

    Bietenholz, Wolfgang

    2008-11-01

    This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is a process of modest energy in the proton rest frame. It can be investigated to a high precision in the laboratory, if Lorentz transformations apply even at factors γ ∝ O(10 11 ). For heavier nuclei the energy attenuation is even faster due to photo-disintegration, again if this process is Lorentz invariant. Hence the viability of Lorentz symmetry up to tremendous γ-factors - far beyond accelerator tests - is a central issue. Next we comment on conceptual aspects of Lorentz Invariance and the possibility of its spontaneous breaking. This could lead to slightly particle dependent ''Maximal Attainable Velocities''. We discuss their effect in decays, Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays. We also review the search for LIV in cosmic γ-rays. For multi TeV γ-rays we possibly encounter another puzzle related to the transparency of the CMB, similar to the GZK cutoff, due to electron/positron creation and subsequent inverse Compton scattering. The photons emitted in a Gamma Ray Burst occur at lower energies, but their very long path provides access to information not far from the Planck scale. We discuss conceivable non-linear photon dispersions based on non-commutative geometry or effective approaches. No LIV has been observed so far. However, even extremely tiny LIV effects could change the predictions for cosmic ray physics drastically. An Appendix is devoted to the recent hypothesis by the Pierre Auger Collaboration, which identifies nearby Active Galactic Nuclei - or objects next to them - as probable UHECR sources. (orig.)

  5. Simulating Cosmic Reionisation

    NARCIS (Netherlands)

    Pawlik, Andreas Heinz

    2009-01-01

    The first stars formed a few hundred million years after the Big Bang, when the Universe was only a small fraction of its present age. Their radiation transformed the previously cold and neutral hydrogen that filled intergalactic space into the hot and ionised cosmic plasma that is observed today.

  6. Instrument development of the CMB polarization POLARBEAR-2 experiment

    Science.gov (United States)

    Siritanasak, Praween; POLARBEAR Collaboration

    2017-06-01

    We present the status of the development of the Polarbear-2 (PB-2) and Simons Array experiments. PB-2 is a ground-based Cosmic Microwave Back- ground (CMB) polarization experiment located at the James Ax observatory in the Atacama desert of Northern Chile. The Simons Array will consist of three PB-2 receivers on three Huan Tran-style telescopes, each containing a multi-chroic detector array. The first new Simons Array receiver, Polarbear- 2A(PB-2A), will be deployed in 2017. The PB-2A focal plane consists of 1,897 lenslet-coupled, dual-polarization, sinuous-antenna-coupled pixels operating at 95 and 150 GHz, making a total of 7,588 polarization-sensitive transition edge sensor (TES) bolometers. In the order to cover both frequencies, we developed broadband two layer anti-reflection (AR) coating for 5.345 mm diameter lenslets using two types of epoxy: Stycast2850FT and Stycast1090. We developed a mass production AR coating methodology that can control the uniformity and shape to within 25 μm error from the designed value. The second (PB-2B) and third (PB-2C) receivers will employ similar technologies and will cover 95, 150, 220 and 280 GHz. The Simons Array will survey 80% of the sky with broad frequency coverage and high resolution, making it a powerful tool to constrain the tensor-to-scalar ratio through measurements of primordial B-modes and the sum of the neutrino masses through measurements of B-modes produced by gravitational lensing.

  7. Pairing in the cosmic neutrino background

    International Nuclear Information System (INIS)

    Alonso, V.; Paredes, R.

    1981-07-01

    We extend the discussion of the possible superfluidity of the cosmic background of neutrinos beyond the arguments based on the gap equation, originally given by Ginzburg and Zharkov. We show how to develop a simple Ginzburg-Landau liquid model, in analogy with superconductivity. We use it to show how an analysis of the energy spectrum of the universe can be formulated to include general relativistic effects on the superfluid neutrinos. Finally, in view of the Hawking and Collins careful discussion on the rotation and distortion of a spatially homogeneous and isotropic universe, we discuss the vortex dynamics that might be generated on the superfluid by rotations (allowed by the almost isotropy of the microwave background of photons) of up to 2 x 10 -14 second of arc/century, but conclude that rotations of this order of magnitude would be sufficiently strong to deter the existence of the superfluid state. (author)

  8. Ultrahigh-energy cosmic-ray spectrum

    International Nuclear Information System (INIS)

    Hill, C.T.; Schramm, D.N.

    1985-01-01

    We analyze the evolution of the ultrahigh-energy cosmic-ray spectrum upon traversing the 2.7 0 K microwave background with respect to pion photoproduction, pair-production reactions, and cosmological effects. Our approach employs exact transport equations which manifestly conserve nucleon number and embody the laboratory details of these reactions. A spectrum enhancement appears around 6 x 10 19 eV due to the ''pile-up'' of energy-degraded nucleons, and a ''dip'' occurs around 10 19 eV due to combined effects. Both of these features appear in the observational spectrum. We analyze the resulting neutrino spectrum and the effects of cosmological source distributions. We present a complete model of the ultrahigh-energy spectrum and anisotropy in reasonable agreement with observation and which predicts an observable electron-neutrino spectrum

  9. Cosmic Rays at Earth

    Science.gov (United States)

    Grieder, P. K. F.

    In 1912 Victor Franz Hess made the revolutionary discovery that ionizing radiation is incident upon the Earth from outer space. He showed with ground-based and balloon-borne detectors that the intensity of the radiation did not change significantly between day and night. Consequently, the sun could not be regarded as the sources of this radiation and the question of its origin remained unanswered. Today, almost one hundred years later the question of the origin of the cosmic radiation still remains a mystery. Hess' discovery has given an enormous impetus to large areas of science, in particular to physics, and has played a major role in the formation of our current understanding of universal evolution. For example, the development of new fields of research such as elementary particle physics, modern astrophysics and cosmology are direct consequences of this discovery. Over the years the field of cosmic ray research has evolved in various directions: Firstly, the field of particle physics that was initiated by the discovery of many so-called elementary particles in the cosmic radiation. There is a strong trend from the accelerator physics community to reenter the field of cosmic ray physics, now under the name of astroparticle physics. Secondly, an important branch of cosmic ray physics that has rapidly evolved in conjunction with space exploration concerns the low energy portion of the cosmic ray spectrum. Thirdly, the branch of research that is concerned with the origin, acceleration and propagation of the cosmic radiation represents a great challenge for astrophysics, astronomy and cosmology. Presently very popular fields of research have rapidly evolved, such as high-energy gamma ray and neutrino astronomy. In addition, high-energy neutrino astronomy may soon initiate as a likely spin-off neutrino tomography of the Earth and thus open a unique new branch of geophysical research of the interior of the Earth. Finally, of considerable interest are the biological

  10. Practical microwave electron devices

    CERN Document Server

    Meurant, Gerard

    2013-01-01

    Practical Microwave Electron Devices provides an understanding of microwave electron devices and their applications. All areas of microwave electron devices are covered. These include microwave solid-state devices, including popular microwave transistors and both passive and active diodes; quantum electron devices; thermionic devices (including relativistic thermionic devices); and ferrimagnetic electron devices. The design of each of these devices is discussed as well as their applications, including oscillation, amplification, switching, modulation, demodulation, and parametric interactions.

  11. Tracing the cosmic web

    Science.gov (United States)

    Libeskind, Noam I.; van de Weygaert, Rien; Cautun, Marius; Falck, Bridget; Tempel, Elmo; Abel, Tom; Alpaslan, Mehmet; Aragón-Calvo, Miguel A.; Forero-Romero, Jaime E.; Gonzalez, Roberto; Gottlöber, Stefan; Hahn, Oliver; Hellwing, Wojciech A.; Hoffman, Yehuda; Jones, Bernard J. T.; Kitaura, Francisco; Knebe, Alexander; Manti, Serena; Neyrinck, Mark; Nuza, Sebastián E.; Padilla, Nelson; Platen, Erwin; Ramachandra, Nesar; Robotham, Aaron; Saar, Enn; Shandarin, Sergei; Steinmetz, Matthias; Stoica, Radu S.; Sousbie, Thierry; Yepes, Gustavo

    2018-01-01

    The cosmic web is one of the most striking features of the distribution of galaxies and dark matter on the largest scales in the Universe. It is composed of dense regions packed full of galaxies, long filamentary bridges, flattened sheets and vast low-density voids. The study of the cosmic web has focused primarily on the identification of such features, and on understanding the environmental effects on galaxy formation and halo assembly. As such, a variety of different methods have been devised to classify the cosmic web - depending on the data at hand, be it numerical simulations, large sky surveys or other. In this paper, we bring 12 of these methods together and apply them to the same data set in order to understand how they compare. In general, these cosmic-web classifiers have been designed with different cosmological goals in mind, and to study different questions. Therefore, one would not a priori expect agreement between different techniques; however, many of these methods do converge on the identification of specific features. In this paper, we study the agreements and disparities of the different methods. For example, each method finds that knots inhabit higher density regions than filaments, etc. and that voids have the lowest densities. For a given web environment, we find a substantial overlap in the density range assigned by each web classification scheme. We also compare classifications on a halo-by-halo basis; for example, we find that 9 of 12 methods classify around a third of group-mass haloes (i.e. Mhalo ∼ 1013.5 h-1 M⊙) as being in filaments. Lastly, so that any future cosmic-web classification scheme can be compared to the 12 methods used here, we have made all the data used in this paper public.

  12. Cosmographic Constraints and Cosmic Fluids

    Directory of Open Access Journals (Sweden)

    Salvatore Capozziello

    2013-12-01

    Full Text Available The problem of reproducing dark energy effects is reviewed here with particular interest devoted to cosmography. We summarize some of the most relevant cosmological models, based on the assumption that the corresponding barotropic equations of state evolve as the universe expands, giving rise to the accelerated expansion. We describe in detail the ΛCDM (Λ-Cold Dark Matter and ωCDM models, considering also some specific examples, e.g., Chevallier–Polarsky–Linder, the Chaplygin gas and the Dvali–Gabadadze–Porrati cosmological model. Finally, we consider the cosmological consequences of f(R and f(T gravities and their impact on the framework of cosmography. Keeping these considerations in mind, we point out the model-independent procedure related to cosmography, showing how to match the series of cosmological observables to the free parameters of each model. We critically discuss the role played by cosmography, as a selection criterion to check whether a particular model passes or does not present cosmological constraints. In so doing, we find out cosmological bounds by fitting the luminosity distance expansion of the redshift, z, adopting the recent Union 2.1 dataset of supernovae, combined with the baryonic acoustic oscillation and the cosmic microwave background measurements. We perform cosmographic analyses, imposing different priors on the Hubble rate present value. In addition, we compare our results with recent PLANCK limits, showing that the ΛCDM and ωCDM models seem to be the favorite with respect to other dark energy models. However, we show that cosmographic constraints on f(R and f(T cannot discriminate between extensions of General Relativity and dark energy models, leading to a disadvantageous degeneracy problem.

  13. Cosmology Quantized in Cosmic Time

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, M

    2004-06-03

    This paper discusses the problem of inflation in the context of Friedmann-Robertson-Walker Cosmology. We show how, after a simple change of variables, to quantize the problem in a way which parallels the classical discussion. The result is that two of the Einstein equations arise as exact equations of motion and one of the usual Einstein equations (suitably quantized) survives as a constraint equation to be imposed on the space of physical states. However, the Friedmann equation, which is also a constraint equation and which is the basis of the Wheeler-deWitt equation, acquires a welcome quantum correction that becomes significant for small scale factors. We discuss the extension of this result to a full quantum mechanical derivation of the anisotropy ({delta} {rho}/{rho}) in the cosmic microwave background radiation, and the possibility that the extra term in the Friedmann equation could have observable consequences. To clarify the general formalism and explicitly show why we choose to weaken the statement of the Wheeler-deWitt equation, we apply the general formalism to de Sitter space. After exactly solving the relevant Heisenberg equations of motion we give a detailed discussion of the subtleties associated with defining physical states and the emergence of the classical theory. This computation provides the striking result that quantum corrections to this long wavelength limit of gravity eliminate the problem of the big crunch. We also show that the same corrections lead to possibly measurable effects on the CMB radiation. For the sake of completeness, we discuss the special case, {lambda} = 0, and its relation to Minkowski space. Finally, we suggest interesting ways in which these techniques can be generalized to cast light on the question of chaotic or eternal inflation. In particular, we suggest one can put an experimental lower bound on the distance to a universe with a scale factor very different from our own, by looking at its effects on our CMB

  14. Plasma polarization spectroscopy

    CERN Document Server

    Iwamae, Atsushi

    2008-01-01

    Plasma Polarization Spectroscopy (PPS) is now becoming a standard diagnostic technique for working with laboratory plasmas. This new area needs a comprehensive framework, both experimental and theoretical. This book reviews the historical development of PPS, develops a general theoretical formulation to deal with this phenomenon, along with an overview of relevant cross sections, and reports on laboratory experiments so far performed. It also includes various facets that are interesting from this standpoint, e.g. X-ray lasers and effects of microwave irradiation. It also offers a timely discussion of instrumentation that is quite important in a practical PPS experiment.

  15. Air breakdown induced by a high-power short-pulse microwave

    International Nuclear Information System (INIS)

    Wakisaka, T.; Yatsuzuka, M.; Nobuhara, S.

    1996-01-01

    At Himeji Institute of Technology, the high power microwaves with the peak power of 20 MW, frequency of 12 GHz and pulse duration of 14 ns have been produced with a virtual cathode oscillator (vircator). These high power microwaves offer new applications in various fields. One problem in laser-triggered lightning experiment is the strong attenuation of laser energy by rain, cloud and laser-produced plasma. Microwaves propagate in thundercloud with small loss, and also are able to irradiate much extensive region of targets. In this paper, the fundamental experiment on the air breakdown induced by high power, short pulse microwaves is reported. The experimental setup of the vircator diode for microwave generation is shown. The typical evolution of diode voltage, electron beam current and microwave emission from the top in the course of time is shown. The experimental setup for microwave-induced air breakdown and the experimental procedure are explained. The results of negative polarity and positive polarity are reported. In the pressure range lower than 150 Torr, microwave-induced breakdown occurred without corona discharge in both polarities. Microwave-induced breakdown occurred more easily in negative polarity than in positive polarity. (K.I.)

  16. Design of microwave active devices

    CERN Document Server

    Gautier , Jean-Luc

    2014-01-01

    This book presents methods for the design of the main microwave active devices. The first chapter focuses on amplifiers working in the linear mode. The authors present the problems surrounding narrowband and wideband impedance matching, stability, polarization and the noise factor, as well as specific topologies such as the distributed amplifier and the differential amplifier. Chapter 2 concerns the power amplifier operation. Specific aspects on efficiency, impedance matching and class of operation are presented, as well as the main methods of linearization and efficiency improvement. Freq

  17. Cosmic microwave background: present status and future prospects

    International Nuclear Information System (INIS)

    Muller, R.A.

    1978-12-01

    After a brief review of the origin of the radiation according to the standard model, the status of present measurements of the spectrum and the large-scale isotropy is discussed. Finally, it is indicated what are the prospects for improved measurements in the next decade. 17 references

  18. Cosmic microwave background and inflation in multi-fractional spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Calcagni, Gianluca [Instituto de Estructura de la Materia,CSIC, Serrano 121, 28006 Madrid (Spain); Kuroyanagi, Sachiko [Department of Physics, Nagoya University,Chikusa, Nagoya 464-8602 (Japan); Institute for Advanced Research, Nagoya University,Chikusa, Nagoya 464-8602 (Japan); Tsujikawa, Shinji [Department of Physics, Faculty of Science, Tokyo University of Science,1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

    2016-08-18

    We use FIRAS and Planck 2015 data to place observational bounds on inflationary scenarios in multi-fractional spacetimes with q-derivatives. While a power-law expansion in the geometric time coordinate is subject to the usual constraints from the tensor-to-scalar ratio, model-independent best fits of the black-body and scalar spectra yield upper limits on the free parameters of the multi-fractal measure of the theory. When the measure describing the fractal spacetime geometry is non-oscillating, information on the CMB black-body spectrum places constraints on the theory independent from but weaker than those obtained from the Standard Model, astrophysical gravitational waves and gamma-ray bursts (GRBs). When log oscillations are included and the measure describes a discrete fractal spacetime at microscopic scales, we obtain the first observational constraints on the amplitudes of such oscillations and find, in general, strong constraints on the multi-scale geometry and on the dimension of space. These results complete the scan and reduction of the parameter space of the theory. Black-body bounds are obtained also for the theory with weighted derivatives.

  19. Cosmic microwave background: present status and future prospects. [Review

    Energy Technology Data Exchange (ETDEWEB)

    Muller, R.A.

    1978-12-01

    After a brief review of the origin of the radiation according to the standard model, the status of present measurements of the spectrum and the large-scale isotropy is discussed. Finally, it is indicated what are the prospects for improved measurements in the next decade. 17 references. (JFP)

  20. Exhaustive Study of Cosmic Microwave Background Anisotropies in Quintessential Scenarios

    CERN Document Server

    Brax, P; Riazuelo, A; Brax, Philippe; Martin, Jerome; Riazuelo, Alain

    2000-01-01

    Recent high precision measurements of the CMB anisotropies performed by the BOOMERanG and MAXIMA-1 experiments provide an unmatched set of data allowing to probe different cosmological models. Among these scenarios, motivated by the recent measurements of the luminosity distance versus redshift relation for type Ia supernovae, is the quintessence hypothesis. It consists in assuming that the acceleration of the Universe is due to a scalar field whose final evolution is insensitive to the initial conditions. Within this framework we investigate the cosmological perturbations for two well-motivated potentials: the Ratra-Peebles and the SUGRA tracking potentials. We show that the solutions of the perturbed equations possess an attractor and that, as a consequence, the insensitivity to the initial conditions is preserved at the perturbed level. Then, we study the predictions of these two models for structure formation and CMB anisotropies and investigate the general features of the multipole moments in the presenc...

  1. A Measurement of the Cosmic Microwave Background Temperature ...

    Indian Academy of Sciences (India)

    Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately.

  2. Detectors for Measurements of the Cosmic Microwave Background Radiation

    Data.gov (United States)

    National Aeronautics and Space Administration — Inflation theory predicts gravity waves in the early universe. These gravity waves are caused by tensor fluctuations, which we expect to have left an imprint in the...

  3. The Balloon-borne Large Aperture Telescope for Polarization - BLASTPol

    Science.gov (United States)

    Devlin, Mark

    We are proposing a comprehensive program to study the link between Galactic magnetic fields and star formation. After decades of study, the physical processes regulating star formation still remain poorly understood. Large-scale observations of star forming regions provide counts of the number of dense clouds each of which will eventually evolve into tens to hundreds of stars. However, when simple models of gravitational collapse are applied to the clouds they yield a Galactic star formation rate (SFR) which is many times what is actually observed. Some process or combination of processes must be slowing the collapse of the clouds. The two prevailing theories involve turbulence which prevents the effective dissipation of energy and Galactic magnetic fields which are captured and squeezed by the collapsing cloud provide a mechanism for mechanical support. Understanding these effects fits very well the SMD 2010 Science Plan's Cosmic Origins program. The Balloon-borne Large Aperture Telescope - BLAST was originally designed to conduct confusion-limited and wide-area extragalactic and Galactic surveys at submillimeter wavelengths from a long-duration balloon (LDB) platform. These wavelengths are impossible or very difficult to observe from even the best groundbased telescope sites. After a series of successful flights (Ft. Sumner 2003, Sweden 2005, and Antarctica 2006) resulting in over 25 publications, BLAST was converted to BLASTPol. The combination of a polarizing grid in front of each of the 266 feed horns at 250, 350 and 500 micron with a stepped Half Wave Plate (HWP) provided a quick and inexpensive way to make initial measurements of polarized dust emission in star forming regions. By mapping polarization from dust grains aligned with respect to their local magnetic field, the field orientation (projected on the sky) can be traced. The development of the Next Generation BLASTPol instrument is now complete. It has increased spatial resolution (22 arcseconds at

  4. Measurement of cosmic-ray muons with the Distributed Electronic Cosmic-ray Observatory, a network of smartphones

    International Nuclear Information System (INIS)

    Vandenbroucke, J.; Bravo, S.; Karn, P.; Meehan, M.; Plewa, M.; Schultz, D.; Tosi, D.; BenZvi, S.; Jensen, K.; Peacock, J.; Ruggles, T.; Santander, M.; Simons, A.L.

    2016-01-01

    Solid-state camera image sensors can be used to detect ionizing radiation in addition to optical photons. We describe the Distributed Electronic Cosmic-ray Observatory (DECO), an app and associated public database that enables a network of consumer devices to detect cosmic rays and other ionizing radiation. In addition to terrestrial background radiation, cosmic-ray muon candidate events are detected as long, straight tracks passing through multiple pixels. The distribution of track lengths can be related to the thickness of the active (depleted) region of the camera image sensor through the known angular distribution of muons at sea level. We use a sample of candidate muon events detected by DECO to measure the thickness of the depletion region of the camera image sensor in a particular consumer smartphone model, the HTC Wildfire S. The track length distribution is fit better by a cosmic-ray muon angular distribution than an isotropic distribution, demonstrating that DECO can detect and identify cosmic-ray muons despite a background of other particle detections. Using the cosmic-ray distribution, we measure the depletion thickness to be 26.3 ± 1.4 μm. With additional data, the same method can be applied to additional models of image sensor. Once measured, the thickness can be used to convert track length to incident polar angle on a per-event basis. Combined with a determination of the incident azimuthal angle directly from the track orientation in the sensor plane, this enables direction reconstruction of individual cosmic-ray events using a single consumer device. The results simultaneously validate the use of cell phone camera image sensors as cosmic-ray muon detectors and provide a measurement of a parameter of camera image sensor performance which is not otherwise publicly available

  5. Testing cosmology with cosmic sound waves

    International Nuclear Information System (INIS)

    Corasaniti, Pier Stefano; Melchiorri, Alessandro

    2008-01-01

    Wilkinson Microwave Anisotropy Probe (WMAP) observations have accurately determined the position of the first two peaks and dips in the cosmic microwave background (CMB) temperature power spectrum. These encode information on the ratio of the distance to the last scattering surface to the sound horizon at decoupling. However prerecombination processes can contaminate this distance information. In order to assess the amplitude of these effects, we use the WMAP data and evaluate the relative differences of the CMB peak and dip multipoles. We find that the position of the first peak is largely displaced with respect to the expected position of the sound horizon scale at decoupling. In contrast, the relative spacings of the higher extrema are statistically consistent with those expected from perfect harmonic oscillations. This provides evidence for a scale dependent phase shift of the CMB oscillations which is caused by gravitational driving forces affecting the propagation of sound waves before recombination. By accounting for these effects we have performed a Markov Chain Monte Carlo likelihood analysis of the location of WMAP extrema to constrain, in combination with recent BAO data, a constant dark energy equation of state parameter w. For a flat universe we find a strong 2σ upper limit w a of the acoustic horizon at decoupling for several cosmologies, to test their dependence on model assumptions. Although the analysis of the full CMB spectra should always be preferred, using the position of the CMB peaks and dips provides a simple and consistent method for combining CMB constraints with other data sets

  6. Dark cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Ping-Kai, E-mail: pingkai.hu@physics.ucla.edu [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095-1547 (United States); Kusenko, Alexander, E-mail: kusenko@ucla.edu [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095-1547 (United States); Kavli Institute for the Physics and Mathematics of the Universe (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Takhistov, Volodymyr, E-mail: vtakhist@physics.ucla.edu [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095-1547 (United States); Department of Physics and Astronomy, University of California, Irvine, Irvine, CA 92697-4575 (United States)

    2017-05-10

    If dark matter particles have an electric charge, as in models of millicharged dark matter, such particles should be accelerated in the same astrophysical accelerators that produce ordinary cosmic rays, and their spectra should have a predictable rigidity dependence. Depending on the charge, the resulting “dark cosmic rays” can be detected as muon-like or neutrino-like events in Super-Kamiokande, IceCube, and other detectors. We present new limits and propose several new analyses, in particular, for the Super-Kamiokande experiment, which can probe a previously unexplored portion of the millicharged dark matter parameter space. Most of our results are fairly general and apply to a broad class of dark matter models.

  7. Dark cosmic rays

    Directory of Open Access Journals (Sweden)

    Ping-Kai Hu

    2017-05-01

    Full Text Available If dark matter particles have an electric charge, as in models of millicharged dark matter, such particles should be accelerated in the same astrophysical accelerators that produce ordinary cosmic rays, and their spectra should have a predictable rigidity dependence. Depending on the charge, the resulting “dark cosmic rays” can be detected as muon-like or neutrino-like events in Super-Kamiokande, IceCube, and other detectors. We present new limits and propose several new analyses, in particular, for the Super-Kamiokande experiment, which can probe a previously unexplored portion of the millicharged dark matter parameter space. Most of our results are fairly general and apply to a broad class of dark matter models.

  8. Cosmic rays and climate

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    The current understanding of climate change in the industrial age is that it is predominantly caused by anthropogenic greenhouse gases, with relatively small natural contributions due to solar irradiance and volcanoes. However, palaeoclimatic reconstructions show that the climate has frequently varied on 100-year time scales during the Holocene (last 10 kyr) by amounts comparable to the present warming - and yet the mechanism or mechanisms are not understood. Some of these reconstructions show clear associations with solar variability, which is recorded in the light radio-isotope archives that measure past variations of cosmic ray intensity. However, despite the increasing evidence of its importance, solar-climate variability is likely to remain controversial until a physical mechanism is established. Estimated changes of solar irradiance on these time scales appear to be too small to account for the climate observations. This raises the question of whether cosmic rays may directly affect the climate, provi...

  9. Microwave heating type evaporator

    International Nuclear Information System (INIS)

    Taura, Masazumi; Nishi, Akio; Morimoto, Takashi; Izumi, Jun; Tamura, Kazuo; Morooka, Akihiko.

    1987-01-01

    Purpose: To prevent evaporization stills against corrosion due to radioactive liquid wastes. Constitution: Microwaves are supplied from a microwave generator by way of a wave guide tube and through a microwave permeation window to the inside of an evaporatization still. A matching device is attached to the wave guide tube for transmitting the microwaves in order to match the impedance. When the microwaves are supplied to the inside of the evaporization still, radioactive liquid wastes supplied from a liquid feed port by way of a spray tower to the inside of the evaporization still is heated and evaporated by the induction heating of the microwaves. (Seki, T.)

  10. Cosmic Rays in Thunderstorms

    Science.gov (United States)

    Buitink, Stijn; Scholten, Olaf; van den Berg, Ad; Ebert, Ute

    2013-04-01

    Cosmic Rays in Thunderstorms Cosmic rays are protons and heavier nuclei that constantly bombard the Earth's atmosphere with energies spanning a vast range from 109 to 1021 eV. At typical altitudes up to 10-20 km they initiate large particle cascades, called extensive air showers, that contain millions to billions of secondary particles depending on their initial energy. These particles include electrons, positrons, hadrons and muons, and are concentrated in a compact particle front that propagates at relativistic speed. In addition, the shower leaves behind a trail of lower energy electrons from ionization of air molecules. Under thunderstorm conditions these electrons contribute to the electrical and ionization processes in the cloud. When the local electric field is strong enough the secondary electrons can create relativistic electron run-away avalanches [1] or even non-relativistic avalanches. Cosmic rays could even trigger lightning inception. Conversely, strong electric fields also influence the development of the air shower [2]. Extensive air showers emit a short (tens of nanoseconds) radio pulse due to deflection of the shower particles in the Earth's magnetic field [3]. Antenna arrays, such as AERA, LOFAR and LOPES detect these pulses in a frequency window of roughly 10-100 MHz. These systems are also sensitive to the radiation from discharges associated to thunderstorms, and provide a means to study the interaction of cosmic ray air showers and the electrical processes in thunderstorms [4]. In this presentation we discuss the involved radiation mechanisms and present analyses of thunderstorm data from air shower arrays [1] A. Gurevich et al., Phys. Lett. A 165, 463 (1992) [2] S. Buitink et al., Astropart. Phys. 33, 1 (2010) [3] H. Falcke et al., Nature 435, 313 (2005) [4] S. Buitink et al., Astron. & Astrophys. 467, 385 (2007)

  11. Carl Sagan's Cosmic Connection

    Science.gov (United States)

    Sagan, Carl; Agel, Jerome

    2000-08-01

    Foreword Freeman Dyson; Personal reflections Ann Druyan; Preface; Part I. Cosmic Perspective: 1. A transitional animal; 2. The Unicorn of Cetus; 3. A message from earth; 4. A message to earth; 5. Experiments in utopias; 6. Chauvinism; 7. Space exploration as a human enterprise I. The scientific interest; 8. Space exploration as a human enterprise II. The public interest; 9. Space exploration as a human enterprise III. The historical interest; Part II. The Solar System: 10. On teaching the first grade; 11. 'The ancient and legendary Gods of old'; 12. The Venus detective story; 13. Venus is hell; 14. Science and 'intelligence'; 15. The moons of Barsoom; 16. The mountains of Mars I. Observations from earth; 17. The mountains of Mars II. Observations from space; 18. The canals of Mars; 19. The lost pictures of Mars; 20. The Ice Age and the cauldron; 21. Beginnings and ends of the Earth; 22. Terraforming the plants; 23. The exploration and utlization of the solar system; Part III. Beyond the Solar System: 24. Some of my best friends are dolphins; 25. 'Hello, central casting? Send me twenty extraterrestrials'; 26. The cosmic connection; 27. Extraterrestrial life: an idea whose time has come; 28. Has the Earth been visited?; 29. A search strategy for detecting extraterrestrial intelligence; 30. If we succeed 31. Cables, drums, and seashells; 32. The night freight to the stars; 33. Astroengineering; 34. Twenty questions: a classification of cosmic civilisations; 35. Galactic cultural exchanges; 36. A passage to elsewhere; 37. Starfolk I. A Fable; 38. Starfolk II. A future; 39. Starfolk III. The cosmic Cheshire cats; Epilog David Morrison; Index.

  12. CMB Polarization B-mode Delensing with SPTpol and Herschel

    Energy Technology Data Exchange (ETDEWEB)

    Manzotti, A.; et al.

    2017-01-16

    We present a demonstration of delensing the observed cosmic microwave background (CMB) B-mode polarization anisotropy. This process of reducing the gravitational-lensing generated B-mode component will become increasingly important for improving searches for the B modes produced by primordial gravitational waves. In this work, we delens B-mode maps constructed from multi-frequency SPTpol observations of a 90 deg$^2$ patch of sky by subtracting a B-mode template constructed from two inputs: SPTpol E-mode maps and a lensing potential map estimated from the $\\textit{Herschel}$ $500\\,\\mu m$ map of the CIB. We find that our delensing procedure reduces the measured B-mode power spectrum by 28% in the multipole range $300 < \\ell < 2300$; this is shown to be consistent with expectations from theory and simulations and to be robust against systematics. The null hypothesis of no delensing is rejected at $6.9 \\sigma$. Furthermore, we build and use a suite of realistic simulations to study the general properties of the delensing process and find that the delensing efficiency achieved in this work is limited primarily by the noise in the lensing potential map. We demonstrate the importance of including realistic experimental non-idealities in the delensing forecasts used to inform instrument and survey-strategy planning of upcoming lower-noise experiments, such as CMB-S4.

  13. THE ATACAMA COSMOLOGY TELESCOPE: THE POLARIZATION-SENSITIVE ACTPol INSTRUMENT

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, R. J. [Department of Physics, West Chester University of Pennsylvania, West Chester, PA 19383 (United States); Ade, P. A. R. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff, Wales, CF24 3AA (United Kingdom); Aiola, S. [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Angilè, F. E.; Devlin, M. J.; Dicker, S. R. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Amiri, M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z4 (Canada); Beall, J. A.; Becker, D. T.; Fowler, J. W.; Fox, A. E.; Gao, J. [NIST Quantum Sensors Group, 325 Broadway Mailcode 817.03, Boulder, CO 80305 (United States); Cho, H-M. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Choi, S. K.; Grace, E. [Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544 (United States); Corlies, P.; Gallardo, P. A. [Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Coughlin, K. P.; Datta, R. [Department of Physics, University of Michigan Ann Arbor, MI 48109 (United States); Dünner, R. [Instituto de Astrofísica and Centro de Astro-Ingeniería, Facultad de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 7820436 Macul, Santiago (Chile); and others

    2016-12-01

    The Atacama Cosmology Telescope (ACT) makes high angular resolution measurements of anisotropies in the Cosmic Microwave Background (CMB) at millimeter wavelengths. We describe ACTPol, an upgraded receiver for ACT, which uses feedhorn-coupled, polarization-sensitive detector arrays, a 3° field of view, 100 mK cryogenics with continuous cooling, and meta material antireflection coatings. ACTPol comprises three arrays with separate cryogenic optics: two arrays at a central frequency of 148 GHz and one array operating simultaneously at both 97 GHz and 148 GHz. The combined instrument sensitivity, angular resolution, and sky coverage are optimized for measuring angular power spectra, clusters via the thermal Sunyaev–Zel’dovich (SZ) and kinetic SZ signals, and CMB lensing due to large-scale structure. The receiver was commissioned with its first 148 GHz array in 2013, observed with both 148 GHz arrays in 2014, and has recently completed its first full season of operations with the full suite of three arrays. This paper provides an overview of the design and initial performance of the receiver and related systems.

  14. The Atacama Cosmology Telescope: The Polarization-Sensitive ACTPol Instrument

    Science.gov (United States)

    Thornton, R. J.; Ade, P. A. R.; Aiola, S.; Angile, F. E.; Amiri, M.; Beall, J. A.; Becker, D. T.; Cho, H.-M.; Choi, S. K.; Corlies, P.; hide

    2016-01-01

    The Atacama Cosmology Telescope (ACT) makes high angular resolution measurements of anisotropies in the Cosmic Microwave Background (CMB) at millimeter wavelengths. We describe ACTPol, an upgraded receiver for ACT, which uses feedhorn-coupled, polarization-sensitive detector arrays, a 3deg field of view, 100 mK cryogenics with continuous cooling, and meta material antireflection coatings. ACTPol comprises three arrays with separate cryogenic optics: two arrays at a central frequency of 148 GHz and one array operating simultaneously at both 97 GHz and 148 GHz. The combined instrument sensitivity, angular resolution, and sky coverage are optimized for measuring angular power spectra, clusters via the thermal Sunyaev-Zel'dovich (SZ) and kinetic SZ signals, and CMB lensing due to large-scale structure. The receiver was commissioned with its first 148 GHz array in 2013, observed with both 148 GHz arrays in 2014, and has recently completed its first full season of operations with the full suite of three arrays. This paper provides an overview of the design and initial performance of the receiver and related systems.

  15. Microwave mediated synthesis of semiconductor quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Afrasiabi, Roodabeh; Sugunan, Abhilash; Shahid, Robina; Toprak, Muhammet S.; Muhammed, Mamoun [Division of Functional Materials, Royal Institute of Technology (KTH), Stockholm (Sweden)

    2012-07-15

    Colloidal quantum dots (QD) have tuneable optoelectronic properties and can be easily handled by simple solution processing techniques, making them very attractive for a wide range of applications. Over the past decade synthesis of morphology controlled high quality (crystalline, monodisperse) colloidal QDs by thermal decomposition of organometallic precursors has matured and is well studied. Recently, synthesis of colloidal QDs by microwave irradiation as heating source is being studied due to the inherently different mechanisms of heat transfer, when compared to solvent convection based heating. Under microwave irradiation, polar precursor molecules directly absorb the microwave energy and heat up more efficiently. Here we report synthesis of colloidal II-VI semiconductor QDs (CdS, CdSe, CdTe) by microwave irradiation and compare it with conventional synthesis based on convection heating. Our findings show that QD synthesis by microwave heating is more efficient and the chalcogenide precursor strongly absorbs the microwave radiation shortening the reaction time and giving a high reaction yield (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Cosmological constraints from a joint analysis of cosmic growth and expansion

    Science.gov (United States)

    Moresco, M.; Marulli, F.

    2017-10-01

    Combining measurements on the expansion history of the Universe and on the growth rate of cosmic structures is key to discriminate between alternative cosmological frameworks and to test gravity. Recently, Linder proposed a new diagram to investigate the joint evolutionary track of these two quantities. In this letter, we collect the most recent cosmic growth and expansion rate data sets to provide the state-of-the-art observational constraints on this diagram. By performing a joint statistical analysis of both probes, we test the standard Λcold dark matter model, confirming a mild tension between cosmic microwave background predictions from Planck mission and cosmic growth measurements at low redshift (z 1 will be crucial to discriminate between alternative models.

  17. Planck intermediate results. L. Evidence of spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB B-mode analysis

    Science.gov (United States)

    Planck Collaboration; Aghanim, N.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Ballardini, M.; Banday, A. J.; Barreiro, R. B.; Bartolo, N.; Basak, S.; Benabed, K.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bracco, A.; Burigana, C.; Calabrese, E.; Cardoso, J.-F.; Chiang, H. C.; Colombo, L. P. L.; Combet, C.; Comis, B.; Crill, B. P.; Curto, A.; Cuttaia, F.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Di Valentino, E.; Dickinson, C.; Diego, J. M.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Dusini, S.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Fantaye, Y.; Finelli, F.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frolov, A.; Galeotta, S.; Galli, S.; Ganga, K.; Génova-Santos, R. T.; Gerbino, M.; Ghosh, T.; Giard, M.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Helou, G.; Herranz, D.; Hivon, E.; Huang, Z.; Jaffe, A. H.; Jones, W. C.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Krachmalnicoff, N.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Le Jeune, M.; Levrier, F.; Liguori, M.; Lilje, P. B.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Matarrese, S.; Mauri, N.; McEwen, J. D.; Melchiorri, A.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Moss, A.; Naselsky, P.; Nørgaard-Nielsen, H. U.; Oxborrow, C. A.; Pagano, L.; Paoletti, D.; Partridge, B.; Patrizii, L.; Perdereau, O.; Perotto, L.; Pettorino, V.; Piacentini, F.; Plaszczynski, S.; Polenta, G.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renzi, A.; Rocha, G.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Ruiz-Granados, B.; Salvati, L.; Sandri, M.; Savelainen, M.; Scott, D.; Sirignano, C.; Sirri, G.; Stanco, L.; Suur-Uski, A.-S.; Tauber, J. A.; Tenti, M.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Trombetti, T.; Valiviita, J.; Vansyngel, F.; Van Tent, F.; Vielva, P.; Wandelt, B. D.; Wehus, I. K.; Zacchei, A.; Zonca, A.

    2017-03-01

    The characterization of the Galactic foregrounds has been shown to be the main obstacle in thechallenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution (SED), and its potential impact on the determination of the tensor-to-scalar ratio, r. We use the correlation ratio of the angular power spectra between the 217 and 353 GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is marginally detected on each region, but the statistical combination of all the regions gives more than 99% confidence for this variation in polarized dust properties. In addition, we show that the decorrelation increases when there is a decrease in the mean column density of the region of the sky being considered, and we propose a simple power-law empirical model for this dependence, which matches what is seen in the Planck data. We explore the effect that this measured decorrelation has on simulations of the BICEP2-Keck Array/Planck analysis and show that the 2015 constraints from these data still allow a decorrelation between the dust at 150 and 353 GHz that is compatible with our measured value. Finally, using simplified models, we show that either spatial variation of the dust SED or of the dust polarization angle are able to produce decorrelations between 217 and 353 GHz data similar to the values we observe in the data.

  18. BICEP2 / Keck Array IX: New bounds on anisotropies of CMB polarization rotation and implications for axionlike particles and primordial magnetic fields

    Science.gov (United States)

    BICEP2 Collaboration; Keck Array Collaboration; Ade, P. A. R.; Ahmed, Z.; Aikin, R. W.; Alexander, K. D.; Barkats, D.; Benton, S. J.; Bischoff, C. A.; Bock, J. J.; Bowens-Rubin, R.; Brevik, J. A.; Buder, I.; Bullock, E.; Buza, V.; Connors, J.; Crill, B. P.; Duband, L.; Dvorkin, C.; Filippini, J. P.; Fliescher, S.; Germaine, T. St.; Ghosh, T.; Grayson, J.; Harrison, S.; Hildebrandt, S. R.; Hilton, G. C.; Hui, H.; Irwin, K. D.; Kang, J.; Karkare, K. S.; Karpel, E.; Kaufman, J. P.; Keating, B. G.; Kefeli, S.; Kernasovskiy, S. A.; Kovac, J. M.; Kuo, C. L.; Larson, N.; Leitch, E. M.; Megerian, K. G.; Moncelsi, L.; Namikawa, T.; Netterfield, C. B.; Nguyen, H. T.; O'Brient, R.; Ogburn, R. W.; Pryke, C.; Richter, S.; Schillaci, A.; Schwarz, R.; Sheehy, C. D.; Staniszewski, Z. K.; Steinbach, B.; Sudiwala, R. V.; Teply, G. P.; Thompson, K. L.; Tolan, J. E.; Tucker, C.; Turner, A. D.; Vieregg, A. G.; Weber, A. C.; Wiebe, D. V.; Willmert, J.; Wong, C. L.; Wu, W. L. K.; Yoon, K. W.

    2017-11-01

    We present the strongest constraints to date on anisotropies of cosmic microwave background (CMB) polarization rotation derived from 150 GHz data taken by the BICEP2 & Keck Array CMB experiments up to and including the 2014 observing season (BK14). The definition of the polarization angle in BK14 maps has gone through self-calibration in which the overall angle is adjusted to minimize the observed T B and E B power spectra. After this procedure, the Q U maps lose sensitivity to a uniform polarization rotation but are still sensitive to anisotropies of polarization rotation. This analysis places constraints on the anisotropies of polarization rotation, which could be generated by CMB photons interacting with axionlike pseudoscalar fields or Faraday rotation induced by primordial magnetic fields. The sensitivity of BK14 maps (˜3 μ K -arc min ) makes it possible to reconstruct anisotropies of the polarization rotation angle and measure their angular power spectrum much more precisely than previous attempts. Our data are found to be consistent with no polarization rotation anisotropies, improving the upper bound on the amplitude of the rotation angle spectrum by roughly an order of magnitude compared to the previous best constraints. Our results lead to an order of magnitude better constraint on the coupling constant of the Chern-Simons electromagnetic term ga γ≤7.2 ×10-2/HI (95% confidence) than the constraint derived from the B -mode spectrum, where HI is the inflationary Hubble scale. This constraint leads to a limit on the decay constant of 10-6≲fa/Mpl at mass range of 10-33≤ma≤10-28 eV for r =0.01 , assuming ga γ˜α /(2 π fa) with α denoting the fine structure constant. The upper bound on the amplitude of the primordial magnetic fields is 30 nG (95% confidence) from the polarization rotation anisotropies.

  19. A polarized target for the CLAS detector

    CERN Document Server

    Keith, C D; Battaglieri, M; Bosted, P; Branford, D; Bültmann, S; Burkert, V D; Comer, S A; Crabb, D G; De Vita, R; Dodge, G; Fatemi, R; Kashy, D; Kuhn, S E; Prok, Y; Ripani, M; Seely, M L; Taiuti, M; Witherspoon, S

    2003-01-01

    We describe the design, construction, and performance of a polarized solid target for use in electron scattering experiments with the CEBAF Large Acceptance Spectrometer. Protons and deuterons are continuously polarized by microwave-induced spin-flip transitions at 1 K and 5 T. The target operated successfully during two cycles in 1998 and 2000, providing proton and deuteron polarizations as high as 96% and 46%, respectively. The unique features of the target which permit its use inside a 4 pi spectrometer are stressed. Comparison is made between the target polarization measured by the traditional method of NMR and by electron elastic scattering.

  20. The Cosmic Linear Anisotropy Solving System (CLASS) II: Approximation schemes

    CERN Document Server

    Blas, Diego; Tram, Thomas

    2011-01-01

    Boltzmann codes are used extensively by several groups for constraining cosmological parameters with Cosmic Microwave Background and Large Scale Structure data. This activity is computationally expensive, since a typical project requires from 10'000 to 100'000 Boltzmann code executions. The newly released code CLASS (Cosmic Linear Anisotropy Solving System) incorporates improved approximation schemes leading to a simultaneous gain in speed and precision. We describe here the three approximations used by CLASS for basic LambdaCDM models, namely: a baryon-photon tight-coupling approximation which can be set to first order, second order or to a compromise between the two; an ultra-relativistic fluid approximation which had not been implemented in public distributions before; and finally a radiation streaming approximation taking reionisation into account.

  1. Cosmic Education: Formation of a Planetary and Cosmic Personality

    Directory of Open Access Journals (Sweden)

    Bazaluk Oleg

    2012-04-01

    Full Text Available The major stages of development of cosmic pedagogy have been researched. Based on the achievements of the modern neurosciences as well as of psychology, cosmology, and philosophy, the authors provide their reasoning for the cosmic education and its outlooks for the educational systems of the world. Through the studies of how important human mind is for the Earth and the cosmos and by researching the evolution of human mind within the structure of the Universe, the authors create a more advanced scientific and philosophic basis for the cosmic education where the subject is a comprehensive process of formation and directed progress of both an individual mind and a conglomerate of minds called the "psychospace". The cosmic education researches the permanent progress of the intelligent matter of the Earth. The purpose of the cosmic education has been determined as formation of a planetary and cosmic personality. According to the authors, a planetary and cosmic personality is a harmony of mind, soul, and body, and such harmony is directed to use the internal creative potential of mind to the benefit of the intelligent matter of the entire Earth and the cosmos. The properties of such a planetary and cosmic personality are being improved continuously; they are a sample (the ideal of the cosmic pedagogy and the image of a human being of the future. Through the usage of the entire potential and art of upbringing and educating, the cosmic pedagogy is called to embody the major properties of the image of a human being of the future in the new generations of minds and to form a planetary and cosmic personality capable of self-actualization to the benefit of the permanent progress of the intelligent matter.

  2. Cosmic ray: Studying the origin

    Energy Technology Data Exchange (ETDEWEB)

    Szabelski, J. [Cosmic Ray Laboratory, Soltan Institute for Nuclear Studies, Lodz (Poland)

    1997-12-31

    Investigations of the origin of cosmic rays are presented. Different methods are discussed: studies of cosmic gamma rays of energy from 30 MeV to about 10{sup 15} eV (since photons point to their places of origin), studies of the mass composition of cosmic rays (because it reflects source morphology), and studies of cosmic rays with energy above 1O{sup 19} eV (for these are the highest energies observed in nature). (author) 101 refs, 19 figs, 7 tabs

  3. Advances in microwaves 7

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 7 covers the developments in the study of microwaves. The book discusses the effect of surface roughness on the propagation of the TEM mode, as well as the voltage breakdown of microwave antennas. The text also describes the theory and design considerations of single slotted-waveguide linear arrays and the techniques and theories that led to the achievement of wide bandwidths and ultralow noise temperatures for communication applications. The book will prove invaluable to microwave engineers.

  4. Radiative processes of two entangled atoms in cosmic string spacetime

    Science.gov (United States)

    Cai, Huabing; Ren, Zhongzhou

    2018-01-01

    We investigate the radiative processes of two static two-level atoms in a maximally entangled state coupled to vacuum electromagnetic field in the cosmic string spacetime. We find that the decay rate from the entangled state to the ground state crucially depends on the atomic separation, the polarization directions of the individual atoms, the atom-string distance and the deficit angle induced by the string. As the atom-string distance increases, the decay rate oscillates around the result in Minkowski spacetime and the amplitude gradually decreases. The oscillation is more severe for larger planar angle deficit. We analyze the decay rate in different circumstances such as near zone and specific polarization cases. Some comparisons between symmetric and antisymmetric states are performed. By contrast with the case in Minkowski spacetime, we can reveal the effects of the cosmic string on the radiative properties of the entangled atoms.

  5. Microwave dielectrics: solid solution, ordering and microwave ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 40; Issue 6. Microwave dielectrics: solid solution, ordering and microwave dielectric properties of ( 1 − x ) Ba(Mg 1 / 3 Nb 2 / 3 )O 3 − x Ba(Mg 1 / 8 Nb 3 / 4 )O3 ceramics. YOGITA BISHT RICHA TOMAR PULLANCHIYODAN ABHILASH DEEPA RAJENDRAN LEKSHMI M ...

  6. Microwave processing heats up

    Science.gov (United States)

    Microwaves are a common appliance in many households. In the United States microwave heating is the third most popular domestic heating method food foods. Microwave heating is also a commercial food processing technology that has been applied for cooking, drying, and tempering foods. It's use in ...

  7. The influence of gravitational binding energy on cosmic expansion dynamics: new perspectives for cosmology

    Science.gov (United States)

    Fahr, Hans-Jörg; Sokaliwska, Michael

    2012-06-01

    Confronted with microwave background observations by WMAP and with consternating supernova locations in the magnitude-redshift diagram modern cosmology feels enforced to call for cosmic vacuum energy as a necessary cosmological ingredient. Most often this vacuum energy is associated with Einstein's cosmological constant Λ or with so-called "dark energy". A positive value of Λ describes an inflationary action on cosmic dynamics which in view of recent cosmological data appears as an absolute need. In this article, however, we question the hypothesis of a constant vacuum energy density since not justifiable on physical grounds. Instead we show that gravitational binding energy of cosmic matter, connected with ongoing structure formation during cosmic expansion, acts similar to vacuum energy, since it reduces the effective gravitating proper mass density. Thus one may be encouraged to believe that actions of cosmic vacuum energy and gravitational binding energy concerning their cosmological effects are closely related to each other, perhaps in some respects even have identical phenomenologies. Based on results presented in this article we propose that the generally wanted action of vacuum energy on cosmic spacetime dynamics inevitably leads to a decay of vacuum energy density. Connected with this decay is a decrease of cosmic binding energy and the generation of new effective gravitating mass in the universe. If this all is adequately taken into account by the energy-momentum tensor of the GR field equations, one is then led to non-standard cosmologies which for the first time can guarantee the conservation of the total energy both in static and expanding universes. We describe the structuring of cosmic matter by a change in time of the 2-point correlation-function. We do show here that cosmic structure formation drives accelerated cosmic expansion and feigns the action of vacuum energy density.

  8. Study of the microwave emissivity characteristics over Gobi Desert

    International Nuclear Information System (INIS)

    Yubao, Qiu; Lijuan, Shi; Wenbo, Wu

    2014-01-01

    The microwave emissivity represents the capacity of the thermal radiation of the surface, and it is the significant parameter for understanding the geophysical processes such as surface energy budget and surface radiation. Different land covers have different emissivity properties, and the Gobi Desert in Central Asia seriously impact the sandstorms occur and develop in China, because of its special geographical environment and surface soil characteristics. In this study half-month averaged microwave emissivity from March 2003 to February 2004 over the Gobi Desert has been estimated. Emissivities in this area at different frequencies, polarization and their seasonal variations are discussed respectively. The results showed that emissivity polarization difference decrease as the frequency increases, and the polarization difference is large (0.03–0.127). The H polarization emissivity increases with increasing frequency, but the V-polarized microwave emissivity is reduced with increasing frequency because of the body scattering. In winter, emissivity decreases sharply in snow covered area, especially for higher frequencies (such as 89GHz). In addition, we compared emissivity with MODIS NDVI data at the same time in the Gobi Desert, and the results indicate that NDVI derived the good negative correlation with microwave emissivity polarization difference at 37GHz

  9. Studies in cosmic rays

    International Nuclear Information System (INIS)

    Bemalkhedkar, M.M.

    1974-03-01

    The investigation of the diurnal variation in the cosmic ray intensity on individual days has revealed a new class of diurnal variation showing a maximum around 09 hour direction in the interplanetary space. It is shown to occur during the recovery phase of Forbush decreases as well as during quiet periods. The rigidity spectrum of the anomalous diurnal variation has an exponent around zero, the same as that for the average diurnal variation exhibiting maximum around 18 hours in the interplanetary space. It is shown that the Forbush decreases associated with the diurnal variation exhibiting morning maximum, are 27 day recurrent in nature and are preceded by east limb solar flares on most of the occasions. A qualitative model of the transient modulation by solar corotating corpuscular streams of enhanced solar wind velocity, emanating from the active regions on the solar disc, is proposed to explain the anomalous diurnal anisotropy in the recovery phase of 27 day recurrent Forbush decreases. From this model, the cosmic ray diffusion coefficients, parallel and perpendicular to the interplanetary magnetic field inside the corotating stream, are derived and compared with the average values. To investigate the possibility of determining the energy spectra of cosmic ray intensity variations from a single station, a continuous record of neutron multiplicity spectrum has been obtained for the period October, 1967 - October, 1971, using the Gulmarg neutron monitor. The average multiplicity spectrum in the Gulmarg neutron monitor shows a mean multiplicity approximately equal to 1.4 for 12 Boron-tri-fluoride counters and is an increasing function of the number of counters used. The mean multiplicity measured in various other neutron monitors, when normalized to the cutoff rigidity of Gulmurg (11.91 GV), shows a systematic increase with the altitude of the station. (author)

  10. Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes

    Science.gov (United States)

    Planck Collaboration; Adam, R.; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Bartolo, N.; Battaner, E.; Benabed, K.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bracco, A.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chiang, H. C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dolag, K.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Falgarone, E.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Ghosh, T.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Guillet, V.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Helou, G.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hivon, E.; Hobson, M.; Holmes, W. A.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jewell, J.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Krachmalnicoff, N.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leahy, J. P.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Mazzotta, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Rebolo, R.; Remazeilles, M.; Renault, C.; Renzi, A.; Ricciardi, S.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rouillé d'Orfeuil, B.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Soler, J. D.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vibert, L.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Watson, R.; Wehus, I. K.; White, M.; White, S. D. M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2016-02-01

    The polarized thermal emission from diffuse Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100 GHz. In this paper we exploit the uniqueness of the Planck HFI polarization data from 100 to 353 GHz to measure the polarized dust angular power spectra CℓEE and CℓBB over the multipole range 40 <ℓ< 600 well away from the Galactic plane. These measurements will bring new insights into interstellar dust physics and allow a precise determination of the level of contamination for CMB polarization experiments. Despite the non-Gaussian and anisotropic nature of Galactic dust, we show that general statistical properties of the emission can be characterized accurately over large fractions of the sky using angular power spectra. The polarization power spectra of the dust are well described by power laws in multipole, Cℓ ∝ ℓα, with exponents αEE,BB = -2.42 ± 0.02. The amplitudes of the polarization power spectra vary with the average brightness in a way similar to the intensity power spectra. The frequency dependence of the dust polarization spectra is consistent with modified blackbody emission with βd = 1.59 and Td = 19.6 K down to the lowest Planck HFI frequencies. We find a systematic difference between the amplitudes of the Galactic B- and E-modes, CℓBB/CℓEE = 0.5. We verify that these general properties are preserved towards high Galactic latitudes with low dust column densities. We show that even in the faintest dust-emitting regions there are no "clean" windows in the sky where primordial CMB B-mode polarization measurements could be made without subtraction of foreground emission. Finally, we investigate the level of dust polarization in the specific field recently targeted by the BICEP2 experiment. Extrapolation of the Planck 353 GHz data to 150 GHz gives a dust power 𝒟ℓBB ≡ ℓ(ℓ+1)CℓBB/(2π) of 1.32 × 10-2 μKCMB2 over the multipole range

  11. Garden of cosmic speculation

    CERN Document Server

    Jencks, Charles

    2005-01-01

    This book tells the story of one of the most important gardens in Europe, created by the architectural critic and designer Charles Jencks and his late wife, the landscape architect and author Maggie Keswick. The Garden of Cosmic Speculation is a landscape that celebrates the new sciences of complexity and chaos theory and consists of a series of metaphors exploring the origins, the destiny and the substance of the Universe. The book is illustrated with year-round photography, bringing the garden's many dimensions vividly to life.

  12. Discovery of cosmic fractals

    CERN Document Server

    Baryshev, Yuri

    2002-01-01

    This is the first book to present the fascinating new results on the largest fractal structures in the universe. It guides the reader, in a simple way, to the frontiers of astronomy, explaining how fractals appear in cosmic physics, from our solar system to the megafractals in deep space. It also offers a personal view of the history of the idea of self-similarity and of cosmological principles, from Plato's ideal architecture of the heavens to Mandelbrot's fractals in the modern physical cosmos. In addition, this invaluable book presents the great fractal debate in astronomy (after Luciano Pi

  13. Cosmic strings and inflation

    International Nuclear Information System (INIS)

    Vishniac, E.T.

    1987-01-01

    We examine the compatibility of inflation with the cosmic string theory for galaxy formation. There is a general conflict between having sufficient string tension to effect galaxy formation, and reheating after inflation to a high enough temperature that strings may form in a thermal phase transition. To escape this conflict, we propose a class of models where the inflation is coupled to the string-producing field. The strings are formed late in inflation as the inflaton rolls towards its zero-temperature value. A large subset of these models have a novel large-scale distribution of galaxies that is fractal, displays biasing without dynamics or feedback mechanisms, and contains voids. (orig.)

  14. Testing the association between anomalous microwave emission and PAHs in the diffuse ISM

    Science.gov (United States)

    Berkeley, Matthew R.; Chuss, David; Kogut, Al

    2018-01-01

    Testing cosmic inflation is currently a primary focus of the Cosmology community. In order to verify the theory and to determine the energy scale of inflation, it is necessary to identify the characteristic B-mode polarization signal in the CMB. This signal, predicted by inflation theory, is expected to be very faint. It is therefore important to accurately characterize and remove foreground polarization components such as thermal dust and synchrotron emission.Some of these components have already been accurately characterized, but there are others that are not so well understood. In 1996, a new galactic foreground emission component was discovered. Dubbed 'anomalous microwave emission' (AME), this new foreground has yet to be identified. Though its physical origin remains uncertain, the leading hypothesis for the origin of this foreground proposes that the emission comes from rapidly rotating small dust grains called Polycyclic Aromatic Hydrocarbons (PAHs), or 'spinning dust'. PAHs are a family of hydrocarbon molecules with characteristic bending and stretching modes that have identifiable emission spectra in the mid-infrared region. The Wide-field Infrared Survey Explorer (WISE) is a satellite that was launched in 2010 into a polar orbit, enabling it to take images of the entire sky at four different mid-infrared wavelengths. These wavelengths cover the spectral region with the aforementioned PAH emission features in the mid-infrared. WISE archival data therefore makes it possible to construct a full-sky map of PAH emission.We present full sky maps using WISE data as a preliminary result towards creating a full sky PAH map.

  15. Proceedings of microwave processing of materials 3

    International Nuclear Information System (INIS)

    Beatty, R.L.

    1992-01-01

    This book contains proceedings of the third MRS Symposium on Microwave Processing of Materials. Topics covered include: Microwave Processing Overviews, Numerical Modeling Techniques, Microwave Processing System Design, Microwave/Plasma Processing, Microwave/Materials Interactions, Microwave Processing of Ceramics, Microwave Processing of Polymers, Microwave Processing of Hazardous Wastes, Microwave NDE Techniques and Dielectric Properties and Measurements

  16. Stable atomic hydrogen: Polarized atomic beam source

    International Nuclear Information System (INIS)

    Niinikoski, T.O.; Penttilae, S.; Rieubland, J.M.; Rijllart, A.

    1984-01-01

    We have carried out experiments with stable atomic hydrogen with a view to possible applications in polarized targets or polarized atomic beam sources. Recent results from the stabilization apparatus are described. The first stable atomic hydrogen beam source based on the microwave extraction method (which is being tested ) is presented. The effect of the stabilized hydrogen gas density on the properties of the source is discussed. (orig.)

  17. An analytical approach to the CMB polarization in a spatially closed background

    Science.gov (United States)

    Niazy, Pedram; Abbassi, Amir H.

    2018-03-01

    The scalar mode polarization of the cosmic microwave background is derived in a spatially closed universe from the Boltzmann equation using the line of sight integral method. The EE and TE multipole coefficients have been extracted analytically by considering some tolerable approximations such as considering the evolution of perturbation hydrodynamically and sudden transition from opacity to transparency at the time of last scattering. As the major advantage of analytic expressions, CEE,ℓS and CTE,ℓ explicitly show the dependencies on baryon density ΩB, matter density ΩM, curvature ΩK, primordial spectral index ns, primordial power spectrum amplitude As, Optical depth τreion, recombination width σt and recombination time tL. Using a realistic set of cosmological parameters taken from a fit to data from Planck, the closed universe EE and TE power spectrums in the scalar mode are compared with numerical results from the CAMB code and also latest observational data. The analytic results agree with the numerical ones on the big and moderate scales. The peak positions are in good agreement with the numerical result on these scales while the peak heights agree with that to within 20% due to the approximations have been considered for these derivations. Also, several interesting properties of CMB polarization are revealed by the analytic spectra.

  18. Vibrational characteristics of a superconducting magnetic bearing employed for a prototype polarization modulator

    Science.gov (United States)

    Sakurai, Yuki; Matsumura, Tomotake; Sugai, Hajime; Katayama, Nobuhiko; Ohsaki, Hiroyuki; Terao, Yutaka; Terachi, Yusuke; Kataza, Hirokazu; Utsunomiya, Shin; Yamamoto, Ryo

    2017-07-01

    We present the vibrational characteristics of a levitating rotor in a superconducting magnetic bearing (SMB) system operating at below 10 K. We develop a polarization modulator that requires a continuously rotating optical element, called half-wave plate (HWP), for a cosmic microwave background polarization experiment. The HWP has to operate at the temperature below 10 K, and thus an SMB provides a smooth rotation of the HWP at the cryogenic temperature of about 10 K with minimal heat dissipation. In order to understand the potential interference to the cosmological observations due to the vibration of the HWP, it is essential to characterize the vibrational properties of the levitating rotor of the SMB. We constructed a prototype model that consists of an SMB with an array of high temperature superconductors, YBCO, and a permanent magnet ring, NdFeB. The rotor position is monitored by a laser displacement gauge, and a cryogenic Hall sensor via the magnetic field. In this presentation, we present the measurement results of the vibration characteristics using our prototype SMB system. We characterize the vibrational properties as the spring constant and the damping, and discuss the projected performance of this technology toward the use in future space missions.

  19. L3 + Cosmics Experiment

    CERN Multimedia

    2002-01-01

    %RE4 %title\\\\ \\\\The L3+C experiment takes advantage of the unique properties of the L3 muon spectrometer to get an accurate measurement of cosmic ray muons 30 m underground. A new muon trigger, readout and DAQ system have been installed, as well as a scintillator array covering the upper surfaces of the L3 magnet for timing purposes. The acceptance amounts to 200 $m^2 sr$. The data are collected independently in parallel with L3 running. In spring 2000 a scintillator array will be installed on the roof of the SX hall in order to estimate the primary energy of air showers associated with events observed in L3+C.\\\\ \\\\The cosmic ray muon momentum spectrum, the zenith angular dependence and the charge ratio are measured with high accuracy between 20 and 2000 GeV/c. The results will provide new information about the primary composition, the shower development in the atmosphere, and the inclusive pion and kaon (production-) cross sections (specifically the "$\\pi$/K ratio") at high energies. These data will also hel...

  20. COSMIC monthly progress report

    Science.gov (United States)

    1994-01-01

    Activities of the Computer Software Management and Information Center (COSMIC) are summarized for the month of May 1994. Tables showing the current inventory of programs available from COSMIC are presented and program processing and evaluation activities are summarized. Nine articles were prepared for publication in the NASA Tech Brief Journal. These articles (included in this report) describe the following software items: (1) WFI - Windowing System for Test and Simulation; (2) HZETRN - A Free Space Radiation Transport and Shielding Program; (3) COMGEN-BEM - Composite Model Generation-Boundary Element Method; (4) IDDS - Interactive Data Display System; (5) CET93/PC - Chemical Equilibrium with Transport Properties, 1993; (6) SDVIC - Sub-pixel Digital Video Image Correlation; (7) TRASYS - Thermal Radiation Analyzer System (HP9000 Series 700/800 Version without NASADIG); (8) NASADIG - NASA Device Independent Graphics Library, Version 6.0 (VAX VMS Version); and (9) NASADIG - NASA Device Independent Graphics Library, Version 6.0 (UNIX Version). Activities in the areas of marketing, customer service, benefits identification, maintenance and support, and dissemination are also described along with a budget summary.

  1. George's cosmic treasure hunt

    CERN Document Server

    Hawking, Lucy; Parsons, Gary

    2009-01-01

    George and Annie explore the galaxy in this cosmic adventure from Stephen Hawking and Lucy Hawking, complete with essays from Professor Hawking about the latest in space travel. George is heartbroken when he learns that his friend Annie and her father are moving to the US. Eric has a new job working for the space program, looking for signs of life in the Universe. Eric leaves George with a gift—a book called The User’s Guide to the Universe. But Annie and Eric haven’t been gone for very long when Annie believes that she is being contacted by aliens, who have a terrible warning for her. George joins her in the US to help her with her quest—and before he knows it, he, Annie, Cosmos, and Annie’s annoying cousin Emmett have been swept up in a cosmic treasure hunt, spanning the whole galaxy and beyond. Lucy Hawking's own experiences in zero-gravity flight and interviews with astronauts at Cape Kennedy and the Johnson Space Center lend the book a sense of realism and excitement that is sure to fire up ima...

  2. Cosmic rays and global warming

    Energy Technology Data Exchange (ETDEWEB)

    Erlykin, A.D. [P.N. Lebedev Physical Institute, Moscow (Russian Federation); Sloan, T. [Lancaster University (United Kingdom); Wolfendale, A.W. [Durham University (United Kingdom)

    2010-07-01

    The possible effects of cosmic rays on clouds could contribute to global warming. The argument is that the observed increased solar activity during the last century caused a decrease in the ionization due to cosmic rays since the lower energy cosmic particles are deflected by the magnetic field created by the increasing solar wind. This would lead to a decrease in cloud cover allowing more heating of the earth by the sun. Meteorological data combined to solar activity observations and simulations show that any effect of solar activity on clouds and the climate is likely to be through irradiance rather than cosmic rays. Since solar irradiance transfers 8 orders of magnitude more energy to the atmosphere than cosmic rays it is more plausible that this can produce a real effect. The total contribution of variable solar activity to global warming is shown to be less than 14% of the total temperature rise. (A.C.)

  3. Supernova origin of cosmic rays

    Science.gov (United States)

    Bhat, C. L.; Houston, B. P.

    Evidence has recently been presented from gamma-ray observations for the acceleration of cosmic rays in the Loop I supernova remnant. The cosmic ray intensity thus inferred is in agreement with the predictions of the shock acceleration model of Blandford and Cowie (1980). Here, this model is examined further, specifically by comparing its predictions with the presently available information on the cosmic-ray pre-history as well as with the cosmic ray anisotropy measurements in the energy range 10 to the 9th to 10 to the 15th eV. A cosmic ray conversion efficiency of 10-20 percent is found sufficient to exlain the observations. The present study leads also to the interesting suggestion that the bump observed in the primary energy spectrum at 10 to the 14th to 10 to the 15th eV may be due to an excess contribution from local supernovae.

  4. Using CMB polarization to constrain the anomalous nature of the Cold Spot with an incomplete-sky coverage

    Science.gov (United States)

    Fernández-Cobos, R.; Vielva, P.; Martínez-González, E.; Tucci, M.; Cruz, M.

    2013-11-01

    Recent results of the ESA Planck satellite have confirmed the existence of some anomalies in the statistical distribution of the cosmic microwave background (CMB) anisotropies. One of the most intriguing anomalies is the cold spot, first detected in the Wilkinson Microwave Anisotropy Probe (WMAP) data by Vielva et al. In a later paper, Vielva et al. (2011) developed a method to probe the anomalous nature of the cold spot by using the cross-correlation of temperature and polarization of the CMB fluctuations. Whereas this work was built under the assumption of analysing full-sky data, in this paper we extend such approach to deal with realistic data sets with a partial-sky coverage. In particular, we exploit the radial and tangential polarization patterns around temperature spots. We explore the capacity of the method to distinguish between a standard Gaussian CMB scenario and an alternative one, in which the cold spot arises from a physical process that does not present correlated polarization features (e.g. topological defects), as a function of the instrumental-noise level. Moreover, we consider more in detail the case of an ideal noise-free experiment and the ones with the expected instrumental-noise levels in QUIJOTE and Planck experiments. We also present an application to the 9-year WMAP data, without being able to obtain firm conclusions, with a significance level of 32 per cent. In the ideal case, the alternative scenario could be rejected at a significance level of around 1 per cent, whereas for expected noise levels of QUIJOTE and Planck experiments the corresponding significance levels are 1.5 and 7.4 per cent, respectively.

  5. COMPARISONS OF THE INTERSTELLAR MAGNETIC FIELD DIRECTIONS OBTAINED FROM THE IBEX RIBBON AND INTERSTELLAR POLARIZATIONS

    International Nuclear Information System (INIS)

    Frisch, Priscilla C.; Andersson, B-G; Berdyugin, Andrei; Piirola, Vilppu; Funsten, Herbert O.; Magalhaes, Antonio M.; McComas, David J.; Schwadron, Nathan A.; Slavin, Jonathan D.; Wiktorowicz, Sloane J.

    2010-01-01

    Variations in the spatial configuration of the interstellar magnetic field (ISMF) near the Sun can be constrained by comparing the ISMF direction at the heliosphere found from the Interstellar Boundary Explorer (IBEX) spacecraft observations of a 'Ribbon' of energetic neutral atoms (ENAs), with the ISMF direction derived from optical polarization data for stars within ∼40 pc. Using interstellar polarization observations toward ∼30 nearby stars within ∼90 0 of the heliosphere nose, we find that the best fits to the polarization position angles are obtained for a magnetic pole directed toward ecliptic coordinates of λ, β ∼ 263 0 , 37 0 (or galactic coordinates of l, b ∼ 38 0 , 23 0 ), with uncertainties of ±35 0 based on the broad minimum of the best fits and the range of data quality. This magnetic pole is 33 0 from the magnetic pole that is defined by the center of the arc of the ENA Ribbon. The IBEX ENA ribbon is seen in sight lines that are perpendicular to the ISMF as it drapes over the heliosphere. The similarity of the polarization and Ribbon directions for the local ISMF suggests that the local field is coherent over scale sizes of tens of parsecs. The ISMF vector direction is nearly perpendicular to the flow of local interstellar material (ISM) through the local standard of rest, supporting a possible local ISM origin related to an evolved expanding magnetized shell. The local ISMF direction is found to have a curious geometry with respect to the cosmic microwave background dipole moment.

  6. Cosmic Tachyon Background Radiation

    CERN Document Server

    Tomaschitz, R

    1999-01-01

    The equilibrium statistical mechanics of a background radiation of superluminal particles is investigated, based on a vectorial wave equation for tachyons of the Proca type. The partition function, the spectral energy density, and the various thermodynamic variables of an ideal Bose gas of tachyons in an open Robertson-Walker cosmology are derived. The negative mass square in the wave equation changes the frequency scaling in the Rayleigh-Jeans law, and there are also significant changes in the low temperature regime as compared to the microwave background, in particular in the caloric and thermal equations of state.

  7. Microwave Measurements of Coronal Magnetic Field

    Science.gov (United States)

    Shibasaki, K.

    2006-08-01

    Magnetic field measurements of the solar corona using microwave observation are reviewed. The solar corona is filled with highly ionised plasma and magnetic field. Moving charged particles interact with magnetic field due to Lorentz force. This results in gyration motion perpendicular to the magnetic field and free motion along the magnetic field. Circularly polarized electro-magnetic waves interact with gyrating electrons efficiently and the interaction depends on the sense of circular polarization (right-handed or left-handed). This is the reason why we can measure magnetic field strength through microwave observations. This process does not require complicated quantum physics but the classical treatment is enough. Hence the inversion of measured values to magnetic field strength is simpler than in the case of optical and infrared measurements. There are several methods to measure magnetic field strength through microwave observations. We can divide them into two categories: one is based on emission mechanisms and the other is based on wave propagation. In the case of emission mechanisms, thermal f-f emission, thermal gyro-resonance emission and non-thermal gyro-synchrotron emission can be used to measure magnetic field strength. In the case of wave propagation, polarization reversal due to propagation through quasi-transverse magnetic field region can be used. Examples of distribution of magnetic field strength in the solar corona measured by Nobeyama Radioheliograph will be presented.

  8. Cosmic dust in the earth's atmosphere

    Science.gov (United States)

    Plane, John M. C.

    2012-04-01

    This review discusses the magnitude of the cosmic dust input into the earth's atmosphere, and the resulting impacts from around 100 km to the earth's surface. Zodiacal cloud observations and measurements made with a spaceborne dust detector indicate a daily mass input of interplanetary dust particles ranging from 100 to 300 tonnes, which is in agreement with the accumulation rates of cosmic-enriched elements (Ir, Pt, Os and super-paramagnetic Fe) in polar ice cores and deep-sea sediments. In contrast, measurements in the middle atmosphere - by radar, lidar, high-flying aircraft and satellite remote sensing - indicate that the input is between 5 and 50 tonnes per day. There are two reasons why this huge discrepancy matters. First, if the upper range of estimates is correct, then vertical transport in the middle atmosphere must be considerably faster than generally believed; whereas if the lower range is correct, then our understanding of dust evolution in the solar system, and transport from the middle atmosphere to the surface, will need substantial revision. Second, cosmic dust particles enter the atmosphere at high speeds and undergo significant ablation. The resulting metals injected into the atmosphere are involved in a diverse range of phenomena, including: the formation of layers of metal atoms and ions; the nucleation of noctilucent clouds, which are a sensitive marker of climate change; impacts on stratospheric aerosols and O3 chemistry, which need to be considered against the background of a cooling stratosphere and geo-engineering plans to increase sulphate aerosol; and fertilization of the ocean with bio-available Fe, which has potential climate feedbacks.

  9. Exploring cosmic origins with CORE: Inflation

    Science.gov (United States)

    Finelli, F.; Bucher, M.; Achúcarro, A.; Ballardini, M.; Bartolo, N.; Baumann, D.; Clesse, S.; Errard, J.; Handley, W.; Hindmarsh, M.; Kiiveri, K.; Kunz, M.; Lasenby, A.; Liguori, M.; Paoletti, D.; Ringeval, C.; Väliviita, J.; van Tent, B.; Vennin, V.; Ade, P.; Allison, R.; Arroja, F.; Ashdown, M.; Banday, A. J.; Banerji, R.; Bartlett, J. G.; Basak, S.; de Bernardis, P.; Bersanelli, M.; Bonaldi, A.; Borril, J.; Bouchet, F. R.; Boulanger, F.; Brinckmann, T.; Burigana, C.; Buzzelli, A.; Cai, Z.-Y.; Calvo, M.; Carvalho, C. S.; Castellano, G.; Challinor, A.; Chluba, J.; Colantoni, I.; Coppolecchia, A.; Crook, M.; D'Alessandro, G.; D'Amico, G.; Delabrouille, J.; Desjacques, V.; De Zotti, G.; Diego, J. M.; Di Valentino, E.; Feeney, S.; Fergusson, J. R.; Fernandez-Cobos, R.; Ferraro, S.; Forastieri, F.; Galli, S.; García-Bellido, J.; de Gasperis, G.; Génova-Santos, R. T.; Gerbino, M.; González-Nuevo, J.; Grandis, S.; Greenslade, J.; Hagstotz, S.; Hanany, S.; Hazra, D. K.; Hernández-Monteagudo, C.; Hervias-Caimapo, C.; Hills, M.; Hivon, E.; Hu, B.; Kisner, T.; Kitching, T.; Kovetz, E. D.; Kurki-Suonio, H.; Lamagna, L.; Lattanzi, M.; Lesgourgues, J.; Lewis, A.; Lindholm, V.; Lizarraga, J.; López-Caniego, M.; Luzzi, G.; Maffei, B.; Mandolesi, N.; Martínez-González, E.; Martins, C. J. A. P.; Masi, S.; McCarthy, D.; Matarrese, S.; Melchiorri, A.; Melin, J.-B.; Molinari, D.; Monfardini, A.; Natoli, P.; Negrello, M.; Notari, A.; Oppizzi, F.; Paiella, A.; Pajer, E.; Patanchon, G.; Patil, S. P.; Piat, M.; Pisano, G.; Polastri, L.; Polenta, G.; Pollo, A.; Poulin, V.; Quartin, M.; Ravenni, A.; Remazeilles, M.; Renzi, A.; Roest, D.; Roman, M.; Rubiño-Martin, J. A.; Salvati, L.; Starobinsky, A. A.; Tartari, A.; Tasinato, G.; Tomasi, M.; Torrado, J.; Trappe, N.; Trombetti, T.; Tucci, M.; Tucker, C.; Urrestilla, J.; van de Weygaert, R.; Vielva, P.; Vittorio, N.; Young, K.; Zannoni, M.

    2018-04-01

    We forecast the scientific capabilities to improve our understanding of cosmic inflation of CORE, a proposed CMB space satellite submitted in response to the ESA fifth call for a medium-size mission opportunity. The CORE satellite will map the CMB anisotropies in temperature and polarization in 19 frequency channels spanning the range 60–600 GHz. CORE will have an aggregate noise sensitivity of 1.7 μKṡ arcmin and an angular resolution of 5' at 200 GHz. We explore the impact of telescope size and noise sensitivity on the inflation science return by making forecasts for several instrumental configurations. This study assumes that the lower and higher frequency channels suffice to remove foreground contaminations and complements other related studies of component separation and systematic effects, which will be reported in other papers of the series "Exploring Cosmic Origins with CORE." We forecast the capability to determine key inflationary parameters, to lower the detection limit for the tensor-to-scalar ratio down to the 10‑3 level, to chart the landscape of single field slow-roll inflationary models, to constrain the epoch of reheating, thus connecting inflation to the standard radiation-matter dominated Big Bang era, to reconstruct the primordial power spectrum, to constrain the contribution from isocurvature perturbations to the 10‑3 level, to improve constraints on the cosmic string tension to a level below the presumptive GUT scale, and to improve the current measurements of primordial non-Gaussianities down to the fNLlocal level. For all the models explored, CORE alone will improve significantly on the present constraints on the physics of inflation. Its capabilities will be further enhanced by combining with complementary future cosmological observations.

  10. GPM Microwave Imager Engineering Model Results

    Science.gov (United States)

    Newell, David; Krimchansky, Sergey

    2010-01-01

    The Global Precipitation Measurement (GPM) Microwave Imager (GMI) Instrument is being developed by Ball Aerospace and Technology Corporation (BATC) for the GPM program at NASA Goddard. The Global Precipitation Measurement (GPM) mission is an international effort managed by the National Aeronautics and Space Administration (NASA) to improve climate, weather, and hydro-meteorological predictions through more accurate and more frequent precipitation measurements. The GPM Microwave Imager (GMI) will be used to make calibrated, radiometric measurements from space at multiple microwave frequencies and polarizations. GMI will be placed on the GPM Core Spacecraft together with the Dualfrequency Precipitation Radar (DPR). The DPR is two-frequency precipitation measurement radar, which will operate in the Ku-band and Ka-band of the microwave spectrum. The Core Spacecraft will make radiometric and radar measurements of clouds and precipitation and will be the central element ofGPM's space segment. The data products from GPM will provide information concerning global precipitation on a frequent, near-global basis to meteorologists and scientists making weather forecasts and performing research on the global energy and water cycle, precipitation, hydrology, and related disciplines. In addition, radiometric measurements from GMI and radar measurements from the DPR will be used together to develop a retrieval transfer standard for the purpose of calibrating precipitation retrieval algorithms. This calibration standard will establish a reference against which other retrieval algorithms using only microwave radiometers (and without the benefit of the DPR) on other satellites in the GPM constellation will be compared.

  11. Reconstructing the long-term cosmic ray intensity: linear relations do not work

    Directory of Open Access Journals (Sweden)

    K. Mursula

    Full Text Available It was recently suggested (Lockwood, 2001 that the cosmic ray intensity in the neutron monitor energy range is linearly related to the coronal source flux, and can be reconstructed for the last 130 years using the long-term coronal flux estimated earlier. Moreover, Lockwood (2001 reconstructed the coronal flux for the last 500 years using a similar linear relation between the flux and the concentration of cosmogenic 10 Be isotopes in polar ice. Here we show that the applied linear relations are oversimplified and lead to unphysical results on long time scales. In particular, the cosmic ray intensity reconstructed by Lockwood (2001 for the last 130 years has a steep trend which is considerably larger than the trend estimated from observations during the last 65 years. Accordingly, the reconstructed cosmic ray intensity reaches or even exceeds the local interstellar cosmic ray flux around 1900. We argue that these unphysical results obtained when using linear relations are due to the oversimplified approach which does not take into account the complex and essentially nonlinear nature of long-term cosmic ray modulation in the heliosphere. We also compare the long-term cosmic ray intensity based on a linear treatment with the reconstruction based on a recent physical model which predicts a considerably lower cosmic ray intensity around 1900.

    Key words. Interplanetary physics (cosmic rays; heliopause and solar wind termination – Geomagnetism and paleomagnetism (time variations, secular and long-term

  12. Reconstructing the long-term cosmic ray intensity: linear relations do not work

    Directory of Open Access Journals (Sweden)

    K. Mursula

    2003-04-01

    Full Text Available It was recently suggested (Lockwood, 2001 that the cosmic ray intensity in the neutron monitor energy range is linearly related to the coronal source flux, and can be reconstructed for the last 130 years using the long-term coronal flux estimated earlier. Moreover, Lockwood (2001 reconstructed the coronal flux for the last 500 years using a similar linear relation between the flux and the concentration of cosmogenic 10 Be isotopes in polar ice. Here we show that the applied linear relations are oversimplified and lead to unphysical results on long time scales. In particular, the cosmic ray intensity reconstructed by Lockwood (2001 for the last 130 years has a steep trend which is considerably larger than the trend estimated from observations during the last 65 years. Accordingly, the reconstructed cosmic ray intensity reaches or even exceeds the local interstellar cosmic ray flux around 1900. We argue that these unphysical results obtained when using linear relations are due to the oversimplified approach which does not take into account the complex and essentially nonlinear nature of long-term cosmic ray modulation in the heliosphere. We also compare the long-term cosmic ray intensity based on a linear treatment with the reconstruction based on a recent physical model which predicts a considerably lower cosmic ray intensity around 1900.Key words. Interplanetary physics (cosmic rays; heliopause and solar wind termination – Geomagnetism and paleomagnetism (time variations, secular and long-term

  13. Passive microwave remote sensing of soil moisture

    International Nuclear Information System (INIS)

    Jackson, T.J.; Schmugge, T.J.

    1986-01-01

    Microwave remote sensing provides a unique capability for direct observation of soil moisture. Remote measurements from space afford the possibility of obtaining frequent, global sampling of soil moisture over a large fraction of the Earth's land surface. Microwave measurements have the benefit of being largely unaffected by cloud cover and variable surface solar illumination, but accurate soil moisture estimates are limited to regions that have either bare soil or low to moderate amounts of vegetation cover. A particular advantage of passive microwave sensors is that in the absence of significant vegetation cover soil moisture is the dominant effect on the received signal. The spatial resolutions of passive microwave soil moisture sensors currently considered for space operation are in the range 10–20 km. The most useful frequency range for soil moisture sensing is 1–5 GHz. System design considerations include optimum choice of frequencies, polarizations, and scanning configurations, based on trade-offs between requirements for high vegetation penetration capability, freedom from electromagnetic interference, manageable antenna size and complexity, and the requirement that a sufficient number of information channels be available to correct for perturbing geophysical effects. This paper outlines the basic principles of the passive microwave technique for soil moisture sensing, and reviews briefly the status of current retrieval methods. Particularly promising are methods for optimally assimilating passive microwave data into hydrologic models. Further studies are needed to investigate the effects on microwave observations of within-footprint spatial heterogeneity of vegetation cover and subsurface soil characteristics, and to assess the limitations imposed by heterogeneity on the retrievability of large-scale soil moisture information from remote observations

  14. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

  15. Correcting for Precipitation Effects in Satellite-Based Passive Microwave Tropical Cyclone Intensity Estimates

    National Research Council Canada - National Science Library

    Wacker, Robert S

    2005-01-01

    .... The Advanced Microwave Sounding Unit (AMSU) has operated since 1998 on polar-orbiting environmental satellites and is able to measure the warm temperature anomaly in the upper troposphere above a TC's center...

  16. Topological px+ipy superfluid phase of fermionic polar molecules

    NARCIS (Netherlands)

    Levinsen, J.; Cooper, N.R.; Shlyapnikov, G.V.

    2011-01-01

    We discuss the topological px+ipy superfluid phase in a 2D gas of single-component fermionic polar molecules dressed by a circularly polarized microwave field. This phase emerges because the molecules may interact with each other via a potential Vo(r) that has an attractive dipole-dipole 1/r^3 tail,

  17. Cosmic mass spectrometer

    Science.gov (United States)

    Anchordoqui, Luis A.; Barger, Vernon; Weiler, Thomas J.

    2018-03-01

    We argue that if ultrahigh-energy (E ≳1010GeV) cosmic rays are heavy nuclei (as indicated by existing data), then the pointing of cosmic rays to their nearest extragalactic sources is expected for 1010.6 ≲ E /GeV ≲1011. This is because for a nucleus of charge Ze and baryon number A, the bending of the cosmic ray decreases as Z / E with rising energy, so that pointing to nearby sources becomes possible in this particular energy range. In addition, the maximum energy of acceleration capability of the sources grows linearly in Z, while the energy loss per distance traveled decreases with increasing A. Each of these two points tend to favor heavy nuclei at the highest energies. The traditional bi-dimensional analyses, which simultaneously reproduce Auger data on the spectrum and nuclear composition, may not be capable of incorporating the relative importance of all these phenomena. In this paper we propose a multi-dimensional reconstruction of the individual emission spectra (in E, direction, and cross-correlation with nearby putative sources) to study the hypothesis that primaries are heavy nuclei subject to GZK photo-disintegration, and to determine the nature of the extragalactic sources. More specifically, we propose to combine information on nuclear composition and arrival direction to associate a potential clustering of events with a 3-dimensional position in the sky. Actually, both the source distance and maximum emission energy can be obtained through a multi-parameter likelihood analysis to accommodate the observed nuclear composition of each individual event in the cluster. We show that one can track the level of GZK interactions on an statistical basis by comparing the maximum energy at the source of each cluster. We also show that nucleus-emitting-sources exhibit a cepa stratis structure on Earth which could be pealed off by future space-missions, such as POEMMA. Finally, we demonstrate that metal-rich starburst galaxies are highly-plausible candidate

  18. Exploring cosmic origins with CORE: Cosmological parameters

    Science.gov (United States)

    Di Valentino, E.; Brinckmann, T.; Gerbino, M.; Poulin, V.; Bouchet, F. R.; Lesgourgues, J.; Melchiorri, A.; Chluba, J.; Clesse, S.; Delabrouille, J.; Dvorkin, C.; Forastieri, F.; Galli, S.; Hooper, D. C.; Lattanzi, M.; Martins, C. J. A. P.; Salvati, L.; Cabass, G.; Caputo, A.; Giusarma, E.; Hivon, E.; Natoli, P.; Pagano, L.; Paradiso, S.; Rubiño-Martin, J. A.; Achúcarro, A.; Ade, P.; Allison, R.; Arroja, F.; Ashdown, M.; Ballardini, M.; Banday, A. J.; Banerji, R.; Bartolo, N.; Bartlett, J. G.; Basak, S.; Baumann, D.; de Bernardis, P.; Bersanelli, M.; Bonaldi, A.; Bonato, M.; Borrill, J.; Boulanger, F.; Bucher, M.; Burigana, C.; Buzzelli, A.; Cai, Z.-Y.; Calvo, M.; Carvalho, C. S.; Castellano, G.; Challinor, A.; Charles, I.; Colantoni, I.; Coppolecchia, A.; Crook, M.; D'Alessandro, G.; De Petris, M.; De Zotti, G.; Diego, J. M.; Errard, J.; Feeney, S.; Fernandez-Cobos, R.; Ferraro, S.; Finelli, F.; de Gasperis, G.; Génova-Santos, R. T.; González-Nuevo, J.; Grandis, S.; Greenslade, J.; Hagstotz, S.; Hanany, S.; Handley, W.; Hazra, D. K.; Hernández-Monteagudo, C.; Hervias-Caimapo, C.; Hills, M.; Kiiveri, K.; Kisner, T.; Kitching, T.; Kunz, M.; Kurki-Suonio, H.; Lamagna, L.; Lasenby, A.; Lewis, A.; Liguori, M.; Lindholm, V.; Lopez-Caniego, M.; Luzzi, G.; Maffei, B.; Martin, S.; Martinez-Gonzalez, E.; Masi, S.; Matarrese, S.; McCarthy, D.; Melin, J.-B.; Mohr, J. J.; Molinari, D.; Monfardini, A.; Negrello, M.; Notari, A.; Paiella, A.; Paoletti, D.; Patanchon, G.; Piacentini, F.; Piat, M.; Pisano, G.; Polastri, L.; Polenta, G.; Pollo, A.; Quartin, M.; Remazeilles, M.; Roman, M.; Ringeval, C.; Tartari, A.; Tomasi, M.; Tramonte, D.; Trappe, N.; Trombetti, T.; Tucker, C.; Väliviita, J.; van de Weygaert, R.; Van Tent, B.; Vennin, V.; Vermeulen, G.; Vielva, P.; Vittorio, N.; Young, K.; Zannoni, M.

    2018-04-01

    We forecast the main cosmological parameter constraints achievable with the CORE space mission which is dedicated to mapping the polarisation of the Cosmic Microwave Background (CMB). CORE was recently submitted in response to ESA's fifth call for medium-sized mission proposals (M5). Here we report the results from our pre-submission study of the impact of various instrumental options, in particular the telescope size and sensitivity level, and review the great, transformative potential of the mission as proposed. Specifically, we assess the impact on a broad range of fundamental parameters of our Universe as a function of the expected CMB characteristics, with other papers in the series focusing on controlling astrophysical and instrumental residual systematics. In this paper, we assume that only a few central CORE frequency channels are usable for our purpose, all others being devoted to the cleaning of astrophysical contaminants. On the theoretical side, we assume ΛCDM as our general framework and quantify the improvement provided by CORE over the current constraints from the Planck 2015 release. We also study the joint sensitivity of CORE and of future Baryon Acoustic Oscillation and Large Scale Structure experiments like DESI and Euclid. Specific constraints on the physics of inflation are presented in another paper of the series. In addition to the six parameters of the base ΛCDM, which describe the matter content of a spatially flat universe with adiabatic and scalar primordial fluctuations from inflation, we derive the precision achievable on parameters like those describing curvature, neutrino physics, extra light relics, primordial helium abundance, dark matter annihilation, recombination physics, variation of fundamental constants, dark energy, modified gravity, reionization and cosmic birefringence. In addition to assessing the improvement on the precision of individual parameters, we also forecast the post-CORE overall reduction of the allowed

  19. Our cosmic habitat

    CERN Document Server

    Rees, Martin

    2001-01-01

    Our universe seems strangely 'biophilic,' or hospitable to life. Is this providence or coincidence? According to Martin Rees, the answer depends on the answer to another question, the one posed by Einstein's famous remark: 'What interests me most is whether God could have made the world differently.' This highly engaging book centres on the fascinating consequences of the answer being 'yes'. Rees explores the notion that our universe is just part of a vast 'multiverse,' or ensemble of universes, in which most of the other universes are lifeless. What we call the laws of nature would then be local by laws, imposed in the aftermath of our own Big Bang. In this scenario, our cosmic habitat would be a special, possibly unique universe where the prevailing laws of physics allowed life to emerge.

  20. Cosmic magnetic fields

    CERN Document Server

    Sánchez Almeida, Jorge

    2018-01-01

    Magnetic fields pervade the universe and play an important role in many astrophysical processes. However, they require specialised observational tools, and are challenging to model and understand. This volume provides a unified view of magnetic fields across astrophysical and cosmological contexts, drawing together disparate topics that are rarely covered together. Written by the lecturers of the XXV Canary Islands Winter School, it offers a self-contained introduction to cosmic magnetic fields on a range of scales. The connections between the behaviours of magnetic fields in these varying contexts are particularly emphasised, from the relatively small and close ranges of the Sun, planets and stars, to galaxies and clusters of galaxies, as well as on cosmological scales. Aimed at young researchers and graduate students, this up-to-date review uniquely brings together a subject often tackled by disconnected communities, conveying the latest advances as well as highlighting the limits of our current understandi...

  1. Cosmic ray synergies

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    In laboratories, cosmic rays have been the subject of scientific research for many years. A more recent development is their appearance in schools, as educational tools. A recent workshop at CERN, organised by ASPERA in collaboration with EPPOG and EPPCN, had the goal of bringing together ideas and initiatives with a view to setting up a future common project.   Presentation at the workshop on 15 October. In research, as in education, you can sometimes get things done more rapidly and easily by joining forces. For roughly the past decade, physicists have been taking their particle detectors to secondary schools. “The challenge now is to bring all of these existing projects together in a network,” says Arnaud Marsollier, in charge of communication for the ASPERA network and organiser of the workshop. The workshop held on Friday, 15 October was attended by representatives of major European educational projects and members of the European Particle Physics Communication Network...

  2. Microphysics of cosmic plasmas

    CERN Document Server

    Bykov, Andrei; Cargill, Peter; Dendy, Richard; Wit, Thierry; Raymond, John

    2014-01-01

    This title presents a review of the detailed aspects of the physical processes that underlie the observed properties, structures and dynamics of cosmic plasmas. An assessment of the status of understanding of microscale processes in all astrophysical collisionless plasmas is provided. The topics discussed include  turbulence in astrophysical and solar system plasmas as a phenomenological description of their dynamic properties on all scales; observational, theoretical and modelling aspects of collisionless magnetic reconnection; the formation and dynamics of shock waves; and a review and assessment of microprocesses, such as the hierarchy of plasma instabilities, non-local and non-diffusive transport processes and ionisation and radiation processes.  In addition, some of the lessons that have been learned from the extensive existing knowledge of laboratory plasmas as applied to astrophysical problems are also covered.   This volume is aimed at graduate students and researchers active in the areas of cosmi...

  3. Overproduction of cosmic superstrings

    International Nuclear Information System (INIS)

    Barnaby, Neil; Berndsen, Aaron; Cline, James M.; Stoica, Horace

    2005-01-01

    We show that the naive application of the Kibble mechanism seriously underestimates the initial density of cosmic superstrings that can be formed during the annihilation of D-branes in the early universe, as in models of brane-antibrane inflation. We study the formation of defects in effective field theories of the string theory tachyon both analytically, by solving the equation of motion of the tachyon field near the core of the defect, and numerically, by evolving the tachyon field on a lattice. We find that defects generically form with correlation lengths of order M s -1 rather than H -1 . Hence, defects localized in extra dimensions may be formed at the end of inflation. This implies that brane-antibrane inflation models where inflation is driven by branes which wrap the compact manifold may have problems with overclosure by cosmological relics, such as domain walls and monopoles

  4. Cosmic Ray Antimatter

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Over the last decade, space-born experiments have delivered new measurements of high energy cosmic-ray (CR) antiprotons and positrons, opening new frontiers in energy reach and precision. While being a promising discovery tool for new physics or exotic astrophysical phenomena, an irreducible background of antimatter comes from CR collisions with interstellar matter in the Galaxy. Understanding this irreducible source or constraining it from first principles is an interesting challenge: a game of hide-and-seek where the objective is to identify the laws of basic particle physics among the forest of astrophysical uncertainties. I describe an attempt to obtain such understanding, combining information from a zoo of CR species including massive nuclei and relativistic radioisotopes. I show that: (i) CR antiprotons most likely come from CR-gas collisions; (ii) positron data is consistent with, and suggestive of the same astrophysical production mechanism responsible for antiprotons and dominated by proton-proton c...

  5. Cosmic magnetic fields

    CERN Document Server

    Kronberg, Philipp P

    2016-01-01

    Magnetic fields are important in the Universe and their effects contain the key to many astrophysical phenomena that are otherwise impossible to understand. This book presents an up-to-date overview of this fast-growing topic and its interconnections to plasma processes, astroparticle physics, high energy astrophysics, and cosmic evolution. The phenomenology and impact of magnetic fields are described in diverse astrophysical contexts within the Universe, from galaxies to the filaments and voids of the intergalactic medium, and out to the largest redshifts. The presentation of mathematical formulae is accessible and is designed to add insight into the broad range of topics discussed. Written for graduate students and researchers in astrophysics and related disciplines, this volume will inspire readers to devise new ways of thinking about magnetic fields in space on galaxy scales and beyond.

  6. What is cosmic radiation?

    International Nuclear Information System (INIS)

    2004-01-01

    The earth was indeed receiving ionizing radiations from the heavens. This cosmic radiation consists of particles travelling near the speed of light. It consists of two components, the first of which is permanent and of galactic origin, while the other is more sporadic, depending on the sun's activities. Natural land-based sources expose each of us to an average total dose of 2.4 mSv per year (source UNSCEAR). In addition, the human activities using ionizing radiation contribute to an average annual exposure of 1.4 mSv, originating primarily with medical activities ( radiodiagnostic and radiation therapy). Members of flights crew are subject to exposure. The total dose of cosmic radiation received is is directly proportional with the duration of exposure, and thus with the duration of the flight. Measurement taken on board aircraft during the 1990's showed that flight personnel (on long haul flights) receive an average dose of approximately the same magnitude as the one due to exposure to natural radioactivity in France. The damage caused by ionizing radiation depends on the quantity of energy released by radiation into the cells of each organ or tissue of the human body(exposure dose). For a given quantity of absorbed energy (dose expressed in Gray), the damage will vary according to the nature of the radiation and the affected organ. These effects are of two types: acute effects and deferred effects. Two measurements are essential for radiation protection: the measurements of the dose of radiation absorbed by the body and the assessment of the risk associated with the absorbed dose. Two units were thus created: the gray and the sievert. (N.C.)

  7. THE COSMIC ORIGINS SPECTROGRAPH

    Energy Technology Data Exchange (ETDEWEB)

    Green, James C.; Michael Shull, J.; Snow, Theodore P.; Stocke, John [Department of Astrophysical and Planetary Sciences, University of Colorado, 391-UCB, Boulder, CO 80309 (United States); Froning, Cynthia S.; Osterman, Steve; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin [Center for Astrophysics and Space Astronomy, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Ebbets, Dennis [Ball Aerospace and Technologies Corp., 1600 Commerce Street, Boulder, CO 80301 (United States); Heap, Sara H. [NASA Goddard Space Flight Center, Code 681, Greenbelt, MD 20771 (United States); Leitherer, Claus; Sembach, Kenneth [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Linsky, Jeffrey L. [JILA, University of Colorado and NIST, Boulder, CO 80309-0440 (United States); Savage, Blair D. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Siegmund, Oswald H. W. [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Spencer, John; Alan Stern, S. [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Welsh, Barry [Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720 (United States); and others

    2012-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in 2009 May, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F{sub {lambda}} Almost-Equal-To 1.0 Multiplication-Sign 10{sup -14} erg cm{sup -2} s{sup -1} A{sup -1}, COS can achieve comparable signal to noise (when compared to Space Telescope Imaging Spectrograph echelle modes) in 1%-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (2009 September-2011 June) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is nine times than sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of 2011 June. COS has measured, for the first time with high reliability, broad Ly{alpha} absorbers and Ne VIII in the intergalactic medium, and observed the He II reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  8. Primary cosmic radiation

    International Nuclear Information System (INIS)

    Anderson, H.R.

    1972-01-01

    The term cosmic radiation means the charged particle flux that reaches the earth from outside its magnetosphere with energies above the solar wind energy of a few keV. There are two sources of flux. Sporadically the sun produces such particles, generally within the energy range 1--200 MeV, and these solar cosmic rays arrive at the earth for a period ranging from hours to days. There may be a small, rather constant flux from the sun also, but the bulk of the steady flux originates outside the earth's orbit. Although some have conjectured that part of this latter flux may be accelerated in the outer portions of the solar system where the outward flowing interplanetary medium meets the interstellar medium, it is generally thought that most or all of it arises in unique systems such as supernovae, and is distributed throughout the galaxy. These galactic particles range in energy from a few MeV to at least 10 13 MeV and consist primarily of protons with significant numbers of heavier nuclei, positrons and electrons. They are supposed to fill our galaxy, or at least the disc, more or less uniformly. However, the flux with energies below a few GeV that reaches earth's orbit is modulated by the interplanetary medium so that the number at earth varies inversely with solar activity and is always somewhat below the interstellar flux. A discussion is presented of primary galactic radiation at earth, its modulation by solar activity, and its interaction with the geomagnetic field. (U.S.)

  9. The Cosmic Origins Spectrograph

    Science.gov (United States)

    Green, James C.; Froning, Cynthia S.; Osterman, Steve; Ebbets, Dennis; Heap, Sara H.; Leitherer, Claus; Linsky, Jeffrey L.; Savage, Blair D.; Sembach, Kenneth; Shull, J. Michael; a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20120013029'); toggleEditAbsImage('author_20120013029_show'); toggleEditAbsImage('author_20120013029_hide'); "> hide

    2010-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in May 2009, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F(sub lambda) approximates 1.0 X 10(exp -14) ergs/s/cm2/Angstrom, COS can achieve comparable signal to noise (when compared to STIS echelle modes) in 1-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (September 2009 - June 2011) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is 9 times that sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of June 2011. COS has measured, for the first time with high reliability, broad Lya absorbers and Ne VIII in the intergalactic medium, and observed the HeII reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  10. Interaction of microwave radiation with the high mobility two-dimensional electron system in GaAs/AlGaAs heterostructures

    International Nuclear Information System (INIS)

    Ramanayaka, A.N.; Ye, Tianyu; Liu, H.-C.; Wegscheider, W.; Mani, R.G.

    2014-01-01

    The influence of microwave excitation on the magnetotransport properties of the high mobility two-dimensional electron system (2DES) in the GaAs/AlGaAs heterostructure system is investigated by exploring (a) the dependence of the amplitude of the microwave-induced magnetoresistance-oscillations on the polarization direction of the linearly polarized microwaves and (b) the microwave reflection from the 2DES. The polarization study indicates that the amplitude of the magnetoresistance oscillations is remarkably responsive to the relative orientation between the linearly polarized microwaves and the current-axis in the specimen. At low microwave power, P, experiments indicate a strong sinusoidal variation in the diagonal resistance R xx vs. θ at the oscillatory extrema of the microwave-induced magnetoresistance oscillations. The reflection study indicates strong correlations between the microwave induced magnetoresistance oscillations and oscillatory features in the microwave reflection in a concurrent measurement of the magnetoresistance and the microwave magnetoreflection from the 2DES. The correlations are followed as a function of the microwave frequency and the microwave power, and the results are reported

  11. Test particle trajectories near cosmic strings

    Indian Academy of Sciences (India)

    We present a detailed analysis of the motion of test particle in the gravitational field of cosmic strings in different situations using the Hamilton–Jacobi (H–J) formalism. We have discussed the trajectories near static cosmic string, cosmic string in Brans–Dicke theory and cosmic string in dilaton gravity.

  12. Interaction of cosmic strings with gravitational waves

    International Nuclear Information System (INIS)

    Frolov, V.P.; Garfinkle, D.

    1990-01-01

    We find solutions of Einstein's equation representing a gravitational wave interacting with a cosmic-string traveling wave. The motion of test cosmic strings in the gravitational field of a cosmic-string traveling wave is also examined. A solution representing traveling waves on several parallel cosmic strings is also found

  13. Cosmic rays and stochastic magnetic reconnection in the heliotail

    Directory of Open Access Journals (Sweden)

    P. Desiati

    2012-06-01

    Full Text Available Galactic cosmic rays are believed to be generated by diffusive shock acceleration processes in Supernova Remnants, and the arrival direction is likely determined by the distribution of their sources throughout the Galaxy, in particular by the nearest and youngest ones. Transport to Earth through the interstellar medium is expected to affect the cosmic ray properties as well. However, the observed anisotropy of TeV cosmic rays and its energy dependence cannot be explained with diffusion models of particle propagation in the Galaxy. Within a distance of a few parsec, diffusion regime is not valid and particles with energy below about 100 TeV must be influenced by the heliosphere and its elongated tail. The observation of a highly significant localized excess region of cosmic rays from the apparent direction of the downstream interstellar flow at 1–10 TeV energies might provide the first experimental evidence that the heliotail can affect the transport of energetic particles. In particular, TeV cosmic rays propagating through the heliotail interact with the 100–300 AU wide magnetic field polarity domains generated by the 11 yr cycles. Since the strength of non-linear convective processes is expected to be larger than viscous damping, the plasma in the heliotail is turbulent. Where magnetic field domains converge on each other due to solar wind gradient, stochastic magnetic reconnection likely occurs. Such processes may be efficient enough to re-accelerate a fraction of TeV particles as long as scattering processes are not strong. Therefore, the fractional excess of TeV cosmic rays from the narrow region toward the heliotail direction traces sightlines with the lowest smearing scattering effects, that can also explain the observation of a harder than average energy spectrum.

  14. Polarization, political

    NARCIS (Netherlands)

    Wojcieszak, M.; Mazzoleni, G.; Barnhurst, K.G.; Ikeda, K.; Maia, R.C.M.; Wessler, H.

    2015-01-01

    Polarization has been studied in three different forms: on a social, group, and individual level. This entry first focuses on the undisputed phenomenon of elite polarization (i.e., increasing adherence of policy positions among the elites) and also outlines different approaches to assessing mass

  15. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  16. Cosmic rays and the search for a Lorentz Invariance Violation

    Energy Technology Data Exchange (ETDEWEB)

    Bietenholz, Wolfgang [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2008-11-15

    This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is a process of modest energy in the proton rest frame. It can be investigated to a high precision in the laboratory, if Lorentz transformations apply even at factors {gamma} {proportional_to} O(10{sup 11}). For heavier nuclei the energy attenuation is even faster due to photo-disintegration, again if this process is Lorentz invariant. Hence the viability of Lorentz symmetry up to tremendous {gamma}-factors - far beyond accelerator tests - is a central issue. Next we comment on conceptual aspects of Lorentz Invariance and the possibility of its spontaneous breaking. This could lead to slightly particle dependent ''Maximal Attainable Velocities''. We discuss their effect in decays, Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays. We also review the search for LIV in cosmic {gamma}-rays. For multi TeV {gamma}-rays we possibly encounter another puzzle related to the transparency of the CMB, similar to the GZK cutoff, due to electron/positron creation and subsequent inverse Compton scattering. The photons emitted in a Gamma Ray Burst occur at lower energies, but their very long path provides access to information not far from the Planck scale. We discuss conceivable non-linear photon dispersions based on non-commutative geometry or effective approaches. No LIV has been observed so far. However, even extremely tiny LIV effects could change the predictions for cosmic ray physics drastically. An Appendix is devoted to the recent hypothesis by the Pierre Auger Collaboration, which identifies nearby Active Galactic Nuclei - or objects

  17. Advances in microwaves 3

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 3 covers the advances and applications of microwave signal transmission and Gunn devices. This volume contains six chapters and begins with descriptions of ground-station antennas for space communications. The succeeding chapters deal with beam waveguides, which offer interesting possibilities for transmitting microwave energy, as well as with parallel or tubular beams from antenna apertures. A chapter discusses the electron transfer mechanism and the velocity-field characteristics, with a particular emphasis on the microwave properties of Gunn oscillators. The l

  18. The microwave market

    International Nuclear Information System (INIS)

    Bybokas, J.

    1989-01-01

    As superconductors move from the laboratory to the marketplace, it becomes more important for researchers and manufacturers to understand the markets for this technology. The large market for microwave systems represents a major opportunity for high-T c superconductors. Conductor losses are a primary design limitation in conventional microwave systems. The low losses of superconductors at microwave frequencies will allow component designers and system designers to improve their products in many ways. The most important market segments for microwave systems are outlined in this discussion

  19. Experimental aspects of cosmic rays

    CERN Document Server

    Sommers, P

    2006-01-01

    High-energy cosmic rays are detected as extensive air showers, and properties of the primary cosmic rays are deduced from measurements of those air showers. The physics of air showers is reviewed here in order to explain how the measurement techniques work. The Pierre Auger Cosmic Ray Observatory (near this school in Malargue) is used to illustrate the experimental methods. The Auger Observatory combines a surface array of water Cherenkov detectors with atmospheric uorescence detectors. This `hybrid' measurement technique provides high resolution and measurement cross-checks. In conjunction with a complementary site in the northern hemisphere, the Auger Observatory expects to map the arrival directions over the full sky as well as measuring the cosmic-ray energy spectrum and statistical properties of the mass distribution.

  20. Cosmic rays, clouds, and climate.

    Science.gov (United States)

    Carslaw, K S; Harrison, R G; Kirkby, J

    2002-11-29

    It has been proposed that Earth's climate could be affected by changes in cloudiness caused by variations in the intensity of galactic cosmic rays in the atmosphere. This proposal stems from an observed correlation between cosmic ray intensity and Earth's average cloud cover over the course of one solar cycle. Some scientists question the reliability of the observations, whereas others, who accept them as reliable, suggest that the correlation may be caused by other physical phenomena with decadal periods or by a response to volcanic activity or El Niño. Nevertheless, the observation has raised the intriguing possibility that a cosmic ray-cloud interaction may help explain how a relatively small change in solar output can produce much larger changes in Earth's climate. Physical mechanisms have been proposed to explain how cosmic rays could affect clouds, but they need to be investigated further if the observation is to become more than just another correlation among geophysical variables.

  1. Dynamic polarization of 19F in a fluorinated alcohol

    International Nuclear Information System (INIS)

    Hill, D.; Kasprzyk, T.; Jarmer, J.J.; Penttilae, S.; Krumpolc, M.; Hoffmann, G.W.; Purcell, M.

    1988-01-01

    We have studied microwave dynamic cooling of 19 F and 1 H nuclei in mixtures of 1,1,1,3,3,3-hexafluoro-2-propanol and water, doped with Cr(V) complex. Equal spin temperatures of the two nuclei are produced, and the highest spin polarizations (/approximately/80%) are found in mixtures near the eutectic ratio. The high fluorine content and polarization make this a suitable material for polarized nuclear scattering experiments. 11 refs., 3 figs., 1 tab

  2. Review of cosmic background radiation spectrum measurements: limits on distortions, energy release, and cosmological processes

    International Nuclear Information System (INIS)

    Smoot, G.F.

    1986-01-01

    This paper reviews the three major cosmic microwave background radiation (CMBR) spectrum measurement programs conducted and published since the last (XVII) IAU General Assembly. The results are consistent with a Planckian spectrum with temperature 2.72 +- 0.03 K spanning a wavelength range of 0.1 to 12 cm. Limits on possible distortions and implications are outlined. Ongoing and future measurements are discussed

  3. Precision calculations of the cosmic shear power spectrum projection

    Science.gov (United States)

    Kilbinger, Martin; Heymans, Catherine; Asgari, Marika; Joudaki, Shahab; Schneider, Peter; Simon, Patrick; Van Waerbeke, Ludovic; Harnois-Déraps, Joachim; Hildebrandt, Hendrik; Köhlinger, Fabian; Kuijken, Konrad; Viola, Massimo

    2017-12-01

    We compute the spherical-sky weak-lensing power spectrum of the shear and convergence. We discuss various approximations, such as flat-sky, and first- and second-order Limber equations for the projection. We find that the impact of adopting these approximations is negligible when constraining cosmological parameters from current weak-lensing surveys. This is demonstrated using data from the Canada-France-Hawaii Telescope Lensing Survey. We find that the reported tension with Planck cosmic microwave background temperature anisotropy results cannot be alleviated. For future large-scale surveys with unprecedented precision, we show that the spherical second-order Limber approximation will provide sufficient accuracy. In this case, the cosmic-shear power spectrum is shown to be in agreement with the full projection at the sub-percent level for ℓ > 3, with the corresponding errors an order of magnitude below cosmic variance for all ℓ. When computing the two-point shear correlation function, we show that the flat-sky fast Hankel transformation results in errors below two percent compared to the full spherical transformation. In the spirit of reproducible research, our numerical implementation of all approximations and the full projection are publicly available within the package NICAEA at http://www.cosmostat.org/software/nicaea.

  4. Cosmic rays and Earth's climate

    DEFF Research Database (Denmark)

    Svensmark, Henrik

    2000-01-01

    During the last solar cycle the Earth's cloud cover underwent a modulation in phase with the cosmic ray flux. Assuming that there is a causal relationship between the two, it is expected and found that the Earth's temperature follows more closely decade variations in cosmic ray flux than other...... solar activity parameters. If the relationship is real the state of the Heliosphere affects the Earth's climate....

  5. Assessment of NOAA NUCAPS upper air temperature profiles using COSMIC GPS radio occultation and ARM radiosondes

    Science.gov (United States)

    Feltz, M. L.; Borg, L.; Knuteson, R. O.; Tobin, D.; Revercomb, H.; Gambacorta, A.

    2017-09-01

    The U.S. National Oceanic and Atmospheric Administration (NOAA) recently began operational processing to derive vertical temperature profiles from two new sensors, Cross-Track Infrared Sounder and Advanced Technology Microwave Sounder, which were developed for the next generation of U.S. weather satellites. The NOAA-Unique Combined Atmospheric Processing System (NUCAPS) has been developed by NOAA to routinely process data from future Joint Polar Satellite System operational satellites and the preparatory Suomi-NPP satellite. This paper assesses the NUCAPS vertical temperature profile product from the upper troposphere into the middle stratosphere using radiosonde and GPS radio occultation (RO) data. Radiosonde data from the Department of Energy Atmospheric Radiation Measurement (ARM) program are=] compared to both the NUCAPS and GPS RO temperature products to evaluate bias and RMS errors. At all three fixed ARM sites for time periods investigated the NUCAPS temperature in the 100-40 hPa range is found to have an average bias to the radiosondes of less than 0.45 K and an RMS error of less than 1 K when temperature averaging kernels are applied. At a 95% confidence level, the radiosondes and RO were found to agree within 0.4 K at the North Slope of Alaska site and within 0.83 K at Southern Great Plains and Tropical Western Pacific. The GPS RO-derived dry temperatures, obtained from the University Corporation for Atmospheric Research Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission, are used as a common reference for the intercomparison of NUCAPS temperature products to similar products produced by NASA from Atmospheric Infrared Sounder (AIRS) and by European Organisation for the Exploitation of Meteorological Satellites from MetOp-B Infrared Atmospheric Sounding Interferometer (IASI). For seasonal and zonal scales, the NUCAPS agreement with AIRS and IASI is less than 0.5 K after application of averaging kernels.

  6. Polar Bears

    Science.gov (United States)

    Amstrup, Steven C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting polar bears of the Beaufort Sea region are exposed to mineral and petroleum extraction and related human activities such as shipping road-building, and seismic testing (Stirling 1990).Little was known at the start of this project about how polar bears move about in their environment, and although it was understood that many bears travel across political borders, the boundaries of populations had not been delineated (Amstrup 1986, Amstrup et al. 1986, Amstrup and DeMaster 1988, Garner et al. 1994, Amstrup 1995, Amstrup et al. 1995, Amstrup 2000).As human populations increase and demands for polar bears and other arctic resources escalate, managers must know the sizes and distributions of the polar bear populations. Resource managers also need reliable estimates of breeding rates, reproductive intervals, litter sizes, and survival of young and adults.Our objectives for this research were 1) to determine the seasonal and annual movements of polar bears in the Beaufort Sea, 2) to define the boundaries of the population(s) using this region, 3) to determine the size and status of the Beaufort Sea polar bear population, and 4) to establish reproduction and survival rates (Amstrup 2000).

  7. Update of the Polar SWIFT model for polar stratospheric ozone loss (Polar SWIFT version 2)

    Science.gov (United States)

    Wohltmann, Ingo; Lehmann, Ralph; Rex, Markus

    2017-07-01

    original training on satellite data. Hence, the new version allows for an implementation into climate models in combination with an existing stratospheric transport scheme. Finally, the model is now formulated on several vertical levels encompassing the vertical range in which polar ozone depletion is observed. The results of the Polar SWIFT model are validated with independent Microwave Limb Sounder (MLS) satellite observations and output from the original detailed chemistry model of ATLAS.

  8. Equivalence principles, spacetime structure and the cosmic connection

    Science.gov (United States)

    Ni, Wei-Tou

    2016-03-01

    After reviewing the meaning of various equivalence principles and the structure of electrodynamics, we give a fairly detailed account of the construction of the light cone and a core metric from the equivalence principle for photons (no birefringence, no polarization rotation and no amplification/attenuation in propagation) in the framework of linear electrodynamics using cosmic connections/observations as empirical support. The cosmic nonbirefringent propagation of photons independent of energy and polarization verifies the Galileo Equivalence Principle (Universality of Propagation) for photons/electromagnetic wave packets in spacetime. This nonbirefringence constrains the spacetime constitutive tensor to high precision to a core metric form with an axion degree and a dilaton degree of freedom. Thus comes the metric with axion and dilation. Constraints on axion and dilaton from astrophysical/cosmic propagation are reviewed. Eötvös-type experiments, Hughes-Drever-type experiments, redshift experiments then constrain and tie this core metric to agree with the matter metric, and hence a unique physical metric and universality of metrology. We summarize these experiments and review how the Galileo equivalence principle constrains the Einstein Equivalence Principle (EEP) theoretically. In local physics this physical metric gives the Lorentz/Poincaré covariance. Understanding that the metric and EEP come from the vacuum as a medium of electrodynamics in the linear regime, efforts to actively look for potential effects beyond this linear scheme are warranted. We emphasize the importance of doing Eötvös-type experiments or other type experiments using polarized bodies/polarized particles. We review the theoretical progress on the issue of gyrogravitational ratio for fundamental particles and update the experimental progress on the measurements of possible long range/intermediate range spin-spin, spin-monopole and spin-cosmos interactions.

  9. Switchable and tunable microwave frequency multiplication based on a dual-passband microwave photonic filter.

    Science.gov (United States)

    Chen, Hao; Xu, Zuowei; Fu, Hongyan; Zhang, Shiwei; Wu, Congxian; Wu, Hao; Xu, Huiying; Cai, Zhiping

    2015-04-20

    In this paper, a novel approach to implement switchable and tunable microwave frequency multiplication has been proposed and experimentally demonstrated. High order harmonics of microwave signal with external modulation technique can be selected by using a novel switchable dual-passband microwave photonic filter (MPF) based on a modified fiber Mach-Zehnder interferometer (FMZI) and a dispersive medium. By adjusting the polarization controllers in the modified FMZI, the passbands of the MPF can switch between lower frequency, higher frequency or dual-passband states, and by changing the length of the variable optical delay line (VODL) in the modified FMZI, the central frequencies of these passbands can also be tuned. Therefore, tunable and switchable microwave signal frequency multiplication can be achieved. The experimental results show that by modulating a driving signal with frequency of 2.5 GHz, a signal with frequency of 7.5 GHz, which is three times of the driving frequency, the other one with the frequency of 15 GHz, which is six times of the driving frequency can be generated and freely switchable between two frequencies and dual frequency states by simply adjusting the polarization controllers in the modified FMZI.

  10. The Cosmic Century

    Science.gov (United States)

    Longair, Malcolm S.

    2013-04-01

    Part I. Stars and Stellar Evolution up to the Second World War: 1. The legacy of the nineteenth century; 2. The classification of stellar spectra; 3. Stellar structure and evolution; 4. The end points of stellar evolution; Part II. The Large-Scale Structure of the Universe, 1900-1939: 5. The Galaxy and the nature of spiral nebulae; 6. The origins of astrophysical cosmology; Part III. The Opening up of the Electromagnetic Spectrum: 7. The opening up of the electromagnetic spectrum and the new astronomies; Part IV. The Astrophysics of Stars and Galaxies since 1945: 8. Stars and stellar evolution; 9. The physics of the interstellar medium; 10. The physics of galaxies and clusters of galaxies; 11. High-energy astrophysics; Part V. Astrophysical Cosmology since 1945: 12. Astrophysical cosmology; 13. The determination of cosmological parameters; 14. The evolution of galaxies and active galaxies with cosmic epoch; 15. The origin of galaxies and the large-scale structure of the Universe; 16. The very early Universe; References; Name index; Object index; Subject index.

  11. Nonthermal cosmic neutrino background

    Science.gov (United States)

    Chen, Mu-Chun; Ratz, Michael; Trautner, Andreas

    2015-12-01

    We point out that, for Dirac neutrinos, in addition to the standard thermal cosmic neutrino background (C ν B ), there could also exist a nonthermal neutrino background with comparable number density. As the right-handed components are essentially decoupled from the thermal bath of standard model particles, relic neutrinos with a nonthermal distribution may exist until today. The relic density of the nonthermal (nt) background can be constrained by the usual observational bounds on the effective number of massless degrees of freedom Neff and can be as large as nν nt≲0.5 nγ. In particular, Neff can be larger than 3.046 in the absence of any exotic states. Nonthermal relic neutrinos constitute an irreducible contribution to the detection of the C ν B and, hence, may be discovered by future experiments such as PTOLEMY. We also present a scenario of chaotic inflation in which a nonthermal background can naturally be generated by inflationary preheating. The nonthermal relic neutrinos, thus, may constitute a novel window into the very early Universe.

  12. Illustrated cosmic monopole

    CERN Document Server

    Seagrave, Wyken

    2015-01-01

    Truly bizarre, utterly unique I've never read a novel quite like this before. The author takes you on an exciting adventure full of unforgettable and vivid imagery. Solidly written with each character's personality shining through. If you find physics fascinating you will not be disappointed by the author's keen intellect and clear understanding of this most challenging (for me anyway) scientific subject. This is not a novel I will forget anytime soon, I would highly recommend it. Andrewly Very imaginative tale Anybody interested in a very imaginative and engrossing sci fi story needs to check this one out. I have been reading sci fi for decades and this story has elements that surprise me which is very unusual considering the number of novels and stories I have over the years. ric freeman Summary of the story The cosmic monopole has been wandering the Universe since it was created in the Big Bang. Its existence is fundamental to the way the Universe works. It is finally trapped by the powerful magnetic f...

  13. Integrated microwave photonics

    NARCIS (Netherlands)

    Marpaung, D.A.I.; Roeloffzen, C.G.H.; Heideman, Rene; Leinse, Arne; Sales, S.; Capmany, J.

    2013-01-01

    Microwave photonics (MWP) is an emerging field in which radio frequency (RF) signals are generated, distributed, processed and analyzed using the strength of photonic techniques. It is a technology that enables various functionalities which are not feasible to achieve only in the microwave domain. A

  14. Microwave Enhanced Reactive Distillation

    NARCIS (Netherlands)

    Altman, E.

    2011-01-01

    The application of electromagnetic irradiation in form of microwaves (MW) has gathered the attention of the scientific community in recent years. MW used as an alternative energy source for chemical syntheses (microwave chemistry) can provide clear advantages over conventional heating methods in

  15. Microwave Breast Imaging Techniques

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Rubæk, Tonny

    2010-01-01

    This paper outlines the applicability of microwave radiation for breast cancer detection. Microwave imaging systems are categorized based on their hardware architecture. The advantages and disadvantages of various imaging techniques are discussed. The fundamental tradeoffs are indicated between...... various requirements to be fulfilled in the design of an imaging system for breast cancer detection and some strategies to overcome these limitations....

  16. The microwave heating mechanism of N-(4-methoxybenzyliden)-4-butylaniline in liquid crystalline and isotropic phases as determined using in situ microwave irradiation NMR spectroscopy.

    Science.gov (United States)

    Tasei, Yugo; Tanigawa, Fumikazu; Kawamura, Izuru; Fujito, Teruaki; Sato, Motoyasu; Naito, Akira

    2015-04-14

    Microwave heating effects are widely used in the acceleration of organic, polymerization and enzymatic reactions. These effects are primarily caused by the local heating induced by microwave irradiation. However, the detailed molecular mechanisms associated with microwave heating effects on the chemical reactions are not yet well understood. This study investigated the microwave heating effect of N-(4-methoxybenzylidene)-4-butylaniline (MBBA) in liquid crystalline and isotropic phases using in situ microwave irradiation nuclear magnetic resonance (NMR) spectroscopy, by obtaining (1)H NMR spectra of MBBA under microwave irradiation. When heated simply using the temperature control unit of the NMR instrument, the liquid crystalline MBBA was converted to the isotropic phase exactly at its phase transition temperature (Tc) of 41 °C. The application of microwave irradiation at 130 W for 90 s while maintaining the instrument temperature at 20 °C generated a small amount of isotropic phase within the bulk liquid crystal. The sample temperature of the liquid crystalline state obtained during microwave irradiation was estimated to be 35 °C by assessing the linewidths of the (1)H NMR spectrum. This partial transition to the isotropic phase can be attributed to a non-equilibrium local heating state induced by the microwave irradiation. The application of microwave at 195 W for 5 min to isotropic MBBA while maintaining an instrument temperature of 50 °C raised the sample temperature to 160 °C. In this study, the MBBA temperature during microwave irradiation was estimated by measuring the temperature dependent chemical shifts of individual protons in the sample, and the different protons were found to indicate significantly different temperatures in the molecule. These results suggest that microwave heating polarizes bonds in polar functional groups, and this effect may partly explain the attendant acceleration of organic reactions.

  17. Microwave ion source

    Science.gov (United States)

    Leung, Ka-Ngo; Reijonen, Jani; Thomae, Rainer W.

    2005-07-26

    A compact microwave ion source has a permanent magnet dipole field, a microwave launcher, and an extractor parallel to the source axis. The dipole field is in the form of a ring. The microwaves are launched from the middle of the dipole ring using a coaxial waveguide. Electrons are heated using ECR in the magnetic field. The ions are extracted from the side of the source from the middle of the dipole perpendicular to the source axis. The plasma density can be increased by boosting the microwave ion source by the addition of an RF antenna. Higher charge states can be achieved by increasing the microwave frequency. A xenon source with a magnetic pinch can be used to produce intense EUV radiation.

  18. The Polarized Radiation Imaging and Spectroscopy Mission

    CERN Document Server

    André, Philippe; Banday, Anthony; Barbosa, Domingos; Barreiro, Belen; Bartlett, James; Bartolo, Nicola; Battistelli, Elia; Battye, Richard; Bendo, George; Benoȋt, Alain; Bernard, Jean-Philippe; Bersanelli, Marco; Béthermin, Matthieu; Bielewicz, Pawel; Bonaldi, Anna; Bouchet, François; Boulanger, François; Brand, Jan; Bucher, Martin; Burigana, Carlo; Cai, Zhen-Yi; Camus, Philippe; Casas, Francisco; Casasola, Viviana; Castex, Guillaume; Challinor, Anthony; Chluba, Jens; Chon, Gayoung; Colafrancesco, Sergio; Comis, Barbara; Cuttaia, Francesco; D'Alessandro, Giuseppe; Da Silva, Antonio; Davis, Richard; de Avillez, Miguel; de Bernardis, Paolo; de Petris, Marco; de Rosa, Adriano; de Zotti, Gianfranco; Delabrouille, Jacques; Désert, François-Xavier; Dickinson, Clive; Diego, Jose Maria; Dunkley, Joanna; Enßlin, Torsten; Errard, Josquin; Falgarone, Edith; Ferreira, Pedro; Ferrière, Katia; Finelli, Fabio; Fletcher, Andrew; Fosalba, Pablo; Fuller, Gary; Galli, Silvia; Ganga, Ken; García-Bellido, Juan; Ghribi, Adnan; Giard, Martin; Giraud-Héraud, Yannick; Gonzalez-Nuevo, Joaquin; Grainge, Keith; Gruppuso, Alessandro; Hall, Alex; Hamilton, Jean-Christophe; Haverkorn, Marijke; Hernandez-Monteagudo, Carlos; Herranz, Diego; Jackson, Mark; Jaffe, Andrew; Khatri, Rishi; Kunz, Martin; Lamagna, Luca; Lattanzi, Massimiliano; Leahy, Paddy; Lesgourgues, Julien; Liguori, Michele; Liuzzo, Elisabetta; Lopez-Caniego, Marcos; Macias-Perez, Juan; Maffei, Bruno; Maino, Davide; Mangilli, Anna; Martinez-Gonzalez, Enrique; Martins, Carlos J.A.P.; Masi, Silvia; Massardi, Marcella; Matarrese, Sabino; Melchiorri, Alessandro; Melin, Jean-Baptiste; Mennella, Aniello; Mignano, Arturo; Miville-Deschênes, Marc-Antoine; Monfardini, Alessandro; Murphy, Anthony; Naselsky, Pavel; Nati, Federico; Natoli, Paolo; Negrello, Mattia; Noviello, Fabio; O'Sullivan, Créidhe; Paci, Francesco; Pagano, Luca; Paladino, Rosita; Palanque-Delabrouille, Nathalie; Paoletti, Daniela; Peiris, Hiranya; Perrotta, Francesca; Piacentini, Francesco; Piat, Michel; Piccirillo, Lucio; Pisano, Giampaolo; Polenta, Gianluca; Pollo, Agnieszka; Ponthieu, Nicolas; Remazeilles, Mathieu; Ricciardi, Sara; Roman, Matthieu; Rosset, Cyrille; Rubino-Martin, Jose-Alberto; Salatino, Maria; Schillaci, Alessandro; Shellard, Paul; Silk, Joseph; Starobinsky, Alexei; Stompor, Radek; Sunyaev, Rashid; Tartari, Andrea; Terenzi, Luca; Toffolatti, Luigi; Tomasi, Maurizio; Trappe, Neil; Tristram, Matthieu; Trombetti, Tiziana; Tucci, Marco; Van de Weijgaert, Rien; Van Tent, Bartjan; Verde, Licia; Vielva, Patricio; Wandelt, Ben; Watson, Robert; Withington, Stafford; Cabrera, Nicolas

    2014-01-01

    PRISM (Polarized Radiation Imaging and Spectroscopy Mission) was proposed to ESA in May 2013 as a large-class mission for investigating within the framework of the ESA Cosmic Vision program a set of important scientific questions that require high resolution, high sensitivity, full-sky observations of the sky emission at wavelengths ranging from millimeter-wave to the far-infrared. PRISM's main objective is to explore the distant universe, probing cosmic history from very early times until now as well as the structures, distribution of matter, and velocity flows throughout our Hubble volume. PRISM will survey the full sky in a large number of frequency bands in both intensity and polarization and will measure the absolute spectrum of sky emission more than three orders of magnitude better than COBE FIRAS. The aim of this Extended White Paper is to provide a more detailed overview of the highlights of the new science that will be made possible by PRISM

  19. Measurements of the Temperature and E-mode Polarization of the CMB from 500 Square Degrees of SPTpol Data

    Science.gov (United States)

    Henning, J. W.; Sayre, J. T.; Reichardt, C. L.; Ade, P. A. R.; Anderson, A. J.; Austermann, J. E.; Beall, J. A.; Bender, A. N.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Chiang, H. C.; Cho, H.-M.; Citron, R.; Corbett Moran, C.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Dobbs, M. A.; Everett, W.; Gallicchio, J.; George, E. M.; Gilbert, A.; Halverson, N. W.; Harrington, N.; Hilton, G. C.; Holder, G. P.; Holzapfel, W. L.; Hoover, S.; Hou, Z.; Hrubes, J. D.; Huang, N.; Hubmayr, J.; Irwin, K. D.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Li, D.; Lowitz, A.; Manzotti, A.; McMahon, J. J.; Meyer, S. S.; Mocanu, L.; Montgomery, J.; Nadolski, A.; Natoli, T.; Nibarger, J. P.; Novosad, V.; Padin, S.; Pryke, C.; Ruhl, J. E.; Saliwanchik, B. R.; Schaffer, K. K.; Sievers, C.; Smecher, G.; Stark, A. A.; Story, K. T.; Tucker, C.; Vanderlinde, K.; Veach, T.; Vieira, J. D.; Wang, G.; Whitehorn, N.; Wu, W. L. K.; Yefremenko, V.

    2018-01-01

    We present measurements of the E-mode polarization angular auto-power spectrum (EE) and temperature–E-mode cross-power spectrum (TE) of the cosmic microwave background (CMB) using 150 GHz data from three seasons of SPTpol observations. We report the power spectra over the spherical harmonic multipole range 50 1050 and {\\ell }> 1475, respectively. The observations cover 500 {\\deg }2, a fivefold increase in area compared to previous SPTpol analyses, which increases our sensitivity to the photon diffusion damping tail of the CMB power spectra enabling tighter constraints on ΛCDM model extensions. After masking all sources with unpolarized flux > 50 mJy, we place a 95% confidence upper limit on residual polarized point-source power of {D}{\\ell }={\\ell }({\\ell }+1){C}{\\ell }/2π 1000 results in a preference for a higher value of the expansion rate ({H}0=71.3+/- 2.1 {km} {{{s}}}-1{{Mpc}}-1 ) and a lower value for present-day density fluctuations ({σ }8=0.77+/- 0.02).

  20. Development of a Multi-Point Microwave Interferometry (MPMI) Method

    Energy Technology Data Exchange (ETDEWEB)

    Specht, Paul Elliott [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cooper, Marcia A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jilek, Brook Anton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    A multi-point microwave interferometer (MPMI) concept was developed for non-invasively tracking a shock, reaction, or detonation front in energetic media. Initially, a single-point, heterodyne microwave interferometry capability was established. The design, construction, and verification of the single-point interferometer provided a knowledge base for the creation of the MPMI concept. The MPMI concept uses an electro-optic (EO) crystal to impart a time-varying phase lag onto a laser at the microwave frequency. Polarization optics converts this phase lag into an amplitude modulation, which is analyzed in a heterodyne interfer- ometer to detect Doppler shifts in the microwave frequency. A version of the MPMI was constructed to experimentally measure the frequency of a microwave source through the EO modulation of a laser. The successful extraction of the microwave frequency proved the underlying physical concept of the MPMI design, and highlighted the challenges associated with the longer microwave wavelength. The frequency measurements made with the current equipment contained too much uncertainty for an accurate velocity measurement. Potential alterations to the current construction are presented to improve the quality of the measured signal and enable multiple accurate velocity measurements.

  1. Nearest Cosmic Mirage

    Science.gov (United States)

    2003-07-01

    Discovery of quadruply lensed quasar with Einstein ring Summary Using the ESO 3.6-m telescope at La Silla (Chile), an international team of astronomers [1] has discovered a complex cosmic mirage in the southern constellation Crater (The Cup). This "gravitational lens" system consists of (at least) four images of the same quasar as well as a ring-shaped image of the galaxy in which the quasar resides - known as an "Einstein ring". The more nearby lensing galaxy that causes this intriguing optical illusion is also well visible. The team obtained spectra of these objects with the new EMMI camera mounted on the ESO 3.5-m New Technology Telescope (NTT), also at the La Silla observatory. They find that the lensed quasar [2] is located at a distance of 6,300 million light-years (its "redshift" is z = 0.66 [3]) while the lensing elliptical galaxy is rougly halfway between the quasar and us, at a distance of 3,500 million light-years (z = 0.3). The system has been designated RXS J1131-1231 - it is the closest gravitationally lensed quasar discovered so far . PR Photo 20a/03 : Image of the gravitational lens system RXS J1131-1231 (ESO 3.6m Telescope). PR Photo 20b/03 : Spectra of two lensed images of the source quasar and the lensing galaxy. Cosmic mirages The physical principle behind a "gravitational lens" (also known as a "cosmic mirage") has been known since 1916 as a consequence of Albert Einstein's Theory of General Relativity . The gravitational field of a massive object curves the local geometry of the Universe, so light rays passing close to the object are bent (like a "straight line" on the surface of the Earth is necessarily curved because of the curvature of the Earth's surface). This effect was first observed by astronomers in 1919 during a total solar eclipse. Accurate positional measurements of stars seen in the dark sky near the eclipsed Sun indicated an apparent displacement in the direction opposite to the Sun, about as much as predicted by Einstein

  2. Cosmic Dust and the Earth's Atmosphere (Vilhelm Bjerknes Medal Lecture)

    Science.gov (United States)

    Plane, John M. C.

    2017-04-01

    Cosmic dust particles are produced in the solar system from the sublimation of comets as they orbit close to the sun, and also from collisions between asteroids in the belt between Mars and Jupiter. Dust particles enter the atmosphere at hyperthermal velocities (11 - 72 km s-1), and ablate at heights between 80 and 120 km in the mesosphere/lower thermosphere (MLT). The resulting metallic vapours (Fe, Mg, Si and Na etc.) then oxidize and recondense to form nm-size particles, termed "meteoric smoke particles (MSPs)". MSPs are too small to sediment downwards and so are transported by the general circulation of the atmosphere, taking roughly 4 years to reach the surface. Smoke particles play a potentially important role as condensation nuclei of noctilucent ice clouds in the mesosphere, and polar stratospheric clouds in the lower stratosphere, where they also facilitate freezing of the clouds. There are also potential implications for climate, as the input of bio-available cosmic Fe in the Southern Ocean can increase biological productivity and stimulate CO2 drawdown from the atmosphere. However, current estimates of the magnitude of the cosmic dust mass input rate into the Earth's atmosphere range from 2 to over 200 tonnes per day, depending on whether the measurements are made in space, in the middle atmosphere, or in polar ice cores. This nearly 2 order-of-magnitude discrepancy indicates that there must be serious flaws in the interpretation of observations that have been used to make the estimates. Furthermore, given this degree of uncertainty, the significance of these potential atmospheric impacts remains speculative. In this lecture I will describe the results of a large study designed to determine the size of the cosmic dust input rate using a self-consistent treatment of cosmic dust from the outer solar system to the Earth's surface. An astronomical model which tracks the evolution of dust from various sources into the inner solar system was combined with a

  3. Cosmic Dawn Intensity Mapper

    Science.gov (United States)

    Cooray, Asantha

    2018-01-01

    Cosmic Dawn Intensity Mapper (CDIM) is a 1.0m-class infrared telescope capable of three-dimensional spectro-imaging observations over the wavelength range of 0.75 to 7.5 microns, at a spectral resolving power at or better than 300. This will be achieved with linear variablefilters (LVFs) and a large field-of-view (FoV). The survey strategy using spacecraft operations following a shift and stare mode will result in more than 1300 independent narrow-band spectral images of the sky at a given location. Currently prioritized science programs, taking over three-years of a five-year mission, will be accomplished with a two-tiered wedding-cake survey with the shallowest spanning close to 300 sq. degrees and the deepest tier of about 25 sq. degrees.The remaining two-years could be used for additional survey programs (the wide tier can be expanded to 1000 sq. degrees) or for use by the astronomical community through a General Observing (GO) campaign. CDIM survey data will allow us to (i) establish the initial mass function of stars in galaxies present during reionization, (ii) definitively address AGN/quasar contribution to the reionization photon budget; (iii) establish the environmental dependence of star-formation during reionization through clustering and other environmental measurements; (iv) establish the metal abundance of first-light galaxies during reionization over two decades of stellar mass; (v) measure 3D intensity fluctuations during reionization in both Ly-alpha and H-alpha; and (vi) combine intensity fluctuations with 21-cm data to establish the topology of reionization bubbles.

  4. Dual-Polarization, Multi-Frequency Antenna Array for use with Hurricane Imaging Radiometer

    Science.gov (United States)

    Little, John

    2013-01-01

    Advancements in common aperture antenna technology were employed to utilize its proprietary genetic algorithmbased modeling tools in an effort to develop, build, and test a dual-polarization array for Hurricane Imaging Radiometer (HIRAD) applications. Final program results demonstrate the ability to achieve a lightweight, thin, higher-gain aperture that covers the desired spectral band. NASA employs various passive microwave and millimeter-wave instruments, such as spectral radiometers, for a range of remote sensing applications, from measurements of the Earth's surface and atmosphere, to cosmic background emission. These instruments such as the HIRAD, SFMR (Stepped Frequency Microwave Radiometer), and LRR (Lightweight Rainfall Radiometer), provide unique data accumulation capabilities for observing sea surface wind, temperature, and rainfall, and significantly enhance the understanding and predictability of hurricane intensity. These microwave instruments require extremely efficient wideband or multiband antennas in order to conserve space on the airborne platform. In addition, the thickness and weight of the antenna arrays is of paramount importance in reducing platform drag, permitting greater time on station. Current sensors are often heavy, single- polarization, or limited in frequency coverage. The ideal wideband antenna will have reduced size, weight, and profile (a conformal construct) without sacrificing optimum performance. The technology applied to this new HIRAD array will allow NASA, NOAA, and other users to gather information related to hurricanes and other tropical storms more cost effectively without sacrificing sensor performance or the aircraft time on station. The results of the initial analysis and numerical design indicated strong potential for an antenna array that would satisfy all of the design requirements for a replacement HIRAD array. Multiple common aperture antenna methodologies were employed to achieve exceptional gain over the entire

  5. Cosmic logic: a computational model

    International Nuclear Information System (INIS)

    Vanchurin, Vitaly

    2016-01-01

    We initiate a formal study of logical inferences in context of the measure problem in cosmology or what we call cosmic logic. We describe a simple computational model of cosmic logic suitable for analysis of, for example, discretized cosmological systems. The construction is based on a particular model of computation, developed by Alan Turing, with cosmic observers (CO), cosmic measures (CM) and cosmic symmetries (CS) described by Turing machines. CO machines always start with a blank tape and CM machines take CO's Turing number (also known as description number or Gödel number) as input and output the corresponding probability. Similarly, CS machines take CO's Turing number as input, but output either one if the CO machines are in the same equivalence class or zero otherwise. We argue that CS machines are more fundamental than CM machines and, thus, should be used as building blocks in constructing CM machines. We prove the non-computability of a CS machine which discriminates between two classes of CO machines: mortal that halts in finite time and immortal that runs forever. In context of eternal inflation this result implies that it is impossible to construct CM machines to compute probabilities on the set of all CO machines using cut-off prescriptions. The cut-off measures can still be used if the set is reduced to include only machines which halt after a finite and predetermined number of steps

  6. Signs of cosmic rays in gravitational wave detectors

    International Nuclear Information System (INIS)

    Tavares, Denis Borgarelli

    2010-01-01

    One of the phenomena predicted by Einstein in the derivation of general relativity is the existence of small perturbations of the metric that he named gravitational waves. As they travel through space oscillates the space-time according to its polarization. This is the only major prediction of general relativity not yet proven completely. The small signal generated by the passage of a gravitational wave compared to the noise in the system of detection makes their direct detection one challenge of modern science. In this paper we study the noise generated by cosmic rays in the gravitational antenna Mario Schenberg, located in the city of Sao Paulo. Single muons and hadrons flux measurements held in the northern hemisphere were used to calculate the expected flux of these particles in the city of Sao Paulo. The calculation of the energy deposited in the detector of gravitational waves from cosmic rays was performed by Monte Carlo simulations using Geant4. The transport of muons and protons, with several energy and some different angles of incidence, across the building and the resonant sphere was simulated. We developed a thermo-acoustic model, called multi-point, suitable for calculating the energy deposited in the normal modes from the energy deposited on the sphere by elementary particles. With these results we calculate the expected rate of cosmic ray signals in the main detection mode of gravitational waves, nl = 12, of the Mario Schenberg detector, for temperatures T noise between 10 -5 and 10 -7 K. The results showed for the designed for 4.2 K sensitivity of the Mario Schenberg detector that the rate of signals due to cosmic rays is very small, being around 5 events per day. However, when it will reach the quantum limit will be needed a more detailed analysis of the antenna signal output, since the expected number of cosmic ray noise increases considerably, reaching about 250 signals per day. (author)

  7. MICROWAVE STABILIZATION AND MICROWAVE-STIMULATED FIXATION

    NARCIS (Netherlands)

    BOON, ME; KOK, LP

    1990-01-01

    In microwave stabilization the tissue is prepared for histoprocessing through the uniformly distributed increased temperature. This procedure can be called unique: Exclusively by the uniform well-controlled temperature rise to 55-degrees-C it is possible to stabilize the tissue to the needed

  8. Microwaves - the hidden danger

    International Nuclear Information System (INIS)

    Brodeur, P.

    1987-01-01

    Today, highly frequent radio waves are regarded as undangerous to man. Diseases seen at radar-technicians during the 2nd World War, however, indicated that microwaves applied in radar systems were hazardous to health. The Russian work medicine has been knowing microwave-caused hazards in industry since the beginning of the thirties. Therefore in some East-European countries there are terms of protection and severe norms of safety for the staying of persons in the radiation sphere of microwaves. (orig.) [de

  9. Advances in microwaves

    CERN Document Server

    Young, Leo

    1967-01-01

    Advances in Microwaves, Volume 2 focuses on the developments in microwave solid-state devices and circuits. This volume contains six chapters that also describe the design and applications of diplexers and multiplexers. The first chapter deals with the parameters of the tunnel diode, oscillators, amplifiers and frequency converter, followed by a simple physical description and the basic operating principles of the solid state devices currently capable of generating coherent microwave power, including transistors, harmonic generators, and tunnel, avalanche transit time, and diodes. The next ch

  10. Advances in microwaves 4

    CERN Document Server

    Young, Leo

    2013-01-01

    Advances in Microwaves, Volume 4 covers some innovations in the devices and applications of microwaves. This volume contains three chapters and begins with a discussion of the application of microwave phasers and time delay elements as beam steering elements in array radars. The next chapter provides first an overview of the technical aspects and different types of millimeter waveguides, followed by a survey of their application to railroads. The last chapter examines the general mode of conversion properties of nonuniform waveguides, such as waveguide tapers, using converted Maxwell's equatio

  11. Aerosols Produced by Cosmic Rays

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker

    mechanism linking cosmic rays to clouds and climate is currently speculative, there have been various suggestions of the role atmospheric ions may play; these involve any one of a number of processes from the nucleation of aerosols up to the collection processes of cloud droplets. We have chosen to start......Satellite observations have shown that the Earth’s cloud cover is strongly correlated with the galactic cosmic ray flux. While this correlation is indicative of a possible physical connection, there is currently no confirmation that a physical mechanism exists. We are therefore setting up...... an experiment in order to investigate the underlying microphysical processes. The results of this experiment will help to understand whether ionization from cosmic rays, and by implication the related processes in the universe, has a direct influence on Earth’s atmosphere and climate. Since any physical...

  12. Cosmic rays, clouds, and climate

    DEFF Research Database (Denmark)

    Marsh, N.; Svensmark, Henrik

    2000-01-01

    cloud radiative properties. Thus, a moderate influence on atmospheric aerosol distributions from cosmic ray ionisation would have a strong influence on the Earth's radiation budget. Historical evidence over the past 1000 years indicates that changes in climate have occurred in accord with variability......A correlation between a global average of low cloud cover and the flux of cosmic rays incident in the atmosphere has been observed during the last solar cycle. The ionising potential of Earth bound cosmic rays are modulated by the state of the heliosphere, while clouds play an important role...... in the Earth's radiation budget through trapping outgoing radiation and reflecting incoming radiation. If a physical link between these two features can be established, it would provide a mechanism linking solar activity and Earth's climate. Recent satellite observations have further revealed a correlation...

  13. Cosmic Ray Energetics and Mass

    CERN Multimedia

    Baylon cardiel, J L; Wallace, K C; Anderson, T B; Copley, M

    The cosmic-ray energetics and mass (CREAM) investigation is designed to measure cosmic-ray composition to the supernova energy scale of 10$^{15}$ eV in a series of ultra long duration balloon (ULDB) flights. The first flight is planned to be launched from Antarctica in December 2004. The goal is to observe cosmic-ray spectral features and/or abundance changes that might signify a limit to supernova acceleration. The particle ($\\{Z}$) measurements will be made with a timing-based charge detector and a pixelated silicon charge detector to minimize the effect of backscatter from the calorimeter. The particle energy measurements will be made with a transition radiation detector (TRD) for $\\{Z}$ > 3 and a sampling tungsten/scintillator calorimeter for $\\{Z}$ $\\geq$1 particles, allowing inflight cross calibration of the two detectors. The status of the payload construction and flight preparation are reported in this paper.

  14. Cosmic rays, clouds, and climate

    DEFF Research Database (Denmark)

    Marsh, N.; Svensmark, Henrik

    2000-01-01

    between cosmic ray flux and low cloud top temperature. The temperature of a cloud depends on the radiation properties determined by its droplet distribution. Low clouds are warm (> 273 K) and therefore consist of liquid water droplets. At typical atmospheric supersaturations (similar to1%) a liquid cloud...... that a mechanism to explain the cosmic ray-cloud link might be found through the role of atmospheric ionisation in aerosol production and/or growth. Observations of local aerosol increases in low cloud due to ship exhaust indicate that a small perturbation in atmospheric aerosol can have a major impact on low...... cloud radiative properties. Thus, a moderate influence on atmospheric aerosol distributions from cosmic ray ionisation would have a strong influence on the Earth's radiation budget. Historical evidence over the past 1000 years indicates that changes in climate have occurred in accord with variability...

  15. Cosmic rays and particle physics

    CERN Document Server

    Gaisser, Thomas K; Resconi, Elisa

    2016-01-01

    Fully updated for the second edition, this book introduces the growing and dynamic field of particle astrophysics. It provides an overview of high-energy nuclei, photons and neutrinos, including their origins, their propagation in the cosmos, their detection on Earth and their relation to each other. Coverage is expanded to include new content on high energy physics, the propagation of protons and nuclei in cosmic background radiation, neutrino astronomy, high-energy and ultra-high-energy cosmic rays, sources and acceleration mechanisms, and atmospheric muons and neutrinos. Readers are able to master the fundamentals of particle astrophysics within the context of the most recent developments in the field. This book will benefit graduate students and established researchers alike, equipping them with the knowledge and tools needed to design and interpret their own experiments and, ultimately, to address a number of questions concerning the nature and origins of cosmic particles that have arisen in recent resea...

  16. A 282 GHz Probe for Dynamic Nuclear Polarization

    DEFF Research Database (Denmark)

    Rybalko, Oleksandr; Bowen, Sean; Zhurbenko, Vitaliy

    of the coil is976 MHz. A magnetic field distribution at 108 MHz and 430 MHz was calculated for the RF coil, the results revealedgood homogeneity and intensity along x,y,z axes. Figure 1 shows the general view of the probe and cross section through the microwave container with field distribution. Operating......Introduction In DNP, microwave irradiation of a sample facilitates the transfer of spin polarization from electrons tonuclei. One of the way to improve the DNP enhancement is to transfer microwave power from the mm-wave source tothe sample more effectively. Several methods and techniques...... to efficiently transport microwave energy from the microwave source to the sample have been developed. For example, a corrugated waveguide allows to deliver mm-wave energy from external source to the probe with minimum losses1.The conventional approach at high frequencies is to irradiate the sample directly from...

  17. The Cosmic Shoreline

    Science.gov (United States)

    Zahnle, Kevin J.; Catling, D. C.

    2013-01-01

    in 2004 when there were just two transiting exoplanets to consider. The trend was well-defined by late 2007. Figure 1 shows how matters stood in Dec 2012 with approx.240 exoplanets. The figure shows that the boundary between planets with and without active volatiles - the cosmic shoreline, as it were - is both well-defined and follows a power law.

  18. Cosmic Humanity: Utopia, Realities, Prospects

    Directory of Open Access Journals (Sweden)

    Sergey Krichevsky

    2017-07-01

    Full Text Available The philosophical foundations of the theory and practice of the creation of cosmic humanity as a process of the evolution of human civilization, the emergence into space, with the prospect of resettlement outside the Earth are considered. There is a connection between myths, fantasies, ideas, concepts and projects aimed at the exploration of outer space, the creation of cosmic humanity. A new and voluminous definition of cosmic humanity in the evolutionary paradigm is given. Cosmic humanity is (essence and 4 stages of evolution: 1. Humanity living on Earth, sensing, knowing, understanding its cosmic origin, relationship with the cosmos and cosmic destiny. 2. Humanity living on Earth, leading aerospace activity for the purposes of exploration and use of aerospace space (Heaven, Space for survival and development. 3. Humanity living on Earth and outside the Earth — in the solar system, preserving the Earth and mastering the Cosmos for survival and development. 4. Humanity, settled and living in the Cosmos. Now humanity is in the process of transition from the second to the third stage. In the process of this evolution, a complex transformation of man and society takes place. The problem-semantic field of cosmic humanity is described and its general model is presented. The meta-goal-setting is the justification of cosmic humanity with the application of the anthropic principle and its “active” super (post anthropic supplement: “Cosmic humanity has an evolutionary purpose to actively manage evolution: change man, humanity and the universe.” The evolution of the “cosmic dream”, goals and technologies of space activities is formalized in the form of a conceptual model. Challenges and negative trends are considered in connection with the crisis of space activity, criticism and attempts to limit the flights of people into space. The prototype of cosmic humanity, its basis and acting model is the cosmonauts’ community. The main

  19. The Cosmic Infrared Background Experiment

    OpenAIRE

    Bock, James; Battle, John; Cooray, Asantha; Kawada, Mitsunobu; Keating, Brian; Lange, Andrew; Lee, Dae-Hea; Matsumoto, Toshio; Matsuura, Shuji; Pak, Soojong; Renbarger, Tom; Sullivan, Ian; Tsumura, Kohji; Wada, Takehiko; Watabe, Toyoki

    2005-01-01

    We are developing a rocket-borne instrument (the Cosmic Infrared Background ExpeRiment, or CIBER) to search for signatures of primordial galaxy formation in the cosmic near-infrared extra-galactic background. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. The cameras will search for spatial fluctuations in the background on angular scales from 7 arcseconds to 2 degrees over a range of angular sca...

  20. Cosmic Rays and Global Warming

    OpenAIRE

    Sloan, T.; Wolfendale, A W

    2007-01-01

    It has been claimed by others that observed temporal correlations of terrestrial cloud cover with `the cosmic ray intensity' are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We have examined this claim to look for evidence to corroborate it. So far we have not found any and so our tentative conclusions are to doubt it. Such correlations as appear are more likely to be due to the small variatio...