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Sample records for bk990025 cobe trima

  1. COBE: A Radiological Analysis

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2009-10-01

    Full Text Available The COBE Far Infrared Absolute Spectrophotometer (FIRAS operated from ~30 to ~3,000 GHz (1-95 cm$^{-1}$ and monitored, from polar orbit (~900 km, the ~3 K microwave background. Data released from FIRAS has been met with nearly universal admiration. However, a thorough review of the literature reveals significant problems with this instrument. FIRAS was designed to function as a differential radiometer, wherein the sky signal could be nulled by the reference horn, Ical. The null point occurred at an Ical temperature of 2.759 K. This was 34 mK above the reported sky temperature, 2.725$pm$0.001 K, a value where the null should ideally have formed. In addition, an 18 mK error existed between the thermometers in Ical, along with a drift in temperature of ~3 mK. A 5 mK error could be attributed to Xcal; while a 4 mK error was found in the frequency scale. A direct treatment of all these systematic errors would lead to a ~64 mK error bar in the microwave background temperature. The FIRAS team reported ~1 mK, despite the presence of such systematic errors. But a 1 mK error does not properly reflect the experimental state of this spectrophotometer. In the end, all errors were essentially transferred into the calibration files, giving the appearance of better performance than actually obtained. The use of calibration procedures resulted in calculated Ical emissivities exceeding 1.3 at the higher frequencies, whereas an emissivity of 1 constitutes the theoretical limit. While data from 30-60 GHz was once presented, these critical points are later dropped, without appropriate discussion, presumably because they reflect too much microwave power. Data obtained while the Earth was directly illuminating the sky antenna, was also discarded. From 300-660 GHz, initial FIRAS data had systematically growing residuals as frequencies increased. This suggested that the signal was falling too quickly in the Wien region of the spectrum. In later data releases, the

  2. COBE: A Radiological Analysis

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2009-10-01

    Full Text Available The COBE Far Infrared Absolute Spectrophotometer (FIRAS operated from 30 to 3,000 GHz (1–95 cm -1 and monitored, from polar orbit ( 900 km, the 3 K mi- crowave background. Data released from FIRAS has been met with nearly universal ad- miration. However, a thorough review of the literature reveals significant problems with this instrument. FIRAS was designed to function as a differential radiometer, wherein the sky signal could be nulled by the reference horn, Ical. The null point occurred at an Ical temperature of 2.759 K. This was 34 mK above the reported sky temperature, 2.725 0.001 K, a value where the null should ideally have formed. In addition, an 18 mK error existed between the thermometers in Ical, along with a drift in temper- ature of 3 mK. A 5 mK error could be attributed to Xcal; while a 4 mK error was found in the frequency scale. A direct treatment of all these systematic errors would lead to a 64 mK error bar in the microwave background temperature. The FIRAS team reported 1 mK, despite the presence of such systematic errors. But a 1 mK er- ror does not properly reflect the experimental state of this spectrophotometer. In the end, all errors were essentially transferred into the calibration files, giving the appear- ance of better performance than actually obtained. The use of calibration procedures resulted in calculated Ical emissivities exceeding 1.3 at the higher frequencies, whereas an emissivity of 1 constitutes the theoretical limit. While data from 30–60 GHz was once presented, these critical points are later dropped, without appropriate discussion, presumably because they reflect too much microwave power. Data obtained while the Earth was directly illuminating the sky antenna, was also discarded. From 300–660 GHz, initial FIRAS data had systematically growing residuals as frequencies increased. This suggested that the signal was falling too quickly in the Wien region of the spec- trum. In later data

  3. Medžių trimačių modelių generavimo įrankio kūrimas

    OpenAIRE

    Šukytė, Jolanta

    2010-01-01

    Bakalauro baigiamojo darbo tikslas – sukurti įrankį, generuojantį trimačių medžių modelius. Sukurtas medžių generatorius (įrankis) pritaikytas Lietuvos rinkai. Generuoja Lietuvoje augančių skirtingų rūšių, trimačių medžių modelius, pagal vartotojo įvestus parametrus. Generatorius realizuotas naudojantis 3ds Max programa ir jos sava MAXScript kalba. The purpose of this bachelor‘s work is creation of a tool, used for generation of three dimentional trees. The created tool is designed for Lit...

  4. Summary of Results from COBE

    OpenAIRE

    Smoot, George F.

    1999-01-01

    This work presents a summary of major cosmological results from the COBE (Cosmic Background Explorer) satellite mission. The results include a precise measurement of the Cosmic Microwave Background (CMB) radiation intensity, discovery and maps of the CMB anisotropy, large scale observations of the CMB polarization, and the detection and measurement of the diffuse infrared background. This summary was occassioned by and is part of the proceedings for the 3K Cosmology Conference held at Rome in...

  5. Summary of Results from COBE

    CERN Document Server

    Smoot, G F

    1999-01-01

    This work presents a summary of major cosmological results from the COBE (Cosmic Background Explorer) satellite mission. The results include a precise measurement of the Cosmic Microwave Background (CMB) radiation intensity, discovery and maps of the CMB anisotropy, large scale observations of the CMB polarization, and the detection and measurement of the diffuse infrared background. This summary was occassioned by and is part of the proceedings for the 3K Cosmology Conference held at Rome in October 1998.

  6. COBE experience with filter QUEST

    Science.gov (United States)

    Filla, O.; Keat, J.; Chu, D.

    1991-10-01

    A gyro based filter variation on the standard QUEST attitude determination algorithm is applied to the Cosmic Background Explorer (COBE). Filter QUEST is found to be three times as fast as the batch estimator and slightly more accurate than regular QUEST. Perhaps more important than its speed or accuracy is the fact that Filter QUEST can provide real time attitude solutions when regular QUEST cannot, due to lack of observability. Filter QUEST is also easy to use and adjust for the proper memory length. Suitable applications for Filter QUEST include coarse and real time attitude determination.

  7. Cosmic Background Explorer (COBE): Emergency support

    Science.gov (United States)

    Stanford, R.; Mattson, R.

    1991-01-01

    The Cosmic Background Explorer (COBE) Mission will measure the diffuse radiation from the universe in the wavelength band 1 micron to 9.6 mm. The band includes the 3 K cosmic background radiation, the known relic of the primeval cosmic explosion. The COBE satellite will be launched from the Western Space and Missile Center (EWSMC) via a Delta launch vehicle into a circular parking orbit of about 300 km. COBE will be placed into a 900-km altitude circular orbit. Coverage will be provided by the Deep Space Network (DSN) for COBE emergencies that would prevent communications via the normal channels of the Tracking and Data Relay Satellite System (TDRSS). Emergency support will be provided by the DSN 26-m subnetwork. Information is given in tabular form for DSN network support, frequency assignments, telemetry, and command.

  8. COBE looks back to the Big Bang

    Science.gov (United States)

    Mather, John C.

    1993-01-01

    An overview is presented of NASA-Goddard's Cosmic Background Explorer (COBE), the first NASA satellite designed to observe the primeval explosion of the universe. The spacecraft carries three extremely sensitive IR and microwave instruments designed to measure the faint residual radiation from the Big Bang and to search for the formation of the first galaxies. COBE's far IR absolute spectrophotometer has shown that the Big Bang radiation has a blackbody spectrum, proving that there was no large energy release after the explosion.

  9. COBE-DMR-Normalized Dark Energy Cosmogony

    OpenAIRE

    Mukherjee, Pia; Banday, Anthony J.; Riazuelo, Alain; Górski, Krzysztof M.; Ratra, Bharat

    2003-01-01

    Likelihood analyses of the COBE-DMR sky maps are used to determine the normalization of the inverse-power-law-potential scalar field dark energy model. Predictions of the DMR-normalized model are compared to various observations to constrain the allowed range of model parameters. Although the derived constraints are restrictive, evolving dark energy density scalar field models remain an observationally-viable alternative to the constant cosmological constant model.

  10. Inflation after COBE: Lectures on inflationary cosmology

    International Nuclear Information System (INIS)

    In these lectures I review the standard hot big-bang cosmology, emphasizing its successes, its shortcomings, and its major challenge-a detailed understanding of the formation of structure in the Universe. I then discuss the motivations for and the fundamentals of inflationary cosmology, particularly emphasizing the quantum origin of metric (density and gravity-wave) perturbations. Inflation addresses the shortcomings of the standard cosmology and provides the ''initial data'' for structure formation. I conclude by addressing the implications of inflation for structure formation, evaluating the various cold dark matter models in the light of the recent detection of temperature anisotropies in the cosmic background radiation by COBE. In the near term, the study of structure formation offers a powerful probe of inflation, as well as specific inflationary models

  11. Inflation after COBE: Lectures on inflationary cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Turner, M.S. [Chicago Univ., IL (United States). Enrico Fermi Inst.]|[Fermi National Accelerator Lab., Batavia, IL (United States)

    1992-12-31

    In these lectures I review the standard hot big-bang cosmology, emphasizing its successes, its shortcomings, and its major challenge-a detailed understanding of the formation of structure in the Universe. I then discuss the motivations for and the fundamentals of inflationary cosmology, particularly emphasizing the quantum origin of metric (density and gravity-wave) perturbations. Inflation addresses the shortcomings of the standard cosmology and provides the ``initial data`` for structure formation. I conclude by addressing the implications of inflation for structure formation, evaluating the various cold dark matter models in the light of the recent detection of temperature anisotropies in the cosmic background radiation by COBE. In the near term, the study of structure formation offers a powerful probe of inflation, as well as specific inflationary models.

  12. Interpretation of the COBE FIRAS CMBR spectrum

    Science.gov (United States)

    Wright, E. L.; Mather, J. C.; Fixsen, D. J.; Kogut, A.; Shafer, R. A.; Bennett, C. L.; Boggess, N. W.; Cheng, E. S.; Silverberg, R. F.; Smoot, G. F.

    1994-01-01

    The cosmic microwave background radiation (CMBR) spectrum measured by the Far-Infrared Absolute Spectrophotometer (FIRAS) instrument on NASA's Cosmic Background Explorer (COBE) is indistinguishable from a blackbody, implying stringent limits on energy release in the early universe later than the time t = 1 yr after the big bang. We compare the FIRAS data to previous precise measurements of the cosmic microwave background spectrum and find a reasonable agreement. We discuss the implications of the absolute value of y is less than 2.5 x 10(exp -5) and the absolute value of mu is less than 3.3 x 10(exp -4) 95% confidence limits found by Mather et al. (1994) on many processes occurring after t = 1 yr, such as explosive structure formation, reionization, and dissipation of small-scale density perturbations. We place limits on models with dust plus Population III stars, or evolving populations of IR galaxies, by directly comparing the Mather et al. spectrum to the model predictions.

  13. Optical alignments of the Cosmic Background Explorer (COBE) observatory

    Science.gov (United States)

    Sampler, Henry P.

    1990-01-01

    The angular alignments and stabilities of multiple components in a single coordinate system were determined using various alignment tooling techniques. These techniques use autocollimation measurements with a first order theodolite and transformation of coordinates to determine the relative alignment between various components with respect to a common set of COBE spacecraft coordinate axes. Optical-mechanical alignment techniques were also used to integrate the flight COBE observatory attitude control system module that consists of gyros, reaction wheels, and a momentum wheel. Particular attention is given to the techniques for alignments and stabilities of the earth scanners, sun sensors, far IR absolute spectrophotometer, Diffuse Infrared Background Experiment, and differential microwave radiometer antenna horn boresights.

  14. COBE's search for structure in the Big Bang

    Science.gov (United States)

    Soffen, Gerald (Editor); Guerny, Gene (Editor); Keating, Thomas (Editor); Moe, Karen (Editor); Sullivan, Walter (Editor); Truszkowski, Walt (Editor)

    1989-01-01

    The launch of Cosmic Background Explorer (COBE) and the definition of Earth Observing System (EOS) are two of the major events at NASA-Goddard. The three experiments contained in COBE (Differential Microwave Radiometer (DMR), Far Infrared Absolute Spectrophotometer (FIRAS), and Diffuse Infrared Background Experiment (DIRBE)) are very important in measuring the big bang. DMR measures the isotropy of the cosmic background (direction of the radiation). FIRAS looks at the spectrum over the whole sky, searching for deviations, and DIRBE operates in the infrared part of the spectrum gathering evidence of the earliest galaxy formation. By special techniques, the radiation coming from the solar system will be distinguished from that of extragalactic origin. Unique graphics will be used to represent the temperature of the emitting material. A cosmic event will be modeled of such importance that it will affect cosmological theory for generations to come. EOS will monitor changes in the Earth's geophysics during a whole solar color cycle.

  15. Early results from the Cosmic Background Explorer (COBE)

    Science.gov (United States)

    Mather, J. C.; Hauser, M. G.; Bennett, C. L.; Boggess, N. W.; Cheng, E. S.; Eplee, R. E., Jr.; Freudenreich, H. T.; Isaacman, R. B.; Kelsall, T.; Gulkis, S.

    1991-01-01

    Data obtained with the FIR Absolute Spectrophotometer, Differential Microwave Radiometers, and Diffuse IR Background Experiment (DIRBE) on the COBE satellite since its launch in November 1989 are briefly characterized. The COBE spacecraft and its 900-km 99-deg orbit are described; the scientific goals and capabilities of the instruments are reviewed; and sample DIRBE data are presented in a map and graph. Upper limits on the Comptonization parameter (y less than 0.001) and the chemical potential (mu less than 0.01 at the 3sigma level) are determined, and the spectrum of the dipole anisotropy is shown to be that of a Doppler-shifted blackbody. The DIRBE 100-micron sky brightness values at the ecliptic poles are found to be significantly lower than those measured by IRAS.

  16. Assessment of Models of Galactic Thermal Dust Emission Using COBE/FIRAS and COBE/DIRBE Observations

    CERN Document Server

    Odegard, N; Chuss, D T; Miller, N J

    2016-01-01

    Accurate modeling of the spectrum of thermal dust emission at millimeter wavelengths is important for improving the accuracy of foreground subtraction for CMB measurements, for improving the accuracy with which the contributions of different foreground emission components can be determined, and for improving our understanding of dust composition and dust physics. We fit four models of dust emission to high Galactic latitude COBE/FIRAS and COBE/DIRBE observations from 3 millimeters to 100 microns and compare the quality of the fits. We consider the two-level systems model because it provides a physically motivated explanation for the observed long wavelength flattening of the dust spectrum and the anticorrelation between emissivity index and dust temperature. We consider the model of Finkbeiner, Davis, and Schlegel because it has been widely used for CMB studies, and the generalized version of this model recently applied to Planck data by Meisner and Finkbeiner. For comparison we have also fit a phenomenologic...

  17. A Study of External Galaxies Detected by COBE-DIRBE

    OpenAIRE

    Odenwald, Sten; Newmark, Jeffrey; Smoot, George

    1996-01-01

    A comparison of the COBE, Diffuse Infrared Background Experiment (DIRBE) all-sky survey with the locations of known galaxies in the IRAS Catalog of Extragalactic Objects and the Center for Astrophysics Catalog of Galaxies led to the detection of as many as 56 galaxies. In this paper, we present the photometric analysis of these detections and an analysis of their dust properties. The sample is dominated by late-type spirals and active galaxies, and their far-IR continuua between 25-240 micron...

  18. COBE DMR results and implications. [Differential Microwave Radiometer

    Science.gov (United States)

    Smoot, George F.

    1992-01-01

    This lecture presents early results obtained from the first six months of measurements of the Cosmic Microwave Background (CMB) by Differential Microwave Radiometers (DMR) aboard COBE and discusses significant cosmological implications. The DMR maps show the dipole anisotropy and some galactic emission but otherwise a spatially smooth early universe. The measurements are sufficiently precise that we must pay careful attention to potential systematic errors. Maps of galactic and local emission such as those produced by the FIRAS and DIRBE instruments will be needed to identify foregrounds from extragalactic emission and thus to interpret the results in terms of events in the early universe. The current DMR results are significant for Cosmology.

  19. COBE DMR-normalized open inflation cold dark matter cosmogony

    Science.gov (United States)

    Gorski, Krzysztof M.; Ratra, Bharat; Sugiyama, Naoshi; Banday, Anthony J.

    1995-01-01

    A cut-sky orthogonal mode analysis of the 2 year COBE DMR 53 and 90 GHz sky maps (in Galactic coordinates) is used to determine the normalization of an open inflation model based on the cold dark matter (CDM) scenario. The normalized model is compared to measures of large-scale structure in the universe. Although the DMR data alone does not provide sufficient discriminative power to prefer a particular value of the mass density parameter, the open model appears to be reasonably consistent with observations when Omega(sub 0) is approximately 0.3-0.4 and merits further study.

  20. COBE-DMR-normalisation for inflationary flat dark matter models

    CERN Document Server

    Stompor, R; Banday, A J

    1995-01-01

    The two-year COBE-DMR 53 and 90 GHz sky maps, in both galactic and ecliptic coordinates, are used to determine the normalisation of inflationary universe models with a flat global geometry and adiabatic density perturbations. The appropriately normalised cold and mixed dark matter models and cosmological constant dominated, cold dark matter models, computed for a range of values of Omega_b and h, are then compared to various measures of structure in the universe. Critical density CDM models appear to be irreconcilable with observations on both large and small scales simultaneously, whereas MDM models provide a somewhat better fit to the data. Although the COBE-DMR data alone prefer a nearly critical value for the total density, low-density cosmological constant models with Omega_0 greater than or equal to 0.15 can not be rejected at a confidence level exceeding 95%. Such models may also provide a significantly better fit to the matter distribution data than critical density CDM.

  1. Reconstructing the inflaton potential for an almost flat cobe spectrum

    CERN Document Server

    Mielke, E W; Mielke, Eckehard W; Schunck, Franz E

    1995-01-01

    Using the Hubble parameter as new `inverse time' coordinate (H-formalism), a new method of reconstructing the inflaton potential is developed also using older results which, in principle, is applicable to any order of the slow-roll approximation. In first and second order, we need three observational data as inputs: the scalar spectral index n_s and the amplitudes of the scalar and the tensor spectrum. We find constraints between the values of n_s and the corresponding values for the wavelength \\lambda . By imposing a dependence \\lambda (n_s), we were able to reconstruct and visualize inflationary potentials which are compatible with recent COBE and other astrophysical observations. >From the reconstructed potentials, it becomes clear that one cannot find only one special value of the scalar spectral index n_s.

  2. The COBE normalization for standard cold dark matter

    Science.gov (United States)

    Bunn, Emory F.; Scott, Douglas; White, Martin

    1995-01-01

    The Cosmic Background Explorer Satellite (COBE) detection of microwave anisotropies provides the best way of fixing the amplitude of cosmological fluctuations on the largest scales. This normalization is usually given for an n = 1 spectrum, including only the anisotropy caused by the Sachs-Wolfe effect. This is certainly not a good approximation for a model containing any reasonable amount of baryonic matter. In fact, even tilted Sachs-Wolfe spectra are not a good fit to models like cold dark matter (CDM). Here, we normalize standard CDM (sCDM) to the two-year COBE data and quote the best amplitude in terms of the conventionally used measures of power. We also give normalizations for some specific variants of this standard model, and we indicate how the normalization depends on the assumed values on n, Omega(sub B) and H(sub 0). For sCDM we find the mean value of Q = 19.9 +/- 1.5 micro-K, corresponding to sigma(sub 8) = 1.34 +/- 0.10, with the normalization at large scales being B = (8.16 +/- 1.04) x 10(exp 5)(Mpc/h)(exp 4), and other numbers given in the table. The measured rms temperature fluctuation smoothed on 10 deg is a little low relative to this normalization. This is mainly due to the low quadrupole in the data: when the quadrupole is removed, the measured value of sigma(10 deg) is quite consistent with the best-fitting the mean value of Q. The use of the mean value of Q should be preferred over sigma(10 deg), when its value can be determined for a particular theory, since it makes full use of the data.

  3. Report on 3- and 4-Point Correlation Statistics in COBE DMR Anisotropy Maps

    Science.gov (United States)

    Hinshaw, Gary; Gorski, Krzystof M.; Bennett, Charles L.; Banday, Anthony J.

    1996-01-01

    As part of the work performed under this contract, we have computed the 3- and 4-point correlation functions of the COBE-DMR 2-year and 4-year anisotropy maps. The results of our work showed that the 3-point correlation function is consistent with zero and that the 4-point function is not a very sensitive probe of non-Gaussian behavior in the COBE-DMR data.

  4. A Study of External Galaxies Detected by COBE-DIRBE

    CERN Document Server

    Odenwald, S; Smoot, G F; Odenwald, Sten; Newmark, Jeffrey; Smoot, George

    1996-01-01

    A comparison of the COBE, Diffuse Infrared Background Experiment (DIRBE) all-sky survey with the locations of known galaxies in the IRAS Catalog of Extragalactic Objects and the Center for Astrophysics Catalog of Galaxies led to the detection of as many as 56 galaxies. In this paper, we present the photometric analysis of these detections and an analysis of their dust properties. The sample is dominated by late-type spirals and active galaxies, and their far-IR continuua between 25-240 microns suggest a single dust component dominating the far-IR emission. We show that for the spirals, T(dust)= 27.6 K, and for the active galaxies, T(dust) = 35.5 K. Estimates of the ratio of the mass of the dust component detected at T(dust) = 20 - 30 K to a hypothetical component with T(dust) = 15 K provide modest constraints to the Very Cold Dust (VCD) component present in the galaxies detected at 140 and 240 microns. VCD components with less than times the mass of the 20-30 K dust are consistent with all of the upper limits...

  5. Reappraising foreground contamination in the COBE-DMR data

    CERN Document Server

    Banday, A J; Davies, R D; Davis, R J; Górski, K M

    2003-01-01

    With the advent of all-sky H-Alpha surveys it is possible to determine a reliable free-free template of the diffuse interstellar medium (Dickinson, Davies & Davis 2003) which can be used in conjunction with the synchrotron and dust templates to correct CMB observations for diffuse Galactic foregrounds. We have used the COBE-DMR data at 31.5, 53 and 90 GHz and employed cross- correlation techniques to re-evaluate the foreground contributions, particularly that due to dust which is known to be correlated with H-Alpha (and free-free) emission. The DMR microwave maps are found to contain, as well as the expected synchrotron and free-free components, a component tightly correlated to the 140 micron dust maps of DIRBE. At 31.5, 53 and 90 GHz this emission is 6.3 +/- 0.6, 2.4 +/- 0.4 and 2.2 +/- 0.4 microK/(MJy/sr) at 140 microns respectively. When corrected for the contribution from thermal dust following model 7 of Finkbeiner, Davis & Schlegel (1999), a strong anomalous dust emission component remains, whi...

  6. Cosmic Background Explorer (COBE) transfer orbit attitude control system

    Science.gov (United States)

    Placanica, Samuel J.; Flatley, Thomas W.

    1986-01-01

    The Cosmic Background Explorer (COBE) spacecraft will be launched by the Shuttle from Vandenberg AFB into a 300 km altitude, 99 deg inclination, 6 a.m. or 6 p.m. ascending node orbit. After release from the Remote Manipulator System (RMS) arm, an on-board monopropellant hydrazine propulsion system will raise the orbit altitude to 900 km. The spacecraft continuously spins during transfer orbit operations with the spin axis nominally horizontal and in or near the orbit plane. The blowdown propulsion system consists of twelve 5 lb thrusters (3 'spin', 3 'despin', and 6 'axial') with the latter providing initially 30 lb of force parallel to the spin axis for orbit raising. The spin/despin jets provide a constant roll rate during the transfer orbit phase of the mission and the axials control pitch and yaw. The axial thrusters are pulsed on for attitude control during coast periods and are normally on- and off-modulated for control during orbit raising. Attitude sensors employed in the control loops include an array of two-axis digital sun sensors and three planar earth scanners for position measurements, as well as six gyroscopes for rate information. System redundancy is achieved by means of unique three-axes-in-a-plane geometry. This triaxial concept results in a fail-safe operational system with no performance degradation for many different component failure modes.

  7. The Implications of the COBE-DMR Results for Cosmic Strings

    OpenAIRE

    Bennett, David P.; Stebbins, Albert; Bouchet, Francois R.

    1992-01-01

    We compare the anisotropies in the cosmic microwave background radiation measured by the COBE experiment to the predictions of cosmic strings. We use an analytic model for the $\\Delta T/T$ power spectrum that is based on our previous numerical simulations to show that the COBE results imply a value for the string mass per unit length, $\\mu$ under the assumption that cosmic strings are the source of the measured anisotropy. We find $G\\mu = 1.5\\pm 0.5 \\times 10^{-6}$ which is consistent with th...

  8. On-orbit attitude control of the Cosmic Background Explorer (COBE)

    Science.gov (United States)

    Bramberg, B.; Croft, J.

    1985-01-01

    The way in which COBE (launched by the SS in late 1982) performs its attitude control is described, along with the design of its on-orbit system. COBE, to be situated in a 900 km high, sun-synchronous orbit, contains two unique control features: (1) the orientation of the spinning satellite is controlled to a sun-normal attitude in the sun/local vertical plane; and (2) pitch and roll control is maintained by a unique triaxial arrangement of reaction wheels, magnetic torque bars and sensors, located in the body's tranverse plane. Inherent in this triaxial configuration concept is a built-in redundancy that will maintain attitude control in the event of any single-point sensor/actuator component failure. Each of the three control drive electronics operates independently and directly of a system of dedicated sensors. This system functions independently of a computer or an ephemeris communication link, leading to greater reliability.

  9. Science objectives lead to contamination requirements for the Cosmic Background Explorer (COBE)

    Science.gov (United States)

    Abrams, Eve M.; Carosso, Nancy J. P.

    1990-01-01

    The mission aims and related requirements of the Cosmic Background Explorer (COBE) are described in order to assess the measure needed for adequate control of optical system contamination. Instrument requirements are set forth so that the Diffuse IR Background Experiment (DIRBE), the Far IR Absolute Spectrophotometer (FIRAS), and the Differential Microwave Radiometers (DMRs) can achieve performance goals. The BRDF requirement for the primary mirror of the DIRBE is a maximum change of 50 percent on clean versus contaminated mirrors. The most critical components of the FIRAS and the DMR are discussed which are the sky horn and the antennae throats, respectively. The contamination-control devices include contamination covers, cleanroom assembly, and retractable cover assembly. The COBE is not found to perform unreliably due to contamination problems which suggests that the contamination program is effective.

  10. Large-scale structure after COBE: Peculiar velocities and correlations of cold dark matter halos

    Science.gov (United States)

    Zurek, Wojciech H.; Quinn, Peter J.; Salmon, John K.; Warren, Michael S.

    1994-01-01

    Large N-body simulations on parallel supercomputers allow one to simultaneously investigate large-scale structure and the formation of galactic halos with unprecedented resolution. Our study shows that the masses as well as the spatial distribution of halos on scales of tens of megaparsecs in a cold dark matter (CDM) universe with the spectrum normalized to the anisotropies detected by Cosmic Background Explorer (COBE) is compatible with the observations. We also show that the average value of the relative pairwise velocity dispersion sigma(sub v) - used as a principal argument against COBE-normalized CDM models-is significantly lower for halos than for individual particles. When the observational methods of extracting sigma(sub v) are applied to the redshift catalogs obtained from the numerical experiments, estimates differ significantly between different observation-sized samples and overlap observational estimates obtained following the same procedure.

  11. Hot and Cold Spots in the First plus Second Year COBE/DMR Maps

    OpenAIRE

    Cayon, Laura; Smoot, George

    1995-01-01

    Density perturbations at the decoupling epoch produce angular fluctuations in the temperature of the Cosmic Microwave Background (CMB) radiation that may appear as hot and cold spots. Observational data of the CMB includes instrumental noise in addition to the cosmological signal. One would like to determine which of the observed spots are produced by the noise and which correspond to signal. In this work we first present a statistical analysis of the first plus second year COBE/DMR map at 53...

  12. Constraints on the topology of the universe from the 2-yr COBE data

    OpenAIRE

    de Oliveira-Costa, Angelica; Smoot, George F.

    1994-01-01

    The cosmic microwave background (CMB) is a unique probe of cosmological parameters and conditions. There is a connection between anisotropy in the CMB and the topology of the Universe. Adopting a universe with the topology of a 3-Torus, or a universe where only harmonics of the fundamental mode are allowed, and using 2-years of COBE/DMR data, we obtain constraints on the topology of the Universe. Previous work constrained the topology using the slope information and the correlation function o...

  13. The COBE cosmic 3 K anisotropy experiment: A gravity wave and cosmic string probe

    Science.gov (United States)

    Bennett, Charles L.; Smoot, George F.

    1989-01-01

    Among the experiments to be carried into orbit next year, by the COBE satellite, are differential microwave radiometers. They will make sensitive all-sky maps of the temperature of the cosmic microwave background radiation at three frequencies, giving dipole, quadrupole, and higher order multipole measurements of the background radiation. The experiment will either detect, or place significant constraints on, the existence of cosmic strings and long wavelength gravity waves.

  14. On the Origins of the CMB: Insight from the COBE, WMAP, and Relikt-1 Satellites

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2007-01-01

    Full Text Available The powerful “Cosmic Microwave Background (CMB” signal currently associated with the origins of the Universe is examined from a historical perspective and relative to the experimental context in which it was measured. Results from the COBE satellite are reviewed, with particular emphasis on the systematic error observed in determining the CMB temperature. The nature of the microwave signal emanating from the oceans is also discussed. From this analysis, it is demonstrated that it is improper for the COBE team to model the Earth as a 285 K blackbody source. The assignment of temperatures to objects that fail to meet the requirements set forth in Kirchhoff’s law constitutes a serious overextension of the laws of thermal emission. Using this evidence, and the general rule that powerful signals are associated with proximal sources, the CMB monopole signal is reassigned to the oceans. In turn, through the analysis of COBE, WMAP, and Relikt-1 data, the dipole signal is attributed to motion through a much weaker microwave field present both at the position of the Earth and at the second Lagrange point.

  15. A New Blackbody Radiation Law Based on Fractional Calculus and its Application to NASA COBE Data

    OpenAIRE

    Biyajima, Minoru; Mizoguchi, Takuya; Suzuki, Naomichi

    2015-01-01

    By applying fractional calculus to the equation proposed by M. Planck in 1900, we obtain a new blackbody radiation law described by a Mittag-Leffler (ML) function. We have analyzed NASA COBE data by means of a non-extensive formula with a parameter $(q-1)$, a formula proposed by Ertik et al. with a fractional parameter $(\\alpha-1)$, and our new formula including a parameter $(p-1)$, as well as the Bose-Einstein distribution with a dimensionless chemical potential $\\mu$. It can be said that on...

  16. Limits on the cosmic infrared background from clustering in COBE/DIRBE maps

    CERN Document Server

    Kashlinsky, A; Odenwald, S

    1997-01-01

    We discuss a new method of estimating the cosmic infrared background (CIB) from the spatial properties of infrared maps and give the limits on the CIB from applying it to the COBE/DIRBE maps. The strongest limits are obtained at mid- to far-IR where foregrounds are bright, but smooth. If the CIB comes from matter clustered like galaxies, the smoothness of the maps implies CIB levels less than $\\sim$(10-15) nW/m$^2$/sr over this wavelength range.

  17. An overview of the Cosmic Background Explorer (COBE) and its observations - New sky maps of the early universe

    Science.gov (United States)

    Smoot, George F.

    1992-01-01

    This paper discusses the three instruments aboard NASA's Cosmic Background Explorer (COBE) satellite and presents early results obtained from the first six months of observations. The three instruments (FIRAS, DMR, and DIRBE) have operated well and produced significant new results. The FIRAS measurement of the CMB spectrum supports the standard Big Bang model. The maps made from the DMR instrument measurements show a spatially smooth early universe. The maps of galactic and zodiacal emission produced by the DIRBE instrument are needed to identify the foreground emissions from extragalactic and thus to interpret its and the other COBE results in terms of events in the early universe.

  18. Cryogenic Optical Assembly (COA) cooldown analysis for the Cosmic Background Explorer (COBE)

    Science.gov (United States)

    Coladonato, Robert J.; Irish, Sandra M.; Mosier, Carol L.

    1990-01-01

    The Cosmic Background Explorer (COBE) spacecraft, developed by Goddard Space Flight Center (GSFC), was successfully launched on November 18, 1989 aboard a Delta expendable launch vehicle. Two of the three instruments for this mission were mounted inside a liquid helium (LHe) dewar which operates at a temperature of 2 K. These two instruments are the Diffuse Infrared Background Experiment (DIRBE) and the Far Infrared Absolute Spectrophotometer (FIRAS). They are mounted to a common Instrument Interface Structure (IIS) and the entire assembly is called the Cryogenic Optical Assembly (COA). As part of the structural verification requirement, it was necessary to show that the entire COA exhibited adequate strength and would be capable of withstanding the launch environment. This requirement presented an unique challenge for COBE because the COA is built and assembled at room temperature (300 K), cooled to 2 K, and then subjected to launch loads. However, strength testing of the entire COA at 2 K could not be done because of facility limitations. Therefore, it was decided to perform the strength verification of the COA by analysis.

  19. Do wavelets really detect non-Gaussianity in the 4-year COBE data?

    CERN Document Server

    Mukherjee, P; Lasenby, A N

    2001-01-01

    We investigate the detection of non-Gaussianity in the 4-year COBE data reported by Pando, Valls-Gabaud & Fang (1998), using a technique based on the discrete wavelet transform. Their analysis was performed on the two DMR faces centred on the North and South Galatic poles respectively, using the Daubechies 4 wavelet basis. We are unable to reproduce the numerical results of Pando et al., but note that the results we present here have been independently verified (Valls-Gabaud, private communication). By calculating unbiassed estimates of the skewness, kurtosis and scale-scale correlation of the wavelet coefficients in all of the available scale domains of the transform, we obtain several detections of non-Gaussianity in the DMR-DSMB map at greater than the 99 per cent confidence level, but these occur mainly on pixel-pixel scales and are therefore not cosmological in origin. Indeed, after removing all multipoles beyond l = 40 from the COBE maps, these detections disappear. We repeat the analysis for the 53...

  20. Report on 3 and 4-point correlation statistics in the COBE DMR anisotrophy maps

    Science.gov (United States)

    Hinshaw, Gary (Principal Investigator); Gorski, Krzystof M.; Banday, Anthony J.; Bennett, Charles L.

    1996-01-01

    As part of the work performed under NASA contract # NAS5-32648, we have computed the 3-point and 4-point correlation functions of the COBE-DNIR 2-year and 4-year anisotropy maps. The motivation for this study was to search for evidence of non-Gaussian statistical fluctuations in the temperature maps: skewness or asymmetry in the case of the 3-point function, kurtosis in the case of the 4-point function. Such behavior would have very significant implications for our understanding of the processes of galaxy formation, because our current models of galaxy formation predict that non-Gaussian features should not be present in the DMR maps. The results of our work showed that the 3-point correlation function is consistent with zero and that the 4-point function is not a very sensitive probe of non-Gaussian behavior in the COBE-DMR data. Our computation and analysis of 3-point correlations in the 2-year DMR maps was published in the Astrophysical Journal Letters, volume 446, page L67, 1995. Our computation and analysis of 3-point correlations in the 4-year DMR maps will be published, together with some additional tests, in the June 10, 1996 issue of the Astrophysical Journal Letters. Copies of both of these papers are attached as an appendix to this report.

  1. A new blackbody radiation law based on fractional calculus and its application to NASA COBE data

    Science.gov (United States)

    Biyajima, Minoru; Mizoguchi, Takuya; Suzuki, Naomichi

    2015-12-01

    By applying fractional calculus to the equation proposed by M. Planck in 1900, we obtain a new blackbody radiation law described by a Mittag-Leffler (ML) function. We have analyzed NASA COBE data by means of a non-extensive formula with a parameter (q - 1) , a formula proposed by Ertik et al. with a fractional parameter (α - 1) , and our new formula including a parameter (p - 1) , as well as the Bose-Einstein distribution with a dimensionless chemical potential μ. It can be said that one role of the fractional parameter (p - 1) is almost the same as that of chemical potential (μ) as well as that of the parameter (q - 1) in the non-extensive approach.

  2. The Big Bang, COBE, and the Relic Radiation of Creation (LBNL Science at the Theater)

    Energy Technology Data Exchange (ETDEWEB)

    Smoot, George

    2007-03-05

    Berkeley Lab's George Smoot won the 2006 Physics Nobel Prize, together with John Mather of NASA Goddard Space Flight Center, for "the discovery of the blackbody form and anisotropy of the cosmic microwave background radiation." The anisotropy showed as small variations in the map of the early universe. This research looks back into the infant universe and provides a better understanding of the origin of galaxies and stars. The cosmic background radiation is a tool to understand the structure and history of the universe and the structure of space-time. These observations have provided increased support for the big bang theory of the universe's origin. The Cosmic Background Explorer (COBE) NASA satellite, launched in 1989, carries instruments that measured various aspects of cosmic microwave background radiation, and produced the data for these compelling scientific results, which opened up a field that continues very actively today.

  3. WMAP confirming the ellipticity in BOOMERanG and COBE CMB maps

    CERN Document Server

    Gurzadyan, V G; De Bernardis, P; Bianco, C L; Bock, J J; Boscaleri, A; Crill, B P; De Troia, G; Hivon, E; Hristov, V V; Kashin, A L; Kuloghlian, H; Lange, A E; Masi, S; Mauskopf, P D; Montroy, T; Natoli, P; Netterfield, C B; Pascale, E; Piacentini, F; Polenta, G; Ruhl, J; Yegorian, G

    2003-01-01

    The recent study of BOOMERanG 150 GHz Cosmic Microwave Background (CMB) radiation maps have detected ellipticity of the temperature anisotropy spots independent on the temperature threshold. The effect has been found for spots up to several degrees in size, where the biases of the ellipticity estimator and of the noise are small. To check the effect, now we have studied, with the same algorithm and in the same sky region, the WMAP maps. We find ellipticity of the same average value also in WMAP maps, despite of the different sensitivity of the two experiments to low multipoles. Large spot elongations had been detected also for the COBE-DMR maps. If this effect is due to geodesic mixing and hence due to non precisely zero curvature of the hypebolic Universe, it can be linked to the origin of WMAP low multipoles anomaly.

  4. 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.

  5. COBE DIRBE near-infrared polarimetry of the zodiacal light: Initial results

    Science.gov (United States)

    Berriman, G. B.; Boggess, N. W.; Hauser, M. G.; Kelsall, T.; Lisse, C. M.; Moseley, S. H.; Reach, W. T.; Silverberg, R. F.

    1994-01-01

    This Letter describes near-infrared polarimetry of the zodiacal light at 2.2 micrometers, measured with the Diffuse Infrared Background Experiment (DIRBE) aboard the Cosmic Background Explorer (COBE) spacecraft. The polarization is due to scattering of sunlight. The polarization vector is perpendicular to the scattering plane, and its observed amplitude on the ecliptic equator at an elongation of 90 deg and ecliptic longitude of 10 deg declines from 12.0 +/- 0.4% at 1.25 micrometers to 8.0 +/- 0.6% at 3.5 micrometers (cf. 16% in the visible); the principal source of uncertainty is photometric noise due to stars. The observed near-infrared colors at this location are redder than Solar, but at 3.5 micrometers this is due at least in part to the thermal emission contribution from the interplanetary dust. Mie theory calculations show that both polarizations and colors are important in constraining models of interplanetary dust.

  6. Can the lack of symmetry in the COBE/DMR maps constrain the topology of the universe?

    CERN Document Server

    De Oliveira-Costa, A; Starobinsky, A A; de Oliveira-Costa, Angelica; Smoot, George F; Starobinsky, Alexei A

    1995-01-01

    Although the cubic T^3 ``small universe" has been ruled out by COBE/DMR results as an interesting cosmological model, we still have the possibility of living in a universe with a more anisotropic topology such as a rectangular T^3 ``small universe" with one or two of its dimensions significantly smaller than the present horizon (which we refer to as T^1- and T^2-models, respectively). In order to rule out these anisotropic topologies as well, we apply a new data analysis method that searches for the specific kind of symmetries that these models should produce. We find that the 2 year COBE/DMR data set a lower limit on the smallest cell size for T^1- and T^2-models of 3000 h^{-1} Mpc, at 95% confidence, for a scale invariant power spectrum (n=1). These results imply that {\\it all} toroidal universes (cubes and rectangles) are ruled out as interesting cosmological models.

  7. Crystallization and preliminary structure analysis of CobE, an essential protein of cobalamin (vitamin B{sub 12}) biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Vévodová, Jitka [Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW (United Kingdom); Graham, Ross M.; Raux, Evelyne; Warren, Martin J. [School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Wilson, Keith S., E-mail: keith@ysbl.york.ac.uk [Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW (United Kingdom)

    2005-04-01

    P. aeruginosa CobE, a protein implicated in vitamin B{sub 12} biosynthesis, has been crystallized and data on the native and SeMet forms recorded to resolutions of 1.9 and 1.7 Å, respectively. The anomalous measurements will be used for phasing. CobE, a protein implicated in vitamin B{sub 12} biosynthesis, from Pseudomonas aeruginosa has been overexpressed in Escherichia coli, purified and crystallized using hanging-drop vapour diffusion. The crystals belong to the primitive orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 31.86, b = 41.07, c = 87.41 Å. The diffraction extends to a resolution of 1.9 Å. There is one molecule per asymmetric unit and the estimated solvent content is 35%. SeMet-labelled CobE has been prepared and crystallizes under the same conditions as the native protein with diffraction to 1.7 Å. The anomalous measurements will be used for phasing.

  8. Crystallization and preliminary structure analysis of CobE, an essential protein of cobalamin (vitamin B12) biosynthesis

    International Nuclear Information System (INIS)

    P. aeruginosa CobE, a protein implicated in vitamin B12 biosynthesis, has been crystallized and data on the native and SeMet forms recorded to resolutions of 1.9 and 1.7 Å, respectively. The anomalous measurements will be used for phasing. CobE, a protein implicated in vitamin B12 biosynthesis, from Pseudomonas aeruginosa has been overexpressed in Escherichia coli, purified and crystallized using hanging-drop vapour diffusion. The crystals belong to the primitive orthorhombic space group P212121, with unit-cell parameters a = 31.86, b = 41.07, c = 87.41 Å. The diffraction extends to a resolution of 1.9 Å. There is one molecule per asymmetric unit and the estimated solvent content is 35%. SeMet-labelled CobE has been prepared and crystallizes under the same conditions as the native protein with diffraction to 1.7 Å. The anomalous measurements will be used for phasing

  9. Comments on the statistical analysis of excess variance in the COBE differential microwave radiometer maps

    Science.gov (United States)

    Wright, E. L.; Smoot, G. F.; Kogut, A.; Hinshaw, G.; Tenorio, L.; Lineweaver, C.; Bennett, C. L.; Lubin, P. M.

    1994-01-01

    Cosmic anisotrophy produces an excess variance sq sigma(sub sky) in the Delta maps produced by the Differential Microwave Radiometer (DMR) on cosmic background explorer (COBE) that is over and above the instrument noise. After smoothing to an effective resolution of 10 deg, this excess sigma(sub sky)(10 deg), provides an estimate for the amplitude of the primordial density perturbation power spectrum with a cosmic uncertainty of only 12%. We employ detailed Monte Carlo techniques to express the amplitude derived from this statistic in terms of the universal root mean square (rms) quadrupole amplitude, (Q sq/RMS)(exp 0.5). The effects of monopole and dipole subtraction and the non-Gaussian shape of the DMR beam cause the derived (Q sq/RMS)(exp 0.5) to be 5%-10% larger than would be derived using simplified analytic approximations. We also investigate the properties of two other map statistics: the actual quadrupole and the Boughn-Cottingham statistic. Both the sigma(sub sky)(10 deg) statistic and the Boughn-Cottingham statistic are consistent with the (Q sq/RMS)(exp 0.5) = 17 +/- 5 micro K reported by Smoot et al. (1992) and Wright et al. (1992).

  10. Hot and cold spots in the first plus second year COBE/DMR maps

    CERN Document Server

    Cayon, L; Cayon, Laura; Smoot, George

    1995-01-01

    Density perturbations at the decoupling epoch produce angular fluctuations in the temperature of the Cosmic Microwave Background (CMB) radiation that may appear as hot and cold spots. Observational data of the CMB includes instrumental noise in addition to the cosmological signal. One would like to determine which of the observed spots are produced by the noise and which correspond to signal. In this work we first present a statistical analysis of the first plus second year COBE/DMR map at 53 GHz that reveals the presence of cosmological signal in the data. The analysis is based on Harrison-Zeldovich Monte Carlo realizations and utilizes a generalized \\chi^2 statistic. The method is applied to the number of spots and the fraction of the total area that appear above/below a certain value of the dispersion of the noise, including and excluding the quadrupole, giving Q_{rms-PS}=15^{+3}_{-6}, 18^{+5}_{-7} \\mu K and Q_{rms-PS}=18^{+3}_{-4}, 21\\pm6 \\mu K, at the 95\\% confidence level, respectively. The data taken b...

  11. Constraints on the topology of the universe from the 2-year COBE data

    CERN Document Server

    Smoot, G F

    1994-01-01

    The cosmic microwave background (CMB) is a unique probe of cosmological parameters and conditions. There is a connection between anisotropy in the CMB and the topology of the Universe. Adopting a universe with the topology of a 3-Torus, or a universe where only harmonics of the fundamental mode are allowed, and using 2-years of COBE/DMR data, we obtain constraints on the topology of the Universe. Previous work constrained the topology using the quadrupole component and the correlation function of the CMB. In this letter, we obtain more accurate results by using all multipole moments, avoiding approximations by computing their full covariance matrix. We obtain the best fit for a cubic toroidal universe of scale 7200h^{-1}Mpc for n=1. The data set a lower limit on the cell size of 4320h^{-1}Mpc at 95\\% confidence and 5880h^{-1}Mpc at 68\\% confidence. These results show that the most probable cell size would be around 1.2 times larger than the horizon scale, implying that the 3-Torus topology is no longer an int...

  12. Cosmic Ray Exposure & Linear-Energy-Transfer Evaluations for the COBE Mission

    Science.gov (United States)

    Stassinopoulos, E. G.; Barth, J. M.

    1984-01-01

    Magnetospherically attenuated, orbit integrated, surface incident cosmic ray fluxes of galactic origin were determined for the COBE mission. All heavy ions up to Nickel (z=28) were considered in this, evaluation. In order to provide worst case approximations, estimates were based on solar minimum conditions. Transport and material shielding calculations were then performed for these vehicle encountered particles, for a simple spherical 3-D aluminum geometry, and the materially attenuated cosmic ray distributions emerging behind selected shield thicknesses were obtained. Finally, Linear-Energy-Transfer (LET) spectra were evaluated for the energy spectra of each ion specie and these were, in turn, integrated into the sum-total LET distribution contained in this report. The results are presented in tabular and graphical form for eight (8) different shield thicknesses from.01 to 10.0 gm/cm2 of aluminum. They show most conclusively, and not unexpectedly, that material shielding has virtually no 'effect on the final LET spectrum, at least not for aluminum shields. This was predictable. Please note that in the LET graphs, two curves were plotted. Of these, please ignore the one labeled "grazing" and use only the one labeled "normal". Again, it should be remembered that the end results contain contributions from all elements up to Nickel (z=28).

  13. Search for unresolved sources in the COBE-DMR two-year sky maps

    Science.gov (United States)

    Kogut, A.; Banday, A. J.; Bennett, C. L.; Hinshaw, G.; Loewenstein, K.; Lubin, P.; Smoot, G. F.; Wright, E. L.

    1994-01-01

    We have searched the temperature maps from the Cosmic Background Explorer (COBE) Differential Microwave Radiometers (DMR) first two years of data for evidence of unresolved sources. The high-latitude sky (absolute value of b greater than 30 deg) contains no sources brighter than 192 microKelvin thermodynamic temperature (322 Jy at 53 GHz). The cumulative count of sources brighter than threshold T, N(greater than T), is consistent with a superposition of instrument noise plus scale-invariant spectrum of cosmic temperature fluctuations normalized to Q(sub rms-PS) = 17 microKelvin. We examine the temperature maps toward nearby clusters and find no evidence for any Sunyaev-Zel'dovich effect, delta y less than 7.3 x 10(exp -6) (95% CL) averaged over the DMR beam. We examine the temperature maps near the brightest expected radio sources and detect no evidence of significant emission. The lack of bright unresolved sources in the DMR maps, taken with anisotropy measurements on smaller angular scales, places a weak constraint on the integral number density of any unresolved Planck-spectrum sources brighter than flux density S, n(greater than S) less than 2 x 10(exp 4)/(S/1 Jy)(exp 2)/sr.

  14. The Relativistic Effect of the Deviation between the CMB Temperatures Obtained by the COBE Satellite

    Directory of Open Access Journals (Sweden)

    Rabounski D.

    2007-01-01

    Full Text Available The Far-Infrared Absolute Spectrophotometer (FIRAS on the COBE satellite, gives different temperatures of the Cosmic Microwave Background. This deviation has a theoretical explanation in the Doppler effect on the dipole (weak component of the radiation, the true microwave background of the Universe that moves at 365 km/sec, if the monopole (strong component of the radiation is due to the Earth. Owing to the Doppler effect, the dipole radiation temperature (determined by the 1st derivative of the monopole is lower than the monopole radiation temperature, with a value equal to the observed deviation. By this theory, the WMAP and PLANCK satellites, targeting the L2 point in the Sun-Earth-Moon system, should be insensitive to the monopole radiation. In contrast to the launched WMAP satellite, the PLANCK satellite will have on board absolute instruments which will not be able to detect the measured temperature of the Cosmic Microwave Background. That the monopole (strong component of the observed Cosmic Microwave Background is generated by the Earth is given a complete theoretical proof herein.

  15. A Study of External Galaxies Detected by the COBE Diffuse Infrared Background Experiment

    International Nuclear Information System (INIS)

    A comparison of the COBE Diffuse Infrared Background Experiment (DIRBE) all-sky survey with the locations of known galaxies in the IRAS Catalog of Extragalactic Objects and the Center for Astrophysics Catalog of Galaxies led to the detection of as many as 57 galaxies. In this paper, we present the photometric data for these galaxies and an analysis of the seven galaxies that were detected at λ > 100 μm. Estimates of the ratio of the mass of the cold dust (CD) component detected at Td = 20 endash 30 K to a very cold dust (VCD) component with Td ∼ 10 endash 15 K suggest that between 2%endash 100% of the cirrus-like CD mass can also exist in many of these galaxies as VCD. In one galaxy, M33, the DIRBE photometry at 240 μm suggests as much as 26 times as much VCD may be present as compared to the cirrus-like component. Further submillimeter measurements of this galaxy are required to verify such a large population of VCD. We also present 10 galaxies that were detected in the sky region not previously surveyed by IRAS and that can be used to construct a flux-limited all-sky catalog of galaxies brighter than 1000 Jy with a modest completeness limit of about 65%. copyright copyright 1998. The American Astronomical Society

  16. Can the lack of symmetry in the COBE/DMR maps constrain the topology of the universe?

    OpenAIRE

    de Oliveira-Costa, Angelica; Smoot, George F.; Starobinsky, Alexei A.

    1995-01-01

    Although the cubic T^3 "small universe" has been ruled out by COBE/DMR results as an interesting cosmological model, we still have the possibility of living in a universe with a more anisotropic topology such as a rectangular T^3 "small universe" with one or two of its dimensions significantly smaller than the present horizon (which we refer to as T^1- and T^2-models, respectively). In order to rule out these anisotropic topologies as well, we apply a new data analysis method that searches fo...

  17. A Search for Resonant Structures in the Zodiacal Cloud with COBE DIRBE: The Mars Wake and Jupiter's Trojan Clouds

    OpenAIRE

    Kuchner, Marc J.; Reach, William T.; Brown, Michael E.

    2000-01-01

    We searched the COBE DIRBE Sky and Zodi Atlas for a wake of dust trailing Mars and for Trojan dust near Jupiter's L5 Lagrange point. We compare the DIRBE images to a model Mars wake based on the empirical model of the Earth's wake as seen by the DIRBE and place a 3-sigma upper limit on the fractional overdensity of particles in the Mars wake of 18% of the fractional overdensity trailing the Earth. We place a 3-sigma upper limit on the effective emitting area of large (10-100 micron diameter) ...

  18. One-way return-link Doppler navigation with the Tracking and Data Satellite System (TDRSS) - The ultrastable oscillator (USO) experiment on the Cosmic Background Explorer (COBE)

    Science.gov (United States)

    Dunham, J. B.; Nemesure, M.; Teles, J.; Brown-Conwell, E. R.; Jackson, J. A.; Reamy, V. L.; Maher, M. J.; Elrod, B. D.

    1990-01-01

    The principal objectives of the USO experiment on the COBE spacecraft are defined, and results of space qualification studies for the COBE USO experiment are summarized. The principal objectives of the experiment are: (1) to determine flight performance of the USO coupled to the second-generation TDRSS transponder; (2) space qualify TDRSS noncoherent one-way return-link Doppler tracking; and (3) analyze algorithms for one-way navigation with real data. The three objectives of the experiment have been met in the first stage of the experiment analysis.

  19. On the radiative and thermodynamic properties of the Cosmic Microwave Background radiation using COBE FIRAS instrument data

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Use formulas to describe the monopole and dipole spectra of the Cosmic Microwave Background (CMB) radiation, the exact expressions for the temperature dependences of the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume, pressure, enthalpy density, and internal energy density in the finite range of frequencies are obtained. Since the dependence of temperature upon the redshift z is known, the obtained expressions can be simply presented in z representation. Utilizing experimental data for the monopole and dipole spectra measured by the COBE FIRAS instrument in the 60 - 600 GHz frequency interval at the temperature T = 2.728 K, the values of the radiative and thermodynamic functions, as well as the radiation density constant a and the Stefan-Boltzmann constant are calculated. In the case of the dipole spectrum, the constants a and the Stefan-Bol...

  20. The effect of Community Based Education and Service (COBES) on medical graduates’ choice of specialty and willingness to work in rural communities in Ghana

    OpenAIRE

    Amalba, Anthony; van Mook, Walther Nicolaas Karel Anton; Mogre, Victor; Scherpbier, Albert Jakob Johannus Antonius

    2016-01-01

    Background Career choices and placements of healthcare professionals in rural areas are a major problem worldwide, and their recruitment and retention to these areas have become a challenge to the health sector. The purpose of this study was to investigate the effect of Community Based Education and Service (COBES) on medical graduates' choice of specialty and willingness to work in a rural area. Method This cross sectional survey was conducted among 56 pioneering graduates that followed a Pr...

  1. On the radiative and thermodynamic properties of the cosmic radiations using COBE FIRAS instrument data: III. Galactic far-infrared radiation

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Using the three-component spectral model describing the FIRAS average continuum spectra, the analytical expressions for the temperature dependence of the thermodynamic and radiative functions of the galactic far-infrared radiation are obtained. The COBE FIRAS instrument data in the 0.15 - 2.88 THz frequency interval at the mean temperatures T = 17.72 K, T = 14 K, and T =6.73 K are used for calculating the radiative and thermodynamic functions, such as the total radiation power per unit area, total energy density, total emissivity, number density of photons, Helmholtz free energy density, entropy density, heat capacity at constant volume and pressure for the warm, intermediate-temperature and very cold components of the Galactic continuum spectra. The generalized Stefan-Boltzmann laws for the warm, intermediate-temperature and very cold components are constructed. This result is important when we construct the cosmological models of radiative transfer in the inner Galaxy. Within the framework of the three- com...

  2. Clustering of the Diffuse Infrared Light from the COBE DIRBE maps; 3, Power spectrum analysis and excess isotropic component of fluctuations

    CERN Document Server

    Kashlinsky, A; Odenwald, S

    1999-01-01

    The cosmic infrared background (CIB) radiation is the cosmic repository for energy release throughout the history of the universe. Using the all-sky data from the COBE DIRBE instrument at wavelengths 1.25 - 100 mic we attempt to measure the CIB fluctuations. In the near-IR, foreground emission is dominated by small scale structure due to stars in the Galaxy. There we find a strong correlation between the amplitude of the fluctuations and Galactic latitude after removing bright foreground stars. Using data outside the Galactic plane ($|b| > 20\\deg$) and away from the center ($90\\deg< l <270\\deg$) we extrapolate the amplitude of the fluctuations to cosec$|b|=0$. We find a positive intercept of $\\delta F_{\\rm rms} = 15.5^{+3.7}_{-7.0},5.9^{+1.6}_{-3.7}, 2.4^{+0.5}_{-0.9}, 2.0^{+0.25}_{-0.5}$ nW/m2/sr at 1.25, 2.2,3.5 and 4.9 mic respectively, where the errors are the range of 92% confidence limits. For color subtracted maps between band 1 and 2 we find the isotropic part of the fluctuations at $7.6^{+1.2}_...

  3. WINNICOTT Y HEIDEGGER: LA APERTURA DEL MUNDO Y EL CO-ESTAR // WINNICOTT AND HEIDEGGER: OPENING UP OF WORLD AND CO-BEING

    Directory of Open Access Journals (Sweden)

    Julieta Bareiro

    2013-06-01

    Full Text Available Este trabajo integra la investigación de la tesis doctoral defendida en la Facultad de Psicología (UBA y tiene por propósito establecer un diálogo entre Winnicott y Heidegger respecto de la apertura del mundo y los otros. En efecto, ambos pensadores desde sus respectivas disciplinas han reflexionado sobre la experiencia del ser y el existir. Winnicott desde el ámbito de la clínica psicoanalítica y Heidegger desde la fenomenología hermenéutica. El hecho de que la apertura del mundo en el filósofo alemán sea compartida, permite una mayor comprensión del rol materno en el proceso del desarrollo del niño winnicottiano. A partir de la afirmación de que el Dasein es esencialmente ser con otros, co-estar, (Mitsein y que los otros son ahí con el Dasein, es posible pensar que el desarrollo de la subjetividad winnicottiana tiene el rasgo de la co-existencia. // This work integrates the research of the doctoral thesis defended at the Faculty of Psychology (UBA and aims to establish a dialogue between Winnicott and Heidegger regarding the opening up of world and the others. Indeed, both thinkers, from their respective disciplines, have thought about the experience of being and existing. Winnicott from the field of psychoanalytic clinic and Heidegger from the hermeneutic phenomenology. The fact that opening up of world in the German philosopher is shared allows a better understanding of the maternal role in the Winnicottian child development process. From the statement that Dasein is essentially being with others, co-being, (Mitsein and that others are there with the Dasein, it is conceivable that the development of the Winnicottian subjectivity has the trait of coexistence.

  4. COBE-SST2 Sea Surface Temperature and Ice

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A new sea surface temperature (SST) analysis on a centennial time scale is presented. The dataset starts in 1850 with monthly 1x1 means and is periodically updated....

  5. A new blackbody radiation law based on fractional calculus and its application to NASA COBE data

    OpenAIRE

    Biyajima, Minoru; Mizoguchi, Takuya; Suzuki, Naomichi

    2015-01-01

    By applying fractional calculus to the equation proposed by M. Planck in 1900, we obtain a new blackbody radiation law described by a Mittag-Leffler (ML) function. We have analyzed NASA CODE data by means of a non-extensive formula with a parameter (q - 1), a formula proposed by Ertik et al. with a fractional parameter (alpha - 1), and our new formula including a parameter (p - 1), as well as the Bose-Einstein distribution with a dimensionless chemical potential mu. It can be said that one ro...

  6. Trimatės vartotojo sąsajos, kuriamos atkuriamosios grafikos priemonėmis

    OpenAIRE

    Vižinienė, Asta

    2007-01-01

    Atkuriamosios grafikos priemonės leidžia sukurti trimatę vartotojo sąsają, panaudojant įvarius trimačius modelius. Darbo tikslas: Trimačių modelių aprašymo kalbų analizė ir trimatės vartotojo sąsajos modelio sukūrimas. Darbo uždaviniai: išnagrinėti literatūrą apie trimatės vartotojo sąsajos kūrimą, atlikti atkuriamosios grafikos priemonių, skirtų kurti trimačius objektus, analizę bei pagrindinių virtualios realybės aprašymo kalbų analizę, pasinaudojant atkuriamosios grafikos priemonėmis sukur...

  7. The infrared and submillimetre sky after COBE; Proceedings of the NATO Advanced Study Institute, Les Houches, France, Mar. 20-30, 1991

    Science.gov (United States)

    Signore, Monique; Dupraz, Christophe

    The present conference discusses first-order cosmological inflation, the great attractor and the anisotropies of the relic radiation, the role of string theory in cosmology, the cosmic microwave background radiation, dark matter candidates and candidate detection methods, and the thermal history of the cosmological gas. Also discussed are Galactic IR emission, sources of cosmic IR-to-submillimeter background radiation, cosmic background anisotropies in the millimetric region, and linear and nonlinear gravitational effects on the cosmic microwave background.

  8. Protestantska radna etika i hedonizam među kirgiskim, turskim i australskim studentima

    OpenAIRE

    BOZKURT, Veysel; Bayram, Nuran; Furnham, Adrian; Dawes, Glenn

    2010-01-01

    Ovaj rad temelji se na međukulturnom istraživanju koje uspoređuje vrijednosti protestantske radne etike (PWE) među trima skupinama sveučilišnih studenata iz postindustrijalizirane Australije, novoindustrijalizirane Turske i razmjerno slabo razvijenoga predindustrijskog Kirgistana. Nalazi istraživanja pokazuju da je protestantska radna etika (PWE) bolje prihvaćena u manje razvijenim zemljama, poput Kirgistana, a za njom slijede razvijenije zemlje, primjerice Turska, i na ...

  9. MOLIŠKI HRVATI. Rekonstrukcija kreiranja i reprezentacije jednog etničkog identiteta

    OpenAIRE

    Perinić, Ana

    2006-01-01

    Rad govori o moliškim Hrvatima, najmanjom i najstarijom hrvatskom dijasporom u Europi, koja se nalazi u trima selima južne talijanske pokrajine Molise. Na primjeru ove zajednice vidljiva je kompleksnost i konstruiranje identiteta, koji izmiče probranim, stvarnim, objektivnim sličnostima i različitostima zajednice iznesenima u šest kriterija potrebnih za njegovu tvorbu prema A. D. Smithu.

  10. Mapping the cold glow of the big bang

    International Nuclear Information System (INIS)

    The United States has recently launched a satellite solely dedicated to cosmology in an attempt to provide insight into the early formation of the Universe. The Cosmic Background Explorer (COBE) satellite is producing astonishing precise data which supports the Big Bang theory of the Universe's origins. Continued analysis of COBE data may provide clues as to how stars and galaxies formed. (UK)

  11. Perception and valuations of community-based education and service by alumni at Makerere University College of Health Sciences

    Directory of Open Access Journals (Sweden)

    Mbalinda Scovia

    2011-03-01

    Full Text Available Abstract Background Training of health professionals can be deliberately structured to enhance rural recruitment by exposing the trainees to the realities of rural life and practice through Community-Based Education and Service (COBE programs. Few studies have surveyed the alumni of these programs to establish their post-university views and whether the positive impact of COBE programs endures into the post-university life. This study surveyed the alumni of COBE at Makerere to obtain their perceptions of the management and administration of COBE and whether COBE had helped develop their confidence as health workers, competence in primary health care and willingness and ability to work in rural communities. Objectives • To assess the efficiency of the management and administration of COBES. • To obtain the views of the impact of COBES on its alumni. Methods A mixed qualitative and quantitative study was conducted using focus group discussions (FGD and a telephone administered questionnaire. From a total of 300 COBES alumni 150 were contacted. Twenty four Alumni (13 females and 11 males were purposefully selected by discipline, gender and place of work, and invited for the focus group discussion. The discussions were transcribed and analyzed using a manifest content analysis table. The thematic issues from the FGDs were used to develop a structured questionnaire which was administered by telephone by the authors. The data were entered into Microsoft excel template and exported to Stata for analysis. The findings of the telephone survey were used to cross-match the views expressed during the focus group discussions. Results The alumni almost unanimously agree that the initial three years of COBES were very successful in terms of administration and coordination. COBES was credited for contributing to development of confidence as health workers, team work, communication skills, competence in primary health care and willingness to work in rural

  12. Prikazivanje čudovišno-ženskoga u odabranim djelima C. S. Lewisa, Roalda Dahla i Philipa Pullmana

    OpenAIRE

    Tso, Anna Wing Bo

    2012-01-01

    Rad istražuje načine prikazivanja ženskih likova u ulozi protivnika u trima popularnim književnim pripovijedima za djecu – u ciklusu Chronicles of Narnia [Kronike iz Narnije] C. S. Lewisa te u romanima The Witches [Vještice] Roalda Dahla i The Amber Spyglass [Jantarni dalekozor] Philipa Pullmana – pozivajući se na teoriju abjekcije Julije Kristeve i na raspravu o čudovišno-ženskom Barbare Creed. I u ciklusu o Narniji i u romanu Vještice, ženski su protivnički likovi pojednostavljeni, stereoti...

  13. VELIKI TJEDAN U CRKVENO-PUČKOJ BAŠTINI ŠIROKOBRIJEŠKOG KRAJA

    OpenAIRE

    Barać, Ivana

    2015-01-01

    U radu se opisuje razdoblje Velikog tjedna u crkveno-pučkoj baštini Širokog Brijega. Veliki tjedan se smatra čvorištem crkvene i liturgijske godine. Vrijeme Velikog tjedna je ispunjeno trima krepostima, pokorom, postom i molitvom koji su ljudima pomagali u pripravi za nadolazeće vrijeme koje se veže uz muku i smrt Isusa Krista. U radu su navedeni suvremeni izvorni terenski zapisi molitvenih pjesama, običaja i vjerovanja koji su karakteristični za razdoblje od Cvjetne nedjelje do Velike sub...

  14. Ispitivanje vezne čvrstoće između zlatne slitine i hidrotermalne keramike

    OpenAIRE

    Živko-Babić, Jasenka; Pandurić, Josip; Janez, Indof; Tomislav, Ivaniš; Zdravko, Schauperl

    2001-01-01

    Svrha rada bila je ispitati utječe li brzina hlađenja odljeva na strukturne promjene visokokaratne zlatne slitine i mijenjaju li te promjene istodobno kakvoću veze između zlatne slitine i hidrotermalne keramike. Prije napečenja keramike odljevi su hlađeni brzo (gašenjem), normalno (na zraku) i sporo (u peći). Istraživanje je obavljeno testom opterećenja u trima točkama na ukupno petnaest uzoraka definiranih dimenzija. Izmjerena je vrijednost sile i progib pri kojem je nastalo odvajanje ker...

  15. Zbrinjavanje medicinskog otpada - zakonodavstvo i njegova provedba

    OpenAIRE

    Marinković, Natalija; Vitale, Ksenija; Janev Holcer, Nataša; Džakula, Aleksandar

    2006-01-01

    Gospodarenje medicinskim otpadom, koji po svojim svojstvima može biti opasan i/ili inertan, u Hrvatskoj je regulirano trima temeljnim pravnim aktima: Zakonom o otpadu, Pravilnikom o vrstama otpada te Naputkom o postupanju s otpadom koji nastaje pri pružanju zdravstvene zaštite. Uz njih još su i Zakon o prijevozu opasnih tvari i Zakon o otrovima akti koji podupiru provedbu ovih propisa. Slijedom razvoja suvremenih cjelovitih sustava za gospodarenje otpadom razvijen je i cjeloviti sustav za gos...

  16. Remembering when the big bang seemed so simple

    CERN Multimedia

    Johnson, George

    2006-01-01

    Fourteen years ago, an astronomer at Berkeley declared that he and his satellite, COBE, had detected the astrophysical equivalent of the fingerprints of God, his euphoria was easy to understand. (1 page)

  17. Can the Gravitational Wave Background from Inflation be Detected Locally?

    OpenAIRE

    Liddle, Andrew R.

    1993-01-01

    The Cosmic Background Explorer (COBE) detection of microwave background anisotropies may contain a component due to gravitational waves generated by inflation. It is shown that the gravitational waves from inflation might be seen using `beam-in-space' detectors, but not the Laser Interferometer Gravity Wave Observatory (LIGO). The central conclusion, dependent only on weak assumptions regarding the physics of inflation, is a surprising one. The larger the component of the COBE signal due to g...

  18. Analysis of different norms and corresponding Lipschitz constants for global optimization

    OpenAIRE

    Paulavičius, Remigijus; Žilinskas, Julius

    2006-01-01

    Šiam tikslui buvo įvertintos įvairias normas atitinkančios Lipšico konstantos. Šakų ir rėžių algoritmas buvo naudojamas globalaus maksimumo paieškai. Eksperimento rezultatai parodė, kad geriausi rezultatai gaunami, kai Lipšico viršutiniam rėžiui įvertinti naudojamas kraštinių (begalinės ir pirmosios) normų junginys dvimačiam atvejui ir jų junginys su euklidine norma trimačiam atvejui. The paper discusses how the used norm and corresponding Lipschitz constant influence the speed of algorith...

  19. Gamtamokslinių vadovėlių vizualizacijos pagalba mokymosi procese : diagnostinio tyrimo rezultatai merginų grupėje

    OpenAIRE

    Bilbokaitė, Renata

    2009-01-01

    Technologinis progresas paveikė ugdymo sritį, kuriai itin aktualu tapo atidžiau tirti mokinio ir kompiuterio sąveikas, nes kompiuteris tapo ugdytinio gyvenimo dalimi. Minėtoji technologinė priemonė turi daugybę privalumų, kurie aktyvina besimokančiųjų mąstymo procesus ir įgūdžių formavimą. Stipriausia minėtos priemonės savybė yra trimačių ir keturmečių vaizdų perteikimas, kai tie objektai yra nematomi mūsų akims dėl fiziologinių galimybių ribotumo. Tai žinant, šiame straipsnyje tiriama įprast...

  20. Dark matter, hot and cold

    International Nuclear Information System (INIS)

    Cosmologists responded enthusiastically to the announcement at the Washington meeting of the American Physical Society in April 1992 that the Cosmic Background Explorer (COBE) had succeeded in detecting primordial anisotropies in the cosmic microwave background radiation (CMB - June 1992, page 1). The COBE satellite was launched in November 1989 into an orbit approximately 900 km above the Earth, carrying instruments to make precise measurements of the spectrum and anisotropy of the CMB. Data from the Far-lnfra Red Absolute Spectrophotometer (FIRAS) beautifully shows the CMB spectrum to be that of a black body at a temperature of 2.73±0.06K. An even more important result, at least from the viewpoint of theories of large scale structure formation (LSS), comes from the Differential Microwave Radiometer (DMR) which provided the first evidence for CMB anisotropy. Some anisotropy on the angular slice probed by COBE is expected in any reasonable model of LSS. COBE's measurement of the quadrupole anisotropy at six parts per million provides an important clue for developing a 'standard model' of LSS. The COBE numbers are in remarkably good agreement with the predictions of a particularly simple class of LSS models proposed almost a decade ago, with far reaching implications for dark matter searches

  1. Seeded hot dark matter models with inflation

    Science.gov (United States)

    Gratsias, John; Scherrer, Robert J.; Steigman, Gary; Villumsen, Jens V.

    1993-01-01

    We examine massive neutrino (hot dark matter) models for large-scale structure in which the density perturbations are produced by randomly distributed relic seeds and by inflation. Power spectra, streaming velocities, and the Sachs-Wolfe quadrupole fluctuation are derived for this model. We find that the pure seeded hot dark matter model without inflation produces Sachs-Wolfe fluctuations far smaller than those seen by COBE. With the addition of inflationary perturbations, fluctuations consistent with COBE can be produced. The COBE results set the normalization of the inflationary component, which determines the large-scale (about 50/h Mpc) streaming velocities. The normalization of the seed power spectrum is a free parameter, which can be adjusted to obtain the desired fluctuations on small scales. The power spectra produced are very similar to those seen in mixed hot and cold dark matter models.

  2. Nobel Lecture: From the Big Bang to the Nobel Prize and beyond

    Science.gov (United States)

    Mather, John C.

    NASA’s Cosmic Background Explorer satellite mission, the COBE, laid the foundations for modern cosmology by measuring the spectrum and anisotropy of the cosmic microwave background radiation and discovering the cosmic infrared background radiation. I describe the history of the COBE project, its scientific context, the people who built it, and the scientific results. The COBE observed the universe on the largest scales possible by mapping the cosmic microwave and infrared background radiation fields and determining their spectra. It produced conclusive evidence that the hot Big Bang theory of the early universe is correct, showed that the early universe was very uniform but not perfectly so, and that the total luminosity of post Big Bang objects is twice as great as previously believed. The COBE concept was developed by a Mission Definition Study Team appointed by NASA in 1976, based on three competing proposals submitted in 1974. The COBE was built in-house by Goddard Space Flight Center, with a helium cryostat provided by Ball Aerospace, and was launched on a Delta rocket built by McDonnell Douglas. It is in a circular orbit 900km above the Earth, in a plane inclined 99° to the equator and roughly perpendicular to the line to the Sun. It carried three instruments, a far infrared absolute spectrophotometer (FIRAS), a differential microwave radiometer with three channels (DMR), and a diffuse infrared background experiment (DIRBE). The helium cryostat cooled the FIRAS and DIRBE for 10months until the helium was exhausted, but operations continued for a total of 4years . Subsequent observations have confirmed the COBE results and led to measurements of the main cosmological parameters with a precision of a few percent.

  3. Generalised inflation with a gravitational wave background

    OpenAIRE

    Lukash, V. N.; Mikheeva, E. V.; Muller, V.; Malinovsky, A. M.

    2000-01-01

    We propose a Lambda-inflation model which explains a significant part of the COBE signal by primordial cosmic gravitational waves. The primordial density perturbations fulfill both the constraints of large-scale microwave background and galaxy cluster normalization. The model is tested against the galaxy cluster power spectrum and the high-multipole angular CMB anisotropy.

  4. COBRAS/SAMBA: The European space mission to map the CBR anisotropy

    DEFF Research Database (Denmark)

    Bersanelli, M.; Mandolesi, N.; Cesarsky, C.;

    1996-01-01

    COBRAS/SAMBA is an ESA mission designed for extensive, accurate mapping of the anisotropies of the Cosmic Background Radiation, with angular sensitivity from sub-degree scales up to and overlapping with the COBE-DMR resolution. This will allow a fun identification of the primordial density pertur...

  5. Blue spectral inflation

    CERN Document Server

    Schunck, Franz E

    2008-01-01

    We reconsider the nonlinear second order Abel equation of Stewart and Lyth, which follows from a nonlinear second order slow-roll approximation. We find a new eigenvalue spectrum in the blue regime. Some of the discrete values of the spectral index n_s have consistent fits to the cumulative COBE data as well as to recent ground-base CMB experiments.

  6. Eigenvalues of the Stewart-Lyth equation for inflation with a blue spectrum

    CERN Document Server

    Schunck, F E; Schunck, Franz E.; Mielke, Eckehard W.

    2000-01-01

    By using the rather stringent nonlinear second order slow-roll approximation, we reconsider the nonlinear second order Abel equation of Stewart and Lyth. We determine a new blue eigenvalue spectrum. Some of the discrete values of the spectral index $n_s$ have consistent fits to the cumulative COBE data as well as to recent ground-base CMB experiments.

  7. Effective asymmetric bioreduction of ethyl 4-chloro-3-oxobutanoate to ethyl (R)-4-chloro-3-hydroxybutanoate by recombinant E. coli CCZU-A13 in [Bmim]PF6-hydrolyzate media.

    Science.gov (United States)

    He, Yu-Cai; Tao, Zhi-Cheng; Di, Jun-Hua; Chen, Liang; Zhang, Lin-Bing; Zhang, Dan-Ping; Chong, Gang-Gang; Liu, Feng; Ding, Yun; Jiang, Chun-Xia; Ma, Cui-Luan

    2016-08-01

    It was the first report that the concentrated hydrolyzates from the enzymatic hydrolysis of dilute NaOH (3wt%)-soaking rice straw at 30°C was used to form [Bmim]PF6-hydrolyzate (50:50, v/v) media for bioconverting ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl (R)-4-chloro-3-hydroxybutanoate [(R)-CHBE] (>99% e.e.) with recombinant E. coli CCZU-A13. Compared with pure glucose, the hydrolyzates could promote both initial reaction rate and the intracellular NADH content. Furthermore, emulsifier OP-10 (20mM) was employed to improve the reductase activity. Moreover, Hp-β-cyclodextrin (0.01mol Hp-β-cyclodextrin/mol COBE) was also added into this bioreaction system for enhancing the biosynthesis of (R)-CHBE from COBE by E. coli CCZU-A13 whole-cells. The yield of (R)-CHBE (>99% e.e.) from 800mM COBE was obtained at 100% in the [Bmim]PF6-hydrolyzate (50:50, v/v) media by supplementation of OP-10 (20mM) and Hp-β-CD (8mM). In conclusion, an effective strategy for the biosynthesis of (R)-CHBE was successfully demonstrated. PMID:27155796

  8. Planck early results. II. The thermal performance of Planck

    DEFF Research Database (Denmark)

    Bréelle, E.; Bucher, M.; Delabrouille, J.;

    2011-01-01

    detector technologies with widely different temperature and cooling needs. Active coolers could satisfy these needs; a helium cryostat, as used by previous cryogenic space missions (IRAS, COBE, ISO, Spitzer, AKARI), could not. Radiative cooling is provided by three V-groove radiators and a large telescope...

  9. Cosmic background radiation anisotropy in an open inflation, cold dark matter cosmogony

    Science.gov (United States)

    Kamionkowski, Marc; Ratra, Bharat; Spergel, David N.; Sugiyama, Naoshi

    1994-01-01

    We compute the cosmic background radiation anisotropy, produced by energy-density fluctuations generated during an early epoch of inflation, in an open cosmological model based on the cold dark matter scenario. At Omega(sub 0) is approximately 0.3-0.4, the Cosmic Background Explorer (COBE) normalized open model appears to be consistent with most observations.

  10. Simulation on stern-rudder independent control for submarine motion in vertical plane%尾舵独立控制的潜艇垂直面运动仿真

    Institute of Scientific and Technical Information of China (English)

    颜俐; 许建; 马运义

    2013-01-01

    To independent control the submarine depth and trim,a fuzzy control method on stern-rudder is proposed,and the advantage of single stern-rudder in low noise control is elaborated.According to the character of single stern-rudder,the fuzzy controller is designed.The simulation result showed that the algorithm had very good control precision,which decreased the rudder and radiated noise greatly.%提出一种由尾舵独立控制潜艇深度和纵倾的模糊控制方法,阐述单尾舵在低噪声控制中的优势.针对单尾舵控制特点,设计了模糊控制器.仿真结果表明,该算法具有很好的控制精度,能大大降低潜艇的打舵噪声和辐射噪声.

  11. Tests of the particle physics-physical cosmology interface

    International Nuclear Information System (INIS)

    Three interrelated interfaces of particle physics and physical cosmology are discussed: (1) inflation and other phase transitions; (2) Big Bang Nucleosynthesis (and also the quark-hadron transition); and (3) structure formation (including dark matter). Recent observations that affect each of these topics are discussed. Topic number 1 is shown to be consistent with the COBE observations but not proven and it may be having problems with some age-expansion data. Topic number 2 has now been well-tested and is an established ''pillar'' of the Big Bang. Topic number 3 is the prime arena of current physical cosmological activity. Experiments to resolve the current exciting, but still ambiguous, situation following the COBE results are discussed

  12. Gravity's rainbow

    CERN Document Server

    Smoot, G F; Smoot, George F.; Steinhardt, Paul J.

    1993-01-01

    Could COBE DMR be detecting the imprint from a spectrum of gravitational waves generated during inflation? The conventional inflationary prediction had been that the cosmic microwave anisotropy is dominated by energy density fluctuations generated during inflation and that the gravitational waves contribute negligibly. In this paper, we report on recent work (in collaboration with R. Davis, H. Hodges, and M. Turner) that has shown that the conventional wisdom may be wrong; specifically, gravitational waves may dominate the anisotropy in inflationary models where the spectrum of perturbations deviates significantly from scale invariance (e.g., extended and power-law inflation models and extreme versions of chaotic inflation). If gravitational waves do dominate at the large-angular scales measured by COBE DMR, the expectation and interpretation of anisotropies on small-angular scales is profoundly altered. Invited Paper for Proceedings of the Journees Relativistes, Amsterdam, May 14-16, 1992

  13. From the Big Bang to the Nobel Prize and the JWST

    Science.gov (United States)

    Mather, John C.

    2007-01-01

    I will describe the history of the universe, from the Big Bang to 2013, when the JWST is to be launched to look back towards our beginnings. I will discuss how the COBE results led to the Nobel Prize, how the COBE results have been confirmed and extended, and their implications for future observations. The James Webb Space Telescope will be used to examine every part of our history from the first stars and galaxies to the formation of individual stars and planets and the delivery of life-supporting materials to the Earth. I will describe the plans for the JWST and how observers may use it. With luck, the JWST may produce a Nobel Prize for some discovery we can only guess today.

  14. Structure formation from supersymmetric inflation

    International Nuclear Information System (INIS)

    Recently a supersymmetric inflationary potential was proposed by Ross and Sarkar, (OUTP-95-15p) which when normalised to COBE requires the inflationary scale to be about 3x1014 GeV, implying a reheating temperature of the order of 105 GeV. This is below the upper limit derived from considerations on the thermal generation of unstable gravitinos and their effects on primordial nucleosynthesis, but high enough to allow baryogenesis after inflation. In this project we investigate the consequences for structure formation given by the proposed potential. We calculate the form of the power spectrum normalized to COBE and obtain the theoretical predictions for observations of the distribution of galaxies and clusters of galaxies and the local streaming motion of galaxies. We find agreement with observations. (author)

  15. Tests of the particle physics-physical cosmology interface

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N. (Chicago Univ., IL (United States) Fermi National Accelerator Lab., Batavia, IL (United States))

    1993-01-01

    Three interrelated interfaces of particle physics and physical cosmology are discussed: (1) inflation and other phase transitions; (2) Big Bang Nucleosynthesis (and also the quark-hadron transition); and (3) structure formation (including dark matter). Recent observations that affect each of these topics are discussed. Topic number 1 is shown to be consistent with the COBE observations but not proven and it may be having problems with some age-expansion data. Topic number 2 has now been well-tested and is an established pillar'' of the Big Bang. Topic number 3 is the prime arena of current physical cosmological activity. Experiments to resolve the current exciting, but still ambiguous, situation following the COBE results are discussed.

  16. Tests of the particle physics-physical cosmology interface

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N. [Chicago Univ., IL (United States)]|[Fermi National Accelerator Lab., Batavia, IL (United States)

    1993-01-01

    Three interrelated interfaces of particle physics and physical cosmology are discussed: (1) inflation and other phase transitions; (2) Big Bang Nucleosynthesis (and also the quark-hadron transition); and (3) structure formation (including dark matter). Recent observations that affect each of these topics are discussed. Topic number 1 is shown to be consistent with the COBE observations but not proven and it may be having problems with some age-expansion data. Topic number 2 has now been well-tested and is an established ``pillar`` of the Big Bang. Topic number 3 is the prime arena of current physical cosmological activity. Experiments to resolve the current exciting, but still ambiguous, situation following the COBE results are discussed.

  17. Bounds on QCD axion mass and primordial magnetic field from CMB $\\mu$-distortion

    CERN Document Server

    Ejlli, Damian

    2014-01-01

    Oscillation of CMB photons into axions can cause CMB spectral distortion in presence of large scale magnetic fields. With COBE limit on $\\mu$ parameter and homogeneous magnetic field strength $B\\lesssim 3.2$ nG at horizon scale, constraint on axion mass is found to be $4.8\\times 10^{-5}$ eV $\\lesssim m_a$ for the KSVZ axion model. On the other hand using experimental limit on axion mass $3.5\\times 10^{-6}$ eV $\\lesssim m_a$ from ADMX experiment together with COBE $\\mu$ bound, is found $B\\lesssim 53$ nG (KSVZ axion model) and $B\\lesssim 141$ nG (DFSZ axion model) for homogeneous magnetic field with coherence length at present $\\lambda_B\\sim 1.3$ Mpc. Limits on $B$ and $m_a$ for PIXIE/PRISM expected bound on $\\mu$ are derived.

  18. Can the Local Supercluster explain the low CMB multipoles?

    OpenAIRE

    Abramo, L. Raul; Sodre Jr., L.

    2003-01-01

    We show that the thermal Sunyaev-Zeldovich effect caused by hot electrons in the Local Supercluster (LSC) can explain the abnormal quadrupole and octopole of the cosmic microwave background (CMB) that were measured by WMAP and COBE. The distortion needed to account for the low observed quadrupole is a spot in the direction of the LSC with a temperature decrease of order \\Delta T \\approx - 7 \\mu K for \

  19. Quantum Gravity Scenario of Inflation based on the CMB Anisotropies

    CERN Document Server

    Hamada, K; Hamada, Ken-ji; Yukawa, Tetsuyuki

    2004-01-01

    Inflationary scenario based on a renormalizable model of conformal gravity is proposed and primordial spectrum is derived. The sharp fall off of the angular power spectra at low multipoles in the COBE and WMAP observations are explained by a dynamical scale of quantum gravity. At this scale, the universe would make a sharp transition from the quantum spacetime with conformal invariance to the classical spacetime.

  20. The Cosmic Microwave Background Anisotropy Experiments

    OpenAIRE

    Smoot, George F.

    1997-01-01

    This paper reports a summary of the contents contents of six hours of lectures on the CMB anisotropy experiments given at the Strasbourg NATO school on the CMB and cosmology. (Its companion paper, astro-ph/9705101 reports the lectures on the CMB spectrum.) A context is set as a bridge from the theoretical CMB anisotropy lectures and the experimental situation. The COBE DMR results are reveiwed in detail and as pioneer for future space missions. Current and planned experiments are discussed in...

  1. CMB Experiment Baseline Determination by Minimizing Pixel Observations Dispersion

    OpenAIRE

    Smoot, George F.

    1997-01-01

    This paper discusses a couple of approaches to removing instrument gain and baseline variation from observations of the CMB anisotropy. These techniques were tested on the COBE DMR data, a balloon experiment, and by monte carlo simulations. This work, though considered technical, is made available because CMB anisotropy mapping data processing is currently very active and a significant number of groups are working on this issue. Specifically, time-ordered estimates of the gain and baseline vi...

  2. Constraining topology with the CMB

    CERN Document Server

    De Oliveira-Costa, A; Starobinsky, A A; Oliveira-Costa, Angelica de; Smoot, George F.; Starobinsky, Alexei A.

    1997-01-01

    We present a new data analysis method to study rectangular T^3 ``small universes" with one or two of its dimensions significantly smaller than the present horizon (which we refer to as T^1- and T^2-models, respectively). We find that the 4 year COBE/DMR data set a lower limit on the smallest cell size for T^1- and T^2-models of 3000h^{-1} Mpc, at 95% confidence, for a scale invariant power spectrum (n=1).

  3. Contribution of Extragalactic Infrared Sources to CMB Foreground Anisotropy

    OpenAIRE

    Gawiser, Eric; Smoot, George F.

    1996-01-01

    We estimate the level of confusion to Cosmic Microwave Background anisotropy measurements caused by extragalactic infrared sources. CMB anisotropy observations at high resolution and high frequencies are especially sensitive to this foreground. We use data from the COBE satellite to generate a Galactic emission spectrum covering mm and sub-mm wavelengths. Using this spectrum as a template, we predict the microwave emission of the 5319 brightest infrared galaxies seen by IRAS. We simulate skym...

  4. The large-scale polarization of the microwave background and foreground

    OpenAIRE

    de Oliveira-Costa, Angelica; Tegmark, Max; O'Dell, Chris; Keating, Brian; Timbie, Peter; Efstathiou, George; Smoot, George

    2002-01-01

    The DASI discovery of CMB polarization has opened a new chapter in cosmology. Most of the useful information about inflationary gravitational waves and reionization is on large angular scales where Galactic foreground contamination is the worst, so a key challenge is to model, quantify and remove polarized foregrounds. We use the POLAR experiment, COBE/DMR and radio surveys to provide the strongest limits to date on the TE cross power spectrum of the CMB on large angular scales and to quantif...

  5. Gravity's rainbow

    OpenAIRE

    Smoot, George F.; Steinhardt, Paul J.

    1992-01-01

    Could COBE DMR be detecting the imprint from a spectrum of gravitational waves generated during inflation? The conventional inflationary prediction had been that the cosmic microwave anisotropy is dominated by energy density fluctuations generated during inflation and that the gravitational waves contribute negligibly. In this paper, we report on recent work (in collaboration with R. Davis, H. Hodges, and M. Turner) that has shown that the conventional wisdom may be wrong; specifically, gravi...

  6. Temperature Fluctuation and an Expected Limit of Hubble Parameter in the Self-Consistent Model

    OpenAIRE

    Morcos, A. B.

    2004-01-01

    The temperature gradient of microwave background radiation (CMBR) is calculated in the Self Consistent Model. An expected values for Hubble parameter have been presented in two different cases. In the first case the temperature is treated as a function of time only, while in the other one the temperature depends on relaxation of isotropy condition in the self-consistent model and the assumption that the universe expands adiabatically. The COBE's or WMAP's fluctuations in temperature of CMBR m...

  7. Improved Ways to Compare Simulations to Data

    OpenAIRE

    Primack, Joel R.

    1995-01-01

    Theoretical models for structure formation with Gaussian initial fluctuations have been worked out in considerable detail and compared with observations on various scales. It is on nonlinear scales $\\lsim 10 \\ h^{-1}\\ {\\rm Mpc}$ that the greatest differences exist between $\\Omega=1$ models that have been normalized to agree on the largest scales with the COBE data; here especially there is a need for better statistical tests which are simultaneously {\\it robust}, {\\it discriminatory}, and {\\i...

  8. Cosmological Perturbations of Quantum-Mechanical Origin and Anisotropy of the Microwave Background

    CERN Document Server

    Grishchuk, L P

    1993-01-01

    Cosmological perturbations generated quantum-mechanically (as a particular case, during inflation) possess statistical properties of squeezed quantum states. The power spectra of the perturbations are modulated and the angular distribution of the produced temperature fluctuations of the CMBR is quite specific. An exact formula is derived for the angular correlation function of the temperature fluctuations caused by squeezed gravitational waves. The predicted angular pattern can, in principle, be revealed by the COBE-type observations.

  9. Utilization of Guided Bone Regeneration Techniqes in Treatment of a Single Tooth Missing with Implant Supported Crown

    OpenAIRE

    Adamczyk, E.; Gladkowski, J.; Machnikowski, I.; Mierzwinska, E.; Spiechowicz, E.; Feder, T.; Wojtowicz, A.; Matenko, D.; Ciechowicz, K.

    2002-01-01

    Guided bone regeneration is developing very dynamically in dental surgery and in implantology. It relies on building up bone in places where it is lacking, utilizing a variety of grafting materials. Methods of guided bone regeneration utilize biological materials or synthetic specimens. The use of autogenous platelets rich plasma derived in the thromboforetic process (COBE spectra system) allows the employment of growth factors, which blood platelets contain in the formation of new bone tissu...

  10. Assessing community perspectives of the community based education and service model at Makerere University, Uganda: a qualitative evaluation

    OpenAIRE

    Okullo Isaac; Oria Hussein; Mwanika Andrew; Kaye Dan; Burnham Gilbert; Plover Colin M; Mbalinda Scovia N; Muhwezi Wilson; Groves Sara

    2011-01-01

    Abstract Background Community partnerships are defined as groups working together with shared goals, responsibilities, and power to improve the community. There is growing evidence that these partnerships contribute to the success and sustainability of community-based education and service programs (COBES), facilitating change in community actions and attitudes. Makerere University College of Health Sciences (MakCHS) is forging itself as a transformational institution in Uganda and the region...

  11. Local Pancake Defeats Axis of Evil

    OpenAIRE

    Vale, Chris

    2005-01-01

    Among the biggest surprises revealed by COBE and confirmed by WMAP measurements of the temperature anisotropy of the CMB are the anomalous features in the 2-point angular correlation function on very large angular scales. In particular, the $\\ell = 2$ quadrupole and $\\ell = 3$ octopole terms are surprisingly planar and aligned with one another, which is highly unlikely for a statistically isotropic Gaussian random field, and the axis of the combined low-$\\ell$ signal is perpendicular to eclip...

  12. A tilted cold dark matter cosmological scenario

    Science.gov (United States)

    Cen, Renyue; Gnedin, Nickolay Y.; Kofman, Lev A.; Ostriker, Jeremiah P.

    1992-01-01

    A new cosmological scenario based on CDM but with a power spectrum index of about 0.7-0.8 is suggested. This model is predicted by various inflationary models with no fine tuning. This tilted CDM model, if normalized to COBE, alleviates many problems of the standard CDM model related to both small-scale and large-scale power. A physical bias of galaxies over dark matter of about two is required to fit spatial observations.

  13. Effective pretreatment of sugarcane bagasse with combination pretreatment and its hydrolyzates as reaction media for the biosynthesis of ethyl (S)-4-chloro-3-hydroxybutanoate by whole cells of E. coli CCZU-K14.

    Science.gov (United States)

    He, Yu-Cai; Zhang, Dan-Ping; Di, Jun-Hua; Wu, Yin-Qi; Tao, Zhi-Cheng; Liu, Feng; Zhang, Zhi-Jun; Chong, Gang-Gang; Ding, Yun; Ma, Cui-Luan

    2016-07-01

    In this study, sugarcane bagasse (SB) was pretreated with combination pretreatment (e.g., sequential KOH extraction and ionic liquid soaking, sequential KOH extraction and Fenton soaking, or sequential KOH extraction and glycerol soaking). After the enzymatic hydrolysis of pretreated SBs, it was found that all these three concentrated hydrolyzates could be used for the asymmetric bioreduction of ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl (S)-4-chloro-3-hydroxybutanoate [(S)-CHBE]. Compared with glucose, arabinose and cellobiose couldn't promote the initial reaction rate, and xylose could increase the intracellular NADH content. Moreover, it was the first report that hydrolyzates could be used for the effective biosynthesis of (S)-CHBE (∼500g/L; 98.0% yield) from 3000 COBE by whole cells of Escherichia coli CCZU-K14 in the presence of β-CD (0.4mol β-CD/mol COBE), l-glutamine (200mM) and glycine (500mM). In conclusion, it is a new alternative to utilize bioresource for the synthesis of key chiral intermediate (S)-CHBE. PMID:27060248

  14. From the Big Bang to the Nobel Prize and on to James Webb Space Telescope

    Science.gov (United States)

    Mather, John C.

    2009-01-01

    The history of the universe in a nutshell, from the Big Bang to now, and on to the future - John Mather will tell the story of how we got here, how the Universe began with a Big Bang, how it could have produced an Earth where sentient beings can live, and how those beings are discovering their history. Mather was Project Scientist for NASA s Cosmic Background Explorer (COBE) satellite, which measured the spectrum (the color) of the heat radiation from the Big Bang, discovered hot and cold spots in that radiation, and hunted for the first objects that formed after the great explosion. He will explain Einstein s biggest mistake, show how Edwin Hubble discovered the expansion of the universe, how the COBE mission was built, and how the COBE data support the Big Bang theory. He will also show NASA s plans for the next great telescope in space, the James Webb Space Telescope. It will look even farther back in time than the Hubble Space Telescope, and will look inside the dusty cocoons where stars and planets are being born today. Planned for launch in 2013, it may lead to another Nobel Prize for some lucky observer.

  15. From the Big Bang to the Nobel Prize and on to the James Webb Space Telescope

    Science.gov (United States)

    Mather, John C.

    2008-01-01

    The history of the universe in a nutshell, from the Big Bang to now. and on to the future - John Mather will tell the story of how we got here, how the Universe began with a Big Bang, how it could have produced an Earth where sentient beings can live, and how those beings are discovering their history. Mather was Project Scientist for NASA's Cosmic Background Explorer (COBE) satellite, which measured the spectrum (the color) of the heat radiation from the Big Bang, discovered hot and cold spots in that radiation, and hunted for the first objects that formed after the great explosion. He will explain Einstein's biggest mistake, show how Edwin Hubble discovered the expansion of the univerre, how the COBE mission was built, and how the COBE data support the Big Bang theory. He will also show NASA's plans for the next great telescope in space, the Jarnes Webb Space Telescope. It will look even farther back in time than the Hubble Space Telescope, and will look inside the dusty cocoons where rtars and planets are being born today. Planned for launch in 2013, it may lead to another Nobel Prize for some lucky observer.

  16. Polimerinių implantų, skirtų širdies ir kraujagyslių chirurgijai, formavimas tiesioginio lazerinio rašymo metodu

    Directory of Open Access Journals (Sweden)

    Paulius DANILEVIČIUS

    2012-06-01

    Full Text Available Per pastaruosius porą dešimtmečių sparčiai tobulėja tiesioginio lazerinio rašymo, paremto selektyviai tūryje lokalizuota fotojautrios medžiagos modifikacija, technologija, skirta trimačių mikro- ir nanostruktūrizuotų polimerinių darinių gamybai. Šiame darbe pristatoma galimybė tiesioginio lazerinio rašymo būdu formuoti didelių matmenų (iki cm3 eilės mikroporėtus kamieninėms ląstelėms auginti skirtus karkasus, kurie gali būti taikomi ir širdies bei kraujagyslių chirurgijoje. Lyginant įvairių impulsų trukmių lazerines spinduliuotes, nustatyta, kad, naudojant femtosekundinius lazerius ir derinant spinduliuotės intensyvumą, galima labiau modifikuoti formavimo skyrą, tačiau audinių inžinerijai reikalingai darinių kokybei pasiekti tinka ir pikosekundiniai lazeriai.Tai sudaro palankesnes sąlygas ateityje diegti pigesnes, praktiniams taikymams skirtas tiesioginio lazerinio rašymo polimeruose sistemas.  Karkasų gamybai naudotos keturios skirtingos medžiagos – hibridiniai organiniai-neorganiniai polimerai SZ2080 ir „Ormoclear“, biologiškai skaidus PEG-DA-258 bei akrilatinis AKRE. In vitro ir in vivo tyrimais nustatyta, kad visi keturi polimerai yra biologiškai sutaikomi, nepasižymi citotoksiškumu, todėl gali būti naudojami audinių inžinerijoje. Adekvačių karkasų gamybos našumui paspartinti buvo pritaikytas replikavimas PDMS minkštąja litografija. Tai leido 2 % tikslumu atkartoti replikuojamo darinio paviršiaus šiurkštumą bei keliomis eilėmis sutrumpinti 15´15 mm2 ploto pavyzdinių dvimačių karkasų gamybos trukmę. Taip pat pateikiama suformuotų trimačių polimerinių karkasų pavyzdžių, kurie yra pakankamai didelių matmenų, kad būtų tinkami praktiškai naudoti chirurgijoje. Jų geometrija ir mikrostruktūrizavimo kokybė įvertinta elektronų skenuojamuoju elektroniniu mikroskopu. Šie tiesioginio lazerinio rašymo būdu gauti dirbtiniai karkasai išsiskiria tiksliai

  17. On the Nature of the Microwave Background at the Lagrange 2 Point. Part II

    Directory of Open Access Journals (Sweden)

    Borissova L.

    2007-10-01

    Full Text Available In this work the mathematical methods of General Relativity are used to answer the following questions: if a microwave background originates from the Earth, what would be its density and associated dipole measured at the altitude of a U2 aeroplane (25 km, the COBE satellite (900 km, and the 2nd Lagrange point (1.5 million km, the position of the WMAP and PLANCK satellites? The first problem is solved via Einstein’s equations for the electromagnetic field of the Earth. The second problem is solved using the geodesic equations for light-like particles (photons which are mediators for electromagnetic radiation. We have determined that a microwave background that originates at the Earth (the Earth microwave background decreases with altitude so that the density of the energy of such a background at the altitude of the COBE orbit (900 km is 0.68 times less than that at the altitude of a U2 aeroplane. The density of the energy of the background at the L2 point is only ~1E-7 of the value detected by a U2 aeroplane or at the COBE orbit. The dipole anisotropy of the Earth microwave background, due to the rapid motion of the Earth relative to the source of another field which isn’t connected to the Earth but is located in depths of the cosmos, doesn’t depend on altitute from the surface of the Earth. Such a dipole will be the same irrespective of the position at which measurements are taken.

  18. Comparison of plateletpheresis on three continuous flow cell separators

    Directory of Open Access Journals (Sweden)

    Tendulkar Anita

    2009-01-01

    Full Text Available Introduction: Platelet concentrate (PC remains one of the most important support measures in thrombocytopenic patients. An efficient cell separator is a prerequisite for an optimally functioning apheresis setup. Donor blood count may undergo a temporary reduction after the procedure. Aim: The aim was to find the extent of reduction in donor blood count (hemoglobin, hematocrit, white blood cell, and platelet after plateletpheresis and to evaluate the cell separator for collection efficiency, processing time, and leukoreduction. Study Design and Methods: Two hundred and thirty seven procedures performed on the Amicus (N = 121, Fenwal CS-3000 Plus (N = 50 and Cobe spectra (N = 66 in a one year period were evaluated. The procedures performed on the continuous flow centrifugation (CFC cell separators and donor blood counts (pre and post donation done were included in the study. Results: The percent reduction in hemoglobin (HB, hematocrit (HCT, white blood cell (WBC and platelet count ((PLT ct was 2.9, 3.1, 9, 30.7 (Mean, N = 237 respectively after the procedure. The post donation PLT ct reduced to < 100x109/L (range 80-100 in five donors (N = 5/237, Amicus. The pre donation PLT ct in them was 150-200x109/L. Collection efficiency (percent of Amicus (79.3 was better as compared to the other two machines (CS: 62.5, Cobe: 57.5. PC collected on Cobe spectra had < 1x106 WBC. The donor pre donation PLT levels had a positive correlation to the product PLT yield (r = 0.30, P = 0.000. Conclusion: Monitoring donor blood counts helps to avoid pheresis induced adverse events. A cautious approach is necessary in donors whose pre donation PLT ct is 150-200x109/L. The main variable in PLT yield is donor PLT ct (pre donation. High collection efficiency is a direct measure of an optimally functioning cell separator.

  19. X-ray clusters from a high-resolution hydrodynamic PPM simulation of the cold dark matter universe

    Science.gov (United States)

    Bryan, Greg L.; Cen, Renyue; Norman, Michael L.; Ostriker, Jermemiah P.; Stone, James M.

    1994-01-01

    A new three-dimensional hydrodynamic code based on the piecewise parabolic method (PPM) is utilized to compute the distribution of hot gas in the standard Cosmic Background Explorer (COBE)-normalized cold dark matter (CDM) universe. Utilizing periodic boundary conditions, a box with size 85 h(exp-1) Mpc, having cell size 0.31 h(exp-1) Mpc, is followed in a simulation with 270(exp 3)=10(exp 7.3) cells. Adopting standard parameters determined from COBE and light-element nucleosynthesis, Sigma(sub 8)=1.05, Omega(sub b)=0.06, we find the X-ray-emitting clusters, compute the luminosity function at several wavelengths, the temperature distribution, and estimated sizes, as well as the evolution of these quantities with redshift. The results, which are compared with those obtained in the preceding paper (Kang et al. 1994a), may be used in conjuction with ROSAT and other observational data sets. Overall, the results of the two computations are qualitatively very similar with regard to the trends of cluster properties, i.e., how the number density, radius, and temeprature depend on luminosity and redshift. The total luminosity from clusters is approximately a factor of 2 higher using the PPM code (as compared to the 'total variation diminishing' (TVD) code used in the previous paper) with the number of bright clusters higher by a similar factor. The primary conclusions of the prior paper, with regard to the power spectrum of the primeval density perturbations, are strengthened: the standard CDM model, normalized to the COBE microwave detection, predicts too many bright X-ray emitting clusters, by a factor probably in excess of 5. The comparison between observations and theoretical predictions for the evolution of cluster properties, luminosity functions, and size and temperature distributions should provide an important discriminator among competing scenarios for the development of structure in the universe.

  20. Textures for neutrino mass matrices

    International Nuclear Information System (INIS)

    We give a classification of heavy Majorana neutrino mass matrices with up to three texture zeros, assuming the Dirac masses of the neutrinos to be of the same form as the ones of the up quarks in the five texture zero solutions for the quark matrices. This is the case for many unified and partially unified models. We find that it is possible to have solutions which account for the solar and atmospheric neutrino problems as well as the COBE observations simultaneously, and we motivate the existence of such solutions from symmetries. copyright 1996 The American Physical Society

  1. Exact Solution in the New Inflation Scenario with Induced Gravity

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-Fu

    2001-01-01

    Taking the Hubble parameter directly as a function of the scalar field instead of as a function of time,H = H( ), we present a new exact solution in the new inflation model with induced gravity. This includes solution which is inflation for end, and develops smoothly towards radiation-like evolution for ≥ end. The inflation is driven by the evolution of the field with inflation potential, V( ) = λ 2 v2)2.density, ns, is computed and ns lies well inside the limits set by the cosmic background explorer (COBE) satellite.the dex of the scalar effective cosmological constant Aeff tends to zero when inflation ends.``

  2. Open and closed CDM isocurvature models contrasted with the CMB data

    CERN Document Server

    Enqvist, Kari; Valiviita, J; Enqvist, Kari; Kurki-Suonio, Hannu; Valiviita, Jussi

    2002-01-01

    We consider pure isocurvature CDM models in the case of open and closed universe. We allow for a large spectral tilt and scan the 6-dimensional parameter space for the best fit to the COBE, Boomerang, and Maxima-1 data. Taking into account constraints from large-scale structure and big bang nucleosynthesis, we find a best fit with $\\chi^2 = 121$, which is to be compared to $\\chi^2 = 44$ of a flat adiabatic reference model. Hence the current data strongly disfavour pure isocurvature perturbations.

  3. Cosmic microwave background probes models of inflation

    Science.gov (United States)

    Davis, Richard L.; Hodges, Hardy M.; Smoot, George F.; Steinhardt, Paul J.; Turner, Michael S.

    1992-01-01

    Inflation creates both scalar (density) and tensor (gravity wave) metric perturbations. We find that the tensor-mode contribution to the cosmic microwave background anisotropy on large-angular scales can only exceed that of the scalar mode in models where the spectrum of perturbations deviates significantly from scale invariance. If the tensor mode dominates at large-angular scales, then the value of DeltaT/T predicted on 1 deg is less than if the scalar mode dominates, and, for cold-dark-matter models, bias factors greater than 1 can be made consistent with Cosmic Background Explorer (COBE) DMR results.

  4. Brane in the Relativistic Theory of Gravitation

    CERN Document Server

    Naboulsi, R

    2003-01-01

    It was proven that Logunov RTG predicts a cyclic Universe with no singularities. It is shown in this paper that an additional exotic density term will not affect this important characteristic of the Universe evolution. We assume that this later varies with time according to the law m^2 propto frac{dot{R}^2}{R}. The graviton mass and the density term are of order of Hubble's constant. The classical Einstein's cosmological parameter is excluded to converse the logical structure of the RTG. The age of the Universe and the deceleration parameter agree with recent observational data from BOOMERANG, MAXIMA and COBE.

  5. Strong constraint on ever-present Λ

    International Nuclear Information System (INIS)

    We show that the causal-set approach to creating an ever-present cosmological 'constant' in the expanding universe is strongly constrained by the isotropy of the microwave background. Fluctuations generated by stochastic lambda generation which are consistent with COBE and WMAP observations are far too small to dominate the expansion dynamics at z<1000 and so cannot explain the observed late-time acceleration of the universe. We also discuss other observational constraints from the power spectrum of galaxy clustering and show that the theoretical possibility of ever-present lambda arises only in 3+1 dimensional space-times

  6. A Strong Constraint on Ever-Present Lambda

    CERN Document Server

    Barrow, J D

    2006-01-01

    We show that the causal set approach to creating an ever-present cosmological 'constant' in the expanding universe is strongly constrained by the isotropy of the microwave background. Fluctuations generated by stochastic lambda generation which are consistent with COBE and WMAP observations are far too small to dominate the expansion dynamics at z<1000 and so cannot explain the observed late-time acceleration of the universe. We also discuss other observational constraints from the power spectrum of galaxy clustering and show that the theoretical possibility of ever-present lambda arises only in 3+1 dimensional space-times.

  7. Disponibilidade hídrica, radiação solar e fotossíntese em videiras 'Cabernet Sauvignon' sob cultivo protegido Water supply, solar radiation and photosynthesis in 'Cabernet Sauvignon' grapevines under plastic covering

    OpenAIRE

    Clenilso Sehnen Mota; Cassandro Vidal Talamini do Amarante; Henrique Pessoa dos Santos; Jackson Adriano Albuquerque

    2009-01-01

    O objetivo deste trabalho foi avaliar os efeitos da cobertura de videira 'Cabernet Sauvignon' com lona plástica translúcida sobre a disponibilidade de luz e água, a concentração foliar de clorofila e a fotossíntese. As plantas com cinco anos de idade foram conduzidas em sistema 'Y' sobre porta-enxerto Paulsen 1103. O experimento seguiu o delineamento em blocos ao acaso, com dois tratamentos (plantas sem e com cobertura plástica) e quatro repetições de 15 plantas (unidade experimental). A cobe...

  8. A measurement of Omega from the North American test flight of Boomerang

    International Nuclear Information System (INIS)

    We use the power spectrum of the Cosmic Microwave Background, measured during the North American test flight of the BOOMERANG experiment, to constrain the geometry of the universe. Within the class of Cold Dark Matter models, we find the overall fractional energy density of the universe, Omega, is constrained to be 0.85 < or = Omega < or = 1.25 at the 68 percent confidence level. Combined with the COBE measurement and the high redshift supernovae data we obtain new constraints on the fractional matter density and the cosmological constant

  9. A measurement of $\\Omega$ from the North American test flight of BOOMERANG

    CERN Document Server

    Melchiorri, A; De Bernardis, P; Bock, J J; Borrill, J; Boscaleri, A; Crill, B P; De Troia, G; Farese, P; Ferreira, P G; Ganga, K; De Gasperis, G; Giacometti, M; Hristov, V V; Jaffe, A H; Lange, A E; Masi, S; Mauskopf, P D; Miglio, L; Netterfield, C B; Pascale, E; Piacentini, F; Romeo, G

    2000-01-01

    We use the angular power spectrum of the Cosmic Microwave Background, measured during the North American test flight of the BOOMERANG experiment, to constrain the geometry of the universe. Within the class of Cold Dark Matter models, we find that the overall fractional energy density of the universe, Omega, is constrained to be 0.85 < Omega < 1.25 at the 68% confidence level. Combined with the COBE measurement and the high redshift supernovae data we obtain new constraints on the fractional matter density and the cosmological constant.

  10. A measurement of Omega from the North American test flight of Boomerang

    Energy Technology Data Exchange (ETDEWEB)

    Melchiorri, A.; Ade, P.A.R.; De Bernardis, P.; Bock, J.J.; Borrill, J.; Boscaleri, A.; Crill, B.P.; De Troia, G.; Farese, P.; Ferreira, P.G.; Ganga, K.; de Gasperis, G.; Giacometti, M.; Hristov, V.V.; Jaffe, A.H.; Lange, A.E.; Masi, S.; Mauskopf, P.D.; Miglio, L.; Netterfield, C.B.; Pascale, E.; Piacentini, F.; Romeo, G.; Ruhl, J.E.; Vittorio, N.

    1999-11-01

    We use the power spectrum of the Cosmic Microwave Background, measured during the North American test flight of the BOOMERANG experiment, to constrain the geometry of the universe. Within the class of Cold Dark Matter models, we find the overall fractional energy density of the universe, Omega, is constrained to be 0.85 < or = Omega < or = 1.25 at the 68 percent confidence level. Combined with the COBE measurement and the high redshift supernovae data we obtain new constraints on the fractional matter density and the cosmological constant.

  11. Some Heuristics and Results for Small Cycles of the Discrete Logarithm

    OpenAIRE

    Holden, Joshua; Moree, Pieter

    2004-01-01

    Brizolis asked the question: does every prime p have a pair (g,h) such that h is a fixed point for the discrete logarithm with base g? The first author previously extended this question to ask about not only fixed points but also two-cycles, and gave heuristics (building on work of Zhang, Cobeli, Zaharescu, Campbell, and Pomerance) for estimating the number of such pairs given certain conditions on g and h. In this paper we extend these heuristics and prove results for some of them, building ...

  12. New Conjectures and Results for Small Cycles of the Discrete Logarithm

    OpenAIRE

    Holden, Joshua; Moree, Pieter

    2003-01-01

    Brizolis asked the question: does every prime p have a pair (g,h) such that h is a fixed point for the discrete logarithm with base g? The first author previously extended this question to ask about not only fixed points but also two-cycles, and gave heuristics (building on work of Zhang, Cobeli, Zaharescu, Campbell, and Pomerance) for estimating the number of such pairs given certain conditions on $g$ and $h$. In this paper we give a summary of conjectures and results which follow from these...

  13. Distribution of the Error in Estimated Numbers of Fixed Points of the Discrete Logarithm

    OpenAIRE

    Holden, Joshua

    2004-01-01

    Brizolis asked the question: does every prime p have a pair (g,h) such that h is a fixed point for the discrete logarithm with base g? The author and Pieter Moree, building on work of Zhang, Cobeli, and Zaharescu, gave heuristics for estimating the number of such pairs and proved bounds on the error in the estimates. These bounds are not descriptive of the true situation, however, and this paper is a first attempt to collect and analyze some data on the distribution of the actual error in the...

  14. Evaluation of expert systems - An approach and case study. [of determining software functional requirements for command management of satellites

    Science.gov (United States)

    Liebowitz, J.

    1985-01-01

    Techniques that were applied in defining an expert system prototype for first-cut evaluations of the software functional requirements of NASA satellite command management activities are described. The prototype was developed using the Knowledge Engineering System. Criteria were selected for evaluating the satellite software before defining the expert system prototype. Application of the prototype system is illustrated in terms of the evaluation procedures used with the COBE satellite to be launched in 1988. The limited number of options which can be considered by the program mandates that biases in the system output must be well understood by the users.

  15. Basic Space Science; United Nations/European Space Agency Workshops for Developing Countries, 2nd, Bogota, Colombia, November 9-13, 1992

    Science.gov (United States)

    Haubold, Hans J. (Editor); Torres, Sergio (Editor)

    1994-01-01

    The conference primarily covered astrophysical and astronomical topics on stellar and solar modeling and processes, high magnetic field influence on stellar spectra, cosmological topics utilizing Cosmic Background Explorer (COBE) data and radioastronomic mapping as well as cosmic gravitational instability calculations, astrometry of open clusters amd solar gravitational focusing, extremely energetic gamma rays, interacting binaries, and balloon-borne instrumentation. Other papers proposed an active Search for Extraterrestrial Intelligence (SETI) communication scheme to neighboring solar-like systems and more direct involvement of and with the public in astronomy and space exploration projects.

  16. On the Nature of the Microwave Background at the Lagrange 2 Point. Part II

    OpenAIRE

    Borissova L.; Rabounski D.

    2007-01-01

    In this work the mathematical methods of General Relativity are used to answer the following questions: if a microwave background originates from the Earth, what would be its density and associated dipole measured at the altitude of a U2 aeroplane (25 km), the COBE satellite (900 km), and the 2nd Lagrange point (1.5 million km, the position of the WMAP and PLANCK satellites)? The first problem is solved via Einstein’s equations for the electromagnetic field of the Earth. The secon...

  17. Assessing community perspectives of the community based education and service model at Makerere University, Uganda: a qualitative evaluation

    Directory of Open Access Journals (Sweden)

    Okullo Isaac

    2011-03-01

    Full Text Available Abstract Background Community partnerships are defined as groups working together with shared goals, responsibilities, and power to improve the community. There is growing evidence that these partnerships contribute to the success and sustainability of community-based education and service programs (COBES, facilitating change in community actions and attitudes. Makerere University College of Health Sciences (MakCHS is forging itself as a transformational institution in Uganda and the region. The College is motivated to improve the health of Ugandans through innovative responsive teaching, provision of service, and community partnerships. Evaluating the COBES program from the community perspective can assist the College in refining an innovative and useful model that has potential to improve the health of Ugandans. Methods A stratified random sample of 11 COBES sites was selected to examine the community’s perception of the program. Key Informant Interviews of 11 site tutors and 33 community members were completed. The data was manually analyzed and themes developed. Results Communities stated the students consistently engaged with them with culturally appropriate behaviour. They rated the student’s communication as very good even though translators were frequently needed. Half the community stated they received some feedback from the students, but some communities interpreted any contact after the initial visit as feedback. Communities confirmed and appreciated that the students provided a number of interventions and saw positive changes in health and health seeking behaviours. The community reflected that some programs were more sustainable than others; the projects that needed money to implement were least sustainable. The major challenges from the community included community fatigue, and poor motivation of community leaders to continue to take students without compensation. Conclusions Communities hosting Makerere students valued the

  18. Ponderable soliton stars and cosmic background radiation

    Science.gov (United States)

    Chiu, Hong-Yee

    1990-01-01

    A theory is developed to describe the possible perturbations of the cosmic background radiation (CBR) by radiation from ponderable soliton stars in the early universe. Since the temperature of such stars is in the range of 10 to the 6th K, thermalization of their emitted radiation is possible. Two models are considered: one in which thermalization is ignored and one in which decoupling from thermalization is considered as a sudden process. The expected perturbation of the CBR is probably less than 1 percent and is largely around the short-wavelength end, in the form of point radio sources. This result is consistent with the most recent COBE measurements.

  19. 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.

  20. Science with CMB spectral distortions

    CERN Document Server

    Chluba, Jens

    2014-01-01

    The measurements of COBE/FIRAS have shown that the CMB spectrum is extremely close to a perfect blackbody. There are, however, a number of processes in the early Universe that should create spectral distortions at a level which is within reach of present day technology. In this talk, I will give a brief overview of recent theoretical and experimental developments, explaining why future measurements of the CMB spectrum will open up an unexplored window to early-universe and particle physics with possible non-standard surprises but also several guaranteed signals awaiting us.

  1. The CMB Dipole: The Most Recent Measurement And Some History

    OpenAIRE

    Lineweaver, Charles H.

    1996-01-01

    The largest anisotropy in the cosmic microwave background (CMB) is the $\\approx 3$ mK dipole assumed to be due to our velocity with respect to the CMB. Over the past ten years the precision of our knowledge of the dipole has increased by a factor of ten. We discuss the most recent measurement of this dipole obtained from the four year COBE Differential Microwave Radiometers (DMR) as reported by Lineweaver \\etal (1996). The inferred velocity of the Local Group is $v_{LG}= 627 \\pm 22$ km/s in t...

  2. The Milky Way, The Local Galaxies \\& the IR Tully-Fisher Relation

    OpenAIRE

    Malhotra, Sangeeta; Spergel, David N.; Rhoads, James E; Jing LI

    1996-01-01

    Using the near infrared fluxes of local galaxies derived from COBE/DIRBE J(1.25 $\\mu$m) K (2.2 $\\mu$m) \\& L (3.5 $\\mu$m) band maps and published Cepheid distances, we construct Tully-Fisher (TF) diagrams for the nearby galaxies. The measured dispersions in these luminosity-linewidth diagrams are remarkably small: $\\sigma_J = 0.09$ magnitudes, $\\sigma_K = 0.13$ magnitudes, and $\\sigma_L = 0.20$ magnitudes. For the J and K bands, Monte Carlo simulations give a 95\\% confidence interval upper lim...

  3. Estimación de variables dasométricas del bosque templado de Hidalgo, México mediante datos espectrales y del Inventario Nacional Forestal.

    OpenAIRE

    Muñoz RuIz, Miguel Ángel

    2012-01-01

    Los métodos basados en la percepción remota son herramientas importantes para la medición de variables biofísicas del bosque a un costo menor y a una escala espacial y temporal mayor. En este trabajo se analiza la relación existente entre datos del Inventario Nacional Forestal y de Suelos (INFyS) y datos espectrales provenientes de imágenes de la plataforma SPOT correspondientes al bosque templado y bosque mesófilo de Hidalgo, México. Las estimaciones del área basal (AB), volumen (VOL) y cobe...

  4. A Measurement of Omega from the North American Test Flight of Boomerang.

    Science.gov (United States)

    Melchiorri; Ade; de Bernardis P; Bock; Borrill; Boscaleri; Crill; De Troia G; Farese; Ferreira; Ganga; de Gasperis G; Giacometti; Hristov; Jaffe; Lange; Masi; Mauskopf; Miglio; Netterfield; Pascale; Piacentini; Romeo; Ruhl; Vittorio

    2000-06-20

    We use the angular power spectrum of the cosmic microwave background, measured during the North American test flight of the Boomerang experiment, to constrain the geometry of the universe. Within the class of cold dark matter models, we find that the overall fractional energy density of the universe Omega is constrained to be 0.85COBE measurement, the data on degree scales from the Microwave Anisotropy Telescope in Chile, and the high-redshift supernovae data, we obtain new constraints on the fractional matter density and the cosmological constant. PMID:10859119

  5. On the origin of the cosmic microwave background anisotropies

    OpenAIRE

    Follop, Ria; Rassat, Anais; Cooray, Asantha; Abdalla, Filipe B.

    2007-01-01

    Suggestions have been made that the microwave background observed by COBE and WMAP and dubbed Cosmic Microwave Background (CMB) may have an origin within our own Galaxy or Earth. To consider the signal that may be correlated with Earth, a correlate-by-eye exercise was attempted by overlaying the CMB map from Wilkinson Microwave Anisotropy Probe on a topographical map of Earth. Remarkably, several hot spots in the CMB map are found to be well aligned with either large cities on Earth or region...

  6. Effects of ionizing radiation on cryogenic infrared detectors

    Science.gov (United States)

    Moseley, S. H.; Silverberg, R. F.; Lakew, B.

    1989-01-01

    The Diffuse Infrared Background Experiment (DIRBE) is one of three experiments to be carried aboard the Cosmic Background Explorer (COBE) satellite scheduled to be launched by NASA on a Delta rocket in 1989. The DIRBE is a cryogenic absolute photometer operating in a liquid helium dewar at 1.5 K. Photometric stability is a principal requirement for achieving the scientific objectives of this experiment. The Infrared Astronomy Satellite (IRAS), launched in 1983, which used detectors similar to those in DIRBE, revealed substantial changes in detector responsivity following exposure to ionizing radiation encountered on passage through the South Atlantic Anomaly (SAA). Since the COBE will use the same 900 Km sun-synchronous orbit as IRAS, ionizing radiation-induced performance changes in the detectors were a major concern. Here, ionizing radiation tests carried out on all the DIRBE photodetectors are reported. Responsivity changes following exposure to gamma rays, protons, and alpha particle are discussed. The detector performance was monitored following a simulated entire mission life dose. In addition, the response of the detectors to individual particle interactions was measured. The InSb photovoltaic detectors and the Blocked Impurity Band (BIB) detectors revealed no significant change in responsivity following radiation exposure. The Ge:Ga detectors show large effects which were greatly reduced by proper thermal annealing.

  7. CMB Science: Opportunities for a Cryogenic Filter-Bank Spectrometer

    Science.gov (United States)

    Tartari, A.; Battistelli, E. S.; Piat, M.; Prêle, D.

    2016-01-01

    Cosmic microwave background (CMB) spectral science is experiencing a renewed interest after the impressive result of COBE-FIRAS in the early Nineties. In 2011, the PIXIE proposal contributed to reopen the prospect of measuring deviations from a perfect 2.725 K planckian spectrum. Both COBE-FIRAS and PIXIE are differential Fourier transform spectrometers (FTSes) capable to operate in the null condition across ˜ 2 frequency decades (in the case of PIXIE, the frequency span is 30 GHz-6 THz). We discuss a complementary strategy to observe CMB spectral distortions at frequencies lower than 250 GHz, down to the Rayleigh-Jeans tail of the spectrum. The throughput advantage that makes the FTS capable of achieving exquisite sensitivity via multimode operation becomes limited at lower frequencies. We demonstrate that an array of 100 cryogenic planar filter-bank spectrometers coupled to single mode antennas, on a purely statistical ground, can perform better than an FTS between tens of GHz and 200 GHz (a relevant frequency window for cosmology) in the hypothesis that (1) both instruments have the same frequency resolution and (2) both instruments are operated at the photon noise limit (with the FTS frequency band extending from ˜ tens of GHz up to 1 THz). We discuss possible limitations of these hypotheses, and the constraints that have to be fulfilled (mainly in terms of efficiency) in order to operate a cryogenic filter-bank spectrometer close to its ultimate sensitivity limit.

  8. CMB Science: Opportunities for a Cryogenic Filter-Bank Spectrometer

    Science.gov (United States)

    Tartari, A.; Battistelli, E. S.; Piat, M.; Prêle, D.

    2016-08-01

    Cosmic microwave background (CMB) spectral science is experiencing a renewed interest after the impressive result of COBE-FIRAS in the early Nineties. In 2011, the PIXIE proposal contributed to reopen the prospect of measuring deviations from a perfect 2.725 K planckian spectrum. Both COBE-FIRAS and PIXIE are differential Fourier transform spectrometers (FTSes) capable to operate in the null condition across ˜ 2 frequency decades (in the case of PIXIE, the frequency span is 30 GHz-6 THz). We discuss a complementary strategy to observe CMB spectral distortions at frequencies lower than 250 GHz, down to the Rayleigh-Jeans tail of the spectrum. The throughput advantage that makes the FTS capable of achieving exquisite sensitivity via multimode operation becomes limited at lower frequencies. We demonstrate that an array of 100 cryogenic planar filter-bank spectrometers coupled to single mode antennas, on a purely statistical ground, can perform better than an FTS between tens of GHz and 200 GHz (a relevant frequency window for cosmology) in the hypothesis that (1) both instruments have the same frequency resolution and (2) both instruments are operated at the photon noise limit (with the FTS frequency band extending from ˜ tens of GHz up to 1 THz). We discuss possible limitations of these hypotheses, and the constraints that have to be fulfilled (mainly in terms of efficiency) in order to operate a cryogenic filter-bank spectrometer close to its ultimate sensitivity limit.

  9. The extragalactic background and its fluctuations in the far-infrared wavelengths

    CERN Document Server

    Lagache, G; Abergel, A; Bouchet, F R; Boulanger, F; Ciliegi, P; Clements, D L; Césarsky, C J; Désert, F X; Dole, H; Elbaz, D; Franceschini, A; Gispert, R; Guiderdoni, B; Haffner, L M; Harwit, M; Laureijs, R J; Lemke, D; Moorwood, A F M; Oliver, S; Reach, W T; Reynolds, R J; Rowan-Robinson, M; Stickel, M; Tufte, S L

    2000-01-01

    A Cosmic Far-InfraRed Background (CFIRB) has long been predicted that wouldtraces the intial phases of galaxy formation. It has been first detected byPuget et al.(1996) using COBE data and has been later confirmed by severalrecent studies (Fixsen et al. 1998, Hauser et al. 1998, Lagache et al. 1999).We will present a new determination of the CFIRB that uses for the first time,in addition to COBE data, two independent gas tracers: the HI survey ofLeiden/Dwingeloo (hartmann, 1998) and the WHAM H$_{\\alpha}$ survey (Reynolds etal 1998). We will see that the CFIRB above 100 micron is now very wellconstrained. The next step is to see if we can detect its fluctuations. Tosearch for the CFIRB fluctuations, we have used the FIRBACK observations.FIRBACK is a deep cosmological survey conducted at 170 micron with ISOPHOT(Dole et al., 2000). We show that the emission of unresolved extra-galacticsources clearly dominates, at arcminute scales, the background fluctuations inthe lowest galactic emission regions. This is the f...

  10. The distribution of the ISM in the Milky Way A three-dimensional large-scale model

    CERN Document Server

    Misiriotis, A; Papamastorakis, J; Boumis, P; Goudis, C D

    2006-01-01

    We use the COBE/DIRBE (1.2, 2.2, 60, 100, 140, and 240 $\\mu$m) maps and the COBE/FIRAS spectra (for the wavelength range 100 - 1000 $\\mu$m) to constrain a model for the spatial distribution of the dust, the stars, and the gas in the Milky Way. By assuming exponential axisymmetric distributions for the dust and the stars and by performing the corresponding radiative transfer calculations we closely (given the simple geometry of the model) reproduce the FIR and NIR maps of the Milky Way. Similar distributions for the atomic and molecular hydrogen in the disk are used (with an inner cut-off radius for the atomic hydrogen) to fit the gas data. The star formation rate as a function of the Galactic radius is derived from the FIR emission and is well in agreement with existing estimates from various star formation tracers. The gas surface density is plotted against the star formation rate density and an ``intrinsic'' Galactic Schmidt law is derived with excellent agreement with the ``external'' Schmidt law found for...

  11. Modeling of the zodiacal emission for the AKARI/IRC mid-infrared all-sky diffuse maps

    CERN Document Server

    Kondo, T; Kaneda, H; Nakamichi, K; Takaba, S; Kobayashi, H; Ootsubo, T; Pyo, J; Onaka, T

    2016-01-01

    The zodiacal emission, which is the thermal infrared (IR) emission from the interplanetary dust (IPD) in our Solar System, has been studied for a long time. Nevertheless, accurate modeling of the zodiacal emission has not been successful to reproduce the all-sky spatial distribution of the zodiacal emission, especially in the mid-IR where the zodiacal emission peaks. We therefore aim to improve the IPD cloud model based on Kelsall et al. 1998, using the AKARI 9 and 18 micron all-sky diffuse maps. By adopting a new fitting method based on the total brightness, we have succeeded in reducing the residual levels after subtraction of the zodiacal emission from the AKARI data and thus in improving the modeling of the zodiacal emission. Comparing the AKARI and the COBE data, we confirm that the changes from the previous model to our new model are mostly due to model improvements, but not temporal variations between the AKARI and the COBE epoch, except for the position of the Earth-trailing blob. Our results suggest ...

  12. Modeling of the Zodiacal Emission for the AKARI/IRC Mid-infrared All-sky Diffuse Maps

    Science.gov (United States)

    Kondo, Toru; Ishihara, Daisuke; Kaneda, Hidehiro; Nakamichi, Keichiro; Takaba, Sachi; Kobayashi, Hiroshi; Ootsubo, Takafumi; Pyo, Jeonghyun; Onaka, Takashi

    2016-03-01

    The zodiacal emission, which is the thermal infrared (IR) emission from the interplanetary dust (IPD) in our solar system, has been studied for a long time. Nevertheless, accurate modeling of the zodiacal emission has not been successful to reproduce the all-sky spatial distribution of the zodiacal emission, especially in the mid-IR where the zodiacal emission peaks. Therefore, we aim to improve the IPD cloud model based on Kelsall et al., using the AKARI 9 and 18 μm all-sky diffuse maps. By adopting a new fitting method based on the total brightness, we have succeeded in reducing the residual levels after subtraction of the zodiacal emission from the AKARI data and thus in improving the modeling of the zodiacal emission. Comparing the AKARI and the COBE data, we confirm that the changes from the previous model to our new model are mostly due to model improvements, but not temporal variations between the AKARI and the COBE epoch, except for the position of the Earth-trailing blob. Our results suggest that the size of the smooth cloud, a dominant component in the model, is about 10% more compact than previously thought, and that the dust sizes are not large enough to emit blackbody radiation in the mid-IR. Furthermore, we detect a significant isotropically distributed IPD component, owing to an accurate baseline measurement with AKARI.

  13. Cold dark matter. 2: Spatial and velocity statistics

    Science.gov (United States)

    Gelb, James M.; Bertschinger, Edmund

    1994-01-01

    We examine high-resolution gravitational N-body simulations of the omega = 1 cold dark matter (CDM) model in order to determine whether there is any normalization of the initial density fluctuation spectrum that yields acceptable results for galaxy clustering and velocities. Dense dark matter halos in the evolved mass distribution are identified with luminous galaxies; the most massive halos are also considered as sites for galaxy groups, with a range of possibilities explored for the group mass-to-light ratios. We verify the earlier conclusions of White et al. (1987) for the low-amplitude (high-bias) CDM model-the galaxy correlation function is marginally acceptable but that there are too many galaxies. We also show that the peak biasing method does not accurately reproduce the results obtained using dense halos identified in the simulations themselves. The Cosmic Background Explorer (COBE) anisotropy implies a higher normalization, resulting in problems with excessive pairwise galaxy velocity dispersion unless a strong velocity bias is present. Although we confirm the strong velocity bias of halos reported by Couchman & Carlberg (1992), we show that the galaxy motions are still too large on small scales. We find no amplitude for which the CDM model can reconcile simultaneously and galaxy correlation function, the low pairwise velocity dispersion, and the richness distribution of groups and clusters. With the normalization implied by COBE, the CDM spectrum has too much power on small scales if omega = 1.

  14. Exchange transfusion for severe malaria: A comparison of red cell exchange with whole blood exchange

    Directory of Open Access Journals (Sweden)

    Udani S

    2003-01-01

    Full Text Available Aim: To compare exchange transfusions done for severe malaria using the traditional whole blood exchange method with therapeutic red cell exchange (TREX done using a Cobe spectra cell separator. Methods: 6 children with acute, severe malaria and parasitic infestation rates (IR >50% with multi organ failure, were subjected to exchange transfusions. 3 had whole blood single volume exchanges and 3 had TREX using the Cobe-Spectra cell separator. The two groups were compared for difficulties encountered, time taken, complications, quantity of blood products used, metabolic and hematological derangements and fall in IR. Results: The TREX took less time per 100 ml of blood exchanged, resulted in a 24% more efficient decrease in the IR and required less donor plasma. 3/3 tolerated the TREX well whereas one child had complications of hypocalcemia and acidosis with the whole blood exchange. The rise in hemoglobin/hematocrit was comparable in both and the platelet count was not significantly altered in either group. There was no significant alteration in the DIC profile in either group. All 6 children recovered within comparable time frames. Conclusion: The TREX was safer, more efficacious and less time consuming. This procedure is recommended whenever available for red cell exchange in malaria.

  15. High-z objects and cold dark matter cosmogonies - Constraints on the primordial power spectrum on small scales

    Science.gov (United States)

    Kashlinsky, A.

    1993-01-01

    Modified cold dark matter (CDM) models were recently suggested to account for large-scale optical data, which fix the power spectrum on large scales, and the COBE results, which would then fix the bias parameter, b. We point out that all such models have deficit of small-scale power where density fluctuations are presently nonlinear, and should then lead to late epochs of collapse of scales M between 10 exp 9 - 10 exp 10 solar masses and (1-5) x 10 exp 14 solar masses. We compute the probabilities and comoving space densities of various scale objects at high redshifts according to the CDM models and compare these with observations of high-z QSOs, high-z galaxies and the protocluster-size object found recently by Uson et al. (1992) at z = 3.4. We show that the modified CDM models are inconsistent with the observational data on these objects. We thus suggest that in order to account for the high-z objects, as well as the large-scale and COBE data, one needs a power spectrum with more power on small scales than CDM models allow and an open universe.

  16. Nobel Connection to the Space Program

    Science.gov (United States)

    Ng, Edward W.; Nash, Rebecca

    2007-09-01

    The 2006 Nobel Prize in Physics was heralded by some in the press as the "First Nobel Prize for Space Exploration." Indeed the Nobel Foundation's announcement specifically cited the Cosmic Background Explorer (COBE) satellite launched by NASA in 1989 as the prime-enabling instrument It elaborated further, "The COBE results provided increased support for the Big Bang scenario for the origin of the Universe... These measurements also marked the inception of cosmology as a precise science." NASA also seized this unique moment of fame to honor its favorite son, the first Nobel scientist of the agency, John Mather, of the Goddard Space Flight Center, who shared the honor with Professor G. Smoot of the University of California, the Principal Investigator of the COBE measurement. It is without any dispute that the Nobel Prize is the highest scientific honor and best-known award of admiration and inspiration to the public and educational sectors. Unfortunately in the American culture, youths are mostly exposed to success icons in the sports, entertainment, and business domains. Science icons (of either gender) are largely unknown to them. We sincerely hope that success stories of Nobel scientists will become part of the learning curriculum in the K-16 educational experience. In this paper, we examine the pedigree of a number of Nobel Prizes over the years, and discuss their interactions with, and connections to, the space program. It is advantageous for the context of educational and public outreach to see such connections, because in a number of public surveys, one important customer expectation for the space program is the search for new knowledge, to which the Nobel Prize is a prominent benchmark. We have organized this paper into nine, fairly independent sections for ease of reading: I. "Michael Jordan or Mia Hamm" - Introduction and Background II. "Connecting the Dots Between the Heavens and Earth" - From Newton to Bethe III. "From Cosmic Noise to the Big Bang" - The

  17. The Nobel Connection to the Space Program

    Science.gov (United States)

    Ng, E. N.; Nash, R. L.

    2007-09-01

    The 2006 Nobel Prize in Physics was heralded by some in the press as the "First Nobel Prize for Space Exploration." Indeed the Nobel Foundation's announcement specifically cited the Cosmic Background Explorer (COBE) satellite launched by NASA in 1989 as the prime-enabling instrument It elaborated further, "The COBE results provided increased support for the Big Bang scenario for the origin of the Universe. These measurements also marked the inception of cosmology as a precise science." NASA also seized this unique moment of fame to honor its favorite son, the first Nobel scientist of the agency, John Mather, of the Goddard Space Flight Center, who shared the honor with Professor G. Smoot of the University of California, the Principal Investigator of the COBE measurement. It is without any dispute that the Nobel Prize is the highest scientific honor and best-known award of admiration and inspiration to the public and educational sectors. Unfortunately in the American culture, youths are mostly exposed to success icons in the sports, entertainment, and business domains. Science icons are largely unknown to them. We sincerely hope that success stories of Nobel scientists will become part of the learning curriculum in the K-16 educational experience. In this paper, we examine the pedigree of a number of Nobel Prizes over the years, and discuss their interactions with, and connections to, the space program. It is advantageous for the context of educational and public outreach to see such connections, because in a number of public surveys, one important customer expectation for the space program is the search for new knowledge, to which the Nobel Prize is a prominent benchmark. We have organized this lengthy paper into nine, fairly independent sections for ease of reading:1."Michael Jordan or Mia Hamm" - Introduction and Background2."Connecting the Dots Between the Heavens and Earth" - From Newton to Bethe3."From Cosmic Noise to the Big Bang" - The First Nobel

  18. Constraints on hidden photons from current and future observations of CMB spectral distortions

    CERN Document Server

    Kunze, Kerstin E

    2015-01-01

    A variety of beyond the standard model scenarios contain very light hidden sector U(1) gauge bosons undergoing kinetic mixing with the photon. The resulting oscillation between ordinary and hidden photons leads to spectral distortions of the cosmic microwave background. We update the bounds on the mixing parameter $\\chi_0$ and the mass of the hidden photon $m_{\\gamma'}$ for future experiments measuring CMB spectral distortions, such as PIXIE and PRISM/COrE. For $10^{-14}\\;{\\rm eV}\\lesssim m_{\\gamma'}\\lesssim 10^{-13}\\;{\\rm eV}$, we find the kinetic mixing angle $\\chi_0$ has to be less than $10^{-8}$ at 95\\% CL. These bounds are more than an order of magnitude stronger than those derived from the COBE/FIRAS data.

  19. Introduction and Overview CMB Sessions

    CERN Document Server

    Smoot, G F

    1998-01-01

    This is a very exciting time for the CMB field. It is widely recognized that precision measurements of the CMB can provide a definitive test of cosmological models and determine their parameters accurately. At present observations give us the first rough results but ongoing experiments promise new and improved results soon and eventually satellite missions (MAP and COBRAS/SAMBA now named Planck) are expected to provide the requisite precision measurements. Other areas such as observations of the spectrum and Sunyaev-Zeldovich effect are also making significant progress. There has long been anticipation that cosmic microwave background (CMB) radiation would provide significant information about the early Universe due to its early central role and its general lack of interaction in the later epochs. Though there have been many observations of the CMB since its discovery by Penzias and Wilson in 1964, the Cosmic Background Explorer satellite, COBE, provided two watershed observations: (1) the CMB is extremely we...

  20. The Cosmic Microwave Background Anisotropy Experiments

    CERN Document Server

    Smoot, G F

    1997-01-01

    This paper reports a summary of the contents contents of six hours of lectures on the CMB anisotropy experiments given at the Strasbourg NATO school on the CMB and cosmology. (Its companion paper, astro-ph/9705101 reports the lectures on the CMB spectrum.) A context is set as a bridge from the theoretical CMB anisotropy lectures and the experimental situation. The COBE DMR results are reveiwed in detail and as pioneer for future space missions. Current and planned experiments are discussed in preference to reviewing already completed observations. The NASA MidEX mission MAP is discussed in some detail including figures. The ESA M3 mission Max Planck Surveyor is also reviewed in some detail though its final configuration is not yet fully settled. The recent history and current versions are presented. Tables and references for experiments are included.

  1. CMB Experiment Baseline Determination by Minimizing Pixel Observations Dispersion

    CERN Document Server

    Smoot, G F

    1997-01-01

    This paper discusses a couple of approaches to removing instrument gain and baseline variation from observations of the CMB anisotropy. These techniques were tested on the COBE DMR data, a balloon experiment, and by monte carlo simulations. This work, though considered technical, is made available because CMB anisotropy mapping data processing is currently very active and a significant number of groups are working on this issue. Specifically, time-ordered estimates of the gain and baseline via fitting to limited sections of data or to the full or a large section of data are considered and compared. An expression is given for the correlation between pixels introduced by the residual baseline and removal technique.

  2. Contribution of extragalactic infrared sources to CMB foreground anisotropy

    CERN Document Server

    Gawiser, E; Gawiser, Eric; Smoot, George F

    1996-01-01

    We estimate the level of confusion of CMB anisotropy measurements caused by extragalactic infrared sources. CMB anisotropy observations at high resolution and high frequencies are especially sensitive to this foreground. We have combined IRAS data on bright infrared galaxies with information about the Galaxy from the DIRBE and FIRAS instruments of COBE. Using the spectrum of the Milky Way as a template, we predict the microwave emission of the 5319 brightest infrared galaxes. We simulate skymaps over the relevant range of frequencies (30-900 GHz) and instrument resolutions (10'-10 degrees Full Width Half Max). Analysis of the temperature anisotropy of these skymaps shows a level of extragalactic infrared foreground that is nearly consistent with previous estimates based on galaxy-evolution models. A reasonable observationalwindow is still available for medium- and small-angular scale CMB anisotropy measurements.

  3. Supermassive black holes formed by direct collapse of inflationary perturbations

    CERN Document Server

    Nakama, Tomohiro; Yokoyama, Jun'ichi

    2016-01-01

    We propose a mechanism of producing a new type of primordial perturbations which collapse to primordial black holes whose mass can be as large as necessary for them to grow to the supermassive black holes observed at high redshifts, without contradicting COBE/FIRAS upper limits on cosmic microwave background (CMB) spectral distortions. In our model, the observable Universe consists of two kinds of many small patches which experienced different expansion histories during inflation. Large amplitudes of primordial perturbations enough to form primordial black holes are realized on patches that experienced more Hubble expansion than the others. By making these patches the minor component, the rarity of supermassive black holes can be explained. On the other hand, most regions of the Universe experienced the standard history and hence have only standard almost scale-invariant adiabatic perturbations confirmed by observations of CMB or large-scale structures of the universe. Thus our mechanism can evade the constra...

  4. The inflationary energy scale

    Science.gov (United States)

    Liddle, Andrew R.

    1994-01-01

    The energy scale of inflation is of much interest, as it suggests the scale of grand unified physics, governs whether cosmological events such as topological defect formation can occur after inflation, and also determines the amplitude of gravitational waves which may be detectable using interferometers. The COBE results are used to limit the energy scale of inflation at the time large scale perturbations were imprinted. An exact dynamical treatment based on the Hamilton-Jacobi equations is then used to translate this into limits on the energy scale at the end of inflation. General constraints are given, and then tighter constraints based on physically motivated assumptions regarding the allowed forms of density perturbation and gravitational wave spectra. These are also compared with the values of familiar models.

  5. Elliptic CMB Sky

    CERN Document Server

    Gurzadyan, V G; De Troia, G; Bianco, C L; Kashin, A L; Kuloghlian, H; Masi, S; Piacentini, F; Polenta, G; Yegorian, G

    2005-01-01

    The ellipticity of the anisotropy spots of the Cosmic Microwave Background measured by the Wilkinson Microwave Anisotropy Probe (WMAP) has been studied. We find an average ellipticity of about 2, confirming with a far larger statistics similar results found first for the COBE-DMR CMB maps, and then for the BOOMERanG CMB maps. There are no preferred directions for the obliquity of the anisotropy spots. The average ellipticity is independent of temperature threshold and is present on scales both smaller and larger than the horizon at the last scattering. The measured ellipticity characteristics are consistent with being the effect of geodesics mixing occurring in an hyperbolic Universe, and can mark the emergence of CMB ellipticity as a new observable constant describing the Universe.

  6. Can CMB spectral distortions test the Einstein equivalence principle?

    CERN Document Server

    Arai, Shun; Tashiro, Hiroyuki

    2016-01-01

    The Einstein Equivalence Principle (EEP) can be verified by the measurement of the spectral distortions of the Cosmic Microwave Background (CMB). The existence of energy-dependency in the cosmological redshift effect means the EEP violation. Introducing the energy-dependent Friedmann-Robertson-Walker metric motivated by rainbow gravity, we show that the energy-dependent redshift effect causes the CMB spectral distortions. Assuming the simple energy-dependent form of the metric, we evaluate the distortions. From the COBE/FIRAS bound, we find that the deviation degree from the EEP, which is comparable to the difference of the parameterized-post-Newtonian parameter "gamma" in energy, is less than 10^{-9} at the CMB energy scale. Our bound is the first constraint on the EEP at cosmological time scale.

  7. Cosmological constraints on neutrinos with Planck data

    Energy Technology Data Exchange (ETDEWEB)

    Spinelli, M. [Laboratoire de l’Accélérateur Linéaire, Bat.200, 91400 Orsay (France)

    2015-07-15

    Neutrinos take part in the dance of the evolving Universe influencing its history from leptogenesis, to Big Bang nucleosynthesis, until late time structure formation. This makes cosmology, and in particular one of its primary observables the Cosmic Microwave Background (CMB), an unusual but valuable tool for testing Neutrino Physics. The best measurement to date of full-sky CMB anisotropies comes from the Planck satellite launched in 2009 by the European Space Agency (ESA) and successful follower of COBE and WMAP. Testing Planck data against precise theoretical predictions allow us to shed light on various interesting open questions such as the value of the absolute scale of neutrino masses or their energy density. We revise here the results concerning neutrinos obtained by the Planck Collaboration in the 2013 data release.

  8. 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...

  9. Polylogarithmic representation of radiative and thermodynamic properties of thermal radiation in a given spectral range: I. Blackbody radiation

    CERN Document Server

    Fisenko, Anatoliy I

    2014-01-01

    Using polylogarithm functions the exact analytical expressions for the radiative and thermodynamic properties of blackbody radiation, such as the Wien displacement law, Stefan-Boltzmann law, total energy density, number density of photons, Helmholtz free energy density, internal energy density, enthalpy density, entropy density, heat capacity at constant volume, and pressure in the finite range of frequencies are constructed. The obtained expressions allow us to tabulate these functions in various finite frequency bands at different temperatures for practical applications. As an example, the radiative and thermodynamic functions using experimental data for the monopole spectrum of the Cosmic Microwave Background (CMB) radiation measured by the COBE FIRAS instrument in the 60 - 600 GHz frequency interval at the temperature T = 2.725 K are calculated. The expressions obtained for the radiative and thermodynamic functions can be easily presented in wavelength and wavenumber domains.

  10. Sub-millimeter to centimeter excess emission from the Magellanic Clouds. I. Global spectral energy distribution

    CERN Document Server

    Israel, F P; Raban, D; Reach, W T; Bot, C; Oonk, J B R; Ysard, N; Bernard, J P

    2010-01-01

    In order to reconstruct the global SEDs of the Magellanic Clouds over eight decades in spectral range, we combined literature flux densities representing the entire LMC and SMC respectively, and complemented these with maps extracted from the WMAP and COBE databases covering the missing the 23--90 GHz (13--3.2 mm) and the poorly sampled 1.25--250 THz (240--1.25 micron). We have discovered a pronounced excess of emission from both Magellanic Clouds, but especially the SMC, at millimeter and sub-millimeter wavelengths. We also determined accurate thermal radio fluxes and very low global extinctions for both LMC and SMC. Possible explanations are briefly considered but as long as the nature of the excess emission is unknown, the total dust masses and gas-to-dust ratios of the Magellanic Clouds cannot reliably be determined.

  11. Cosmological constraints on neutrinos with Planck data

    International Nuclear Information System (INIS)

    Neutrinos take part in the dance of the evolving Universe influencing its history from leptogenesis, to Big Bang nucleosynthesis, until late time structure formation. This makes cosmology, and in particular one of its primary observables the Cosmic Microwave Background (CMB), an unusual but valuable tool for testing Neutrino Physics. The best measurement to date of full-sky CMB anisotropies comes from the Planck satellite launched in 2009 by the European Space Agency (ESA) and successful follower of COBE and WMAP. Testing Planck data against precise theoretical predictions allow us to shed light on various interesting open questions such as the value of the absolute scale of neutrino masses or their energy density. We revise here the results concerning neutrinos obtained by the Planck Collaboration in the 2013 data release

  12. 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

  13. Science and the media alternative routes in scientific communication

    CERN Document Server

    Bucchi, Massimiano

    1998-01-01

    In the days of global warming and BSE, science is increasingly a public issue. This book provides a theoretical framework which allows us to understand why and how scientists address the general public. The author develops the argument that turning to the public is not simply a response to inaccurate reporting by journalists or to public curiosity, nor a wish to gain recognition and additional funding. Rather, it is a tactic to which the scientific community are pushed by certain "internal" crisis situations. Bucchi examines three cases of scientists turning to the public: the cold fusion case, the COBE/Big Bang issue and Louis Pasteur's public demonstration of the anthrax vaccine, a historical case of "public science." Finally, Bucchi presents his unique model of communications between science and the public, carried out through the media. This is a thoughtful and wide-ranging treatment of complex contemporary issues, touching upon the history and sociology of science, communication and media studies. Bucchi...

  14. Is a massive tau neutrino just what cold dark matter needs?

    Science.gov (United States)

    Dodelson, Scott; Gyuk, Geza; Turner, Michael S.

    1994-01-01

    The cold dark matter (CDM) scenario for structure formation in the Universe is very attractive and has many successes; however, when its spectrum of density perturbations is normalized to the COBE anisotropy measurement the level of inhomogeneity predicted on small scales is too large. This can be remedied by a tau neutrino of mass 1 MeV - 10MeV and lifetime 0.1 sec - 100 sec whose decay products include electron neutrinos because it allows the total energy density in relativistic particles to be doubled without interfering with nucleosynthesis. The anisotropies predicted on the degree scale for 'tau CDM' are larger than standard CDM. Experiments at e(sup +/-) collides may be able to probe such a mass range.

  15. Measurements of very low-sidelobe conical horn antennas

    Science.gov (United States)

    Toral, Marco A.; Ratliff, Roger B.; Lecha, Maria C.; Maruschak, John G.; Bennett, Charles L.

    1989-01-01

    A description is given of conical corrugated-horn antennas that were designed for millimeter-wave radiometers with a 7 degree field of view, namely the Differential Microwave Radiometers (DMRs) that will measure the large-angular-scale anisotropy of the cosmic background radiation that is generally thought to be the remnant of the primeval explosion, the Big Bang. The DMRs will be part of the Cosmic Background Explorer (COBE) satellite. Measured test results for three radiometers at 31.4, 53, and 90 GHz are reported along with those of a circular polarization orthomode transducer designed and characterized at 31.4 GHz. The measurement techniques and facilities are described, including an outdoor far-field facility where measurements down to levels 90 dB below the main beam maximum were achieved. The goal of achieving very low-sidelobe antennas with good symmetry has been demonstrated.

  16. Confrontation of a Double Inflationary Cosmological Model with Observations

    CERN Document Server

    Gottlöber, S; Starobinsky, A A; Gottloeber, Stefan; Muecket, Jan P.

    1994-01-01

    CDM models with non-scale-free step-like spectra of adiabatic perturbations produced in a realistic double inflationary model are compared with recent observational data. The model contains two additional free parameters relatively to the standard CDM model with the flat ($n=1$) initial spectrum. Results of the COBE experiment are used for the determination of a free overall spectrum normalization. Then predictions for the galaxy biasing parameter, the variance for "counts in cells", the galaxy angular correlation function, bulk flow peculiar velocities and the Mach number test are obtained. Also considered are conditions for galaxy and quasar formation. Observational data strongly restricts allowed values for the two remaining model parameters. However, a non-empty region for them satisfying all considered tests is found.

  17. Towards understanding the dynamics of the bar/bulge region in our Galaxy

    Directory of Open Access Journals (Sweden)

    Athanassoula E.

    2012-02-01

    Full Text Available I review some of the work on bars which is closely linked to the bar/bulge system in our Galaxy. Several independent studies, using totally independent methods, come to the same results about the 3D structure of a bar, i.e., that a bar is composed of a vertically thick inner part and a vertically thin outer part. I give examples of this from simulations and substantiate the discussion with input from orbital structure analysis and from observations. The thick part has a considerably shorter radial extent than the thin part. I then see how this applies to our Galaxy, where two bars have been reported, the COBE/DIRBE bar and the Long bar. Comparing their extents and making the reasonable and necessary assumption that our Galaxy has properties similar to those of other galaxies of similar type, leads to the conclusion that these two bars can not form a standard double bar system. I then discuss arguments in favour of the two bars being simply different parts of the same bar, the COBE/DIRBE bar being the thick inner part and the Long bar being the thin outer part of this bar. I also very briefly discuss some related new results. I first consider bar formation and evolution in disc galaxies with a gaseous component – including star formation, feedback and evolution – and a triaxial halo. Then I consider bar formation in a fully cosmological context using hydrodynamical LCDM simulations, where the host galaxies grow, accrete matter and significantly evolve during the formation and evolution of the bar.

  18. Inflationary scenario in the supersymmetric economical 3-3-1 model

    International Nuclear Information System (INIS)

    We construct the supersymmetric economical 3-3-1 model which contains inflationary scenario and avoids the monopole puzzle. Based on the spontaneous symmetry breaking pattern (with three steps), the F-term inflation is derived. The slow-roll parameters element of and η are calculated. By imposing as experimental five-year WMAP data on the spectral index n, we have derived a constraint on the number of e-folding NQ to be in the range from 25 to 50. The scenario for large-scale structure formation implied by the model is a mixed scenario for inflation and cosmic string, and the contribution to the CMBR temperature anisotropy depends on the ratio MX/MPl. From the COBE data, we have obtained the constraint on the MX to be MX element of [1.22 x 1016, 0.98 x 1017] GeV. The upper value MX ≅ 1017 GeV is a result of the analysis in which the inflationary contribution to the temperature fluctuations measured by the COBE is 90%. The coupling α varies in the range: 10-7-10-1. This value is not so small, and it is a common characteristics of the supersymmetric unified models with the inflationary scenario. The spectral index n is a little bit smaller than 0.98. The SUGRA corrections are slightly different from the previous consideration. When ξ -8. Numerical analysis shows that α ∼ 10-6. To get inflation contribution to the CMBR temperature anisotropy ∼90%, the mass scale MX 14 GeV.

  19. Search for pseudoscalar cold dark matter

    Energy Technology Data Exchange (ETDEWEB)

    van Bibber, K.; Stoeffl, W.; LLNL Collaborators

    1992-05-29

    AH dynamical evidence points to the conclusion that the predominant form of matter in the universe is in a non-luminous form. Furthermore, large scale deviations from uniform Hubble flow, and the recent COBE reports of inhomogeneities in the cosmic microwave background strongly suggest that we live in an exactly closed universe. If this is true, then ordinary baryonic matter could only be a minority component (10% at most) of the missing mass, and that what constitutes the majority of the dark matter must involve new physics. The axion is one of very few well motivated candidates which may comprise the dark matter. Additionally it is a `cold` dark-matter candidate which is preferred by the COBE data. We propose to construct and operate an experiment to search for axions which may constitute the dark matter of our own galaxy. As proposed by Sikivie, dark-matter axions may be detected by their stimulated conversion into monochromatic microwave photons in a tunable high-Q cavity inside a strong magnetic field. Our ability to mount an experiment quickly and take data within one year is due to a confluence of three factors. The first is the availability of a compact high field superconducting magnet and a local industrial partner, Wang NMR, who can make a very thermally efficient and economical cryostat for it. The second is an ongoing joint venture with the Institute for Nuclear Research of the Russian Academy of Sciences to do R&D on metalized precision-formed ceramic microwave cavities for the axion search, and INR has commited to providing all the microwave cavity arrays for this experiment, should this proposal be approved. The third is a commitment of very substantial startup capital monies from MIT for all of the state-of-the-art ultra-low noise microwave electronics, to one of our outstanding young collaborators who is joining their faculty.

  20. All-Sky Observational Evidence for An Inverse Correlation Between Dust Temperature and Emissivity Spectral Index

    Science.gov (United States)

    Liang, Z.; Fixsen, D. J.; Gold, B.

    2012-01-01

    We show that a one-component variable-emissivity-spectral-index model (the free- model) provides more physically motivated estimates of dust temperature at the Galactic polar caps than one- or two-component fixed-emissivity-spectral-index models (fixed- models) for interstellar dust thermal emission at far-infrared and millimeter wavelengths. For the comparison we have fit all-sky one-component dust models with fixed or variable emissivity spectral index to a new and improved version of the 210-channel dust spectra from the COBE-FIRAS, the 100-240 micrometer maps from the COBE-DIRBE and the 94 GHz dust map from the WMAP. The best model, the free-alpha model, is well constrained by data at 60-3000 GHz over 86 per cent of the total sky area. It predicts dust temperature (T(sub dust)) to be 13.7-22.7 (plus or minus 1.3) K, the emissivity spectral index (alpha) to be 1.2-3.1 (plus or minus 0.3) and the optical depth (tau) to range 0.6-46 x 10(exp -5) with a 23 per cent uncertainty. Using these estimates, we present all-sky evidence for an inverse correlation between the emissivity spectral index and dust temperature, which fits the relation alpha = 1/(delta + omega (raised dot) T(sub dust) with delta = -.0.510 plus or minus 0.011 and omega = 0.059 plus or minus 0.001. This best model will be useful to cosmic microwave background experiments for removing foreground dust contamination and it can serve as an all-sky extended-frequency reference for future higher resolution dust models.

  1. Another look at distortions of the Cosmic Microwave Background spectrum

    Science.gov (United States)

    De Zotti, G.; Negrello, M.; Castex, G.; Lapi, A.; Bonato, M.

    2016-03-01

    We review aspects of Cosmic Microwave Background (CMB) spectral distortions which do not appear to have been fully explored in the literature. In particular, implications of recent evidences of heating of the intergalactic medium (IGM) by feedback from active galactic nuclei are investigated. Taking also into account the IGM heating associated to structure formation, we argue that values of the y parameter of several × 10-6, i.e. a factor of a few below the COBE/FIRAS upper limit, are to be expected. The Compton scattering by the re-ionized plasma also re-processes primordial distortions, adding a y-type contribution. Hence no pure Bose-Einstein-like distortions are to be expected. An assessment of Galactic and extragalactic foregrounds, taking into account the latest results from the Planck satellite as well as the contributions from the strong CII and CO lines from star-forming galaxies, demonstrates that a foreground subtraction accurate enough to fully exploit the PIXIE sensitivity will be extremely challenging. Motivated by this fact we also discuss methods to detect spectral distortions not requiring absolute measurements and show that accurate determinations of the frequency spectrum of the CMB dipole amplitude may substantially improve over COBE/FIRAS limits on distortion parameters. Such improvements may be at reach of next generation CMB anisotropy experiments. The estimated amplitude of the Cosmic Infrared Background (CIB) dipole might be detectable by careful analyses of Planck maps at the highest frequencies. Thus Planck might provide interesting constraints on the CIB intensity, currently known with a simeq 30% uncertainty.

  2. PLANCK, the Satellite: a New Experimental Test of General Relativity

    Directory of Open Access Journals (Sweden)

    Borissova L.

    2008-04-01

    Full Text Available If the origin of a microwave background (EMB is the Earth, what would be its density and associated dipole anisotropy measured at different altitudes from the surface of the Earth? The mathematical methods of the General Theory of Relativity are applied herein to answer these questions. The density of the EMB is answered by means of Einstein’s equations for the electromagnetic field of the Earth. The dipole anisotropy, which is due to the rapid motion of the source (the Earth in the weak intergalactic field, is analysed by using the geodesic equations for light-like particles (photons, which are mediators for electromagnetic radiation. It is shown that the EMB decreases with altitude so that the density of its energy at the altitude of the COBE orbit (900km is 0.68 times less than that at the altitude of a U2 aeroplane (25 km. Furthermore, the density at the 2nd Lagrange point (1.5 million km, the position of the WMAP and PLANCK satellites should be only 1E-7 of the value detected by a U2 aeroplane or at the COBE orbit. The dipole anisotropy of the EMB doesn’t depend on altitude from the surface of the Earth, it should be the same irrespective of the altitude at which measurements are taken. This result is in support to the experimental and observational analysis conducted by P.-M. Robitaille, according to which the 2.7 K microwave background, first observed by Penzias and Wilson, is not of cosmic origin, but of the Earth, and is generated by the oceans. WMAP indicated the same anisotropy of the microwave background at the 2nd Lagrange point that near the Earth. Therefore when PLANCK, which is planned on July, 2008, will manifest the 2.7 K monopole microwave signal deceased at the 2nd Langrange point, it will be a new experimental verification of Einstein’s theory.

  3. Primordial Inflation Polarization Explorer (Phase 2)

    Science.gov (United States)

    Kogurt, Alan; Bennett, Charles

    This is the Lead Proposal for the proposed investigation "Primordial Inflation Polarization Explorer (Phase 2)" We propose to fly the Primordial Inflation Polarization Explorer (PIPER) to measure the polarization of the cosmic microwave background (CMB) and search for the imprint of gravitational waves produced during an inflationary epoch in the early universe. Such a signal is expected to exist: the simplest inflation models predict tensor-to-scalar ratio 0.01 optimized to detect the inflationary signal on large angular scales. It consists of two co-aligned telescopes cooled to 1.5 K within a large liquid helium bucket dewar. A variable-delay polarization modulator (VPM) on each telescope chops between linear and circular polarization to isolate the polarized signal while rejecting the much brighter unpolarized emission. PIPER's innovative architecture combines cryogenic optics with kilo-pixel detector arrays to provide unprecedented sensitivity to CMB polarization. The fast modulation between linear and circular polarization takes advantage of the lack of astrophysical circular polarization to eliminate common sources of systematic error. The sensitivity and control of systematic errors in turn enable measurements over most of the sky from mid-latitude launch sites; long-duration Antarctic flights are not required. With sensitivity r proposed work, including detector development, polarization modulation, instrument integration, and cryogenic ballooning. The team includes the Instrument Integration Lead and Instrument Test Lead for the Wilkinson Microwave Anisotropy Probe (WMAP) as well as the lead authors for the systematic error papers for the ground-breaking COBE-DMR, COBE-FIRAS, and WMAP instruments. The team has demonstrated expertise in data analysis including pipeline development, foreground modeling, and cosmological parameter fitting. PIPER began development in 2009 and is nearing completion. With first flight scheduled soon, the development schedule

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

    International Nuclear Information System (INIS)

    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.

  5. X-ray clusters in a cold dark matter + lambda universe: A direct, large-scale, high-resolution, hydrodynamic simulation

    Science.gov (United States)

    Cen, Renyue; Ostriker, Jeremiah P.

    1994-01-01

    A new, three-dimensional, shock-capturing, hydrodynamic code is utilized to determine the distribution of hot gas in a cold dark matter (CDM) + lambda model universe. Periodic boundary conditions are assumed: a box with size 85/h Mpc, having cell size 0.31/h Mpc, is followed in a simulation with 270(exp 3) = 10(exp 7.3) cells. We adopt omega = 0.45, lambda = 0.55, h identically equal to H/100 km/s/Mpc = 0.6, and then, from the cosmic background explorer (COBE) and light element nucleosynthesis, sigma(sub 8) = 0.77, omega(sub b) = 0.043. We identify the X-ray emitting clusters in the simulation box, compute the luminosity function at several wavelength bands, the temperature function and estimated sizes, as well as the evolution of these quantities with redshift. This open model succeeds in matching local observations of clusters in contrast to the standard omega = 1, CDM model, which fails. It predicts an order of magnitude decline in the number density of bright (h nu = 2-10 keV) clusters from z = 0 to z = 2 in contrast to a slight increase in the number density for standard omega = 1, CDM model. This COBE-normalized CDM + lambda model produces approximately the same number of X-ray clusters having L(sub x) greater than 10(exp 43) erg/s as observed. The background radiation field at 1 keV due to clusters is approximately the observed background which, after correction for numerical effects, again indicates that the model is consistent with observations.

  6. Hot gas in the cold dark matter scenario: X-ray clusters from a high-resolution numerical simulation

    Science.gov (United States)

    Kang, Hyesung; Cen, Renyue; Ostriker, Jeremiah P.; Ryu, Dongsu

    1994-01-01

    A new, three-dimensional, shock-capturing hydrodynamic code is utilized to determine the distribution of hot gas in a standard cold dark matter (CDM) model of the universe. Periodic boundary conditions are assumed: a box with size 85 h(exp -1) Mpc having cell size 0.31 h(exp -1) Mpc is followed in a simulation with 270(exp 3) = 10(exp 7.3) cells. Adopting standard parameters determined from COBE and light-element nucleosynthesis, sigma(sub 8) = 1.05, omega(sub b) = 0.06, and assuming h = 0.5, we find the X-ray-emitting clusters and compute the luminosity function at several wavelengths, the temperature distribution, and estimated sizes, as well as the evolution of these quantities with redshift. We find that most of the total X-ray emissivity in our box originates in a relatively small number of identifiable clusters which occupy approximately 10(exp -3) of the box volume. This standard CDM model, normalized to COBE, produces approximately 5 times too much emission from clusters having L(sub x) is greater than 10(exp 43) ergs/s, a not-unexpected result. If all other parameters were unchanged, we would expect adequate agreement for sigma(sub 8) = 0.6. This provides a new and independent argument for lower small-scale power than standard CDM at the 8 h(exp -1) Mpc scale. The background radiation field at 1 keV due to clusters in this model is approximately one-third of the observed background, which, after correction for numerical effects, again indicates approximately 5 times too much emission and the appropriateness of sigma(sub 8) = 0.6. If we have used the observed ratio of gas to total mass in clusters, rather than basing the mean density on light-element nucleosynthesis, then the computed luminosity of each cluster would have increased still further, by a factor of approximately 10. The number density of clusters increases to z approximately 1, but the luminosity per typical cluster decreases, with the result that evolution in the number density of bright

  7. Application of haemocyte pheresis in adjunctive treatment of polycythemia vera using haemocyte separator%红细胞单采术辅助治疗真性红细胞增多症的应用

    Institute of Scientific and Technical Information of China (English)

    辛延; 李晓云

    2013-01-01

    目的 探讨应用COBE Spectra血细胞分离机进行红细胞单采术辅助治疗真性红细胞增多症的疗效.方法 应用COBE Spectra血细胞分离机对18例真性红细胞增多症进行红细胞单采术,共27次,单采后接受羟基脲口服;同时与32例单用羟基脲的真性红细胞增多症患者进行对比,观察疗效的时间为1个月.结果 ①在单采联合羟基脲治疗组,18例患者血红蛋白中位数210(179~ 261) g/L下降至165(155~220) g/L,颜面绛紫色好转,血压下降,与术前比较差异有统计学意义(P<0.01);②32例单用羟基脲的真性红细胞性增多症患者血红蛋白中位数209.5(158~242) g/L下降至183.5(124~228) g/L,颜面绛紫色有所好转,与用药前相比有统计学意义(P<0.01);③单采联合羟基脲组血红蛋白降低更加明显,每次单采后血红蛋白即刻下降,且血红蛋白下降的中位天数(10天)明显少于单用羟基脲组(4天),有统计学意义(P<0.05).结论 利用血细胞分离机进行红细胞单采术,其临床效果肯定,能迅速缓解症状,优于单用羟基脲治疗,且安全、可靠、不良反应小.

  8. Another look to distortions of the CMB spectrum

    CERN Document Server

    De Zotti, G; Castex, G; Lapi, A; Bonato, M

    2015-01-01

    We review aspects of cosmic microwave background spectral distortions which do not appear to have been fully explored in the literature. In particular, implications of recent evidences of heating of the intergalactic medium (IGM) by feedback from active galactic nuclei are investigated. Taking also into account the IGM heating associated to structure formation, we argue that values of the y parameter of several times 10^(-6), i.e. a factor of a few below the COBE/FIRAS upper limit, are to be expected. The Compton scattering by the re-ionized plasma also re-processes primordial Bose Einstein-type distortions, reshaping them; hence no pure Bose-Einstein-like distortions are to be expected. An assessment of Galactic and extragalactic foregrounds, taking into account the latest results from the Planck satellite as well as the contributions from the strong CII and CO lines from star-forming galaxies demonstrates that the foreground subtraction accurate enough to fully exploit the PIXIE sensitivity will be extremel...

  9. On Perturbations in Warm Inflation

    CERN Document Server

    De Oliveira, H P

    2001-01-01

    Warm inflation is an interesting possibility of describing the early universe, whose basic feature is the absence, at least in principle, of a preheating or reheating phase. Here we analyze the dynamics of warm inflation generalizing the usual slow-roll parameters that are useful for characterizing the inflationary phase. We study the evolution of entropy and adiabatic perturbations, where the main result is that for a very small amount of dissipation the entropy perturbations can be neglected and the purely adiabatic perturbations will be responsible for the primordial spectrum of inhomogeneities. Taking into account the COBE-DMR data of the cosmic microwave background anisotropy as well as the fact that the interval of inflation for which the scales of astrophysical interest cross outside the Hubble radius is about 50 e-folds before the end of inflation, we could estimate the magnitude of the dissipation term. It was also possible to show that at the end of inflation the universe is hot enough to provide a ...

  10. Chaotic inflation limits for non-minimal models with a Starobinsky attractor

    International Nuclear Information System (INIS)

    We investigate inflationary attractor points by analysing non-minimally coupled single field inflation models in two opposite limits; the 'flat' limit in which the first derivative of the conformal factor is small and the 'steep' limit, in which the first derivative of the conformal factor is large. We consider a subset of models that yield Starobinsky inflation in the steep conformal factor, strong coupling, limit and demonstrate that they result in φ2n-chaotic inflation in the opposite flat, weak coupling, limit. The suppression of higher order powers of the inflaton field in the potential is shown to be related to the flatness condition on the conformal factor. We stress that the chaotic attractor behaviour in the weak coupling limit is of a different, less universal, character than the Starobinsky attractor. Agreement with the COBE normalisation cannot be obtained in both attractor limits at the same time and in the chaotic attractor limit the scale of inflation depends on the details of the conformal factor, contrary to the strong coupling Starobinsky attractor

  11. 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.

  12. Erythrocyte Fragment Count Predicts Hemolysis in Roller Pumps

    Institute of Scientific and Technical Information of China (English)

    FAN Jun-qiang; XU Shi-wei; CHEN Fang; DING Min-jun

    2007-01-01

    Hemolysis in blood pumps has been measured by various in vitro test methods, in which normalized index of hemolysis (NIH) was established. As NIH is complicated and difficult to calculate, erythrocyte fragment count is proposed in the present study to predict hemolysis in roller pumps. Methods: Five paired in vitro tests wereconducted using the POLYSTAN pediatric pump(group A) and COBE pump(group B). Ten whole blood samples (400 ml ) were circled in the roller pump for 16 h. Erythrocyte fragments count and plasma-free hemoglobin (FHb) were measured before pumping and every two hours through circulation after four-hour-pumping. The morphological changes of erythrocyte were observed by scanning electron microscope. Results: The two groups' EFC and FHb levels were increased linearly during a long duration of pumping and linear regression of erythrocyte fragments count and plasma-free hemoglobin were correlated. Conclusion: Erythrocyte fragments count could be used as an index in evaluating the in vitro hemolytic properties of blood pumps.

  13. Axion production and CMB spectral distortion in cosmological tangled magnetic field

    CERN Document Server

    Ejlli, Damian

    2015-01-01

    Axion production due to photon-axion mixing in tangled magnetic field(s) prior to recombination epoch and magnetic field damping can generate cosmic microwave background (CMB) spectral distortions. In particular, contribution of both processes to CMB $\\mu$ distortion in the case of resonant photon-axion mixing is studied. Assuming that magnetic field power spectrum is approximated by a power law $P_B(k)\\propto k^n$ with spectral index $n$, it is shown that for magnetic field cut-off scales $172.5$ pc $\\leq \\lambda_B\\leq 4\\times 10^3$ pc, axion contribution to CMB $\\mu$ distortion is subdominant in comparison with magnetic field damping in the cosmological plasma. Using COBE upper limit on $\\mu$ and for magnetic field scale $\\lambda_B\\simeq 415$ pc, weaker limit in comparison with other studies on the magnetic field strength ($B_0\\leq 8.5\\times 10^{-8}$ G) up to a factor 10 for the DFSZ axion model and axion mass $m_a\\geq 2.6\\times 10^{-6}$ eV is found. A forecast for the expected sensitivity of PIXIE/PRISM on...

  14. Axion production and CMB spectral distortion in cosmological tangled magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Ejlli, Damian [INFN Laboratori Nazionali del Gran Sasso, Theory group, Assergi, L' Aquila (Italy); Novosibirsk State University, Department of Physics, Novosibirsk (Russian Federation)

    2015-08-15

    Axion production due to photon-axion mixing in tangled magnetic fields prior to the recombination epoch and magnetic field damping can generate cosmic microwave background (CMB) spectral distortions. In particular, the contribution of both processes to the CMB μ distortion in the case of resonant photon-axion mixing is studied. Assuming that the magnetic field power spectrum is approximated by a power law, P{sub B}(k)∝k{sup n} with spectral index n, it is shown that for magnetic field cut-off scales 172.5 pc ≤ λ{sub B} ≤ 4 x 10{sup 3} pc, the axion contribution to the CMB μ distortion is subdominant in comparison with magnetic field damping in the cosmological plasma. Using the COBE upper limit on μ and for the magnetic field scale λ{sub B} ≅ 415 pc, a weaker limit in comparison with other studies on the magnetic field strength (B{sub 0} ≤ 8.5 @ x 10{sup -8} G) up to a factor 10 for the DFSZ axion model and axion mass m{sub a} ≥ 2.6 @ x 10{sup -6} eV is found. A forecast for the expected sensitivity of PIXIE/PRISM on μ is also presented. (orig.)

  15. Planck 2013 results. XIV. Zodiacal emission

    CERN Document Server

    Ade, P A R; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Bartlett, J.G.; Battaner, E.; Benabed, K.; Benoit, A.; Benoit-Levy, A.; Bernard, J.P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J.J.; Bonaldi, A.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R.C.; Cardoso, J.F.; Catalano, A.; Chamballu, A.; Chary, R.-R.; Chen, X.; Chiang, L.Y.; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colley, J.-M.; Colombi, S.; Colombo, L.P.L.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.M.; Desert, F.X.; Dickinson, C.; Diego, J.M.; Dole, H.; Donzelli, S.; Dore, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Ensslin, T.A.; Eriksen, H.K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giraud-Heraud, Y.; Gonzalez-Nuevo, J.; Gorski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F.K.; Hanson, D.; Harrison, D.; Helou, G.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hovest, W.; Huffenberger, K.M.; Jaffe, T.R.; Jaffe, A.H.; Jones, W.C.; Juvela, M.; Keihanen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lahteenmaki, A.; Lamarre, J.M.; Lasenby, A.; Laureijs, R.J.; Lawrence, C.R.; Leonardi, R.; Lesgourgues, J.; Liguori, M.; Lilje, P.B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lubin, P.M.; Macias-Perez, J.F.; Maffei, B.; Maino, D.; Mandolesi, N.; Maris, M.; Marshall, D.J.; Martin, P.G.; Martinez-Gonzalez, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschenes, M.A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Mottet, S.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Norgaard-Nielsen, H.U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; O'Sullivan, C.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polegre, A. M.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G.W.; Prezeau, G.; Prunet, S.; Puget, J.L.; Rachen, J.P.; Reach, W.T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M.D.; Shellard, E.P.S.; Smoot, G. F.; Spencer, L.D.; Starck, J.L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.S.; Sygnet, J.F.; Tauber, J.A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L.A.; Wandelt, B.D.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-01-01

    The Planck satellite provides a set of all-sky maps at nine frequencies from 30 GHz to 857 GHz. Planets, minor bodies, and diffuse interplanetary dust emission (IPD) are all observed. The IPD can be separated from Galactic and other emissions because Planck views a given point on the celestial sphere multiple times, through different columns of IPD. We use the Planck data to investigate the behaviour of zodiacal emission over the whole sky at sub-millimetre and millimetre wavelengths. We fit the Planck data to find the emissivities of the various components of the COBE zodiacal model -- a diffuse cloud, three asteroidal dust bands, a circumsolar ring, and an Earth-trailing feature. The emissivity of the diffuse cloud decreases with increasing wavelength, as expected from earlier analyses. The emissivities of the dust bands, however, decrease less rapidly, indicating that the properties of the grains in the bands are different from those in the diffuse cloud. We fit the small amount of Galactic emission seen t...

  16. Diffuse Baryons in Groups and Clusters of Galaxies

    CERN Document Server

    Cavaliere, A; Tozzi, P

    1998-01-01

    To predict the X-ray observables associated to the diffuse baryons in clusters of galaxies, we develop a new physical approach to model such a hot intra-cluster plasma. Such approach is based on punctuated equilibria. and comprises the following blocks: Monte Carlo ``merging histories'' of dark matter potential wells; the central hydrostatic disposition for the ICP, reset to a new equilibrium after each merging episode; conditions of shock, or of closely adiabatic compression at the boundary with the external gas, preheated by stellar energy feedbacks. We predict the L-T relation, consistent with the data as for shape and scatter. This we combine with the mass distribution provided by the hierarchical clustering for different COBE-normalized CDM models, to predict the z-resolved luminosity functions, the source counts, the redshift distributions and contribution of the unresolved groups and clusters to the soft X-ray background. When compared with the recent ROSAT surveys, our results confirm that the critica...

  17. Large-scale polarization of the microwave background and foreground

    International Nuclear Information System (INIS)

    The DASI discovery of cosmic microwave background (CMB) polarization has opened a new chapter in cosmology. Most of the useful information about inflationary gravitational waves and reionization is on large angular scales where galactic foreground contamination is the worst, so a key challenge is to model, quantify, and remove polarized foregrounds. We use the POLAR experiment, COBE/DMR and radio surveys to provide the strongest limits to date on the TE cross-power spectrum of the CMB on large angular scales and to quantify the polarized synchrotron radiation, which is likely to be the most challenging polarized contaminant for the WMAP satellite. We find that the synchrotron E and B contributions are equal to within 10% from 408-820 MHz with a hint of E domination at higher frequencies. We quantify Faraday rotation and depolarization effects in the two-dimensional (l,ν) plane and show that they cause the synchrotron polarization percentage to drop both towards lower frequencies and towards lower multipoles

  18. The large-scale polarization of the microwave background and foreground

    CERN Document Server

    De Oliveira-Costa, A; O'Dell, C; Keating, B; Timbie, P; Efstathiou, G P; Smoot, G F; Oliveira-Costa, Angelica de; Tegmark, Max; Dell, Chris O'; Keating, Brian; Timbie, Peter; Efstathiou, George; Smoot, George

    2003-01-01

    The DASI discovery of CMB polarization has opened a new chapter in cosmology. Most of the useful information about inflationary gravitational waves and reionization is on large angular scales where Galactic foreground contamination is the worst, so a key challenge is to model, quantify and remove polarized foregrounds. We use the POLAR experiment, COBE/DMR and radio surveys to provide the strongest limits to date on the TE cross power spectrum of the CMB on large angular scales and to quantify the polarized synchrotron radiation, which is likely to be the most challenging polarized contaminant for the MAP satellite. We find that the synchrotron E- and B-contributions are equal to within 10% from 408-820 MHz with a hint of E-domination at higher frequencies. We quantify Faraday Rotation and Depolarization effects in the two-dimensional (multipole,frequency)-plane and show that they cause the synchrotron polarization percentage to drop both towards lower frequencies and towards lower multipoles.

  19. IYL Blog: Astronomers travel in time and space with light

    Science.gov (United States)

    Mather, John C.

    2015-01-01

    also using light to find out whether we are alone in the universe. The Kepler observatory showed that thousands of stars blink a little when their orbiting planets pass between us and them, and other observatories use light to measure the wobble of stars as their planets pull on them. Eventually, we will find out whether planets like Earth have atmospheres like Earth's too - with water, carbon dioxide, oxygen, methane, and other gases that would be evidence of photosynthetic life. I think in a few decades we will have evidence that some planets do have life, and it will be done using light for remote chemical analysis. Also, astronomers at the SETI project are using light (long wavelength light we can pick up with radio telescopes) to look for signals from intelligent civilizations. That's a harder project because we don't know what to look for. But if we wanted to send signals all the way across the Milky Way, we could do it with laser beams, and if somebody over there knew what to look for, he or she could decode the message. On with the search! Dr. John C. Mather is a Senior Astrophysicist and is the Senior Project Scientist for the James Webb Space Telescope at NASA's Goddard Space Flight Center in Greenbelt, MD. His research centers on infrared astronomy and cosmology. With the Cosmic Background Explorer (COBE) team, he showed that the cosmic microwave background radiation has a blackbody spectrum within 50 parts per million, confirming the expanding universe model (aka the Big Bang Theory) to extraordinary accuracy, and initiating the study of cosmology as a precision science. The COBE team also made the first map of the hot and cold spots in the background radiation. The COBE maps have been confirmed and improved by two succeeding space missions, the Wilkinson Microwave Anisotropy Probe (WMAP, built by GSFC with Princeton University), and the Planck mission built by ESA. Based on these maps, astronomers have now developed a "standard model" of cosmology and have

  20. Dynamics of the Galactic Bulge using Planetary Nebulae

    CERN Document Server

    Beaulieu, S F; Kálnay, A J; Saha, P; Zhao, H S; Beaulieu, Sylvie F.; Freeman, Kenneth C.; Kalnajs, Agris J.; Saha, Prasenjit; Zhao, HongSheng

    2000-01-01

    Evidence for a bar at the center of the Milky Way triggered a renewed enthusiasm for dynamical modelling of the Galactic bar-bulge. Our goal is to compare the kinematics of a sample of tracers, planetary nebulae, widely distributed over the bulge with the corresponding kinematics for a range of models of the inner Galaxy. Three of these models are N-body barred systems arising from the instabilities of a stellar disk (Sellwood, Fux and Kalnajs), and one is a Schwarzschild system constructed to represent the 3D distribution of the COBE/DIRBE near-IR light and then evolved as an N-body system for a few dynamical times (Zhao). For the comparison of our data with the models, we use a new technique developed by Saha (1998). The procedure finds the parameters of each model, i.e. the solar galactocentric distance R_o in model units, the orientation angle phi, the velocity scale (in km/s per model unit), and the solar tangential velocity which best fit the data.

  1. Interplanetary Meteoroid Engineering Model Based on Long-Term Particle Dynamics

    Science.gov (United States)

    Dikarev, V.; Grün, E.; Landgraf, M.

    2001-11-01

    We construct a new meteoroid model that replaces the models by Divine (1993, JGR 98(E9), 17029--17048, ``Five population of interplanetary meteoroids'') and Staubach & Grün (1995, Advances in Space Research 16(11), 103--106, ``Development of an upgraded meteoroid model''). Our approach of describing the interplanetary dust cloud, however, is different from that of our predecessors. Instead of empirically found distribution functions, we use distributions that are determined by orbital evolution of various dust populations. The populations correspond to expected structures in zodiacal cloud. We determine the distributions of meteoroid-sized debris dispersed along the orbits of the parent bodies, comets and asteroids, meteoroids residing in the torus of debris scattered by Jupiter, and the distributions of small dust grains spiraling towards the Sun under the Poynting-Robertson drag from their parent bodies, including scattered meteoroids. The interstellar dust particles are represented by a physical model as well. Each distribution function has an arbitrary normalization factor corresponding to the unknown dust production rate for the population. We use several data sets to validate the approach and to infer the population normalisation factors minimizing model residuals: interplanetary meteoroid size distribution observed at 1 AU, COBE DIRBE infrared observations, Galileo & Ulysses DDS in-situ impact counts, particle fluxes derived from the Helios 1 and Pioneer 10 and 11 dust experiments, and AMOR radar meteor survey.

  2. The second coming of cold dark matter?

    Energy Technology Data Exchange (ETDEWEB)

    Zurek, W.H.; Warren, M.S. [Los Alamos National Lab., NM (United States); Quinn, P.J. [Mt. Stromlo Observatory, PB Weston Creek, Canberra, ACT (Australia) ; Salmon, J.K. [Caltech Concurrent Supercomputing Facility, Pasadena, CA (United States)

    1993-12-31

    In recent years standard cold dark matter (CDM) theory, which enjoyed a large following throughout much of the past decade, has been abandoned by virtually all of its early supporters. The most serious argument against CDM was the incompatibility between the relatively high value of the pairwise radial velocity dispersion between galaxies, {sigma}{sub v}, inferred from numerical simulation with the much lower observational estimates. We reexamine this argument in the light of our new, high-resolution, COBE-normalized simulations and conclude that {sigma}{sub v} is significantly overestimated in simulations which do not have sufficient resolution (i.e., which have masses of galaxies comparable to the mass of N-body particles) and that it is also difficult to reliably estimate {sigma}{sub v} from the observational catalogues used for this purpose. We conclude that inflationary cosmology and CDM are not -- contrary to the presently prevailing prejudice -- incompatible with the observations of small scale peculiar velocities, as characterized, for example, by {sigma}{sub v}.

  3. Cosmological Parameters from Cosmic Background Imager Observations and Comparisons with BOOMERANG, DASI, and MAXIMA

    CERN Document Server

    Sievers, J L; Cartwright, J K; Contaldi, C R; Mason, B S; Myers, S T; Padin, S; Pearson, T J; Pen, U L; Pogosyan, D; Prunet, S; Readhead, A C S; Shepherd, M C; Udomprasert, P S; Bronfman, L; Holzapfel, W L; May, J

    2003-01-01

    We report on the cosmological parameters derived from observations with the Cosmic Background Imager (CBI), covering 40 square degrees and the multipole range 300 <~ l <~ 3500. These unique, high-resolution observations show the seeds that gave rise to clusters of galaxies and also show damping in the power spectrum to l ~ 2000. Because the observations extend to much higher l the CBI results provide information complementary to that probed by the BOOMERANG, DASI, and MAXIMA experiments. When the CBI observations are used in combination with those from COBE-DMR, we find evidence for a flat universe, Omega(tot)=0.99 +/- 0.12 (1-sigma), a power law index of primordial fluctuations, n_s = 1.05(-0.08,+0.09), and densities in cold dark matter, Omega(cdm)h^2 = 0.17(-0.06,+0.08), and baryons, Omega(b)h^2 = 0.022(-0.009,+0.15). With the addition of large scale structure priors the Omega(cdm)h^2 value is sharpened to 0.12(-0.03,+0.03), and we find Omega(Lambda) = 0.64(-0.14,+0.11). In the l < 1000 overlap reg...

  4. Theoretical Models of the Galactic Bulge

    CERN Document Server

    Shen, Juntai

    2015-01-01

    Near infrared images from the COBE satellite presented the first clear evidence that our Milky Way galaxy contains a boxy shaped bulge. Recent years have witnessed a gradual paradigm shift in the formation and evolution of the Galactic bulge. Bulges were commonly believed to form in the dynamical violence of galaxy mergers. However, it has become increasingly clear that the main body of the Milky Way bulge is not a classical bulge made by previous major mergers, instead it appears to be a bar seen somewhat end-on. The Milky Way bar can form naturally from a precursor disk and thicken vertically by the internal firehose/buckling instability, giving rise to the boxy appearance. This picture is supported by many lines of evidence, including the asymmetric parallelogram shape, the strong cylindrical rotation (i.e., nearly constant rotation regardless of the height above the disk plane), the existence of an intriguing X-shaped structure in the bulge, and perhaps the metallicity gradients. We review the major theor...

  5. The optimisation, design and verification of feed horn structures for future Cosmic Microwave Background missions

    Science.gov (United States)

    McCarthy, Darragh; Trappe, Neil; Murphy, J. Anthony; O'Sullivan, Créidhe; Gradziel, Marcin; Doherty, Stephen; Huggard, Peter G.; Polegro, Arturo; van der Vorst, Maarten

    2016-05-01

    In order to investigate the origins of the Universe, it is necessary to carry out full sky surveys of the temperature and polarisation of the Cosmic Microwave Background (CMB) radiation, the remnant of the Big Bang. Missions such as COBE and Planck have previously mapped the CMB temperature, however in order to further constrain evolutionary and inflationary models, it is necessary to measure the polarisation of the CMB with greater accuracy and sensitivity than before. Missions undertaking such observations require large arrays of feed horn antennas to feed the detector arrays. Corrugated horns provide the best performance, however owing to the large number required (circa 5000 in the case of the proposed COrE+ mission), such horns are prohibitive in terms of thermal, mechanical and cost limitations. In this paper we consider the optimisation of an alternative smooth-walled piecewise conical profiled horn, using the mode-matching technique alongside a genetic algorithm. The technique is optimised to return a suitable design using efficient modelling software and standard desktop computing power. A design is presented showing a directional beam pattern and low levels of return loss, cross-polar power and sidelobes, as required by future CMB missions. This design is manufactured and the measured results compared with simulation, showing excellent agreement and meeting the required performance criteria. The optimisation process described here is robust and can be applied to many other applications where specific performance characteristics are required, with the user simply defining the beam requirements.

  6. Cosmological Implications of the PSCz PDF and its Moments

    CERN Document Server

    Plionis, M

    2001-01-01

    We compare the PDF and its low-order moments (variance and skewness) of the smoothed PSCz galaxy density field and of the corresponding simulated PSCz look-alikes, generated from N-body simulations of 6 different DM models; four structure normalized with $\\Gamma=0.25$ and $\\sigma_{8}=0.55 \\Omega_{\\circ}^{-0.6}$, one COBE normalized and the old SCDM. The galaxy distributions are smoothed with a Gaussian window at three different smoothing scales $R_{sm}=5$, 10 and $15 h^{-1}$ Mpc. We find that the simulation PSCz look-alike PDF's are sensitive only on the normalization of the power spectrum, probably due to shape similarity of the simulated galaxy power spectrum on the relevant scales. We find that the only models that are consistent, at a high significance level, with the observed PSCz PDF are models with a relatively low power spectrum normalization $(\\sigma_{8}=0.83)$. From the phenomenologically derived $\\sigma_{8}-moments$ relation, fitted from the simulation data, we find that the PSCz moments suggest $\\...

  7. Engineering of a novel carbonyl reductase with coenzyme regeneration in E. coli for efficient biosynthesis of enantiopure chiral alcohols.

    Science.gov (United States)

    Wei, Ping; Gao, Jia-Xin; Zheng, Gao-Wei; Wu, Hong; Zong, Min-Hua; Lou, Wen-Yong

    2016-07-20

    The novel anti-Prelog stereospecific carbonyl reductase from Acetobacter sp. CCTCC M209061 was successfully expressed in E. coli combined with glucose dehydrogenase (GDH) to construct an efficient whole-cell biocatalyst with coenzyme NADH regeneration. The enzymatic activity of GAcCR (AcCR with a GST tag) reached 304.9U/g-dcw, even 9 folds higher than that of wild strain, and the activity of GDH for NADH regeneration recorded 46.0U/mg-protein in the recombinant E. coli. As a whole-cell biocatalyst, the recombinant E. coli BL21(DE3)pLysS (pETDuet-gaccr-gdh) possessed a broad substrate spectrum for kinds of carbonyl compounds with encouraging yield and stereoselectivity. Besides, the asymmetric reduction of ethyl 4-chloroacetoacetate (COBE) to optically pure ethyl 4-chloro-3-hydroxybutyrate (CHBE) catalyzed by the whole-cell biocatalyst was systematically investigated. Under the optimal reaction conditions, the optical purity of CHBE was over 99% e.e. for (S)-enantiomer, and the initial rate and product yield reached 8.04μmol/min and 99.4%, respectively. Moreover, the space-time yield was almost 20 folds higher than that catalyzed by the wild strain. Therefore, a new, high efficiency biocatalyst for asymmetric reductions was constructed successfully, and the enantioselective reduction of prochiral compounds using the biocatalyst was a promising approach for obtaining enantiopure chiral alcohols. PMID:27211999

  8. Non-Linear Clustering in the Cold+Hot Dark Matter Model

    CERN Document Server

    Bonometto, S A; Ghigna, S; Klypin, A A; Primack, Joel R

    1993-01-01

    We use high resolution PM N-body simulations to follow the development of non-linear clustering in a flat Universe, dominated by Cold + Hot Dark Matter (CHDM) with 60% of CDM, 30% of HDM and 10% of baryons; a simulation box of 100 Mpc a side ($h=0.5$) is used. We analyze two CHDM simulations with $b =1.5$ (COBE normalization). We also compare them with CDM simulations with $b=1.5$ and $b=1$. We evaluate high-order correlation functions and the void-probability-function (VPF). Correlation functions are obtained both from counts in cells and counts of neighbors. The analysis is made for DM particles and for galaxies, identified as massive halos in the evolved density field. We also check the effects of dynamical evolution and redshift space distortions. We find that clustering of DM particles exhibits deviations from the hierarchical scaling, which decrease somewhat in redshift space. Galaxies follow hierarchical scaling far more closely, with coefficients S_3=2.5 and S_4=7.5, in general agreement with observat...

  9. Evaluation of ultrasound training in the problem based learning radiography curriculum at Makerere University, Uganda

    International Nuclear Information System (INIS)

    Introduction: The College of Health Sciences (CHS), Makerere University has been training health professionals since 1924. Six years ago, there was a curriculum change to Problem Based Learning/Community based Education and Service (PBL/COBES). A SPICES model (Student centered, problem based, integrated, community based, electives, systematic) was adopted and defined to suit the CHS environment. The radiography program is 3 years in length which involves Ultrasound as an important part of the training. It was a challenge to adopt the new PBL method of learning after having a lecture-based pedagogical method for over 80 years. Objective: To implement the training of ultrasound in the PBL radiography curriculum as well as evaluate the opinions of the staff and students about Ultrasound training in the new curriculum. Methodology: A participatory approach was used. Workshops were conducted and objectives for ultrasound courses refined. Scenarios were written for use in the PBL sessions. A retrospective review of student performance in the ultrasound courses was carried out. A cross-sectional survey involving teachers and current radiography students was also carried out to evaluate learning of ultrasound using the PBL approach. Results: Students have consistently excelled in ultrasound courses using the PBL approach of learning. Both teachers and students rated the teaching of ultrasound to radiography students as being highly important and supported the new approach to training. Conclusion: Ultrasound training using PBL has been successfully implemented. However, this is still an ongoing process and will require the total commitment of both students and teachers.

  10. Open cold dark matter models

    CERN Document Server

    Liddle, A R; Roberts, D; Viana, P T P; Liddle, Andrew R; Lyth, David H; Roberts, David; Viana, Pedro P T

    1995-01-01

    Motivated by recent developments in inflationary cosmology indicating the possibility of obtaining genuinely open universes in some models, we compare the predictions of Cold Dark Matter models in open universes with a variety of observational information. We allow arbitrary variation of the density parameter \\Omega_0 and the Hubble parameter h, and take full account of the baryon content assuming standard nucleosynthesis. We normalize the power spectrum using the recent analysis of the two year COBE DMR data by Gorski et al. (1995). We then consider a variety of observations, namely the galaxy correlation function, bulk flows, the abundance of galaxy clusters and the abundance of damped Lyman alpha systems. For the last two of these, we provide a new treatment appropriate to open universes. We find that if one allows an arbitrary h, then a good fit is available for any \\Omega_0 greater than 0.35, though for \\Omega_0 close to one the required h is alarmingly low. Models with \\Omega_0 0.6, as favoured by rece...

  11. Family symmetry, fermion mass matrices and cosmic texture

    International Nuclear Information System (INIS)

    The observed replication of fermions in three families is undoubtedly a reflection of a deeper symmetry underlying the standard model. In this paper we investigate one very elementary possibility, that physics above the grand unification scale is described by the symmetry group G x SU(3)fam with G a gauged grand unified group, and SU(3)fam a global family symmetry. The breaking of this symmetry at the GUT scale produces global texture, providing a mechanism for structure formation in the universe, and sets strong constraints on the low energy fermion mass matrix. With the addition of a 45 Higgs and certain assumptions about the relative strength of Higgs couplings, the simplest SU(5) theory yields an eight-parameter form for the fermion mass matrices, which we show is consistent with the thirteen observable masses and mixing angles. We discuss the natural suppression of flavour-changing neutral currents (FCNCs) and emphasise the rich low energy Higgs sector. With minor assumptions, the theory unifies consistently with the recent LEP data. We consider the extension to G = SO(10), where some simplification and further predictiveness emerges. Finally we discuss the dynamics of SU(3)fam texture and show that the known constraints on unification ''predict'' a GUT symmetry-breaking scale of the order required for cosmic structure formation, and by the recent detection of cosmic microwave anisotropy by COBE. (orig.)

  12. Search for Anisotropic Light Propagation as a Function of Laser Beam Alignment Relative to the Earth's Velocity Vector

    Directory of Open Access Journals (Sweden)

    Navia C. E.

    2007-01-01

    Full Text Available A laser diffraction experiment was conducted to study light propagation in air. The experiment is easy to reproduce and it is based on simple optical principles. Two optical sensors (segmented photo-diodes are used for measuring the position of diffracted light spots with a precision better than 0.1 μ m. The goal is to look for signals of anisotropic light propagation as function of the laser beam alignment to the Earth’s motion (solar barycenter motion obtained by COBE. Two raster search techniques have been used. First, a laser beam fixed in the laboratory frame scans in space due to Earth’s rotation. Second, a laser beam mounted on a turntable system scans actively in space by turning the table. The results obtained with both methods show that the course of light rays are affected by the motion of the Earth, and a predominant first order quantity with a Δ c/c = − β (1 + 2 a cos θ signature with ˉ a = − 0.393 ± 0.032 describes well the experimental results. This result differs in amount of 21% from the Special Relativity Theory prediction and that supplies the value of a = − 1 2 (isotropy.

  13. CCD Photometry of the Globular Cluster NGC 4833 and Extinction Near the Galactic Plane

    CERN Document Server

    Melbourne, J; Layden, A; Martins, D H; Melbourne, Jason; Sarajedini, Ata; Layden, Andrew; Martins, Donald H.

    2000-01-01

    We present CCD photometry for the Galactic globular cluster NGC 4833. Our BVI color magnitude diagrams (CMD) extend from above the red giant branch (RGB) tip to several magnitudes below the main sequence turnoff. The principal sequences of the cluster show the effects of differential reddening. We have created a local extinction map, consistent with IRAS and COBE/DIRBE dust maps of the region. We use our map to correct the colors and magnitudes of each star to the value at the cluster center. The cluster horizontal branch (HB) is predominately blueward of the instability strip with 13 confirmed RR Lyrae variables and 5 additional RR Lyrae candidates. Using the 11 confirmed RR Lyraes measured on our images, and the differential reddening corrected photometry we calculate V(HB) = 15.56 +/- 0.063. We have used the simultaneous reddening and metallicity method of Sarajedini (1994) to find the mean reddening of the cluster E(B-V) = 0.32 +/- 0.03, and the mean metallicity [Fe/H] = -1.83 +/- 0.14. As for the age of ...

  14. DIRBE Comet Trails

    CERN Document Server

    Arendt, Richard G

    2014-01-01

    Re-examination of the COBE DIRBE data reveals the thermal emission of several comet dust trails. The dust trails of 1P/Halley, 169P/NEAT, and 3200 Phaethon have not been previously reported. The known trails of 2P/Encke, and 73P/Schwassmann-Wachmann 3 are also seen. The dust trails have 12 and 25 micron surface brightnesses of <0.1 and <0.15 MJy/sr, respectively, which is <1% of the zodiacal light intensity. The trails are very difficult to see in any single daily image of the sky, but are evident as rapidly moving linear features in movies of the DIRBE data. Some trails are clearest when crossing through the orbital plane of the parent comet, but others are best seen at high ecliptic latitudes as the Earth passes over or under the dust trail. All these comets have known associations with meteor showers. This re-examination also reveals one additional comet and 13 additional asteroids that had not previously been recognized in the DIRBE data.

  15. The big bang

    Science.gov (United States)

    Silk, Joseph

    Our universe was born billions of years ago in a hot, violent explosion of elementary particles and radiation - the big bang. What do we know about this ultimate moment of creation, and how do we know it? Drawing upon the latest theories and technology, this new edition of The big bang, is a sweeping, lucid account of the event that set the universe in motion. Joseph Silk begins his story with the first microseconds of the big bang, on through the evolution of stars, galaxies, clusters of galaxies, quasars, and into the distant future of our universe. He also explores the fascinating evidence for the big bang model and recounts the history of cosmological speculation. Revised and updated, this new edition features all the most recent astronomical advances, including: Photos and measurements from the Hubble Space Telescope, Cosmic Background Explorer Satellite (COBE), and Infrared Space Observatory; the latest estimates of the age of the universe; new ideas in string and superstring theory; recent experiments on neutrino detection; new theories about the presence of dark matter in galaxies; new developments in the theory of the formation and evolution of galaxies; the latest ideas about black holes, worm holes, quantum foam, and multiple universes.

  16. Superconductivity, the Structure Scale of the Universe

    CERN Document Server

    Saam, R D

    1997-01-01

    A lattice and associated superconducting theory is postulated whereby electromagnetic and gravitational forces are mediated by a particle of mass (110.39 x electron mass) such that the established electron/proton mass is maintained, electron and proton charge is maintained and the universe radius is 1.5E28 cm, the universe mass is 2.00E56 gram, the universe density is 1.45E-29 g/cm3, the universe time or age is 1.57E10 years and the universe Hubble constant is 2.47E-18/sec (76 km/sec-million parsec). The calculated universe mass and density are based on an isotropic homogeneous media filling the vacuum of space analogous to the 'ether' referred to in the 19th century and could be considered a candidate for the 'dark matter' in present universe theories. In this context the COBE satellite universe background microwave black body radiation temperature is linked to universe dark matter superconducting temperature. Also, a reasonable value for the cosmological constant is derived having dimensions of the known un...

  17. Superconductivity, the Structure Scale of the Universe, Second Edition

    CERN Document Server

    Saam, R D

    1999-01-01

    A theoretical framework supported by experimental evidence is presented which indicates that superconductivity is a relativistic phenomenon. A lattice and associated superconducting theory is postulated whereby electromagnetic and gravitational forces are mediated by a particle of relativistic velocity transformed mass (110.39 x electron mass) such that the established electron/proton mass is maintained, electron and proton charge is maintained and the universe radius is 1.5E28 cm, the universe mass is 2.00E56 gram, the universe density is 1.45E-29 g/cm3, the universe time or age is 1.57E10 years and the universe Hubble constant is 2.47E-18/sec (76 km/sec-million parsec). The calculated universe mass and density are based on an isotropic homogeneous media filling the vacuum of space analogous to the 'aether' referred to in the 19th century and could be considered a candidate for the 'dark matter' in present universe theories. In this context the COBE satellite universe background microwave black body radiatio...

  18. Understanding Creation: Cosmology at the Dawn of the 21st Century

    Science.gov (United States)

    Lang, Andrew E.

    1997-01-01

    Cosmology attempts to answer questions concerning the origin of the universe, the way in which it evolves, and the way in which it will end. These are ancient questions that fascinate humanity and attendant metaphysical answers predate recorded history. The dawn of the 21st century has witnessed the first scientific answers. The goal of modern cosmology is to determine the basic properties of the universe. Numerous discoveries have been made in the last century which have had a profound influence on cosmology such as the expansion of the universe and the existence of the cosmic microwave background (CMB). CMB and other phenomena act as fossils for cosmologists who attempt to characterize the early universe through an interpretive methodology similar to that of archaeologists. Programs and tools such as NASA's Cosmic Background Explorer (COBE) have been designed to illuminate the morphologic history of the universe including the big bang theory and the current density of the universe. In this primer for cosmology, these and other discoveries and postulations are discussed.

  19. PRISM (Polarized Radiation Imaging and Spectroscopy Mission): A White Paper on the Ultimate Polarimetric Spectro-Imaging of the Microwave and Far-Infrared Sky

    CERN Document Server

    Andre, Philippe; Barbosa, Domingos; Bartlett, James; Bartolo, Nicola; Battistelli, Elia; Battye, Richard; Bendo, George; Bernard, Jean-Philippe; Bersanelli, Marco; Bethermin, Matthieu; Bielewicz, Pawel; Bonaldi, Anna; Bouchet, Francois; Boulanger, Francois; Brand, Jan; Bucher, Martin; Burigana, Carlo; Cai, Zhen-Yi; Casasola, Viviana; Castex, Guillaume; Challinor, Anthony; Chluba, Jens; Colafrancesco, Sergio; Cuttaia, Francesco; D'Alessandro, Giuseppe; Davis, Richard; de Avillez, Miguel; de Bernardis, Paolo; de Petris, Marco; de Rosa, Adriano; de Zotti, Gianfranco; Delabrouille, Jacques; Dickinson, Clive; Diego, Jose Maria; Falgarone, Edith; Ferreira, Pedro; Ferriere, Katia; Finelli, Fabio; Fletcher, Andrew; Fuller, Gary; Galli, Silvia; Ganga, Ken; Garcia-Bellido, Juan; Ghribi, Adnan; Gonzalez-Nuevo, Joaquin; Grainge, Keith; Gruppuso, Alessandro; Hall, Alex; Hernandez-Monteagudo, Carlos; Jackson, Mark; Jaffe, Andrew; Khatri, Rishi; Lamagna, Luca; Lattanzi, Massimiliano; Leahy, Paddy; Liguori, Michele; Liuzzo, Elisabetta; Lopez-Caniego, Marcos; Macias-Perez, Juan; Maffei, Bruno; Maino, Davide; Masi, Silvia; Mangilli, Anna; Massardi, Marcella; Matarrese, Sabino; Melchiorri, Alessandro; Melin, Jean-Baptiste; Mennella, Aniello; Mignano, Arturo; Miville-Deschenes, Marc-Antoine; Nati, Federico; Natoli, Paolo; Negrello, Mattia; Noviello, Fabio; Paci, Francesco; Paladino, Rosita; Paoletti, Daniela; Perrotta, Francesca; Piacentini, Francesco; Piat, Michel; Piccirillo, Lucio; Pisano, Giampaolo; Polenta, Gianluca; Ricciardi, Sara; Roman, Matthieu; Rubino-Martin, Jose-Alberto; Salatino, Maria; Schillaci, Alessandro; Shellard, Paul; Silk, Joseph; Stompor, Radek; Sunyaev, Rashid; Tartari, Andrea; Terenzi, Luca; Toffolatti, Luigi; Tomasi, Maurizio; Trombetti, Tiziana; Tucci, Marco; Van Tent, Bartjan; Verde, Licia; Wandelt, Ben; Withington, Stafford

    2013-01-01

    PRISM (Polarized Radiation Imaging and Spectroscopy Mission) was proposed to ESA in response to the Call for White Papers for the definition of the L2 and L3 Missions in the ESA Science Programme. PRISM would have two instruments: (1) an imager with a 3.5m mirror (cooled to 4K for high performance in the far-infrared---that is, in the Wien part of the CMB blackbody spectrum), and (2) an Fourier Transform Spectrometer (FTS) somewhat like the COBE FIRAS instrument but over three orders of magnitude more sensitive. Highlights of the new science (beyond the obvious target of B-modes from gravity waves generated during inflation) made possible by these two instruments working in tandem include: (1) the ultimate galaxy cluster survey gathering 10e6 clusters extending to large redshift and measuring their peculiar velocities and temperatures (through the kSZ effect and relativistic corrections to the classic y-distortion spectrum, respectively) (2) a detailed investigation into the nature of the cosmic infrared back...

  20. Search for anisotropic light propagation as a function of laser beam alignment relative to the Earth's velocity vector

    CERN Document Server

    Navia, C E; Franceschini, D F; Robba, M B; Tsui, K H

    2006-01-01

    A laser diffraction experiment was conducted to study light propagation in air. The experiment is easy to reproduce and it is based on simple optical principles. Two optical sensors (segmented photo-diodes) are used for measuring the position of diffracted light spots with a precision better than $0.1 \\mu m$. The goal is to look for signals of anisotropic light propagation as function of the laser beam alignment to the Earth's motion (solar barycenter motion) obtained by COBE. Two raster search techniques have been used. First, a fixed laser beam in the laboratory frame that scans due to Earth's rotation. Second, an active rotation of the laser beam on a turntable system. The results obtained with both methods show that the course of the light rays are affected by the motion of the Earth, and a predominant quantity of first order with a $\\Delta c/c=-\\beta (1+2a)\\cos \\theta$ signature with $a=-0.4106\\pm 0.0225$ describes well the experimental results. This result differs in a amount of 18% from the Special Rel...

  1. Likelihood analysis of large-scale flows

    CERN Document Server

    Jaffe, A; Jaffe, Andrew; Kaiser, Nick

    1994-01-01

    We apply a likelihood analysis to the data of Lauer & Postman 1994. With P(k) parametrized by (\\sigma_8, \\Gamma), the likelihood function peaks at \\sigma_8\\simeq0.9, \\Gamma\\simeq0.05, indicating at face value very strong large-scale power, though at a level incompatible with COBE. There is, however, a ridge of likelihood such that more conventional power spectra do not seem strongly disfavored. The likelihood calculated using as data only the components of the bulk flow solution peaks at higher \\sigma_8, as suggested by other analyses, but is rather broad. The likelihood incorporating both bulk flow and shear gives a different picture. The components of the shear are all low, and this pulls the peak to lower amplitudes as a compromise. The velocity data alone are therefore {\\em consistent} with models with very strong large scale power which generates a large bulk flow, but the small shear (which also probes fairly large scales) requires that the power would have to be at {\\em very} large scales, which is...

  2. Testing Models for Structure Formation

    CERN Document Server

    Kaiser, N

    1993-01-01

    I review a number of tests of theories for structure formation. Large-scale flows and IRAS galaxies indicate a high density parameter $\\Omega \\simeq 1$, in accord with inflationary predictions, but it is not clear how this meshes with the uniformly low values obtained from virial analysis on scales $\\sim$ 1Mpc. Gravitational distortion of faint galaxies behind clusters allows one to construct maps of the mass surface density, and this should shed some light on the large vs small-scale $\\Omega$ discrepancy. Power spectrum analysis reveals too red a spectrum (compared to standard CDM) on scales $\\lambda \\sim 10-100$ $h^{-1}$Mpc, but the gaussian fluctuation hypothesis appears to be in good shape. These results suggest that the problem for CDM lies not in the very early universe --- the inflationary predictions of $\\Omega = 1$ and gaussianity both seem to be OK; furthermore, the COBE result severely restricts modifications such as tilting the primordial spectrum --- but in the assumed matter content. The power s...

  3. Cosmological parameter estimation and Bayesian model comparison using VSA data

    CERN Document Server

    Slosar, A; Cleary, K; Davies, R D; Davis, R J; Dickinson, C; Genova-Santos, R; Grainge, K; Gutíerrez, C M; Hafez, Y A; Hobson, M P; Jones, M E; Kneissl, R; Lancaster, K; Lasenby, A; Leahy, J P; Maisinger, K; Marshall, P J; Pooley, G G; Rebolo, R; Rubiño-Martín, J A; Rusholme, B A; Saunders, R D E; Savage, R; Scott, P F; Molina, P J S; Taylor, A C; Titterington, D; Waldram, E M; Watson, R A; Wilkinson, A; Slosar, Anze; Carreira, Pedro; Cleary, Kieran; Davies, Rod D.; Davis, Richard J.; Dickinson, Clive; Genova-Santos, Ricardo; Grainge, Keith; Gutierrez, Carlos M.; Hafez, Yaser A.; Hobson, Michael P.; Jones, Michael E.; Kneissl, Rudiger; Lancaster, Katy; Lasenby, Anthony; Maisinger, Klaus; Marshall, Phil J.; Pooley, Guy G.; Rebolo, Rafael; Rubino-Martin, Jose Alberto; Rusholme, Ben; Saunders, Richard D. E.; Savage, Richard; Scott, Paul F.; Molina, Pedro J. Sosa; Taylor, Angela C.; Titterington, David; Waldram, Elizabeth; Watson, Robert A.; Wilkinson, Althea

    2003-01-01

    We constrain the basic comological parameters using the first observations by the Very Small Array (VSA) in its extended configuration, together with existing cosmic microwave background data and other cosmological observations. We estimate cosmological parameters for four different models of increasing complexity. In each case, careful consideration is given to implied priors and the Bayesian evidence is calculated in order to perform model selection. We find that the data are most convincingly explained by a simple flat Lambda-CDM cosmology without tensor modes. In this case, combining just the VSA and COBE data sets yields the 68 per cent confidence intervals Omega_b h^2=0.034 (+0.007, -0.007), Omega_dm h^2 = 0.18 (+0.06, -0.04), h=0.72 (+0.15,-0.13), n_s=1.07 (+0.06,-0.06) and sigma_8=1.17 (+0.25, -0.20). The most general model considered includes spatial curvature, tensor modes, massive neutrinos and a parameterised equation of state for the dark energy. In this case, by combining all recent cosmological...

  4. Daily quality assurance software for a satellite radiometer system

    Science.gov (United States)

    Keegstra, P. B.; Smoot, G. F.; Bennett, C. L.; Aymon, J.; Backus, C.; Deamici, G.; Hinshaw, G.; Jackson, P. D.; Kogut, A.; Lineweaver, C.

    1992-01-01

    Six Differential Microwave Radiometers (DMR) on COBE (Cosmic Background Explorer) measure the large-angular-scale isotropy of the cosmic microwave background (CMB) at 31.5, 53, and 90 GHz. Quality assurance software analyzes the daily telemetry from the spacecraft to ensure that the instrument is operating correctly and that the data are not corrupted. Quality assurance for DMR poses challenging requirements. The data are differential, so a single bad point can affect a large region of the sky, yet the CMB isotropy requires lengthy integration times (greater than 1 year) to limit potential CMB anisotropies. Celestial sources (with the exception of the moon) are not, in general, visible in the raw differential data. A 'quicklook' software system was developed that, in addition to basic plotting and limit-checking, implements a collection of data tests as well as long-term trending. Some of the key capabilities include the following: (1) stability analysis showing how well the data RMS averages down with increased data; (2) a Fourier analysis and autocorrelation routine to plot the power spectrum and confirm the presence of the 3 mK 'cosmic' dipole signal; (3) binning of the data against basic spacecraft quantities such as orbit angle; (4) long-term trending; and (5) dipole fits to confirm the spacecraft attitude azimuth angle.

  5. Diffuse Microwave Emission Survey

    Science.gov (United States)

    Shafer, R. A.; Mather, J.; Kogut, A.; Fixsen, D. J.; Seiffert, M.; Lubin, P. M.; Levin, S. M.

    1996-12-01

    The Diffuse Microwave Emission Survey (DIMES) is a mission concept selected by NASA in 1995 to answer fundamental questions about the content and history of the universe. DIMES will use a set of absolutely calibrated cryogenic radiometers from a space platform to measure the frequency spectrum of the cosmic microwave background (CMB) at wavelengths 15--0.3 cm (frequency 2--100 GHz) to precision 0.1 mK or better. Measurements at centimeter wavelengths probe different physical processes than the COBE-FIRAS spectra at shorter wavelengths, and complement the anisotropy measurements from DMR, balloon and ground-based instruments, and the planned MAP and COBRAS/SAMBA satellites. DIMES will observe the free-free signal from early photoionization to establish the precise epoch of structure formation, and will measure or limit energy release at redshift 10(4) theory and allowed by current measurement limits; even an upper limit at the expected sensitivity 10(-5) MJy/sr will place important constraints on the matter content, structure, and evolution of the universe. Detecting these distortions or showing that they do not exist constitutes the last frontier of CMB observations.

  6. [Cosmic Microwave Background (CMB) Anisotropies

    Science.gov (United States)

    Silk, Joseph

    1998-01-01

    One of the main areas of research is the theory of cosmic microwave background (CMB) anisotropies and analysis of CMB data. Using the four year COBE data we were able to improve existing constraints on global shear and vorticity. We found that, in the flat case (which allows for greatest anisotropy), (omega/H)0 less than 10-7, where omega is the vorticity and H is the Hubble constant. This is two orders of magnitude lower than the tightest, previous constraint. We have defined a new set of statistics which quantify the amount of non-Gaussianity in small field cosmic microwave background maps. By looking at the distribution of power around rings in Fourier space, and at the correlations between adjacent rings, one can identify non-Gaussian features which are masked by large scale Gaussian fluctuations. This may be particularly useful for identifying unresolved localized sources and line-like discontinuities. Levin and collaborators devised a method to determine the global geometry of the universe through observations of patterns in the hot and cold spots of the CMB. We have derived properties of the peaks (maxima) of the CMB anisotropies expected in flat and open CDM models. We represent results for angular resolutions ranging from 5 arcmin to 20 arcmin (antenna FWHM), scales that are relevant for the MAP and COBRA/SAMBA space missions and the ground-based interferometer. Results related to galaxy formation and evolution are also discussed.

  7. COBRAS/SAMBA: the ESA Medium Size Mission for measurements of CBR anisotropy

    Science.gov (United States)

    Mandolesi, N.; Bersanelli, M.; Cesarsky, C.; Danese, L.; Efstathiou, G.; Griffin, M.; Lamarre, J. M.; Norgaard-Nielsen, H. U.; Pace, O.; Puget, J. L.; Raisanen, A.; Smoot, G. F.; Tauber, J.; Volonte, S.

    1995-02-01

    The COBRAS/SAMBA mission is designed for extensive, accurate mapping of the anisotropy of the Cosmic Background Radiation. with angular sensitivity from scales of a few arcminutes up to and overlapping with the > 7° COBE-DMR resolution. This will allow a full identification of the primordial density perturbations which grew to Corm the large-scale structures observed in the present universe. The COBRAS/SAMBA maps will provide a major source of information relevant to several cosmological and astrophysical issues, such as testing theories of the early universe and the origin of cosmic structure. One of the main diffuse foreground emissions will be from interstellar dust, and the mission will provide relevant information on its components and emission properties. A combination of bolometric and radiometric detection techniques will ensure the sensitivity and wide spectral coverage required for accurate foreground discrimination. A far-Earth orbit has been selected to minimize the unwanted emission from the Earth as a source of contamination. The project is currently undergoing a feasibility study within the European Space Agency M3 programme.

  8. The SCUBA-2 Cosmology Legacy Survey: blank-field number counts of 450um-selected galaxies and their contribution to the cosmic infrared background

    CERN Document Server

    Geach, J E; Coppin, K E K; Dunlop, J S; Halpern, M; Smail, Ian; van der Werf, P; Serjeant, S; Farrah, D; Roseboom, I; Targett, T; Arumugam, V; Asboth, V; Blain, A; Chrysostomou, A; Clarke, C; Ivison, R J; Jones, S L; Karim, A; Mackenzie, T; Meijerink, R; Michalowski, M J; Scott, D; Simpson, J; Swinbank, A M; Alexander, D; Almaini, O; Aretxaga, I; Best, P; Chapman, S; Clements, D L; Conselice, C; Danielson, A L R; Eales, S; Edge, A C; Gibb, A; Hughes, D; Jenness, T; Knudsen, K K; Lacey, C; Marsden, G; McMahon, R; Oliver, S; Page, M J; Peacock, J A; Rigopoulou, D; Robson, E I; Spaans, M; Stevens, J; Webb, T M A; Willott, C; Wilson, C D; Zemcov, M

    2012-01-01

    The first deep blank-field 450um map (1-sigma~1.3mJy) from the SCUBA-2 Cosmology Legacy Survey (S2CLS), conducted with the James Clerk Maxwell Telescope (JCMT) is presented. Our map covers 140 arcmin^2 of the COSMOS field, in the footprint of the HST CANDELS area. Using 60 submillimetre galaxies (SMGs) detected at >3.75-sigma, we evaluate the number counts of 450um-selected galaxies with flux densities S_450>5mJy. The 8-arcsec JCMT beam and high sensitivity of SCUBA-2 now make it possible to directly resolve a larger fraction of the cosmic infrared background (CIB, peaking at ~200um) into the individual galaxies responsible for its emission than has previously been possible at this wavelength. At S_450>5mJy we resolve (7.4[+/-]0.7)x10^-2 MJy/sr of the CIB at 450um (equivalent to 16[+/-]7% of the absolute brightness measured by COBE at this wavelength) into point sources. A further ~40% of the CIB can be recovered through a statistical stack of 24um emitters in this field, indicating that the majority (~60%) o...

  9. On the origin of the cosmic microwave background anisotropies

    CERN Document Server

    Follop, Ria; Cooray, Asantha; Abdalla, Filipe B

    2007-01-01

    Suggestions have been made that the microwave background observed by COBE and WMAP and dubbed Cosmic Microwave Background (CMB) may have an origin within our own Galaxy or Earth. To consider the signal that may be correlated with Earth, a correlate-by-eye exercise was attempted by overlaying the CMB map from Wilkinson Microwave Anisotropy Probe on a topographical map of Earth. Remarkably, several hot spots in the CMB map are found to be well aligned with either large cities on Earth or regions of high altitude. To further study the correlations between Earth and CMB, we performed a complicated cross-correlation analysis in the multipole space. The overall correlations are detected at more than 5 sigma confidence level. These results can be naively interpreted to suggest that large angular scale fluctuations in CMB are generated on Earth by a process that traces the altitude relative to a mean radius. Simply extending our analysis, we suggest that cross-correlations between CMB and any other map of a Solar sys...

  10. Rapid Asymmetric Inflation and Early Cosmology in Theories with Sub-Millimeter Dimensions

    CERN Document Server

    Arkani-Hamed, N; Kaloper, Nemanja; March-Russell, John David; Arkani-Hamed, Nima; Dimopoulos, Savas; Kaloper, Nemanja; March-Russell, John

    2000-01-01

    It was recently pointed out that the fundamental Planck mass could be close to the TeV scale with the observed weakness of gravity at long distances being due the existence of new sub-millimeter spatial dimensions. In this picture the standard model fields are localized to a $(3+1)$-dimensional wall or ``3-brane''. We show that in such theories there exist attractive models of inflation that occur while the size of the new dimensions are still small. We show that it is easy to produce the required number of efoldings, and further that the density perturbations $\\delta\\rho/\\rho$ as measured by COBE can be easily reproduced, both in overall magnitude and in their approximately scale-invariant spectrum. In the minimal approach, the inflaton field is just the moduli describing the size of the internal dimensions, the role of the inflationary potential being played by the stabilizing potential of the internal space. We show that under quite general conditions, the inflationary era is followed by an epoch of contra...

  11. Dust-filled axially symmetric universes with a cosmological constant

    CERN Document Server

    Aguiar, P; Aguiar, Paulo; Crawford, Paulo

    2000-01-01

    Following the recent recognition of a positive value for the vacuum energy density and the realization that a simple Kantowski-Sachs model might fit the classical tests of cosmology, we study the qualitative behavior of three anisotropic and homogeneous models: Kantowski-Sachs, Bianchi type-I and Bianchi type-III universes, with dust and a cosmological constant, in order to find out which are physically permitted. We find that these models undergo isotropization up to the point that the observations will not be able to distinguish between them and the standard model, except for the Kantowski-Sachs model $(\\Omega_{k_{0}}0)$ with $\\Omega_{\\Lambda_{0}}$ smaller than some critical value $\\Omega_{\\Lambda_{M}}$. Even if one imposes that the Universe should be nearly isotropic since the last scattering epoch ($z\\approx 1000$), meaning that the Universe should have approximately the same Hubble parameter in all directions (considering the COBE 4-Year data), there is still a large range for the matter density paramete...

  12. Annual parallax and a dimming event of a Mira variable star, FV Bootis

    Science.gov (United States)

    Kamezaki, Tatsuya; Nakagawa, Akiharu; Omodaka, Toshihiro; Inoue, Kan-ichiro; Chibueze, James O.; Nagayama, Takumi; Ueno, Yuji; Matsunaga, Noriyuki

    2016-08-01

    We present the first measurement of the trigonometric parallax of water masers associated with a Mira star, FV Bootis (FV Boo) using VLBI Exploration of Radio Astrometry (VERA). Based on our multi-epoch VERA observations, we derived the parallax to be 0.97 ± 0.06 mas, which corresponds to a distance of 1.03^{+0.07}_{-0.06} kpc. The water masers around FV Boo were spatially distributed over an area of 41 au × 41 au, and their internal motions indicate the presence of an outflow. Using the Kagoshima University 1 m optical/infrared telescope, we determined the period to be 305.6 d and the mean apparent magnitude to be +2.91 mag in the K'-band. On the period-luminosity plane, the obtained period and K'-band magnitude puts FV Boo slightly below the sequence of Miras, possibly due to circumstellar reddening. Combining our photometric data with COBE and 2MASS datasets spanning over 20 years, we found in the near infrared that FV Boo was significantly fainter in 2005 compared with preceding and later phases. Its color, however, did not show a large variation through this change. We infer that the dimming could be caused by an eclipse due to a cloud in a binary system.

  13. [Cosmic Microwave Background (CMB) Anisotropies

    Science.gov (United States)

    Silk, Joseph

    1998-01-01

    One of the main areas of research is the theory of cosmic microwave background (CMB) anisotropies and analysis of CMB data. Using the four year COBE data we were able to improve existing constraints on global shear and vorticity. We found that, in the flat case (which allows for greatest anisotropy), (omega/H)0 less than 10(exp -7), where omega is the vorticity and H is the Hubble constant. This is two orders of magnitude lower than the tightest, previous constraint. We have defined a new set of statistics which quantify the amount of non-Gaussianity in small field cosmic microwave background maps. By looking at the distribution of power around rings in Fourier space, and at the correlations between adjacent rings, one can identify non-Gaussian features which are masked by large scale Gaussian fluctuations. This may be particularly useful for identifying unresolved localized sources and line-like discontinuities. Levin and collaborators devised a method to determine the global geometry of the universe through observations of patterns in the hot and cold spots of the CMB. We have derived properties of the peaks (maxima) of the CMB anisotropies expected in flat and open CDM models. We represent results for angular resolutions ranging from 5 arcmin to 20 arcmin (antenna FWHM), scales that are relevant for the MAP and COBRA/SAMBA space missions and the ground-based interferometer. Results related to galaxy formation and evolution are also discussed.

  14. Phase Lags in the Optical-Infrared Light Curves of AGB Stars

    CERN Document Server

    Smith, B J; Moffett, A J; Smith, Beverly J.; Price, Stephan D.; Moffett, Amanda J.

    2005-01-01

    To search for phase lags in the optical-infrared light curves of asymptotic giant branch stars, we have compared infrared data from the COBE DIRBE satellite with optical light curves from the AAVSO and other sources. We found 17 examples of phase lags in the time of maximum in the infrared vs. that in the optical, and 4 stars with no observed lags. There is a clear difference between the Mira variables and the semi-regulars in the sample, with the maximum in the optical preceding that in the near-infrared in the Miras, while in most of the semi-regulars no lags are observed. Comparison to published theoretical models indicates that the phase lags in the Miras are due to strong titanium oxide absorption in the visual at stellar maximum, and suggests that Miras pulsate in the fundamental mode, while at least some semi-regulars are first overtone pulsators. There is a clear optical-near-infrared phase lag in the carbon-rich Mira V CrB; this is likely due to C2 and CN absorption variations in the optical.

  15. When scientists turn to the public alternative routes in science communication

    CERN Document Server

    Bucchi, M

    1998-01-01

    In the days of global warming and BSE, science is increasingly a public issue. But what should scientists communicate to the general public? To what extent can the public understand and be involved in scientific debate? How does this involvement affect the shaping and organisation of scientific activity? Why do scientists sometime turn to the media and publicize their findings rather than communicating their findings only with their peers? In this presentation, Massimiano Bucchi reviews the existing literature in this field and highlights the pitfalls of current approaches. He then develops his core argument that turning to the public is not simply a response to inaccurate reporting by journalists or to public curiosity, nor a wish to gain recognition and additional funding. Rather, it is a tactic to which the scientific community are pushed by certain ÒinternalÓ crisis situations. Three cases of scientists turning to the public are examined: the cold fusion case, the COBE/Big Bang issue and Louis PasteurÕ...

  16. Space and Earth Sciences, Computer Systems, and Scientific Data Analysis Support, Volume 1

    Science.gov (United States)

    Estes, Ronald H. (Editor)

    1993-01-01

    This Final Progress Report covers the specific technical activities of Hughes STX Corporation for the last contract triannual period of 1 June through 30 Sep. 1993, in support of assigned task activities at Goddard Space Flight Center (GSFC). It also provides a brief summary of work throughout the contract period of performance on each active task. Technical activity is presented in Volume 1, while financial and level-of-effort data is presented in Volume 2. Technical support was provided to all Division and Laboratories of Goddard's Space Sciences and Earth Sciences Directorates. Types of support include: scientific programming, systems programming, computer management, mission planning, scientific investigation, data analysis, data processing, data base creation and maintenance, instrumentation development, and management services. Mission and instruments supported include: ROSAT, Astro-D, BBXRT, XTE, AXAF, GRO, COBE, WIND, UIT, SMM, STIS, HEIDI, DE, URAP, CRRES, Voyagers, ISEE, San Marco, LAGEOS, TOPEX/Poseidon, Pioneer-Venus, Galileo, Cassini, Nimbus-7/TOMS, Meteor-3/TOMS, FIFE, BOREAS, TRMM, AVHRR, and Landsat. Accomplishments include: development of computing programs for mission science and data analysis, supercomputer applications support, computer network support, computational upgrades for data archival and analysis centers, end-to-end management for mission data flow, scientific modeling and results in the fields of space and Earth physics, planning and design of GSFC VO DAAC and VO IMS, fabrication, assembly, and testing of mission instrumentation, and design of mission operations center.

  17. Hunting for primordial non-Gaussianity in the cosmic microwave background

    International Nuclear Information System (INIS)

    Since the first limit on the (local) primordial non-Gaussianity parameter, fNL, was obtained from the Cosmic Background Explorer (COBE) data in 2002, observations of the cosmic microwave background (CMB) have been playing a central role in constraining the amplitudes of various forms of non-Gaussianity in primordial fluctuations. The current 68% limit from the 7-year data of the Wilkinson Microwave Anisotropy Probe (WMAP) is fNL = 32 ± 21, and the Planck satellite is expected to reduce the uncertainty by a factor of 4 in a few years from now. If fNL >> 1 is found by Planck with high statistical significance, all single-field models of inflation would be ruled out. Moreover, if the Planck satellite finds fNL ∼ 30, then it would be able to test a broad class of multi-field models using the 4-point function (trispectrum) test of τNL ≥ (6fNL/5)2. In this paper, we review the methods (optimal estimator), results (WMAP 7-year) and challenges (secondary anisotropy, second-order effect and foreground) of measuring primordial non-Gaussianity from the CMB data, present a science case for the trispectrum and conclude with future prospects.

  18. Bars and secular evolution in disk galaxies: Theoretical input

    CERN Document Server

    Athanassoula, E

    2012-01-01

    Bars play a major role in driving the evolution of disk galaxies and in shaping their present properties. They cause angular momentum to be redistributed within the galaxy, emitted mainly from (near-)resonant material at the inner Lindblad resonance of the bar, and absorbed mainly by (near-)resonant material in the spheroid (i.e., the halo and, whenever relevant, the bulge) and in the outer disk. Spheroids delay and slow down the initial growth of the bar they host, but, at the later stages of the evolution, they strengthen the bar by absorbing angular momentum. Increased velocity dispersion in the (near-)resonant regions delays bar formation and leads to less strong bars. When bars form they are vertically thin, but soon their inner parts puff up and form what is commonly known as the boxy/peanut bulge. This gives a complex and interesting shape to the bar which explains a number of observations and also argues that the COBE/DIRBE bar and the Long bar in our Galaxy are, respectively, the thin and the thick p...

  19. Measurements of Diffuse Sky Emission Components in High Galactic Latitudes at 3.5 and 4.9 um Using DIRBE and WISE Data

    CERN Document Server

    Sano, K; Matsuura, S; Kataza, H; Arai, T; Matsuoka, Y

    2015-01-01

    Using all-sky maps obtained from COBE/DIRBE at 3.5 and 4.9 um, we present a reanalysis of diffuse sky emissions such as zodiacal light (ZL), diffuse Galactic light (DGL), integrated starlight (ISL), and isotropic residual emission including the extragalactic background light (EBL). Our new analysis, which includes an improved estimate of ISL using the Wide-field Infrared Survey Explorer (WISE) data, enabled us to find the DGL signal in a direct linear correlation between diffuse near-infrared and 100 um emission at high Galactic latitudes (|b| > 35 degree). At 3.5um, the high-latitude DGL result is comparable to the low-latitude value derived from the previous DIRBE analysis. In comparison with models of the DGL spectrum assuming a size distribution of dust grains composed of amorphous silicate, graphite, and polycyclic aromatic hydrocarbon (PAH), the measured DGL values at 3.5 and 4.9 um constrain the mass fraction of PAH particles in the total dust species to be more than ~ 2%. This was consistent with the ...

  20. 3D Distribution of Molecular Gas in the Barred Milky Way

    CERN Document Server

    Pohl, Martin; Bissantz, Nicolai

    2007-01-01

    We present a new model of the three-dimensional distribution of molecular gas in the Milky Way Galaxy, based on CO line data. Our analysis is based on a gas-flow simulation of the inner Galaxy using smoothed-particle hydrodynamics (SPH) using a realistic barred gravitional potential derived from the observed COBE/DIRBE near-IR light distribution. The gas model prescribes the gas orbits much better than a simple circular rotation model and is highly constrained by observations, but it cannot predict local details. In this study, we provide a 3D map of the observed molecular gas distribution using the velocity field from the SPH model. A comparison with studies of the Galactic Center region suggests that the main structures are reproduced but somewhat stretched along the line-of-sight, probably on account of limited resolution of the underlying SPH simulation. The gas model will be publicly available and may prove useful in a number of applications, among them the analysis of diffuse gamma-ray emission as measu...

  1. The evolution of X-ray clusters in a cold plus hot dark matter universe

    Science.gov (United States)

    Bryan, Greg L.; Klypin, Anatoly; Loken, Chris; Norman, Michael L.; Burns, Jack O.

    1994-01-01

    We present the first self-consistently computed results on the evolution of X-ray properties of galaxy clusters in a cold + hot dark matter (CHDM) model. We have performed a hydrodynamic plus N-body simulation for the COBE-compatible CHDM model with standard mass components: Omega(sub hot) = 0.3, Omega (sub cold) = 0.6 and Omega(sub baryon) = 0.1 (h = 0.5). In contrast with the CDM model, which fails to reproduce the observed temperature distribution function dN/dT (Bryan et al. 1994b), the CHDM model fits the observational dN/dT quite well. Our results on X-ray luminosity are less firm but even more intriguing. We find that the resulting X-ray luminosity functions at redshifts z = 0.0, 0.2, 0.4, 0.7 are well fit by observations, where they overlap. The fact that both temperatures and luminosities provide a reasonable fit to the available observational data indicates that, unless we are missing some essential physics, there is neither room nor need for a large fraction of gas in rich clusters: 10% (or less) in baryons is sufficient to explain their X-ray properties. We also see a tight correlation between X-ray luminosity and gas temperature.

  2. Planck Early Results: The thermal performance of Planck

    CERN Document Server

    Ade, P A R; Arnaud, M; Ashdown, M; Aumont, J; Baccigalupi, C; Baker, M; Balbi, A; Banday, A J; Barreiro, R B; Battaner, E; Benabed, K; Benoit, A; Bernard, J P; Bersanelli, M; Bhandari, P; Bhatia, R; Bock, J J; Bonaldi, A; Bond, J R; Borders, J; Borrill, J; Bouchet, F R; Bowman, B; Bradshaw, T; Breelle, E; Bucher, M; Burigana, C; Butler, R C; Cabella, P; Camus, P; Cantalupo, C M; Cappellini, B; Cardoso, J F; Catalano, A; Cayon, L; Challinor, A; Chamballu, A; Chambelland, J P; Charra, J; Charra, M; Chiang, L Y; Chiang, C; Christensen, P R; Clements, D L; Collaudin, B; Colombi, S; Couchot, F; Coulais, A; Crill, B P; Crook, M; Cuttaia, F; Damasio, C; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Gasperis, G; de Rosa, A; Delabrouille, J; Delouis, J M; Desert, F -X; Doerl, U; Dolag, K; Donzelli, S; Dore, O; Douspis, M; Dupac, X; Efstathiou, G; Enslin, T A; Eriksen, H K; Finelli, F; Foley, S; Forni, O; Fosalba, P; Fourmond, J J; Frailis, M; Franceschi, E; Galeotta, S; Ganga, K; Gavila, E; Giard, M; Giardino, G; Giraud-Heraud, Y; Gonzalez-Nuevo, J; Gorski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Guyot, G; Harrison, D; Helou, G; Henrot-Versille, S; Hernandez-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hovest, W; Hoyland, R J; Huffenberger, K M; Israelsson, U; Jaffe, A H; Jones, W C; Juvela, M; Keihanen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knox, L; Kurki-Suonio, H; Lagache, G; Lamarre, J M; Lami, P; Lasenby, A; Laureijs, R J; Lawrence, C R; Leach, S; Leonardi, R; Leroy, C; Lilje, P B; Lopez-Caniego, M; Lubin, P M; Macias-Perez, J F; Maciaszek, T; MacTavish, C J; Maffei, B; Maino, D; Mandolesi, N; Mann, R; Maris, M; Martinez-Gonzalez, E; Masi, S; Matarrese, S; Matthai, F; Mazzotta, P; McGehee, P; Meinhold, P R; Melchiorri, A; Melot, F; Mendes, L; Mennella, A; Miville-Deschenes, M -A; Moneti, A; Montier, L; Mora, J; Morgante, G; Morisset, N; Mortlock, D; Munshi, D; Murphy, A; Naselsky, P; Nash, A; Natoli, P; Netterfield, C B; Novikov, D; Novikov, I; O'Dwyer, I J; Osborne, S; Pajot, F; Pasian, F; Patanchon, G; Pearson, D; Perdereau, O; Perotto, L; Perrotta, F; Piacentini, F; Piat, M; Plaszczynski, S; Platania, P; Pointecouteau, E; Polenta, G; Ponthieu, N; Poutanen, T; Prezeau, G; Prina, M; Prunet, S; Puget, J L; Rachen, J P; Rebolo, R; Reinecke, M; Renault, C; Ricciardi, S; Riller, T; Ristorcelli, I; Rocha, G; Rosset, C; Rubiino-Martin, J A; Rusholme, B; Sandri, M; Santos, D; Schaefer, B M; Scott, D; Seiffert, M D; Shellard, P; Smoot, G F; Starck, J -L; Stassi, P; Stivoli, F; Stolyarov, V; Stompor, R; Sudiwala, R; Sygnet, J -F; Tauber, J A; Terenzi, L; Toffolatti, L; Tomasi, M; Torre, J -P; Tristram, M; Tuovinen, J; Valenziano, L; Vibert, L; Vielva, P; Villa, F; Vittorio, N; Wade, L A; Wandelt, B D; Watson, C; White, S D M; Wilkinson, A; Wilson, P; Yvon, D; Zacchei, A; Zhang, B; Zonca, A

    2011-01-01

    The performance of the Planck instruments in space is enabled by their low operating temperatures, 20K for LFI and 0.1K for HFI, achieved through a combination of passive radiative cooling and three active mechanical coolers. Active coolers were chosen to minimize straylight on the detectors and to maximize lifetime. The scientific requirement for very broad frequency led to two detector technologies with widely different temperature and cooling needs. This made use of a helium cryostat, as used by previous cryogenic space missions (IRAS, COBE, ISO, SPITZER, AKARI), infeasible. Radiative cooling is provided by three V-groove radiators and a large telescope baffle. The active coolers are a hydrogen sorption cooler (<20K), a 4He Joule-Thomson cooler (4.7K), and a 3He-4He dilution cooler (1.4K and 0.1K). The flight system was at ambient temperature at launch and cooled in space to operating conditions. The bolometer plate of the High Frequency Instrument reached 93mK on 3 July 2009, 50 days after launch. The ...

  3. The evolution of voids in the adhesion approximation

    CERN Document Server

    Sahni, V; Shandarin, S F; Varun Sahni; Sergei F Shandarin

    1994-01-01

    We apply the adhesion approximation to study the formation and evolution of voids in the Universe. Our simulations - carried out using 128.sup(3) particles in a cubical box with side 128 Mpc - indicate that the void spectrum evolves with time and that the mean void size in the standard COBE-normalised Cold Dark Matter (hereafter CDM) model with h_{50} = 1, scales approximately as \\bar D(z) = {\\bar D_0\\over \\sqrt {1+z}}, where \\bar D_0 \\simeq 10.5 Mpc. Interestingly, we find a strong correlation between the sizes of voids and the value of the primordial gravitational potential at void centers. This observation could in principle, pave the way towards reconstructing the form of the primordial potential from a knowledge of the observed void spectrum. Studying the void spectrum at different cosmological epochs, for spectra with a built in k-space cutoff we find that, the number of voids in a representative volume evolves with time. The mean number of voids first increases until a maximum value is reached (indicat...

  4. Detection of an exoplanet around the evolved K giant HD 66141

    CERN Document Server

    Lee, B -C; Han, I; Park, M -G; Kim, K -M

    2012-01-01

    Aims. We have been carrying out a precise radial velocity (RV) survey for K giants to search for and study the origin of the lowamplitude and long-periodic RV variations. Methods. We present high-resolution RV measurements of the K2 giant HD 66141 from December 2003 to January 2011 using the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at Bohyunsan Optical Astronomy Observatory (BOAO). Results. We find that the RV measurements for HD 66141 exhibit a periodic variation of 480.5 +/- 0.5 days with a semi-amplitude of 146.2 +/- 2.7 m/s. The Hipparcos photometry and bisector velocity span (BVS) do not show any obvious correlations with RV variations. We find indeed 706.4 +/- 35.0 day variations in equivalent width (EW) measurements of H_alpha line and 703.0 +/- 39.4 day variations in a space-born measurements 1.25{\\mu} flux of HD 66141 measured during COBE/DIRBE experiment. We reveal that a mean value of long-period variations is about 705 +/- 53 days and the origin is a rotation period of the star ...

  5. Clinical Allograft Islets Post-transplant 1 Year for Type 1 Diabetes Mellitus with A Modified Edmonton Protocol%同种异体胰岛细胞移植治疗1型糖尿病的护理

    Institute of Scientific and Technical Information of China (English)

    张雯

    2015-01-01

    目的:总结同种异体胰岛细胞移植治疗1型糖尿病的护理研究。方法按JDRF标准筛选3例1型糖尿病患者(T1DM),并实施同种异体胰岛细胞移植。在GMP实验室内以Liberase 酶消化胰腺器官、COBE 2991细胞分离机分离、连续密度梯度纯化,获取高纯度与高活性的胰岛细胞。培养12h后,检测其达到移植标准,再经皮穿刺肝脏门静脉主干,经门静脉将胰岛细胞匀速移植到肝脏内。术后应用各种护理方法,密切观察病情变化和各种并发症的变化。结果2例完全脱离胰岛素治疗,1例胰岛素用量较术前减少60%以上。术后血糖稳定,C肽、糖化血红蛋白在正常范围,肾功能得以改善,无移植并发症、以及低血糖发作,患者掌握了术后自我管理的方法,总结出了个体化的护理经验。结论患者护理效果满意,初步建立同种异体胰岛细胞移植治疗1型糖尿病一整套护理方法。%Objective To investigate the pancreatic islet cell isolation technology,quality standards,and allograft islet cell transplantation in the treatment of type 1 diabetes safety and effectiveness. Methods According to Juvenile Diabetes Research Foundation (JDRF) standard screening method,three cases of type 1 diabetes (T1DM) were selected as allograft islet cells recipi-ents. Using Liberase enzyme digested pancreatic organs,COBE 2991 cell separator,and discontinuous density gradient purification-to obtained high purity and high activity of islet cells. All these procedures were conducted in our GMP facilities. Cultured after 12h,testing islets reached transplant standards,then performed percutaneous hepatic portal vein trunk of the recipients,islet cells were through the portal vein into the recipient liver site. After islet transplantation,using a modified Edmonton immunosuppressive protocol controlled rejection,and monitored of blood glucose,C peptide and glycate hemoglobin level changes regularly for 1-year followed

  6. Nursing of Allogeneic Donor Peripheral Blood Stem Cell Collection%异基因外周血造血干细胞供者采集术的护理

    Institute of Scientific and Technical Information of China (English)

    吕翠侠; 陈美珠; 黄爱勤

    2011-01-01

    Objective To probe nursing of donor peripheral blood stem cell collection, to provide sufficient peripheral blood stem cells,and to ensure successful transplantation of peripheral blood stem cell of providers. Methods Data from recipients during 2006 -2010 were analyzed. The peripheral blood stem cell mobilization regimen for recombinant human granulocyte colony stimulating factor( rhG-CSF) 300 μg.sc, 1 day,4 d,or continuously 5 d,as a result,white blood cells rose to 30 × 109/L. Then by COBE Spectra apheresis unit of whole blood cell the patient' s peripheral blood stem cells were collected and separated,and then input into the providers with leukemia. Throughout the entire process,a full range of care was conducted. Results 128 peripheral blood stem cells were collected from 107 donors. In the total cycle 9000-12 000 ml cases,80% or more WBC of peripheral blood stem cells were collected,and CD34 concentration more than 5 times than before collection. The cells were in security input into 107 recipients,and transplantation success rate was 99%. Conclusion Psychological,diet,basic care and a full range of professional care were provided for providers from the beginning to the end of the collection was a prerequisite for success, and was the key to success in transplantation of a peripheral blood stem cell.%目的 探讨供者外周造血干细胞采集术的护理,提供足够细胞数量的外周造血干细胞数,确保受者外周造血干细胞移植的成功.方法 分析2006~ 2010年供者资料,其外周血干细胞动员方案为粒系集落刺激因子或加用粒单核系集落刺激因皮下注射,1次/d,连续4d或5d,白细胞水平升至30×109/L,应用COBE Spectra全血细胞单采机采集和分离供者的外周血干细胞,输给白血病受者,整过程实行全方位的护理.结果 107例供者共采集了128次外周造血干细胞,在总循环9000~12 000 ml情况下,采集的外周血干细胞中的WBC 80%以上,CD34

  7. Vom Urknall zum Durchknall

    Science.gov (United States)

    Unzicker, Alexander

    Lautstarker Applaus erhob sich im Salon III/IV des Marriott-Hotels von Crystal City im amerikanischen Bundesstaat Virginia. In dem überfüllten Konferenzraum starrten alle wie gebannt auf die Leinwand, wo nicht mehr zu sehen war als ein nüchternes Diagramm aus zahlreichen Punkten und einer geschwungenen Kurve. Nureine eigenartige Personengruppe konnte sich davon zu Emotionen hinreißen lassen - Physiker auf der Jahrestagung der Astronomischen Gesellschaft, die ihren Begeisterungssturm noch minutenlang fortsetzten. Was war geschehen? Die im Diagramm aufgetragenen Daten bestätigten mit einer nie da gewesenen Genauigkeit ein fundamentales Naturgesetz zur Wärmeabstrahlung von heißen Körpern. 1900 von Max Planck entdeckt, leuchtete es nun in geradezu mathematischer Reinheit auf. Noch sensationeller war der Ursprung der Daten - Mikrowellensignale verschiedener Frequenzen, die nicht aus einem irdischen Labor stammten, sondern von einem heißen Urzustand des Universums! Ein Feuerball aus Wasserstoff und Helium, noch ohne jegliche Strukturen, die irgendwann Leben ermöglichen sollten, ließ damals seinem Licht freien Lauf. Mehr als zehn Milliarden Jahre war es bis zu den Detektoren des vom Menschen gebauten Satelliten COBE unterwegs, der wenige Tage zuvor die Daten übertragen hatte. Wenn ich das alles wie einen Film in meiner Vorstellung ablaufen lasse, bekomme ich immer eine Gänsehaut, als würde ich die inzwischen extrem abgekühlte Strahlung tatsächlich spüren. Ihre Gleichverteilung im Raum macht uns auch deutlich, dass wir uns nicht einbilden dürfen, an einem besonderen Ort im Universum zu leben - intelligente Aliens könnten sich seitdem überall entwickelt haben! Sollten sie - was nicht wahrscheinlich ist - uns wirklich von Zeit zu Zeit über die Schulter schauen, dann hätten sie an jenem Nachmittag des 13. Januar 1990, als der Vortrag stattfand, bestimmt anerkennend mit ihrem großen Kopf genickt.

  8. Infrared Kuiper Belt Constraints

    International Nuclear Information System (INIS)

    We compute the temperature and IR signal of particles of radius a and albedo α at heliocentric distance R, taking into account the emissivity effect, and give an interpolating formula for the result. We compare with analyses of COBE DIRBE data by others (including recent detection of the cosmic IR background) for various values of heliocentric distance R, particle radius a, and particle albedo α. We then apply these results to a recently developed picture of the Kuiper belt as a two-sector disk with a nearby, low-density sector (40< R<50 endash 90 AU) and a more distant sector with a higher density. We consider the case in which passage through a molecular cloud essentially cleans the solar system of dust. We apply a simple model of dust production by comet collisions and removal by the Poynting-Robertson effect to find limits on total and dust masses in the near and far sectors as a function of time since such a passage. Finally, we compare Kuiper belt IR spectra for various parameter values. Results of this work include: (1) numerical limits on Kuiper belt dust as a function of (R, a, α) on the basis of four alternative sets of constraints, including those following from recent discovery of the cosmic IR background by Hauser et al.; (2) application to the two-sector Kuiper belt model, finding mass limits and spectrum shape for different values of relevant parameters including dependence on time elapsed since last passage through a molecular cloud cleared the outer solar system of dust; and (3) potential use of spectral information to determine time since last passage of the Sun through a giant molecular cloud. copyright copyright 1999. The American Astronomical Society

  9. Space/Time, Supernovae and the Faint Young Sun

    Science.gov (United States)

    Riofrio, L. M.

    2006-08-01

    EVIDENCE from Supernovae, the CMB, and the geological record supports a Unified Space/Time. Theory provides a simple explanation for problems of current cosmology. In review, a simple principle states that Space and Time are one phenomenon, related by factor c the "speed of light". Scale R of the Universe is related to its age t by R = ct. Relativity and gravitation then require that c be related to t by GM = tc^3. Together these expressions form a solution to Einstein-Friedmann equations with stable density (Omega) = 1. Scale, horizon, density and redshift data may be predicted without hypothetical energies. The cosmic microwave background provides a first test of theory. First acoustic peak indicates a density (Omega) = 1 as predicted. Uniformity in the CMB indicates a much higher primordial speed of light. Lack of large-scale fluctuations appears to rule out inflationary models. In contrast, Theory's predicted spectrum is a close fit with both WMAP and COBE data. Observations of Type Ia supernovae provide a second test. Low redshifts increase linearly, again indicating that (Omega)=1. Higher Z data appears to curve upward, leading to speculation about acceleration and repulsive energies. Alternately, the data shows that c has changed exactly as predicted. Theory's predicted curve fits the data more closely than any other model, without conjuring invisible energies. To distinguish "c change" from accelerating Universe models, corroborating data is required. The standard solar model predicts that during formation the Sun was only 70% as luminous and early Earth would have frozen solid. Geology and the fossil record contradict this prediction. Since the Sun converts fuel to energy according to E=mc^2, higher c in the past means that the solar luminosity has been nearly constant over 4 billion years. Combined with supernova data, evidence indicates that c has changed at precisely the rate predicted. Since Space/Time predicts results not epicycles, Theory should be

  10. Backup Attitude Control Algorithms for the MAP Spacecraft

    Science.gov (United States)

    ODonnell, James R., Jr.; Andrews, Stephen F.; Ericsson-Jackson, Aprille J.; Flatley, Thomas W.; Ward, David K.; Bay, P. Michael

    1999-01-01

    The Microwave Anisotropy Probe (MAP) is a follow-on to the Differential Microwave Radiometer (DMR) instrument on the Cosmic Background Explorer (COBE) spacecraft. The MAP spacecraft will perform its mission, studying the early origins of the universe, in a Lissajous orbit around the Earth-Sun L(sub 2) Lagrange point. Due to limited mass, power, and financial resources, a traditional reliability concept involving fully redundant components was not feasible. This paper will discuss the redundancy philosophy used on MAP, describe the hardware redundancy selected (and why), and present backup modes and algorithms that were designed in lieu of additional attitude control hardware redundancy to improve the odds of mission success. Three of these modes have been implemented in the spacecraft flight software. The first onboard mode allows the MAP Kalman filter to be used with digital sun sensor (DSS) derived rates, in case of the failure of one of MAP's two two-axis inertial reference units. Similarly, the second onboard mode allows a star tracker only mode, using attitude and derived rate from one or both of MAP's star trackers for onboard attitude determination and control. The last backup mode onboard allows a sun-line angle offset to be commanded that will allow solar radiation pressure to be used for momentum management and orbit stationkeeping. In addition to the backup modes implemented on the spacecraft, two backup algorithms have been developed in the event of less likely contingencies. One of these is an algorithm for implementing an alternative scan pattern to MAP's nominal dual-spin science mode using only one or two reaction wheels and thrusters. Finally, an algorithm has been developed that uses thruster one shots while in science mode for momentum management. This algorithm has been developed in case system momentum builds up faster than anticipated, to allow adequate momentum management while minimizing interruptions to science. In this paper, each mode and

  11. Effect of using pump on postoperative pleural effusion in the patients that underwent CABG

    Directory of Open Access Journals (Sweden)

    Mehmet Özülkü

    2015-08-01

    Full Text Available Abstract Objective: The present study investigated effect of using pump on postoperative pleural effusion in patients who underwent coronary artery bypass grafting. Methods: A total of 256 patients who underwent isolated coronary artery bypass grafting surgery in the Cardiovascular Surgery clinic were enrolled in the study. Jostra-Cobe (Model 043213 105, VLC 865, Sweden heart-lung machine was used in on-pump coronary artery bypass grafting. Off-pump coronary artery bypass grafting was performed using Octopus and Starfish. Proximal anastomoses to the aorta in both on-pump and off-pump techniques were performed by side clamps. The patients were discharged from the hospital between postoperative day 6 and day 11. Results: The incidence of postoperative right pleural effusion and bilateral pleural effusion was found to be higher as a count in Group 1 (on-pump as compared to Group 2 (off-pump. But the difference was not statistically significant [P>0.05 for right pleural effusion (P=0.893, P>0.05 for bilateral pleural effusion (P=0.780]. Left pleural effusion was encountered to be lower in Group 2 (off-pump. The difference was found to be statistically significant (P<0.05, P=0.006. Conclusion: Under the light of these results, it can be said that left pleural effusion is less prevalent in the patients that underwent off-pump coronary artery bypass grafting when compared to the patients that underwent on-pump coronary artery bypass grafting.

  12. Planck early results. II. The thermal performance of Planck

    Science.gov (United States)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Baker, M.; Balbi, A.; Banday, A. J.; Barreiro, R. B.; Battaner, E.; Benabed, K.; Benoît, A.; Bernard, J.-P.; Bersanelli, M.; Bhandari, P.; Bhatia, R.; Bock, J. J.; Bonaldi, A.; Bond, J. R.; Borders, J.; Borrill, J.; Bouchet, F. R.; Bowman, B.; Bradshaw, T.; Bréelle, E.; Bucher, M.; Burigana, C.; Butler, R. C.; Cabella, P.; Camus, P.; Cantalupo, C. M.; Cappellini, B.; Cardoso, J.-F.; Catalano, A.; Cayón, L.; Challinor, A.; Chamballu, A.; Chambelland, J. P.; Charra, J.; Charra, M.; Chiang, L.-Y.; Chiang, C.; Christensen, P. R.; Clements, D. L.; Collaudin, B.; Colombi, S.; Couchot, F.; Coulais, A.; Crill, B. P.; Crook, M.; Cuttaia, F.; Damasio, C.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Gasperis, G.; de Rosa, A.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dolag, K.; Donzelli, S.; Doré, O.; Dörl, U.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Filliard, C.; Finelli, F.; Foley, S.; Forni, O.; Fosalba, P.; Fourmond, J.-J.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Gavila, E.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Guyot, G.; Harrison, D.; Helou, G.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Hoyland, R. J.; Huffenberger, K. M.; Israelsson, U.; Jaffe, A. H.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knox, L.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lami, P.; Lasenby, A.; Laureijs, R. J.; Lavabre, A.; Lawrence, C. R.; Leach, S.; Lee, R.; Leonardi, R.; Leroy, C.; Lilje, P. B.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maciaszek, T.; MacTavish, C. J.; Maffei, B.; Maino, D.; Mandolesi, N.; Mann, R.; Maris, M.; Martínez-González, E.; Masi, S.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McGehee, P.; Meinhold, P. R.; Melchiorri, A.; Melot, F.; Mendes, L.; Mennella, A.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Mora, J.; Morgante, G.; Morisset, N.; Mortlock, D.; Munshi, D.; Murphy, A.; Naselsky, P.; Nash, A.; Natoli, P.; Netterfield, C. B.; Novikov, D.; Novikov, I.; O'Dwyer, I. J.; Osborne, S.; Pajot, F.; Pasian, F.; Patanchon, G.; Pearson, D.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Plaszczynski, S.; Platania, P.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Poutanen, T.; Prézeau, G.; Prina, M.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Rebolo, R.; Reinecke, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Schaefer, B. M.; Scott, D.; Seiffert, M. D.; Shellard, P.; Smoot, G. F.; Starck, J.-L.; Stassi, P.; Stivoli, F.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Torre, J.-P.; Tristram, M.; Tuovinen, J.; Valenziano, L.; Vibert, L.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Watson, C.; White, S. D. M.; Wilkinson, A.; Wilson, P.; Yvon, D.; Zacchei, A.; Zhang, B.; Zonca, A.

    2011-12-01

    The performance of the Planck instruments in space is enabled by their low operating temperatures, 20 K for LFI and 0.1 K for HFI, achieved through a combination of passive radiative cooling and three active mechanical coolers. The scientific requirement for very broad frequency coverage led to two detector technologies with widely different temperature and cooling needs. Active coolers could satisfy these needs; a helium cryostat, as used by previous cryogenic space missions (IRAS, COBE, ISO, Spitzer, AKARI), could not. Radiative cooling is provided by three V-groove radiators and a large telescope baffle. The active coolers are a hydrogen sorption cooler (<20 K), a 4He Joule-Thomson cooler (4.7 K), and a 3He-4He dilution cooler (1.4 K and 0.1 K). The flight system was at ambient temperature at launch and cooled in space to operating conditions. The HFI bolometer plate reached 93 mK on 3 July 2009, 50 days after launch. The solar panel always faces the Sun, shadowing the rest of Planck, andoperates at a mean temperature of 384 K. At the other end of the spacecraft, the telescope baffle operates at 42.3 K and the telescope primary mirror operates at 35.9 K. The temperatures of key parts of the instruments are stabilized by both active and passive methods. Temperature fluctuations are driven by changes in the distance from the Sun, sorption cooler cycling and fluctuations in gas-liquid flow, and fluctuations in cosmic ray flux on the dilution and bolometer plates. These fluctuations do not compromise the science data.

  13. Cosmology with Sunyaev-Zeldovich observations from space.

    Science.gov (United States)

    Aghanim, N.; de Luca, A.; Bouchet, F. R.; Gispert, R.; Puget, J. L.

    1997-09-01

    In order to assess the potential of future microwave anisotropy space experiments for detecting clusters by their Sunyaev-Zeldovich (SZ) thermal effect, we have simulated maps of the large scale distribution of their Compton parameter y and of the temperature anisotropy {DELTA}T/T induced by their proper motion. Our model is based on a predicted distribution of clusters per unit of redshift and flux density using a Press-Schecter approach (De Luca et al. 1995A&A...300..335D). These maps were used to create simulated microwave sky by adding them to the microwave contributions of the emissions of our Galaxy (free-free, dust and synchrotron) and the primary Cosmic Microwave Background (CMB) anisotropies (corresponding to a COBE-normalized standard Cold Dark Model scenario). In order to simulate measurements representative of what current technology should achieve, "observations" were performed according to the instrumental characteristics (number of spectral bands, angular resolutions and detector sensitivity) of the COBRAS/SAMBA space mission. These observations were separated into physical components by an extension of the Wiener filtering theory (Bouchet et al. 1996, in prep). We then analyzed the resulting y and {DELTA}T/T maps which now include both the primary anisotropies and those superimposed due to cluster motions. A cluster list was obtained from the recovered y maps, and their profiles compared with the input ones. Even for low y-values, the input and output profiles show good agreement, most notably in the outer parts of the profile where values as low as y=~3x10^-7^ are properly mapped. We also construct and optimize a spatial filter which is used to derive the accuracy on the measurement of the radial peculiar velocity of a detected cluster. We derive the accuracy of the mapping of the very large scale cosmic velocity field obtained from such measurements.

  14. The SPHEREx All-Sky Spectroscopic Survey

    Science.gov (United States)

    Unwin, Stephen C.; SPHEREx Science Team, SPHEREx Project Team

    2016-06-01

    SPHEREx is a mission to conduct an optical-near-IR survey of the entire sky with a spectrum at every pixel location. It was selected by NASA for a Phase A study in its Small Explorer Program; if selected, development would begin in 2016, and the observatory would start a 2-year prime mission in 2020. An all-sky spectroscopic survey can be used to tackle a wide range of science questions. The SPHEREx science team is focusing on three: (1) Probing the physics of inflation through measuring non-Gaussianity from the study of large-scale structure; (2) Studying the origin of water and biogenic molecules in a wide range of physical and chemical environments via ice absorption spectra; (3) Charting the history of star formation in the universe through intensity mapping of the large-scale spatial power. The instrument is a small wide-field telescope operating in the range of 0.75 - 4.8 µm at a spectral resolution of 41.5 in the optical and 150 at the long-wavelength end. It observes in a sun-sync low-earth orbit, covering the sky like WISE and COBE. SPHEREx is a simple instrument that requires no new technology. The Phase A design has substantial technical and resource margins and can be built with low risk. It is a partnership between Caltech and JPL, with Ball Aerospace and the Korea Astronomy and Space Science Institute as major partners. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. © 2016 California Institute of Technology. Government sponsorship acknowledged.

  15. Clinico-serologic co-relation in bi-directional ABO incompatible hemopoietic stem cell transplantation

    Directory of Open Access Journals (Sweden)

    Sabita Basu

    2015-01-01

    Full Text Available Background: The ABO blood group system is of prime significance in red cell transfusion and organ transplantation. However, ABO compatibility is not critical in allogenic hemopoietic stem cell transplantation (HSCT and approximately 40-50% of hemopoietic stem cell transplants are ABO incompatible. This incompatibility may be major, minor or bi-directional. Though there are descriptions of transfusion practice and protocols in ABO incompatible HSCT, there are considerable variations and transfusion support in these patients can be very challenging. Aims: The immunohematologic observations in two cases of bi-directional ABO incompatible HSCT have been described, and clinico-serologic correlation has been attempted. Materials and Methods: In both cases, peripheral blood stem cell harvests were obtained using the Cobe spectra cell separator. Immunohematologic assessments in the donor and recipient were done as a part of pre HSCT evaluation. Both the standard tube technique and column agglutination method (Ortho Biovue Micro Bead System was used. Antibody screen was done by column agglutination method using three cell panel (Surgiscreen cells. Isoagglutinin titration was done by the master dilution method and standard validated techniques were used. Results: The pattern of laboratory findings in the two cases was different and so were the clinical outcomes. Although there was early engraftment in the first case, the second case developed pure red cell aplasia and this was well-reflected in the immunohematologic assessments. Conclusion: Immunohematologic assessment correlated well with the clinical picture and could be used to predict clinical outcome and onset of complications in ABO incompatible HSCT.

  16. ESA scientist discovers a way to shortlist stars that might have planets

    Science.gov (United States)

    2002-02-01

    Traces of the disc surrounding our Solar System Credits: Michael Hauser (Space Telescope Science Institute), the COBE/DIRBE Science Team, and NASA Traces of the disc surrounding our Solar System Traces of the disc surrounding our Solar System. The blue band curving across this image is created by the dust disc surrounding our Solar System. Viewed from afar this would show up as a bright ring surrounding the Sun. The bright band running across the centre of the image is from dust in our Galaxy. This image, taken by the COBE satellite, is a composite of three far-infrared wavelengths (60, 100, and 240 microns). (Photo: Michael Hauser (Space Telescope Science Institute), the COBE/DIRBE Science Team, and NASA) Disc surrounding the Sun Credits: Brad Smith (University of Hawaii), Glenn Schneider (University of Arizona), and NASA Viewed from afar our Solar System would have a bright disc surrounding the Sun Viewed from afar our Solar System would have a bright dust disc surrounding the Sun similar to the disc surrounding this star. This image, taken with Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS), shows a dust ring around a star called HR 4796A. The image was taken on March 15, 1998. (Photo: Brad Smith (University of Hawaii), Glenn Schneider (University of Arizona), and NASA) Ulysses in flight configuration hi-res Size hi-res: 117 Kb Credits: ESA/Dave Hardy Ulysses at Jupiter encounter Ulysses in flight configuration passing by Jupiter. Remarkably, their discovery gives astronomers a way to determine which other stars in the Galaxy are most likely to harbour planets and allows mission planners to draw up a 'short-list' of stars to be observed by ESA's future planet-search missions, Eddington and Darwin. The discovery of the Solar System's dust ring strengthens the idea that such features around mature stars are signposts to planetary systems. The reason for this is that planetary systems are thought to condense from a cloud of gas and dust

  17. SPHEREx: An All-Sky Spectral Survey

    Science.gov (United States)

    Bock, James; SPHEREx Science Team

    2016-01-01

    SPHEREx, a mission in NASA's Small Explorer (SMEX) program that was selected for Phase A in July 2015, is an all-sky survey satellite designed to address all three science goals in NASA's astrophysics division, in a single survey, with a single instrument. We will probe the physics of inflation by measuring non-Gaussianity by studying large-scale structure, surveying a large cosmological volume at low redshifts, complementing high-z surveys optimized to constrain dark energy. The origin of water and biogenic molecules will be investigated in all phases of planetary system formation - from molecular clouds to young stellar systems with protoplanetary disks - by measuring ice absorption spectra. We will chart the origin and history of galaxy formation through a deep survey mapping large-scale spatial power. Finally, SPHEREx will be the first all-sky near-infrared spectral survey, creating a legacy archive of spectra (0.75 - 4.8 um at R = 41.5 and 150) with high sensitivity using a cooled telescope with large mapping speed.SPHEREx will observe from a sun-synchronous low-earth orbit, covering the entire sky in a manner similar to IRAS, COBE and WISE. During its two-year mission, SPHEREx will produce four complete all-sky maps for constraining the physics of inflation. These same maps contain numerous high signal-to-noise absorption spectra to study water and biogenic ices. The orbit naturally covers two deep regions at the celestial poles, which we use for studying galaxy evolution. All aspects of the SPHEREx instrument and spacecraft have high heritage. SPHEREx requires no new technologies and carries large technical and resource margins on every aspect of the design. The projected instrument sensitivity, based on conservative performance estimates, meets the driving point source sensitivity requirement with 300 % margin.SPHEREx is a partnership between Caltech and JPL, following the successful management structure of the NuSTAR and GALEX SMEX missions. The spacecraft

  18. PRISM (Polarized Radiation Imaging and Spectroscopy Mission): an extended white paper

    International Nuclear Information System (INIS)

    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 data obtained will allow us to precisely measure the absolute sky brightness and polarization of all the components of the sky emission in the observed frequency range, separating the primordial and extragalactic components cleanly from the galactic and zodiacal light emissions. 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, which include: (1) the ultimate galaxy cluster survey using the Sunyaev-Zeldovich (SZ) effect, detecting approximately 106 clusters extending to large redshift, including a characterization of the gas temperature of the brightest ones (through the relativistic corrections to the classic SZ template) as well as a peculiar velocity survey using the kinetic SZ effect that comprises our entire Hubble volume; (2) a detailed characterization of the properties and evolution of dusty galaxies, where the most of the star formation in the universe took place, the faintest population of which constitute the diffuse CIB (Cosmic Infrared Background); (3) a characterization of the B modes from primordial gravity waves generated during inflation

  19. Spitzer and DIRBE Studies of the Infrared Background

    Science.gov (United States)

    Werner, Michael; Gorjian, Varoujan; Hauser, Michael; Wright, Edward; Arendt, Rick; Chary, Ranga-Ram; Levenson, Louis

    2011-05-01

    The extragalactic background light (EBL), defined as the sky surface brightness of all radiation arising from outside the Milky Way, carries in the 1-5um region the imprint of the nearby Universe, of red-shifted light from the first galaxies, and of any possible pre-galactic contributions. The DIRBE instrument on the COBE satellite has measured the total sky brightness, the Cosmic Infrared Background (CIRB), over the entire sky at 3.6um. The CIRB is the sum of the zodiacal light, galactic starlight, radiation from the ISM, and the EBL. Although the determinations of the EBL are presently limited by uncertainties in the zodiacal light model, experiments now under way can reduce those uncertainties. This Spitzer proposal prepares for that reduction by eliminating other uncertainties. We will use Spitzer to determine the point source components of CIRB at 3.6um, the wavelength of the minimum in the bright foreground from interplanetary dust. We will measure essentially all of the stellar contribution, and more than 80% of the integrated light from resolved galaxies; this can be extrapolated using other Spitzer data to determine IGL. The ultimate objective of this type of study is to search for a currently unknown diffuse component of EBL, DEBL. Symbolically, DEBL = EBL-IGL. In this program, we will execute the following steps aimed at reducing the uncertainties in DEBL once the zodiacal uncertainty in CIRB is minimized and a correction for ISM emission is applied: 1. Cross calibrating DIRBE and Spitzer so that EBL and IGL are on the same flux scale; 2. Reducing the uncertainties in EBL by measuring stars as faint as 19th mag at 3.6um. 3. Determining EBL and IGL at six widely separated positions so that the isotropy - and hence the cosmological significance - of any detection of DEBL can be assessed. We emphasize that this important investigation can be carried out only with Spitzer, and this scientific opportunity is perishable due to Spitzer's finite lifetime.

  20. Productivity and impact of astronomical facilities: A statistical study of publications and citations

    Science.gov (United States)

    Trimble, V.; Ceja, J. A.

    2007-11-01

    In calendar years 2001 and 2002, 20 journals of astronomy and astrophysics published 7768 papers that reported or analyzed observations at wavelengths from meter radio to ultrahigh energy gamma rays. In the three calendar years after publication, these papers were cited more than 97 000 times, according to the Science Citation Index/Web of Science data base (the most complete, we believe, available), for an average rate of 4.19 citations per paper per year. We slice these data up several ways, by subject matter, wavelength band, and the telescopes (etc.) used. Most of the results will not surprise: There are hot topics (cosmology, exoplanets) and not so hot topics (binary stars, planetary nebulae). Papers reporting space-based data are cited a bit more often and radio papers a bit less often than optical papers, but multi-wavelength studies do the best. The total number of telescopes involved is surprisingly large, about 330 optical and infrared (mostly ground based but including HST), 109 radio (including COBE and VSOP satellites), and 90 space based (including satellites, interplanetary probes, things carried on rockets, balloons, the Shuttle, and so forth). The superstar telescopes are (mostly) the ones you would expect, though having the most papers does not always go with largest ratios of citations per paper. HST produces the largest number of optical papers, but SDSS the most highly-cited ones, while the VLA is responsible for the largest number of radio papers and the most highly cited (apart from balloon-borne CMB observatories), and among things that fly, the most recent tend to dominate both paper and citation numbers. If you have to choose, it is probably better to opt for a small telescope on a well-supported site than a larger one with less support, and service to the community, in the form of catalogues and mission definitions, is rewarded, at least in citation counts, if not always in other ways. A few comparisons are made with other studies. The

  1. Productivity and impact of astronomical facilities: Three years of publications and citation rates

    Science.gov (United States)

    Trimble, V.; Ceja, J. A.

    2008-07-01

    In calendar years 2001 to 2003, 20 journals of astronomy and astrophysics published 11 831 papers that reported or analyzed observations at wavelengths from meter radio to ultrahigh energy gamma rays. These were cited 161 556 times in the three calendar years following publication, according to the Science Citation Index/Web of Science, for an average of 13.66 citations per paper or 4.55 citations per paper per year. We examine these numbers as a function of subject matter, wavelength bands, journals, and individual telescopes used and explore a small subset of possible temporal trends, anomalies, and sources of uncertainty, including blockbuster journals, papers and facilities. Many of the results resemble qualitative expectations. There are hot topics (cosmology, exoplanets) and not so hot topics (binary stars, planetary nebulae). Papers reporting data from space are cited a bit more often, and ground-based radio papers a bit less often, than optical papers, while multi-wavelength ones do noticeably better than average. The total number of telescopes involved is surprisingly large, approximately 350 optical and infrared (mostly ground-based but including HST because of its long life), 144 radio facilities on about 100 sites (including WMAP and COBE and a few balloon-borne CMB experiments), and 105 space-based detectors (including satellites, interplanetary probes, things carried on rockets, balloons, the Shuttle, and so forth). The outstanding telescopes are generally both stable with time and predictable. HST and the VLA are responsible for the largest number of optical and radio papers respectively, but the most frequently cited optical papers come from SDSS (by a wide margin), Keck, and the AAT, while the JCMT, Parkes and (especially) CMB observatories lead the radio brigade. Among things that fly, leadership changes more quickly, as missions are launched, vigorously exploited, and turned off, sometimes achieving geostationary, suboceanic orbits. If you have a

  2. Cosmology comes of age

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-11-15

    This year's Nobel prize is welcome recognition for cosmology. Back in the 1960s, according to Paul Davies' new book The Goldilocks Enigma (see 'Seeking anthropic answers' in this issue), cynics used to quip that there is 'speculation, speculation squared - and cosmology'. Anyone trying to understand the origin and fate of the universe was, in other words, dealing with questions that were simply impractical - or even impossible - to answer. But that has all changed with the development of new telescopes, satellites and data-processing techniques - to the extent that cosmology is now generally viewed as a perfectly acceptable branch of science. If anyone was in any doubt of cosmology's new status, the Royal Swedish Academy of Sciences last month gave the subject welcome recognition with the award of this year's Nobel prize to John Mather and George Smoot (see pp6-7; print version only). The pair were the driving force behind the COBE satellite that in 1992 produced the now famous image of the cosmic microwave background. The mission's data almost certainly proved that the universe started with a Big Bang, while tiny fluctuations in the temperature signal between different parts of the sky were shown to be the seeds of the stars and galaxies we see today. These results are regarded by many as the start of a new era of 'precision cosmology'. But for cosmologists, the job is far from over. There are still massive holes in our understanding of the cosmos, notably the nature of dark matter and dark energy, which together account for over 95% of the total universe. Indeed, some regard dark energy and matter as just ad hoc assumptions needed to fit the data. (Hypothetical particles called 'axions' are one possible contender for dark matter (see pp20-23; print version only), but don't bet your house on it.) Some physicists even think it makes more sense to adjust Newtonian gravity rather than invoke dark

  3. Particles and cosmology

    International Nuclear Information System (INIS)

    When the common ground between particle physics, astrophysics and cosmology started to become a developing area, the Institute for Nuclear Research (INR) of the Russian Academy of Sciences had the foresight in 1981 to institute the Baksan Schools on Particles and Cosmology. This now traditional event, held biannually in the Baksan Valley, has gone on to attract international participation. The site is close to the INR Baksan Neutrino Observatory with its underground and surface installations, including the SAGE gallium solar neutrino detector, the Underground Scintillation Telescope, and the 'Carpet' extensive air shower array. Participation is mainly from experimentalists working in non accelerator particle physics and particle astrophysics. The most recent School, held from April 21 to 28, began with an opening address by INR Director V. A. Matveev. J.Frieman reviewed standard big bang cosmology, emphasizing how the recent COBE results and the observations of large scale galaxy clustering fit into a standard cosmology framework. For inflationary cosmology, he showed how different models may be tested through their predictions for large-scale galactic structure and for cosmic microwave background anisotropy. A.Stebbins presented details of the large scale distribution of galaxies which, combined with velocity information and microwave background anisotropy data, provide strong constraints on theories of the origin of primordial inhomogeneities. Inflation requires, and theories of the large scale structure strongly favour the critical value for the cosmic mass density, while, as D.Seckel explained in his lecture on nucleosynthesis and abundances of the light elements, the baryon contribution to this density has to be tens of times smaller. A general review on the observational evidence for dark matter, dark matter particle candidates and the strategy of dark matter searches was given by I. Tkachev, who stressed the gravitational microlensing MACHO

  4. Cosmology comes of age

    International Nuclear Information System (INIS)

    This year's Nobel prize is welcome recognition for cosmology. Back in the 1960s, according to Paul Davies' new book The Goldilocks Enigma (see 'Seeking anthropic answers' in this issue), cynics used to quip that there is 'speculation, speculation squared - and cosmology'. Anyone trying to understand the origin and fate of the universe was, in other words, dealing with questions that were simply impractical - or even impossible - to answer. But that has all changed with the development of new telescopes, satellites and data-processing techniques - to the extent that cosmology is now generally viewed as a perfectly acceptable branch of science. If anyone was in any doubt of cosmology's new status, the Royal Swedish Academy of Sciences last month gave the subject welcome recognition with the award of this year's Nobel prize to John Mather and George Smoot (see pp6-7; print version only). The pair were the driving force behind the COBE satellite that in 1992 produced the now famous image of the cosmic microwave background. The mission's data almost certainly proved that the universe started with a Big Bang, while tiny fluctuations in the temperature signal between different parts of the sky were shown to be the seeds of the stars and galaxies we see today. These results are regarded by many as the start of a new era of 'precision cosmology'. But for cosmologists, the job is far from over. There are still massive holes in our understanding of the cosmos, notably the nature of dark matter and dark energy, which together account for over 95% of the total universe. Indeed, some regard dark energy and matter as just ad hoc assumptions needed to fit the data. (Hypothetical particles called 'axions' are one possible contender for dark matter (see pp20-23; print version only), but don't bet your house on it.) Some physicists even think it makes more sense to adjust Newtonian gravity rather than invoke dark matter. But the notion that cosmology is in crisis, as argued by some

  5. PRISM (Polarized Radiation Imaging and Spectroscopy Mission): an extended white paper

    Energy Technology Data Exchange (ETDEWEB)

    André, Philippe [Laboratoire d' Astrophysique de Paris-Saclay, Gif-sur-Yvette Cedex (France); Baccigalupi, Carlo; Bielewicz, Pawel [SISSA, Via Bonomea 265, 34136, Trieste (Italy); Banday, Anthony [Université de Toulouse, UPS-OMP, IRAP, F-31028 Toulouse cedex 4 (France); Barbosa, Domingos [Grupo de Radio Astronomia Basic Sciences and Enabling Technologies Instituto de Telecomunicações, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal); Barreiro, Belen [Instituto de Fìsica de Cantabria (CSIC-Universidad de Cantabria) Avda. de los Castros s/n, 39005 Santander (Spain); Bartlett, James [APC, AstroParticule et Cosmologie, Université Paris Diderot, CNRS/IN2P3, CEA/lrfu, Observatoire de Paris, Sorbonne Paris, Cité, 10, rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France); Bartolo, Nicola [Dipartimento di Fisica e Astronomia ' ' G. Galilei" , Università degli studi di Padova, via Marzolo 8, I-35131, Padova (Italy); Battistelli, Elia [Dipartimento di Fisica, Università di Roma La Sapienza, P.le A. Moro 2, 00185 Roma (Italy); Battye, Richard; Bonaldi, Anna [Jordell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Bendo, George [U.K. ALMA Regional Centre Node, Jordell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Benoȋt, Alain [Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Bernard, Jean-Philippe [CNRS, IRAP, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France); Bersanelli, Marco [Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria, 16, Milano (Italy); Béthermin, Matthieu, E-mail: naselsky@nbi.dk [European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching (Germany); and others

    2014-02-01

    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 data obtained will allow us to precisely measure the absolute sky brightness and polarization of all the components of the sky emission in the observed frequency range, separating the primordial and extragalactic components cleanly from the galactic and zodiacal light emissions. 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, which include: (1) the ultimate galaxy cluster survey using the Sunyaev-Zeldovich (SZ) effect, detecting approximately 10{sup 6} clusters extending to large redshift, including a characterization of the gas temperature of the brightest ones (through the relativistic corrections to the classic SZ template) as well as a peculiar velocity survey using the kinetic SZ effect that comprises our entire Hubble volume; (2) a detailed characterization of the properties and evolution of dusty galaxies, where the most of the star formation in the universe took place, the faintest population of which constitute the diffuse CIB (Cosmic Infrared Background); (3) a characterization of the B modes from primordial gravity waves generated during

  6. How large is the cosmic dust flux into the Earth's atmosphere?

    Science.gov (United States)

    Plane, John; Janches, Diego; Gomez-Martin, Juan Carlos; Bones, David; Diego Carrillo-Sanchez, Juan; James, Sandy; Nesvorny, David; Pokorny, Petr

    2016-07-01

    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. Current estimates of the magnitude of the cosmic dust input rate into the Earth's atmosphere range from 2 to well over 100 tons per day, depending on whether the measurements are made in space, in the middle atmosphere, or at the surface in polar ice cores. This nearly 2 order-of-magnitude discrepancy indicates that there are serious flaws in the interpretation of observations that have been used to make the estimates. Dust particles enter the atmosphere at hyperthermal velocities (11 - 72 km s ^{-1}), and mostly ablate at heights between 80 and 120 km in a region of the atmosphere known as the mesosphere/lower thermosphere (MLT). The resulting metal vapours (Fe, Mg, Si and Na etc.) then oxidize and recondense to form nm-size particles, termed "meteoric smoke". These particles are too small to sediment downwards. Instead, they are transported by the general circulation of the atmosphere, taking roughly 5 years to reach the surface. There is great interest in the role smoke particles play as condensation nuclei of noctilucent ice clouds in the mesosphere, and polar stratospheric clouds in the lower stratosphere. Various new estimates of the dust input will be discussed. The first is from a zodiacal dust cloud model which predicts that more than 90% of the dust entering the atmosphere comes from Jupiter Family Comets; this model is constrained by observations of the zodiacal cloud using the IRAS, COBE and Planck satellites. The cometary dust is predicted to mostly be in a near-prograde orbit, entering the atmosphere with an average velocity around 14 km s ^{-1}. The total dust input should then be about 40 t d ^{-1}. However, relatively few of these particles are observed, even by the powerful Arecibo 430 MHz radar. Coupled models of meteoroid differential ablation

  7. Allograft islet cell transplantation and postoperatively modified Edmonton protocol for 3 cases of type 1 diabetes mellitus%同种胰岛细胞移植及采用改良Edmonton方案治疗1型糖尿病三例

    Institute of Scientific and Technical Information of China (English)

    黄孝伦; 姚豫桐; 罗兰云; 薛华; 邹海波; 魏玲玲; 杨卯竹; 骆乐; 王冠

    2014-01-01

    Objective To investigate the pancreatic islet cell isolation technology,quality standards,and safety and effectiveness of allograft islet cell transplantation and modified Edmonton protocol in the treatment of type 1 diabetes (T1DM).Method Three cases of T1DM received allograft islet cell transplantation.The pancreas was taken from adult organ donation after cardiac death donor.All pancreatic organs were digested by Liberase enzyme,COBE 2991 cell separator,and discontinuous density gradient purification,to obtain high purity and high activity of islet cells.All these procedures were conducted in our GMP facilities.After culture for 12 h,testing islets reached transplant standards.After the percutaneous puncture of hepatic portal vein trunk of the recipients,islet cells were transplanted evenly through the portal vein into the liver of recipients.After islet cell transplantation,a modified Edmonton immunosuppressive protocol containing antithymocyte globulin (ATG),tacrolimus and mycophenolate mofetil was used,and the changes in blood glucose,C peptide and glycate hemoglobin were monitored regularly during a follow-up period of one year.Result The transplanted islet cells of 3 recipients were 460 00(-505 200 IEQ,and islet purity and viability were 38.5%-49.7% and 95%-97% respectively.The stimulation index of human islet was 2.8-5.4.The glucose levels of 3 recipients in the normal diet were strictly controlled below 7.8 mmol/L.Two recipients remained insulin-independent after 3-5 months.The dosage of insulin was decreased by 60% in 1 patient after 12 months.The levels of C-peptide and HbA1c were all within normal range and renal functions were improved.No complications related to islet infusion including hypoglycemia,adverse drug reactions,acute rejection and infection were observed.Conclusion Our isolation techniques and methods of islet cells are reliable.Allograft islet cell transplantation and the improved Edmonton protocol in the short-term for

  8. The Physics of the Cosmic Microwave Background

    International Nuclear Information System (INIS)

    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 (which this certainly is

  9. Obituary: Andrew Lange (1957-2010)

    Science.gov (United States)

    Kamionkowski, Marc

    2011-12-01

    The worlds of physics and astrophysics were stunned to learn on 22 January 2010 that Andrew Lange, the Marvin L. Goldberger Professor of Physics at Caltech, had taken his own life the night before. He had succumbed to the severe depression that he had suffered from for many years, unbeknownst to even his closest colleagues. Lange will perhaps be best remembered as the co-leader of Boomerang, the balloon-borne experiment that provided the first high-angular-resolution map of the cosmic microwave background (CMB). And while this was certainly his most notable achievement, Andrew amassed a record of accomplishment as an instrumentalist, leader, mentor, and communicator that extended much further. Andrew was born in Urbana, Illinois on July 23, 1957, the son of an architect and a librarian, and raised primarily in Connecticut. His family and early friends remember him as a serious and extremely intelligent child and young man. Andrew Lange's lifelong interest in the CMB was nurtured as an undergraduate at Princeton University by David Wilkinson, and he recalled fondly a summer spent working with John Mather at Goddard Space Flight Center. Andrew Lange went to graduate school in physics at Berkeley where he worked in Paul Richards' group. Although his thesis project, the Berkeley-Nagoya rocket experiment, showed an anomalous sub-millimeter excess in the CMB spectrum that was shortly thereafter shown by a later flight of the same rocket and COBE-FIRAS to be incorrect, Lange's talents were recognized by the physics department at Berkeley who appointed him shortly after his PhD (1987) to their faculty. While on the Berkeley faculty, Andrew obtained early detections of the Sunyaev-Zeldovich effect, upper limits to small-angle CMB fluctuations, and important infrared constraints to the interstellar medium. He also led a pioneering instrument operating 300 mK detectors for a small infrared satellite experiment. This early work showed high ambition and daring, and it pioneered

  10. Book Review:

    Science.gov (United States)

    Peacock, John

    2007-04-01

    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 (which this certainly is

  11. 健康供者外周血造血干细胞动员的临床研究%Clinical study on peripheral blood stem cell mobilization in normal donors

    Institute of Scientific and Technical Information of China (English)

    章卫平; 王健民; 童书鹏; 宋献民; 钱宝华; 周虹; 李红梅; 丁晓勤

    2002-01-01

    目的:探讨造血生长因子(HGFs)对健康供者外周血干细胞(PBSC)的动员作用,并比较粒细胞集落刺激因子(G-CSF)单用及G-CSF联合粒-巨噬细胞集落刺激因子(GM-CSF)的动员效果.方法:52例健康供者分成G-CSF单用组(34例)及与GM-CSF合用组(18例),分别采用G-CSF(5 μg·kg-1·d-1)及G-CSF(3 μg·kg-1·d-1)+GM-CSF(2 μg·kg-1·d-1),连续皮下注射5~6 d动员,采集PBSC.动员前后动态检测外周血及采集物MNC、CD34+细胞、CFU-GM计数.52例血液病患者接受上述供体动员之PBSC并行异基因PBSC移植(Allo-PBSCT).结果:动员后CD34+细胞及CFU-GM分别较动员前增加10.83及8.7倍,并在第5~6天达到高峰;G-CSF单用及与GM-CSF合用均可有效动员CD34+细胞和CFU-GM,但合用较单用更有效(P<0.05);所有患者接受Allo-PBSCT后均满意获得造血重建;随访观察至今应用HGFs对健康供者无明显不良反应.结论:采用中小剂量G-CSF单用和与GM-CSF合用均能安全、有效动员健康供者PBSC,但以合用更为有效.%Objective: To explore the efficiency of hematopoietic growth factors (HGFs) on peripheral blood stem cell (PBSC) mobilization in normal donors. Methods: Granulocyte-colony stimulating factor (G-CSF, 5 μg·kg-1·d-1) was used subcutaneously in 34 donors and G-CSF (3 μg·kg-1·d-1) + granulocyte-macrophage-colony stimulating factor (GM-CSF,2 μg·kg-1·d-1) in 18 donors for 5-6 d. PBSC was harvested with CS-3000 Plus or COBE Spectra blood cell separator. The numbers of MNC, CD34+ cells and CFU-GM were determined during the mobilization. Fifty-two patients with hematologic disease received allogeneic peripheral blood stem cell transplantation (Allo-PBSCT). Results: After mobilization, CD34+ cells and CFU-GM yields increased by 10.83 and 8.7 folds, respectively, and peaked on day 5 of HGFs initiation. Both G-CSF alone and G-CSF + GM-CSF effectively mobilized PBSC, while G-CSF+GM-CSF mobilized CD34+cells and CFU-GM more efficiently than G

  12. Science Archives in the 21st Century: A NASA LAMBDA Report

    Science.gov (United States)

    Butterworth, P.; Greason, M.

    2007-01-01

    Lambda is a thematic data center that focuses on serving the cosmic microwave background (CMB) research community. LAMBDA is an active archive for NASA's Cosmic Background Explorer (COBE) and Wilkinson Microwave Anisotropy Probe (WMAP) mission data sets. In addition, LAMBDA provides analysis software, on-line tools, relevant ancillary data and important web links. LAMBDA also tries to preserve the most important ground-based and suborbital CMB data sets. CMB data is unlike other astrophysical data, consisting of intrinsically diffuse surface brightness photometry with a signal contrast of the order 1 part in 100,000 relative to the uniform background. Because of the extremely faint signal levels, the signal-to-noise ratio is relatively low and detailed instrument-specific knowledge of the data is essential. While the number of data sets being produced is not especially large, those data sets are becoming large and complex. That tendency will increase when the many polarization experiments currently being deployed begin producing data. The LAMBDA experience supports many aspects of the NASA data archive model developed informally over the last ten years-that small focused data centers are often more effective than larger more ambitious collections, for example; that data centers are usually best run by active scientists; that it can be particularly advantageous if those scientists are leaders in the use of the archived data sets; etc. LAMBDA has done some things so well that they might provide lessons for other archives. A lot of effort has been devoted to developing a simple and consistent interface to data sets, for example; and serving all the documentation required via simple 'more' pages and longer explanatory supplements. Many of the problems faced by LAMBDA will also not surprise anyone trying to manage other space science data. These range from persuading mission scientists to provide their data as quickly as possible, to dealing with a high volume of

  13. Predicting the sky from 30 MHz to 800 GHz: the extended Global Sky Model

    Science.gov (United States)

    Liu, Adrian

    We propose to construct the extended Global Sky Model (eGSM), a software package and associated data products that are capable of generating maps of the sky at any frequency within a broad range (30 MHz to 800 GHz). The eGSM is constructed from archival data, and its outputs will include not only "best estimate" sky maps, but also accurate error bars and the ability to generate random realizations of missing modes in the input data. Such views of the sky are crucial in the practice of precision cosmology, where our ability to constrain cosmological parameters and detect new phenomena (such as B-mode signatures from primordial gravitational waves, or spectral distortions of the Cosmic Microwave Background; CMB) rests crucially on our ability to remove systematic foreground contamination. Doing so requires empirical measurements of the foreground sky brightness (such as that arising from Galactic synchrotron radiation, among other sources), which are typically performed only at select narrow wavelength ranges. We aim to transcend traditional wavelength limits by optimally combining existing data to provide a comprehensive view of the foreground sky at any frequency within the broad range of 30 MHz to 800 GHz. Previous efforts to interpolate between multi-frequency maps resulted in the Global Sky Model (GSM) of de Oliveira-Costa et al. (2008), a software package that outputs foreground maps at any frequency of the user's choosing between 10 MHz and 100 GHz. However, the GSM has a number of shortcomings. First and foremost, the GSM does not include the latest archival data from the Planck satellite. Multi-frequency models depend crucially on data from Planck, WMAP, and COBE to provide high-frequency "anchor" maps. Another crucial shortcoming is the lack of error bars in the output maps. Finally, the GSM is only able to predict temperature (i.e., total intensity) maps, and not polarization information. With the recent release of Planck's polarized data products, the

  14. Light propagation in inhomogeneous universes. I. Methodology and preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Premadi, Premana; Matzner, Richard [Center for Relativity and Department of Physics, University of Texas, Austin, Texas78712 (United States)] Martel, Hugo [Department of Astronomy, University of Texas, Austin, Texas 78712 (United States)] Matzner, Richard [Orson Anderson Scholar, Los Alamos National Laboratory, 1996--1997 (United States)

    1998-01-01

    We describe a numerical algorithm that simulates the propagation of light in inhomogeneous universes. This algorithm computes the trajectories of light rays between the observer, located at redshift z=0, and distant sources located at high redshift using the multiple lens plane method. The deformation and deflection of light beams as they interact with each lens plane are computed using the filled-beam approximation. We use a particle-particle/particle-mesh (P{sup 3}M) N-body numerical code to simulate the formation of large-scale structure in the universe. We extend the length resolution of the simulations to sub-megaparsec scales by using a Monte Carlo method for locating galaxies inside the computational volume according to the underlying distribution of background matter. The observed galaxy two-point correlation function is reproduced. This algorithm constitutes a major improvement over previous methods, which either neglected the presence of large-scale structure, neglected the presence of galaxies, neglected the contribution of distant matter (matter located far from the beam), or used the Zeldovich approximation for simulating the formation of large-scale structure. In addition, we take into account the observed morphology-density relation when assigning morphological types to galaxies, something that was ignored in all previous studies. To test this algorithm, we perform 1981 simulations for three different cosmological models: an Einstein-de Sitter model with density parameter {Omega}{sub 0}=1, an open model with {Omega}{sub 0}=0.2, and a flat, low-density model with {Omega}{sub 0}=0.2 and a cosmological constant of {lambda}{sub 0}=0.8. In all models, the initial density fluctuations correspond to a cold dark matter power spectrum normalized to {ital COBE}. In each simulation, we compute the shear and magnification resulting from the presence of inhomogeneities. Our results are the following: (1) The magnification is totally dominated by the convergence

  15. VizieR Online Data Catalog: Planck Early Release Compact Source Catalogue (Planck, 2011)

    Science.gov (United States)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Baker, M.; Balbi, A.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Bennett, K.; Benoit, A.; Bernard, J.-P.; Bersanelli, M.; Bhatia, R.; Bock, J. J.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bradshaw, T.; Bremer, M.; Bucher, M.; Burigana, C.; Butler, R. C.; Cabella, P.; Cantalupo, C. M.; Cappellini, B.; Cardoso, J.-F.; Carr, R.; Casale, M.; Catalano, A.; Cayon, L.; Challinor, A.; Chamballu, A.; Charra, J.; Chary, R.-R.; Chiang, L.-Y.; Chiang, C.; Christensen, P. R.; Clements, D. L.; Colombi, S.; Couchot, F.; Coulais, A.; Crill, B. P.; Crone, G.; Crook, M.; Cuttaia, F.; Danese, L.; D'Arcangelo, O.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Bruin, J.; de Gasperis, G.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Desert, F.-X.; Dick, J.; Dickinson, C.; Dolag, K.; Dole, H.; Donzelli, S.; Dore, O.; Doerl, U.; Douspis, M.; Dupac, X.; Efstathiou, G.; Ensslin, T. A.; Eriksen, H. K.; Finelli, F.; Foley, S.; Forni, O.; Fosalba, P.; Frailis, M.; Franceschi, E.; Freschi, M.; Gaier, T.C.; Galeotta, S.; Gallegos, J.; Gandolfo, B.; Ganga, K.; Giard, M.; Giardino, G.; Gienger, G.; Giraud-Heraud, Y.; Gonzalez, J.; Gonzalez-Nuevo, J.; Gorski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Guyot, G.; Haissinski, J.; Hansen, F. K.; Harrison, D.; Helou, G.; Henrot-Versille, S.; Hernandez-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Hoyland, R. J.; Huffenberger, K. M.; Jaffe, A. H.; Jagemann, T.; Jones, W. C.; Juillet, J. J.; Juvela, M.; Kangaslahti, P.; Keihaenen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knox, L.; Krassenburg, M.; Kurki-Suonio, H.; Lagache, G.; Laehteenmaeki, A.; Lamarre, J.-M.; Lange, A. E.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leach, S.; Leahy, J. P.; Leonardi, R.; Leroy, C.; Lilje, P. B.; Linden-Vornle, M.; Lopez-Caniego, M.; Lowe, S.; Lubin, P. M.; Macias-Perez, J. F.; Maciaszek, T.; MacTavish, C. J.; Maffei, B.; Maino, D.; Mandolesi, N.; Mann, R.; Maris, M.; Martinez-Gonzalez, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McDonald, A.; McGehee, P.; Meinhold, P. R.; Melchiorri, A.; Melin, J.-B.; Mendes, L.; Mennella, A.; Mevi, C.; Miniscalco, R.; Mitra, S.; Miville-Deschenes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; sMorisset, N.; Mortlock, D.; Munshi, D.; Murphy, A.; Naselsky, P.; Natoli, P.; Netterfield, C. B.; Norgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; O'Dwyer, I. J.; Ortiz, I.; Osborne, S.; Osuna, P.; Oxborrow, C. A.; Pajot, F.; Paladini, R.; Partridge, B.; Pasian, F.; Passvogel, T.; Patanchon, G.; Pearson, D.; Pearson, T. J.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Plaszczynski, S.; Platania, P.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Prezeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Reix, J.-M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rowan-Robinson, M.; Rubino-Martin, J. A.; Rusholme, B.; Salerno, E.; Sandri, M.; Santos, D.; Savini, G.; Schaefer, B. M.; Scott, D.; Seiffert, M. D.; Shellard, P.; Simonetto, A.; Smoot, G. F.; Sozzi, C.; Starck, J.-L.; Sternberg, J.; Stivoli, F.; Stolyarov, V.; Stompor, R.; Stringhetti, L.; Sudiwala, R.; Sunyaev, R.; Sygnet, J.-F.; Tapiador, D.; Tauber, J. A.; Tavagnacco, D.; Taylor, D.; Terenzi, L.; Texier, D.; Toffolatti, L.; Tomasi, M.; Torre, J.-P.; Tristram, M.; Tuovinen, J.; Tuerler, M.; Tuttlebee, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Varis, J.; Vibert, L.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Watson, C.; White, S. D. M.; White, M.; Wilkinson, A.; Yvon, D.; Zacchei, A.; Zonca, A.

    2011-01-01

    Planck is a European Space Agency (ESA) mission, with significant contributions from the U.S. National Aeronautics and Space Agency (NASA). It is the third generation of space-based cosmic microwave background experiments, after the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP). Planck was launched on 14 May 2009 on an Ariane 5 rocket from Kourou, French Guiana. Following a cruise to the Earth-Sun L2 Lagrange point, cooling and in orbit checkout, Planck initiated the First Light Survey on 13 August 2009. Since then, Planck has been continuously measuring the intensity of the sky over a range of frequencies from 30 to 857GHz (wavelengths of 1cm to 350μm) with spatial resolutions ranging from about 33' to 5' respectively. The Low Frequency Instrument (LFI) on Planck provides temperature and polarization information using radiometers which operate between 30 and 70GHz. The High Frequency Instrument (HFI) uses pairs of polarization-sensitive bolometers at each of four frequencies between 100 and 353GHz but does not measure polarization information in the two upper HFI bands at 545 and 857GHz. The lowest frequencies overlap with WMAP, and the highest frequencies extend far into the submillimeter in order to improve separation between Galactic foregrounds and the cosmic microwave background (CMB). By extending to wavelengths longer than those at which the Infrared Astronomical Satellite (IRAS) operated, Planck is providing an unprecedented window into dust emission at far-infrared and submillimeter wavelengths. The Planck Early Release Compact Source Catalogue (ERCSC) is a list of all high reliability sources, both Galactic and extragalactic, derived from the first sky coverage. The data that went into this early release comprise all observations undertaken between 13 August 2009 and 6 June 2010, corresponding to Planck operational days 91-389. Since the Planck scan strategy results in the entire sky being observed every 6 months

  16. The Cosmic Microwave Background & Inflation, Then & Now

    Science.gov (United States)

    Bond, J. Richard; Contaldi, Carlo; Pogosyan, Dmitry; Mason, Brian; Myers, Steve; Pearson, Tim; Pen, Ue-Li; Prunet, Simon; Readhead, Tony; Sievers, Jonathan

    2002-12-01

    The most recent results from the Boomerang, Maxima, DASI, CBI and VSA CMB experiments significantly increase the case for accelerated expansion in the early universe (the inflationary paradigm) and at the current epoch (dark energy dominance). This is especially so when combined with data on high redshift supernovae (SN1) and large scale structure (LSS), encoding information from local cluster abundances, galaxy clustering, and gravitational lensing. There are ``7 pillars of Inflation'' that can be shown with the CMB probe, and at least 5, and possibly 6, of these have already been demonstrated in the CMB data: (1) the effects of a large scale gravitational potential, demonstrated with COBE/DMR in 1992-96 (2) acoustic peaks/dips in the angular power spectrum of the radiation, which tell about the geometry of the Universe, with the large first peak convincingly shown with Boomerang and Maxima data in 2000, a multiple peak/dip pattern shown in data from Boomerang and DASI (2nd, 3rd peaks, first and 2nd dips in 2001) and from CBI (2nd, 3rd, 4th, 5th peaks, 3rd, 4th dips at 1-sigma in 2002) (3) damping due to shear viscosity and the width of the region over which hydrogen recombination occurred when the universe was 400000 years old (CBI 2002) (4) the primary anisotropies should have a Gaussian distribution (be maximally random) in almost all inflationary models, the best data on this coming from Boomerang; (5) secondary anisotropies associated with nonlinear phenomena subsequent to 400000 years, which must be there and may have been detected by CBI and another experiment, BIMA. Showing the 5 ``pillars'' involves detailed confrontation of the experimental data with theory; e.g., (5) compares the CBI data with predictions from two of the largest cosmological hydrodynamics simulations ever done. DASI, Boomerang and CBI in 2002, AMiBA in 2003, and many other experiments have the sensitivity to demonstrate the next pillar, (6) polarization, which must be there at the ~ 7

  17. Teleconnections between proxy sites of Arctica Islandica in simulated and observed sea surface temperatures in the North Atlantic Ocean

    Science.gov (United States)

    Pyrina, Maria; Wagner, Sebastian; Zorita, Eduardo

    2015-04-01

    Arctica Islandica, an extremely long lived bivalve, was recently used for long-term climate reconstructions as it combines many characteristics required for being a comprehensive climate archive (Schoene et al., 2005). The North Atlantic Ocean (NA) is a climatic important region where this bivalve shell is widely found. Many studies connect the growth increment indices of this clam with the regional sea surface temperatures (SSTs) (Butler et al., 2013). It is of critical importance to investigate if the SSTs derived from Arctica Islandica collection areas are dependent on the temperatures of different areas of the NA Ocean. The assement of these teleconnection patterns potentially allows the reconstruction of SSTs of other areas in NA, where this bivalve is not found. Using the temperatures derived from the comprehensive COSMOS Earth System Model (Jungclaus et al., 2010) for three fully forced ensemble simulations and re-analysed SSTs of the COBE2 project (Hirahara et al., 2014), we aim at identifying growing season (June-August) temperature patterns associated with the regions were usually Arctica Islandica is being collected. We correlated the time series (1950-2000) calculated by the COSMOS model, between two proxy sites of Arctica Islandica and the NA Ocean (20˚-80˚N and 30˚E-90˚W). The first region is located north of Norway at 24° E, 73.8° N and the second north of Iceland at 18° W, 68.4° N. These sites where chosen based on previous studies (Wanamaker et al., 2012). The comparison between the modelled and the re-analysis teleconnection pattern indicates some similarities concerning a tripole pattern in the North Atlantic Ocean for the Norway proxy site with positive correlation around Norway and the central and western North Atlantic, while the eastern North Atlantic shows slightly negative correlations. This pattern is however more heterogeneous in the COSMOS simulations possibly due to the impact of internal ocean variability in the 2nd half of the

  18. Reionization in a cold dark matter universe: The feedback of galaxy formation on the intergalactic medium

    Science.gov (United States)

    Shapiro, Paul R.; Giroux, Mark L.; Babul, Arif

    1994-01-01

    ) cannot account for the baryon content of the universe at z approximately 3 observed in quasar absorption line gas unless Omega (sub B) significantly exceeds the maximum value allowed by big bang nucleocynthesis. (5) For a CDM model with bias parameter within the allowed range of (lower) values, the lower limit to Omega(sub B) imposed by big bang nucleosynthesis (Omega(sub B) h(sup 2) greater than or equal to 0.01) combines with our results to yield the minimum IGM density for the CDM fodel. For CDM with b = 1 (Cosmic Background Explorer (COBE) normalization), we find Omega(sub IGM)(sup min) (z approximately 4) approx. equal 0.02-0.03, and Omega(sub IGM)(sup min)(z approximately 0) approx. equal 0.005-0.03, depending upon the nature of the sources of IGM reionization. (6) In general, we find that self-consistent reionization of the IGM by the collapsed baryon fraction has a strong effect on the rate of collapse. (7) As a further example, we show that the feedback effect on the IGM of energy release by the collapsed baryon fraction may explain the slow evolution of the observed comoving QSO number density between z = 5 and z = 2, followed by the sharp decline after z = 2.

  19. Wide-Field Infrared Survey Telescope (WFIRST) Interim Report

    Science.gov (United States)

    Green, J.; Schechter, P.; Baltay, C.; Bean, R.; Bennett, D.; Brown, R.; Conselice, C.; Donahue, M.; Gaudi, S.; Lauer, T.; Perlmutter, S.; Rauscher, B.; Rhodes, J.; Roellig, T.; Stern, D.; Sumi, T.; Gerhels, N.; Sambruna, R.; Barry, R. K.; Content, D.; Grady, K; Jackson, C.; Kruk, J.; Melton, M.; Rioux, N.

    2011-01-01

    Satellite (IRAS), the Cosmic Background Explorer (COBE), Herschel, Spitzer, and Wide-field Infrared Sur-vey Explorer (WISE) are all space missions that have produced stunning new scientific advances by going to space to observe in the infrared. This interim report describes progress as of June 2011 on developing a requirements flowdown and an evaluation of scientific performance. An Interim Design Reference Mission (IDRM) configuration is presented that is based on the specifications of NWNH with some refinements to optimize the design in accordance with the new scientific requirements. Analysis of this WFIRST IDRM concept is in progress to ensure the capability of the observatory is compatible with the science requirements. The SDT and Project will continue to refine the mission concept over the coming year as design, analysis and simulation work are completed, resulting in the SDT s WFIRST Design Reference Mission (DRM) by the end of 2012.

  20. 银盘外区的翘曲结构%Warp of the Outer Region of the Galactic Disc

    Institute of Scientific and Technical Information of China (English)

    赵君亮

    2011-01-01

    .In addition to the population I objects, molecular clouds and interstellar dust have also been observed to study the large scale structure of the outer Galaxy, and some interesting conclusions have been obtained. For example, the ensemble of clouds shows the same warped shape and flaring thickness as shown by the outer Galaxy HI gas layer.Interstellar extinction remains a serious obstacle for observing stars near the Galactic plane. Since the extinction suffered in the near infrared is about an order of magnitudelower than in visible, the data provided recently by large scale infrared surveys, including IRAS, DENIS, DIRBE/COBE and 2MASS, have been used to investigate the warp and flare structure of our Galaxy. It is discovered from some studies that a feature of infrared point source counts can be interpreted as a signature of the warp in the Galactic older stellar disc. The warp is less obvious in stars than in the gas and it also shows different shapes of the disc at negative and positive longitudes.Up to date, it is not completely clear how the warped disc of the outer Galaxy was formed and whether the warp is a persistent feature of the Galaxy, or a transient phenomenon. Most recent work has focused on one of the following 3 possible mechanisms: (1) a satellite dwarf orbiting the Galaxy, such as the Large Magellanic Cloud or the Sagittarius dwarf galaxy, causes a warp by tidel interaction with the Galactic disc; (2) the warp is caused by infall and accretion of intergalactic medium onto the disc; (3) the warp can be formed by interaction between the outer Galactic disc and a triaxial or an oblate massive dark matter halo, misaligned with the disc. Anyway, further studies are needed to finally solve the puzzle of the formation mechanism of the Galactic warp.%银盘外区存在翘曲结构和近边增厚现象已是不争的观测事实.自20世纪50年代通过中性氢的射电观测发现此类结构以来,对不同示踪天体(包括各类星族1天体、分子云、

  1. PREFACE: The Sixth International Conference on Gravitation & Cosmology

    Science.gov (United States)

    Date, Ghanashyam; Souradeep, Tarun

    2008-07-01

    programme had 21 plenary talks on current theoretical, observational and experimental topics in Cosmology, General Relativity, detection of gravitational waves, and various approaches to Quantum gravity. The meeting also included three intensive parallel workshops focused on Cosmology, Classical General Relativity & Gravitational waves and Quantum Gravity, respectively. The workshops had around 75 oral presentations. The immensely rich and diverse scientific programme was highlighted in the concluding remarks by the late Professor Juergen Ehlers. A public lecture on `Oldest light in the Universe' by NASA scientist, Professor Gary Hinshaw, who is a member of the WMAP team (formerly, also a member of the COBE-DMR team that won the Nobel prize in 2006) was also organized as part of ICGC-07 and drew sizable audience from the public in Pune. The proceedings contains articles by the plenary speakers, the concluding remarks and a summary of each of the three workshops. We also include an obituary for Professor Juergen Ehlers, who passed away on 20 May 2008. The sentiments expressed in the obituary are shared by the editors and members of IAGRG. Professor Ehlers had participated very actively during the meeting and delivered an excellent concluding talk on the conference. We are indeed fortunate to able to include in this volume, what is perhaps, his last article. A possible reflection of the tight schedule of researchers in the booming period of research in Cosmology and Gravitation is the number of missing articles by plenary speakers. Due to various reasons, we were able to get only 11 of the 21 plenary talks for publication in this volume. In order to ensure that the volume is published within a year of the conference, we decided to publish the proceedings with the available articles. The meeting was financially supported by generous contribution from Indian organizations: ISRO, CSIR, DST, BNRS and IAGRG; and from Indian institutes: HRI (Allahabad), IIA (Bangalore), IMSc

  2. New water and remote galaxies complete ISO's observations

    Science.gov (United States)

    mapping parts of the sky at a wavelength of 200 microns. Activity concerning ISO will continue at the Villafranca ground station until the year 2001, long after the completion of the observational phase of the mission. During the space operations, the main objective was to make as many observations as possible. Thorough analysis and interpretation of the results will take several years. "We still have plenty to do," says Martin Kessler, ESA's project scientist for ISO. "Our team at Villafranca is preparing a complete archive of ISO data on 500-1000 compact disks, after reprocessing with improved software. We'll release part of this archive to the world-wide astronomical community in the autumn of this year, and the rest in 1999. We shall also advise the astronomers who have used ISO, about the particular requirements for handling the data from each instrument, and we'll be doing some astronomy ourselves. There are far more results still to come from ISO." Europe's infrared astronomers are already busy preparing ESA's FIRST and Planck missions, due for launch early in the new century. FIRST will observe long infrared wavelengths in the sub-millimetre range, while Planck will map the cosmic microwave background far more accurately than NASA's COBE mission did, to reveal the clumps of matter from which galaxies evolved. Also under study by ESA is a possible interferometer mission using a combination of infrared telescopes. In principle it might observe and characterize planets in orbit around other stars. Meanwhile, Europe's space astronomy programme continues apace in other directions. ESA's participation in the Hubble Space Telescope and its eventual successor assures access to those important instruments for Europe's astronomers. The release in 1997 of the catalogues from ESA's unique star-mapping mission Hipparcos provided all astronomer with amazingly precise data for sizing up the stars and the wider Universe. Next year will see the launch of ESA's XMM satellite to