Cosmic string induced CMB maps
Landriau, M.; Shellard, E. P. S.
2011-02-15
We compute maps of CMB temperature fluctuations seeded by cosmic strings using high resolution simulations of cosmic strings in a Friedmann-Robertson-Walker universe. We create full-sky, 18 deg. and 3 deg. CMB maps, including the relevant string contribution at each resolution from before recombination to today. We extract the angular power spectrum from these maps, demonstrating the importance of recombination effects. We briefly discuss the probability density function of the pixel temperatures, their skewness, and kurtosis.
Joint Planck and WMAP CMB map reconstruction
NASA Astrophysics Data System (ADS)
Bobin, J.; Sureau, F.; Starck, J.-L.; Rassat, A.; Paykari, P.
2014-03-01
We present a novel estimate of the cosmological microwave background (CMB) map by combining the two latest full-sky microwave surveys: WMAP nine-year and Planck PR1. The joint processing benefits from a recently introduced component separation method coined"local-generalized morphological component analysis" (LGMCA) and based on the sparse distribution of the foregrounds in the wavelet domain. The proposed estimation procedure takes advantage of the IRIS 100 μm as an extra observation on the galactic center for enhanced dust removal. We show that this new CMB map presents several interesting aspects: i) it is a full sky map without using any inpainting or interpolating method; ii) foreground contamination is very low; iii) the Galactic center is very clean with especially low dust contamination as measured by the cross-correlation between the estimated CMB map and the IRIS 100 μm map; and iv) it is free of thermal SZ contamination. Appendix is available in electronic form at http://www.aanda.org
Preferred axis of CMB parity asymmetry in the masked maps
NASA Astrophysics Data System (ADS)
Cheng, Cheng; Zhao, Wen; Huang, Qing-Guo; Santos, Larissa
2016-06-01
Both WMAP and Planck data show a significant odd-multipole preference in the large scales of the cosmic microwave background (CMB) temperature anisotropies. If this pattern originates from cosmological effects, then it can be considered a crucial clue for a violation in the cosmological principle. By defining various direction dependent statistics in the full-sky Planck 2015 maps (see, for instance, Naselsky et al. (2012); W. Zhao (2014)), we found that the CMB parity asymmetry has a preferred direction, which is independent of the choices of the statistics. In particular, this preferred axis is strongly aligned with those in the CMB quadrupole and octopole, as well as that in the CMB kinematic dipole, which hints to their non-cosmological origin. In realistic observations, the foreground residuals are inevitable, and should be properly masked out in order to avoid possible misinterpretation of the results. In this paper, we extend our previous analyses to the masked Planck 2015 data. By defining a similar direction dependent statistic in the masked map, we find a preferred direction of the CMB parity asymmetry, in which the axis also coincides with that found in the full-sky analysis. Therefore, our conclusions on the CMB parity violation and its directional properties are confirmed.
Efficient inversion for CMB topography: benchmarks and preliminary maps
NASA Astrophysics Data System (ADS)
Colombi, A.; Nissen-Meyer, T.; Boschi, L.
2012-12-01
We map lateral topography variations of global seismic discontinuities focusing on the core-mantle boundary (CMB), in the framework of high-resolution forward modeling and seismic imaging. We present a method to compute sensitivity kernels relating seismic travel times (measured by cross-correlation of observed and theoretical seismograms) to the topography of seismic discontinuities at any depth in the Earth using full 3D wave propagation. Calculation of accurate finite-frequency sensitivity kernels is notoriously expensive, but we reduce computational costs drastically by limiting ourselves to spherically symmetric reference models, and exploiting the axial symmetry of the resulting propagating wave-field that collapses to a 2D numerical domain. We compute and analyze a suite of kernels for CMB sensitive phases that can be used for finite frequency waveform inversion. We benchmark and tune our methodology inverting cross-correlation travel-times of PcP, various PKP branches, Pdiff and ScS computed with 3-D wave-propagation with ground-truth Earth models including realistic CMB topography. Finally, we present CMB topography maps derived from two different datasets that we inverted using our technique. One includes ~50000 cross-correlated travel-time measurement for SKSac, and ScS phases while the other consists of ~220000 ISC manually picked travel-time for PKIKP and PcP phases. Prior to interpretation, we analyze the coverage using the approximate Hessian to discriminate well-constrained areas from less determined locations. Although with different amplitudes, our new CMB models reveal a low-elevation ring around the Pacific similar to other studies. While this is a pilot study extending topography inversions to full-wave based imaging mainly showing consistency with previous findings, we expect to further enhance these studies for a new generation of CMB topography models by combining various datasets and joint inversion with mantle structure.
Non-Gaussianity in the foreground-reduced CMB maps
Bernui, A.; Reboucas, M. J.
2010-03-15
A detection or nondetection of primordial non-Gaussianity by using the cosmic microwave background radiation (CMB) data is crucial not only to discriminate inflationary models but also to test alternative scenarios. Non-Gaussianity offers, therefore, a powerful probe of the physics of the primordial Universe. The extraction of primordial non-Gaussianity is a difficult enterprise since several effects of a nonprimordial nature can produce non-Gaussianity. Given the far-reaching consequences of such a non-Gaussianity for our understanding of the physics of the early Universe, it is important to employ a range of different statistical tools to quantify and/or constrain its amount in order to have information that may be helpful for identifying its causes. Moreover, different indicators can in principle provide information about distinct forms of non-Gaussianity that can be present in CMB data. Most of the Gaussianity analyses of CMB data have been performed by using part-sky frequency, where the mask is used to deal with the galactic diffuse foreground emission. However, full-sky map seems to be potentially more appropriate to test for Gaussianity of the CMB data. On the other hand, masks can induce bias in some non-Gaussianity analyses. Here we use two recent large-angle non-Gaussianity indicators, based on skewness and kurtosis of large-angle patches of CMB maps, to examine the question of non-Gaussianity in the available full-sky five-year and seven-year Wilkinson Microwave Anisotropy Probe (WMAP) maps. We show that these full-sky foreground-reduced maps present a significant deviation from Gaussianity of different levels, which vary with the foreground-reducing procedures. We also make a Gaussianity analysis of the foreground-reduced five-year and seven-year WMAP maps with a KQ75 mask, and compare with the similar analysis performed with the corresponding full-sky foreground-reduced maps. This comparison shows a significant reduction in the levels of non
N-body lensed CMB maps: lensing extraction and characterization
Antolini, Claudia; Martinelli, Matteo; Baccigalupi, Carlo; Fantaye, Yabebal; Carbone, Carmelita E-mail: y.t.fantaye@astro.uio.no E-mail: carmelita.carbone@brera.inaf.it
2014-02-01
We reconstruct shear maps and angular power spectra from simulated weakly lensed total intensity (TT) and polarised (EB) maps of the Cosmic Microwave Background (CMB) anisotropies, obtained using Born approximated ray-tracing through the N-body simulated Cold Dark Matter (CDM) structures in the Millennium Simulations (MS). We compare the recovered signal with the ΛCDM prediction, on the whole interval of angular scales which is allowed by the finite box size, extending from the degree scale to the arcminute, by applying a quadratic estimator in the flat sky limit; we consider PRISM-like instrumental specification for future generation CMB satellites, corresponding to arcminute angular resolution of 3.2' and sensitivity of 2.43 μK-arcmin. The noise contribution in the simulations closely follows the estimator prediction, becoming dominated by limits in the angular resolution for the EB signal, at ℓ ≅ 1500. The recovered signal shows no visible departure from predictions of the weak lensing power within uncertainties, when considering TT and EB data singularly. In particular, the reconstruction precision reaches the level of a few percent in bins with Δℓ ≅ 100 in the angular multiple interval 1000∼<ℓ∼<2000 for T, and about 10% for EB. Within the adopted specifications, polarisation data do represent a significant contribution to the lensing shear, which appear to faithfully trace the underlying N-body structure down to the smallest angular scales achievable with the present setup, validating at the same time the latter with respect to semi-analytical predictions from ΛCDM cosmology at the level of CMB lensing statistics. This work demonstrates the feasibility of CMB lensing studies based on large scale simulations of cosmological structure formation in the context of the current and future high resolution and sensitivity CMB experiment.
Cosmological Parameters from CMB Maps without Likelihood Approximation
NASA Astrophysics Data System (ADS)
Racine, B.; Jewell, J. B.; Eriksen, H. K.; Wehus, I. K.
2016-03-01
We propose an efficient Bayesian Markov chain Monte Carlo (MCMC) algorithm for estimating cosmological parameters from cosmic microwave background (CMB) data without the use of likelihood approximations. It builds on a previously developed Gibbs sampling framework that allows for exploration of the joint CMB sky signal and power spectrum posterior, P({\\boldsymbol{s}},{C}{\\ell }| {\\boldsymbol{d}}), and addresses a long-standing problem of efficient parameter estimation simultaneously in regimes of high and low signal-to-noise ratio. To achieve this, our new algorithm introduces a joint Markov chain move in which both the signal map and power spectrum are synchronously modified, by rescaling the map according to the proposed power spectrum before evaluating the Metropolis-Hastings accept probability. Such a move was already introduced by Jewell et al., who used it to explore low signal-to-noise posteriors. However, they also found that the same algorithm is inefficient in the high signal-to-noise regime, since a brute-force rescaling operation does not account for phase information. This problem is mitigated in the new algorithm by subtracting the Wiener filter mean field from the proposed map prior to rescaling, leaving high signal-to-noise information invariant in the joint step, and effectively only rescaling the low signal-to-noise component. To explore the full posterior, the new joint move is then interleaved with a standard conditional Gibbs move for the sky map. We apply our new algorithm to simplified simulations for which we can evaluate the exact posterior to study both its accuracy and its performance, and find good agreement with the exact posterior; marginal means agree to ≲0.006σ and standard deviations to better than ˜3%. The Markov chain correlation length is of the same order of magnitude as those obtained by other standard samplers in the field.
A new map-making algorithm for CMB polarization experiments
NASA Astrophysics Data System (ADS)
Wallis, Christopher G. R.; Bonaldi, A.; Brown, Michael L.; Battye, Richard A.
2015-10-01
With the temperature power spectrum of the cosmic microwave background (CMB) at least four orders of magnitude larger than the B-mode polarization power spectrum, any instrumental imperfections that couple temperature to polarization must be carefully controlled and/or removed. Here we present two new map-making algorithms that can create polarization maps that are clean of temperature-to-polarization leakage systematics due to differential gain and pointing between a detector pair. Where a half-wave plate is used, we show that the spin-2 systematic due to differential ellipticity can also be removed using our algorithms. The algorithms require no prior knowledge of the imperfections or temperature sky to remove the temperature leakage. Instead, they calculate the systematic and polarization maps in one step directly from the time-ordered data (TOD). The first algorithm is designed to work with scan strategies that have a good range of crossing angles for each map pixel and the second for scan strategies that have a limited range of crossing angles. The first algorithm can also be used to identify if systematic errors that have a particular spin are present in a TOD. We demonstrate the use of both algorithms and the ability to identify systematics with simulations of TOD with realistic scan strategies and instrumental noise.
Searching for primordial non-Gaussianity in Planck CMB maps using a combined estimator
NASA Astrophysics Data System (ADS)
Novaes, C. P.; Bernui, A.; Ferreira, I. S.; Wuensche, C. A.
2014-01-01
The extensive search for deviations from Gaussianity in cosmic microwave background radiation (CMB) data is very important due to the information about the very early moments of the universe encoded there. Recent analyses from Planck CMB data do not exclude the presence of non-Gaussianity of small amplitude, although they are consistent with the Gaussian hypothesis. The use of different techniques is essential to provide information about types and amplitudes of non-Gaussianities in the CMB data. In particular, we find interesting to construct an estimator based upon the combination of two powerful statistical tools that appears to be sensitive enough to detect tiny deviations from Gaussianity in CMB maps. This estimator combines the Minkowski functionals with a Neural Network, maximizing a tool widely used to study non-Gaussian signals with a reinforcement of another tool designed to identify patterns in a data set. We test our estimator by analyzing simulated CMB maps contaminated with different amounts of local primordial non-Gaussianity quantified by the dimensionless parameter f NL. We apply it to these sets of CMB maps and find gtrsim 98% of chance of positive detection, even for small intensity local non-Gaussianity like f NL = 38±18, the current limit from Planck data for large angular scales. Additionally, we test the suitability to distinguish between primary and secondary non-Gaussianities: first we train the Neural Network with two sets, one of nearly Gaussian CMB maps (|f NL| <= 10) but contaminated with realistic inhomogeneous Planck noise (i.e., secondary non-Gaussianity) and the other of non-Gaussian CMB maps, that is, maps endowed with weak primordial non-Gaussianity (28 <= f NL <= 48); after that we test an ensemble composed of CMB maps either with one of these non-Gaussian contaminations, and find out that our method successfully classifies ~ 95% of the tested maps as being CMB maps containing primordial or secondary non-Gaussianity. Furthermore
Searching for primordial non-Gaussianity in Planck CMB maps using a combined estimator
Novaes, C.P.; Wuensche, C.A.; Bernui, A.; Ferreira, I.S. E-mail: bernui@on.br E-mail: ca.wuensche@inpe.br
2014-01-01
The extensive search for deviations from Gaussianity in cosmic microwave background radiation (CMB) data is very important due to the information about the very early moments of the universe encoded there. Recent analyses from Planck CMB data do not exclude the presence of non-Gaussianity of small amplitude, although they are consistent with the Gaussian hypothesis. The use of different techniques is essential to provide information about types and amplitudes of non-Gaussianities in the CMB data. In particular, we find interesting to construct an estimator based upon the combination of two powerful statistical tools that appears to be sensitive enough to detect tiny deviations from Gaussianity in CMB maps. This estimator combines the Minkowski functionals with a Neural Network, maximizing a tool widely used to study non-Gaussian signals with a reinforcement of another tool designed to identify patterns in a data set. We test our estimator by analyzing simulated CMB maps contaminated with different amounts of local primordial non-Gaussianity quantified by the dimensionless parameter f{sub NL}. We apply it to these sets of CMB maps and find ∼> 98% of chance of positive detection, even for small intensity local non-Gaussianity like f{sub NL} = 38±18, the current limit from Planck data for large angular scales. Additionally, we test the suitability to distinguish between primary and secondary non-Gaussianities: first we train the Neural Network with two sets, one of nearly Gaussian CMB maps (|f{sub NL}| ≤ 10) but contaminated with realistic inhomogeneous Planck noise (i.e., secondary non-Gaussianity) and the other of non-Gaussian CMB maps, that is, maps endowed with weak primordial non-Gaussianity (28 ≤ f{sub NL} ≤ 48); after that we test an ensemble composed of CMB maps either with one of these non-Gaussian contaminations, and find out that our method successfully classifies ∼ 95% of the tested maps as being CMB maps containing primordial or
CMB anisotropy power spectrum using linear combinations of WMAP maps
Saha, Rajib; Prunet, Simon; Jain, Pankaj; Souradeep, Tarun
2008-07-15
In recent years the goal of estimating different cosmological parameters precisely has set new challenges in the effort to accurately measure the angular power spectrum of the CMB. This has required removal of foreground contamination as well as detector noise bias with reliability and precision. Recently, a novel, model-independent method for the estimation of the CMB angular power spectrum solely from multifrequency observations has been proposed and implemented on the first year WMAP data by Saha et al. 2006. All previous estimates of the power spectrum of the CMB are based upon foreground templates using data sets from different experiments. However, our methodology demonstrates that the CMB angular spectrum can be reliably estimated with precision from a self-contained analysis of the WMAP data. In this work we provide a detailed description of this method. We also study and identify the biases present in our power spectrum estimate. We apply our methodology to extract the power spectrum from the WMAP data.
A special kind of local structure in the CMB intensity maps: duel peak structure
NASA Astrophysics Data System (ADS)
Liu, Hao; Li, Ti-Pei
2009-03-01
We study the local structure of Cosmic Microwave Background (CMB) temperature maps released by the Wilkinson Microwave Anisotropy Probe (WMAP) team, and find a new kind of structure, which can be described as follows: a peak (or valley) of average temperature is often followed by a peak of temperature fluctuation that is 4° away. This structure is important for the following reasons: both the well known cold spot detected by Cruz et al. and the hot spot detected by Vielva et al. with the same technology (the third spot in their article) have such structure; more spots that are similar to them can be found on CMB maps and they also tend to be significant cold/hot spots; if we change the 4° characteristic into an artificial one, such as 3° or 5°, there will be less 'similar spots', and the temperature peaks or valleys will be less significant. The presented 'similar spots' have passed a strict consistency test which requires them to be significant on at least three different CMB temperature maps. We hope that this article could arouse some interest in the relationship of average temperature with temperature fluctuation in local areas; meanwhile, we are also trying to find an explanation for it which might be important to CMB observation and theory.
Designs for a large-aperture telescope to map the CMB 10× faster.
Niemack, Michael D
2016-03-01
Current large-aperture cosmic microwave background (CMB) telescopes have nearly maximized the number of detectors that can be illuminated while maintaining diffraction-limited image quality. The polarization-sensitive detector arrays being deployed in these telescopes in the next few years will have roughly 10⁴ detectors. Increasing the mapping speed of future instruments by at least an order of magnitude is important to enable precise probes of the inflationary paradigm in the first fraction of a second after the big bang and provide strong constraints on cosmological parameters. The CMB community has begun planning a next generation "Stage IV" CMB project that will be comprised of multiple telescopes with between 10⁵-10⁶ detectors to pursue these goals. This paper introduces the new crossed Dragone telescope and receiver optics designs that increase the usable diffraction-limited field-of-view, and therefore the mapping speed, by an order of magnitude compared to the upcoming generation of large-aperture instruments. Polarization systematics and engineering considerations are presented, including a preliminary receiver model to demonstrate that these designs will enable high efficiency illumination of >10⁵ detectors in a next generation CMB telescope. PMID:26974631
SILC: a new Planck internal linear combination CMB temperature map using directional wavelets
NASA Astrophysics Data System (ADS)
Rogers, Keir K.; Peiris, Hiranya V.; Leistedt, Boris; McEwen, Jason D.; Pontzen, Andrew
2016-08-01
We present new clean maps of the cosmic microwave background (CMB) temperature anisotropies (as measured by Planck) constructed with a novel internal linear combination (ILC) algorithm using directional, scale-discretized wavelets - scale-discretized, directional wavelet ILC or Scale-discretised, directional wavelet Internal Linear Combination (SILC). Directional wavelets, when convolved with signals on the sphere, can separate the anisotropic filamentary structures which are characteristic of both the CMB and foregrounds. Extending previous component separation methods, which use the frequency, spatial and harmonic signatures of foregrounds to separate them from the cosmological background signal, SILC can additionally use morphological information in the foregrounds and CMB to better localize the cleaning algorithm. We test the method on Planck data and simulations, demonstrating consistency with existing component separation algorithms, and discuss how to optimize the use of morphological information by varying the number of directional wavelets as a function of spatial scale. We find that combining the use of directional and axisymmetric wavelets depending on scale could yield higher quality CMB temperature maps. Our results set the stage for the application of SILC to polarization anisotropies through an extension to spin wavelets.
Comparing and combining the Saskatoon, QMAP, and COBE CMB maps
Xu, Yongzhong; Tegmark, Max; de Oliveira-Costa, Angelica; Devlin, Mark J.; Herbig, Thomas; Miller, Amber D.; Netterfield, C. Barth; Page, Lyman
2001-05-15
We present a method for comparing and combining maps with different resolutions and beam shapes, and apply it to the Saskatoon, QMAP, and COBE-DMR data sets. Although the Saskatoon and QMAP maps detect signals at the 21{sigma} and 40{sigma} levels, respectively, their difference is consistent with pure noise, placing strong limits on possible systematic errors. In particular, we obtain quantitative upper limits on relative calibration and pointing errors. Splitting the combined data by frequency shows similar consistency between the Ka and Q bands, placing limits on foreground contamination. The visual agreement between the maps is equally striking. Our combined QMAP+Saskatoon map, nicknamed QMASK, is publicly available on the web together with its 6495x6495 noise covariance matrix. This thoroughly tested data set covers a large enough area (648 square degrees -- currently the largest degree-scale map available) to allow a statistical comparison with COBE-DMR, showing good agreement.
VizieR Online Data Catalog: CMB intensity map from WMAP and Planck PR2 data (Bobin+, 2016)
NASA Astrophysics Data System (ADS)
Bobin, J.; Sureau, F.; Starck, J.-L.
2016-05-01
This paper presents a novel estimation of the CMB map reconstructed from the Planck 2015 data (PR2) and the WMAP nine-year data (Bennett et al., 2013ApJS..208...20B), which updates the CMB map we published in (Bobin et al., 2014A&A...563A.105B). This new map is based on the sparse component separation method L-GMCA (Bobin et al., 2013A&A...550A..73B). Additionally, the map benefits from the latest advances in this field (Bobin et al., 2015, IEEE Transactions on Signal Processing, 63, 1199), which allows us to accurately discriminate between correlated components. In this update to our previous work, we show that this new map presents significant improvements with respect to the available CMB map estimates. (3 data files).
Semi-blind Bayesian inference of CMB map and power spectrum
NASA Astrophysics Data System (ADS)
Vansyngel, Flavien; Wandelt, Benjamin D.; Cardoso, Jean-François; Benabed, Karim
2016-04-01
We present a new blind formulation of the cosmic microwave background (CMB) inference problem. The approach relies on a phenomenological model of the multifrequency microwave sky without the need for physical models of the individual components. For all-sky and high resolution data, it unifies parts of the analysis that had previously been treated separately such as component separation and power spectrum inference. We describe an efficient sampling scheme that fully explores the component separation uncertainties on the inferred CMB products such as maps and/or power spectra. External information about individual components can be incorporated as a prior giving a flexible way to progressively and continuously introduce physical component separation from a maximally blind approach. We connect our Bayesian formalism to existing approaches such as Commander, spectral mismatch independent component analysis (SMICA), and internal linear combination (ILC), and discuss possible future extensions.
Non-Gaussian extrema counts for CMB maps
Pogosyan, Dmitri; Pichon, Christophe; Gay, Christophe
2011-10-15
In the context of the geometrical analysis of weakly non-Gaussian cosmic microwave background maps, the 2D differential extrema counts as functions of the excursion set threshold is derived from the full moments expansion of the joint probability distribution of an isotropic random field, its gradient, and invariants of the Hessian. Analytic expressions for these counts are given to second order in the non-Gaussian correction, while a Monte Carlo method to compute them to arbitrary order is presented. Matching count statistics to these estimators is illustrated on fiducial non-Gaussian Planck data.
Van Engelen, A.; Sehgal, N.; Bhattacharya, S.; Holder, G. P.; Zahn, O.; Nagai, D.
2014-05-01
The lensing power spectrum from cosmic microwave background (CMB) temperature maps will be measured with unprecedented precision with upcoming experiments, including upgrades to the Atacama Cosmology Telescope and the South Pole Telescope. Achieving significant improvements in cosmological parameter constraints, such as percent level errors on σ{sub 8} and an uncertainty on the total neutrino mass of ∼50 meV, requires percent level measurements of the CMB lensing power. This necessitates tight control of systematic biases. We study several types of biases to the temperature-based lensing reconstruction signal from foreground sources such as radio and infrared galaxies and the thermal Sunyaev-Zel'dovich effect from galaxy clusters. These foregrounds bias the CMB lensing signal due to their non-Gaussian nature. Using simulations as well as some analytical models we find that these sources can substantially impact the measured signal if left untreated. However, these biases can be brought to the percent level if one masks galaxies with fluxes at 150 GHz above 1 mJy and galaxy clusters with masses above M {sub vir} = 10{sup 14} M {sub ☉}. To achieve such percent level bias, we find that only modes up to a maximum multipole of l {sub max} ∼ 2500 should be included in the lensing reconstruction. We also discuss ways to minimize additional bias induced by such aggressive foreground masking by, for example, exploring a two-step masking and in-painting algorithm.
Cross-correlation of Planck CMB lensing and CFHTLenS galaxy weak lensing maps
NASA Astrophysics Data System (ADS)
Liu, Jia; Hill, J. Colin
2015-09-01
We cross-correlate cosmic microwave background (CMB) lensing and galaxy weak lensing maps using the Planck 2013 and 2015 data and the 154 deg2 Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). This measurement probes large-scale structure at intermediate redshifts ≈0.9 , between the high- and low-redshift peaks of the CMB and CFHTLenS lensing kernels, respectively. Using the noise properties of these data sets and standard Planck 2015 Λ CDM cosmological parameters, we forecast a signal-to-noise ratio ≈4.6 for the cross-correlation. We find that the noise level of our actual measurement agrees well with this estimate, but the amplitude of the signal lies well below the theoretical prediction. The best-fit amplitudes of our measured cross-correlations are A2013=0.48 ±0.26 and A2015=0.44 ±0.22 , using the 2013 and 2015 Planck CMB lensing maps, respectively, where A =1 corresponds to the fiducial Planck 2015 Λ CDM prediction. Due to the low measured amplitude, the detection significance is moderate (≈2 σ ) and the data are in tension with the theoretical prediction (≈2 - 2.5 σ ) . The tension is reduced somewhat when compared to predictions using WMAP9 parameters, for which we find A2013=0.56 ±0.30 and A2015=0.52 ±0.26 . We consider various systematic effects, finding that photometric redshift uncertainties, contamination by intrinsic alignments, and effects due to the masking of galaxy clusters in the Planck 2015 CMB lensing reconstruction are able to help resolve the tension at a significant level (≈10 % each). An overall multiplicative bias in the CFHTLenS shear data could also play a role, which can be tested with existing data. We close with forecasts for measurements of the CMB lensing—galaxy lensing cross-correlation using ongoing and future weak lensing surveys, which will definitively test the significance of the tension in our results with respect to Λ CDM .
Statistical isotropy violation in WMAP CMB maps resulting from non-circular beams
NASA Astrophysics Data System (ADS)
Das, Santanu; Mitra, Sanjit; Rotti, Aditya; Pant, Nidhi; Souradeep, Tarun
2016-06-01
Statistical isotropy (SI) of cosmic microwave background (CMB) fluctuations is a key observational test to validate the cosmological principle underlying the standard model of cosmology. While a detection of SI violation would have immense cosmological ramification, it is important to recognise their possible origin in systematic effects of observations. The WMAP seven year (WMAP-7) release claimed significant deviation from SI in the bipolar spherical harmonic (BipoSH) coefficients and . Here we present the first explicit reproduction of the measurements reported in WMAP-7, confirming that beam systematics alone can completely account for the measured SI violation. The possibility of such a systematic origin was alluded to in WMAP-7 paper itself and other authors but not as explicitly so as to account for it accurately. We simulate CMB maps using the actual WMAP non-circular beams and scanning strategy. Our estimated BipoSH spectra from these maps match the WMAP-7 results very well. It is also evident that only a very careful and adequately detailed modelling, as carried out here, can conclusively establish that the entire signal arises from non-circular beam effect. This is important since cosmic SI violation signals are expected to be subtle and dismissing a large SI violation signal as observational artefact based on simplistic plausibility arguments run the serious risk of "throwing the baby out with the bathwater".
Maps of CMB lensing deflection from N-body simulations in Coupled Dark Energy Cosmologies
Carbone, Carmelita; Baldi, Marco; Baccigalupi, Carlo E-mail: marco.baldi5@unibo.it E-mail: bacci@sissa.it
2013-09-01
We produce lensing potential and deflection-angle maps in order to simulate the weak gravitational lensing of the Cosmic Microwave Background (CMB) via ray-tracing through the COupled Dark Energy Cosmological Simulations (CoDECS), the largest suite of N-body simulations to date for interacting Dark Energy cosmologies. The constructed maps faithfully reflect the N-body cosmic structures on a range of scales going from the arcminute to the degree scale, limited only by the resolution and extension of the simulations. We investigate the variation of the lensing pattern due to the underlying Dark Energy (DE) dynamics, characterised by different background and perturbation behaviours as a consequence of the interaction between the DE field and Cold Dark Matter (CDM). In particular, we study in detail the results from three cosmological models differing in the background and perturbations evolution at the epoch in which the lensing cross section is most effective, corresponding to a redshift of ∼ 1, with the purpose to isolate their imprints in the lensing observables, regardless of the compatibility of these models with present constraints. The scenarios investigated here include a reference ΛCDM cosmology, a standard coupled DE (cDE) scenario, and a ''bouncing'' cDE scenario. For the standard cDE scenario, we find that typical differences in the lensing potential result from two effects: the enhanced growth of linear CDM density fluctuations with respect to the ΛCDM case, and the modified nonlinear dynamics of collapsed structures induced by the DE-CDM interaction. As a consequence, CMB lensing highlights the DE impact in the cosmological expansion, even in the degenerate case where the amplitude of the linear matter density perturbations, parametrised through σ{sub 8}, is the same in both the standard cDE and ΛCDM cosmologies. For the ''bouncing'' scenario, we find that the two opposite behaviours of the lens density contrast and of the matter abundance lead to
Searching for hidden mirror symmetries in CMB fluctuations from WMAP 7 year maps
Finelli, Fabio; Gruppuso, Alessandro; Starobinsky, Alexey A. E-mail: gruppuso@iasfbo.inaf.it E-mail: alstar@landau.ac.ru
2012-07-01
We search for hidden mirror symmetries at large angular scales in the WMAP 7 year Internal Linear Combination map of CMB temperature anisotropies using global pixel based estimators introduced for this aim. Two different axes are found for which the CMB intensity pattern is anomalously symmetric (or anti-symmetric) under reflection with respect to orthogonal planes at the 99.84(99.96)% CL (confidence level), if compared to a result for an arbitrary axis in simulations without the symmetry. We have verified that our results are robust to the introduction of the galactic mask. The direction of such axes is close to the CMB kinematic dipole and nearly orthogonal to the ecliptic plane, respectively. If instead the real data are compared to those in simulations taken with respect to planes for which the maximal mirror symmetry is generated by chance, the confidence level decreases to 92.39(76.65)%. But when the effect in question translates into the anomalous alignment between normals to planes of maximal mirror (anti)-symmetry and these natural axes mentioned. We also introduce the representation of the above estimators in the harmonic domain, confirming the results obtained in the pixel one. The symmetry anomaly is shown to be almost entirely due to low multipoles, so it may have a cosmological and even primordial origin. Contrary, the anti-symmetry one is mainly due to intermediate multipoles that probably suggests its non-fundamental nature. We have demonstrated that these anomalies are not connected to the known issue of the low variance in WMAP observations and we have checked that axially symmetric parts of these anomalies are small, so that the axes are not the symmetry ones.
North-South non-Gaussian asymmetry in Planck CMB maps
Bernui, A.; Oliveira, A.F.; Pereira, T.S. E-mail: adhimar@unifei.edu.br
2014-10-01
We report the results of a statistical analysis performed with the four foreground-cleaned Planck maps by means of a suitably defined local-variance estimator. Our analysis shows a clear dipolar structure in Planck's variance map pointing in the direction (l,b) ≅ (220°,-32°), thus consistent with the North-South asymmetry phenomenon. Surprisingly, and contrary to previous findings, removing the CMB quadrupole and octopole makes the asymmetry stronger. Our results show a maximal statistical significance, of 98.1% CL, in the scales ranging from ℓ=4 to ℓ=500. Additionally, through exhaustive analyses of the four foreground-cleaned and individual frequency Planck maps, we find unlikely that residual foregrounds could be causing this dipole variance asymmetry. Moreover, we find that the dipole gets lower amplitudes for larger masks, evidencing that most of the contribution to the variance dipole comes from a region near the galactic plane. Finally, our results are robust against different foreground cleaning procedures, different Planck masks, pixelization parameters, and the addition of inhomogeneous real noise.
NASA Astrophysics Data System (ADS)
Migliaccio, M.; Natoli, P.; De Troia, G.; Hikage, C.; Komatsu, E.; Ade, P. A. R.; Bock, J. J.; Bond, J. R.; Borrill, J.; Boscaleri, A.; Contaldi, C. R.; Crill, B. P.; de Bernardis, P.; de Gasperis, G.; de Oliveira-Costa, A.; Di Stefano, G.; Hivon, E.; Kisner, T. S.; Jones, W. C.; Lange, A. E.; Masi, S.; Mauskopf, P. D.; MacTavish, C. J.; Melchiorri, A.; Montroy, T. E.; Netterfield, C. B.; Pascale, E.; Piacentini, F.; Polenta, G.; Ricciardi, S.; Romeo, G.; Ruhl, J. E.; Tegmark, M.; Veneziani, M.; Vittorio, N.
2009-10-01
Minkowski functionals are a powerful tool to constrain the Gaussianity of the Cosmic Microwave Background (CMB). In the limit of a weakly non Gaussian field, a perturbative approach can be derived [Hikage C., Komatsu E., & Matsubara T., 2006, ApJ, 653, 11] that is completely based on analytical formulae without requiring computationally intensive, dedicated Monte Carlo non Gaussian simulations of the CMB anisotropy. We apply this machinery to an intensity map derived from the 1998 and 2003 flights of BOOMERanG, analyzed here together for the first time. We set limits on the non-linear coupling parameter f as -1020
CMB Lensing Cross Correlations
NASA Astrophysics Data System (ADS)
Bleem, Lindsey
2014-03-01
A new generation of experiments designed to conduct high-resolution, low-noise observations of the Cosmic Microwave Background (CMB)--including ACTpol, Planck, POLARBEAR and SPTpol--are producing exquisite measurements of the gravitational lensing of the CMB. Such measurements, covering large fractions of the sky, provide detailed maps of the projected mass distribution extending to the surface of the CMB's last scattering. Concurrently, a large number of deep, wide-area imaging and spectroscopic surveys (e.g., the Dark Energy Survey (DES),WISE all-sky survey, Subaru HyperSuprimeCam Survey, LSST, MS-DESI, BigBoss, etc.) are, or will soon be, providing maps of the distribution of galaxies in the Universe. Correlations of such tracer populations with lensing data allows new probes of where and how galaxies form in the dark matter skeleton of the Universe. Recent correlations of maps of galaxy and quasar densities with lensing convergence maps have produced significant measurements of galaxy bias. The near-term prospect for improvements in such measurements is notable as more precise lensing data from CMB polarization experiments will help to break cosmological and astrophysical parameter degeneracies. Work by the Planck, SPT, and POLARBEAR collaborations has also focused on the correlation of the Cosmic Infrared Background (CIB) with CMB lensing convergence maps. This correlation is particularly strong as the redshifts of the CIB and CMB lensing kernel are well matched. Such correlations probe high-redshift structure, constraining models of star-formation and the characteristic mass scale for halos hosting CIB galaxies and have also been used to demonstrate the first detection of CMB B-mode polarization--an important milestone in CMB observations. Finally, combining galaxy number density, cosmic shear and CMB lensing maps has the potential to provide valuable systematic tests for upcoming cosmological results from large optical surveys such as LSST.
Partial covariance mapping techniques at FELs
NASA Astrophysics Data System (ADS)
Frasinski, Leszek
2014-05-01
The development of free-electron lasers (FELs) is driven by the desire to access the structure and chemical dynamics of biomolecules with atomic resolution. Short, intense FEL pulses have the potential to record x-ray diffraction images before the molecular structure is destroyed by radiation damage. However, even during the shortest, few-femtosecond pulses currently available, there are some significant changes induced by massive ionisation and onset of Coulomb explosion. To interpret the diffraction images it is vital to gain insight into the electronic and nuclear dynamics during multiple core and valence ionisations that compete with Auger cascades. This paper focuses on a technique that is capable to probe these processes. The covariance mapping technique is well suited to the high intensity and low repetition rate of FEL pulses. While the multitude of charges ejected at each pulse overwhelm conventional coincidence methods, an improved technique of partial covariance mapping can cope with hundreds of photoelectrons or photoions detected at each FEL shot. The technique, however, often reveals spurious, uninteresting correlations that spoil the maps. This work will discuss the strengths and limitations of various forms of covariance mapping techniques. Quantitative information extracted from the maps will be linked to theoretical modelling of ionisation and fragmentation paths. Special attention will be given to critical experimental parameters, such as counting rate, FEL intensity fluctuations, vacuum impurities or detector efficiency and nonlinearities. Methods of assessing and optimising signal-to-noise ratio will be described. Emphasis will be put on possible future developments such as multidimensional covariance mapping, compensation for various experimental instabilities and improvements in the detector response. This work has been supported the EPSRC, UK (grants EP/F021232/1 and EP/I032517/1).
Sunyaev, Rashid A.; Khatri, Rishi E-mail: khatri@mpa-garching.mpg.de
2013-03-01
y-type spectral distortions of the cosmic microwave background allow us to detect clusters and groups of galaxies, filaments of hot gas and the non-uniformities in the warm hot intergalactic medium. Several CMB experiments (on small areas of sky) and theoretical groups (for full sky) have recently published y-type distortion maps. We propose to search for two artificial hot spots in such y-type maps resulting from the incomplete subtraction of the effect of the motion induced dipole on the cosmic microwave background sky. This dipole introduces, at second order, additional temperature and y-distortion anisotropy on the sky of amplitude few μK which could potentially be measured by Planck HFI and Pixie experiments and can be used as a source of cross channel calibration by CMB experiments. This y-type distortion is present in every pixel and is not the result of averaging the whole sky. This distortion, calculated exactly from the known linear dipole, can be subtracted from the final y-type maps, if desired.
Lensing-induced morphology changes in CMB temperature maps in modified gravity theories
NASA Astrophysics Data System (ADS)
Munshi, D.; Hu, B.; Matsubara, T.; Coles, P.; Heavens, A.
2016-04-01
Lensing of the Cosmic Microwave Background (CMB) changes the morphology of pattern of temperature fluctuations, so topological descriptors such as Minkowski Functionals can probe the gravity model responsible for the lensing. We show how the recently introduced two-to-two and three-to-one kurt-spectra (and their associated correlation functions), which depend on the power spectrum of the lensing potential, can be used to probe modified gravity theories such as f(R) theories of gravity and quintessence models. We also investigate models based on effective field theory, which include the constant-Ω model, and low-energy Hořava theories. Estimates of the cumulative signal-to-noise for detection of lensing-induced morphology changes, reaches Script O(103) for the future planned CMB polarization mission COrE+. Assuming foreground removal is possible to lmax=3000, we show that many modified gravity theories can be rejected with a high level of significance, making this technique comparable in power to galaxy weak lensing or redshift surveys. These topological estimators are also useful in distinguishing lensing from other scattering secondaries at the level of the four-point function or trispectrum. Examples include the kinetic Sunyaev-Zel'dovich (kSZ) effect which shares, with lensing, a lack of spectral distortion. We also discuss the complication of foreground contamination from unsubtracted point sources.
Chingangbam, Pravabati; Park, Changbom E-mail: cbp@kias.re.kr
2009-12-01
We simulate CMB maps including non-Gaussianity arising from cubic order perturbations of the primordial gravitational potential, characterized by the non-linearity parameter g{sub NL}. The maps are used to study the characteristic nature of the resulting non-Gaussian temperature fluctuations. We measure the genus and investigate how it deviates from Gaussian shape as a function of g{sub NL} and smoothing scale. We find that the deviation of the non-Gaussian genus curve from the Gaussian one has an antisymmetric, sine function like shape, implying more hot and more cold spots for g{sub NL} > 0 and less of both for g{sub NL} < 0. The deviation increases linearly with g{sub NL} and also exhibits mild increase as the smoothing scale increases. We further study other statistics derived from the genus, namely, the number of hot spots, the number of cold spots, combined number of hot and cold spots and the slope of the genus curve at mean temperature fluctuation. We find that these observables carry signatures of g{sub NL} that are clearly distinct from the quadratic order perturbations, encoded in the parameter f{sub NL}. Hence they can be very useful tools for distinguishing not only between non-Gaussian temperature fluctuations and Gaussian ones but also between g{sub NL} and f{sub NL} type non-Gaussianities.
Astrophysical Uses Of Cmb Lensing
NASA Astrophysics Data System (ADS)
Das, Sudeep
2009-01-01
The future of Cosmic Microwave Background (CMB) research lies in exploiting the arcminute scale secondary anisotropies which encode information about the late time interaction of the CMB photons with the structure in the Universe. A specific form of such interaction is the gravitational lensing of the CMB - the main topic of this thesis. Upcoming experiments like ACT, SPT and PLANCK will measure these anisotropies with unprecedented resolution and sensitivity. In this thesis, we present new techniques to model and analyse such high resolution data and explore the implications of such measurements on Cosmology. First, we describe a novel method for simulating high resolution large sky lensed CMB maps. Maps simulated through this method will be instrumental in developing the detection and analysis techniques for CMB lensing. Second, we describe a new and efficient method for measuring the power spectrum of arcminute resolution CMB maps. At these resolutions, aliasing of power due to hard edges and point source masks become a serious problem. Our method efficiently remedies these problems and the reduces uncertainties in the final power spectrum estimate by several factors over those obtainable by the now standard methods. This technique will be also useful for estimating higher order statistics from the maps, like the ones related to the detection of CMB lensing and its cross-correlation with large scale structure. Next, we exemplify how such cross-correlations can be turned into Cosmological probes. We propose an estimator for cosmological distance ratios based on CMB and galaxy lensing and show that it can be measured to sufficient accuracy in future experiments to be Cosmologically useful. Finally, we show that CMB lensing can be used to constrain the void and the texture hypotheses that have been put forward for explaining the intriguing Cold Spot anomaly in the WMAP data.
The Kullback-Leibler divergence as an estimator of the statistical properties of CMB maps
NASA Astrophysics Data System (ADS)
Ben-David, Assaf; Liu, Hao; Jackson, Andrew D.
2015-06-01
The identification of unsubtracted foreground residuals in the cosmic microwave background maps on large scales is of crucial importance for the analysis of polarization signals. These residuals add a non-Gaussian contribution to the data. We propose the Kullback-Leibler (KL) divergence as an effective, non-parametric test on the one-point probability distribution function of the data. With motivation in information theory, the KL divergence takes into account the entire range of the distribution and is highly non-local. We demonstrate its use by analyzing the large scales of the Planck 2013 SMICA temperature fluctuation map and find it consistent with the expected distribution at a level of 6%. Comparing the results to those obtained using the more popular Kolmogorov-Smirnov test, we find the two methods to be in general agreement.
Probing the statistical properties of CMB B-mode polarization through Minkowski functionals
NASA Astrophysics Data System (ADS)
Santos, Larissa; Wang, Kai; Zhao, Wen
2016-07-01
The detection of the magnetic type B-mode polarization is the main goal of future cosmic microwave background (CMB) experiments. In the standard model, the B-mode map is a strong non-gaussian field due to the CMB lensing component. Besides the two-point correlation function, the other statistics are also very important to dig the information of the polarization map. In this paper, we employ the Minkowski functionals to study the morphological properties of the lensed B-mode maps. We find that the deviations from Gaussianity are very significant for both full and partial-sky surveys. As an application of the analysis, we investigate the morphological imprints of the foreground residuals in the B-mode map. We find that even for very tiny foreground residuals, the effects on the map can be detected by the Minkowski functional analysis. Therefore, it provides a complementary way to investigate the foreground contaminations in the CMB studies.
Theory of short periodic orbits for partially open quantum maps
NASA Astrophysics Data System (ADS)
Carlo, Gabriel G.; Benito, R. M.; Borondo, F.
2016-07-01
We extend the semiclassical theory of short periodic orbits [M. Novaes et al., Phys. Rev. E 80, 035202(R) (2009), 10.1103/PhysRevE.80.035202] to partially open quantum maps, which correspond to classical maps where the trajectories are partially bounced back due to a finite reflectivity R . These maps are representative of a class that has many experimental applications. The open scar functions are conveniently redefined, providing a suitable tool for the investigation of this kind of system. Our theory is applied to the paradigmatic partially open tribaker map. We find that the set of periodic orbits that belongs to the classical repeller of the open map (R =0 ) is able to support the set of long-lived resonances of the partially open quantum map in a perturbative regime. By including the most relevant trajectories outside of this set, the validity of the approximation is extended to a broad range of R values. Finally, we identify the details of the transition from qualitatively open to qualitatively closed behavior, providing an explanation in terms of short periodic orbits.
Theory of short periodic orbits for partially open quantum maps.
Carlo, Gabriel G; Benito, R M; Borondo, F
2016-07-01
We extend the semiclassical theory of short periodic orbits [M. Novaes et al., Phys. Rev. E 80, 035202(R) (2009)PLEEE81539-375510.1103/PhysRevE.80.035202] to partially open quantum maps, which correspond to classical maps where the trajectories are partially bounced back due to a finite reflectivity R. These maps are representative of a class that has many experimental applications. The open scar functions are conveniently redefined, providing a suitable tool for the investigation of this kind of system. Our theory is applied to the paradigmatic partially open tribaker map. We find that the set of periodic orbits that belongs to the classical repeller of the open map (R=0) is able to support the set of long-lived resonances of the partially open quantum map in a perturbative regime. By including the most relevant trajectories outside of this set, the validity of the approximation is extended to a broad range of R values. Finally, we identify the details of the transition from qualitatively open to qualitatively closed behavior, providing an explanation in terms of short periodic orbits. PMID:27575138
Astrophysical uses of CMB lensing
NASA Astrophysics Data System (ADS)
Das, Sudeep
The future of Cosmic Microwave Background (CMB) research lies in exploiting the arcminute scale secondary anisotropies which encode information about the late time interaction of the CMB photons with the structure in the Universe. A specific form of such interaction is the gravitational lensing of the CMB photons by intervening matter--the main topic of this thesis. Upcoming experiments like the Atacama Cosmology Telescope (ACT) and PLANCK will measure these anisotropies with unprecedented resolution and sensitivity. In four separate papers, laid out as four chapters in this thesis, we present new techniques to model and analyze such high resolution data and explore the implications of such measurements on Cosmology, mainly in the context of CMB lensing. The first chapter describes a novel and accurate method for simulating high resolution lensed CMB maps by ray-tracing through a large scale structure simulation. This method does not adopt the flat sky approximation and retains information from large angular scales in the dark matter distribution. Maps simulated through this method will be instrumental in developing the detection and analysis techniques for CMB lensing in high resolution CMB experiments like ACT. In the second chapter, we describe a new and efficient method for measuring the power spectrum of arcminute resolution CMB maps. At these resolutions, the CMB power spectrum is extremely red and is prone to aliasing of power due to hard edges and point source masks. By combining two new techniques, namely, prewhitening and the adaptive multitaper method, we show that these problems can be efficiently remedied and the uncertainties in the final power spectrum estimate can be reduced by several factors over those obtainable by the now standard methods. These techniques will be also useful for estimating higher order statistics from the maps, like the ones related to the detection of CMB lensing and its cross-correlation with large scale structure tracers. In
Delensing CMB polarization with external datasets
Smith, Kendrick M.; Hanson, Duncan; LoVerde, Marilena; Hirata, Christopher M.; Zahn, Oliver E-mail: duncan.hanson@jpl.nasa.gov E-mail: chirata@tapir.caltech.edu
2012-06-01
One of the primary scientific targets of current and future CMB polarization experiments is the search for a stochastic background of gravity waves in the early universe. As instrumental sensitivity improves, the limiting factor will eventually be B-mode power generated by gravitational lensing, which can be removed through use of so-called ''delensing'' algorithms. We forecast prospects for delensing using lensing maps which are obtained externally to CMB polarization: either from large-scale structure observations, or from high-resolution maps of CMB temperature. We conclude that the forecasts in either case are not encouraging, and that significantly delensing large-scale CMB polarization requires high-resolution polarization maps with sufficient sensitivity to measure the lensing B-mode. We also present a simple formalism for including delensing in CMB forecasts which is computationally fast and agrees well with Monte Carlos.
MAXIMA: Observations of CMB anisotropy
NASA Astrophysics Data System (ADS)
Rabii, Bahman
This document describes the Millimeter Anisotropy eXperiment IMaging Array (MAXIMA), a balloon-borne experiment measuring the temperature anisotropy of the Cosmic Microwave Background (CMB) on angular scales of 10 ' to 5°. MAXIMA data are used to discriminate between cosmological models and to determine cosmological parameters. MAXIMA maps the CMB using 16 bolometric detectors observing in spectral bands centered at 150 GHz, 230 GHz, and 410 GHz, with 10 ' resolution at all frequencies. The combined receiver sensitivity to CMB anisotropy is ˜40 μK
Prototype of Partial Cutting Tool of Geological Map Images Distributed by Geological Web Map Service
NASA Astrophysics Data System (ADS)
Nonogaki, S.; Nemoto, T.
2014-12-01
Geological maps and topographical maps play an important role in disaster assessment, resource management, and environmental preservation. These map information have been distributed in accordance with Web services standards such as Web Map Service (WMS) and Web Map Tile Service (WMTS) recently. In this study, a partial cutting tool of geological map images distributed by geological WMTS was implemented with Free and Open Source Software. The tool mainly consists of two functions: display function and cutting function. The former function was implemented using OpenLayers. The latter function was implemented using Geospatial Data Abstraction Library (GDAL). All other small functions were implemented by PHP and Python. As a result, this tool allows not only displaying WMTS layer on web browser but also generating a geological map image of intended area and zoom level. At this moment, available WTMS layers are limited to the ones distributed by WMTS for the Seamless Digital Geological Map of Japan. The geological map image can be saved as GeoTIFF format and WebGL format. GeoTIFF is one of the georeferenced raster formats that is available in many kinds of Geographical Information System. WebGL is useful for confirming a relationship between geology and geography in 3D. In conclusion, the partial cutting tool developed in this study would contribute to create better conditions for promoting utilization of geological information. Future work is to increase the number of available WMTS layers and the types of output file format.
Bayesian Inference of CMB Gravitational Lensing
NASA Astrophysics Data System (ADS)
Anderes, Ethan; Wandelt, Benjamin D.; Lavaux, Guilhem
2015-08-01
The Planck satellite, along with several ground-based telescopes, has mapped the cosmic microwave background (CMB) at sufficient resolution and signal-to-noise so as to allow a detection of the subtle distortions due to the gravitational influence of the intervening matter distribution. A natural modeling approach is to write a Bayesian hierarchical model for the lensed CMB in terms of the unlensed CMB and the lensing potential. So far there has been no feasible algorithm for inferring the posterior distribution of the lensing potential from the lensed CMB map. We propose a solution that allows efficient Markov Chain Monte Carlo sampling from the joint posterior of the lensing potential and the unlensed CMB map using the Hamiltonian Monte Carlo technique. The main conceptual step in the solution is a re-parameterization of CMB lensing in terms of the lensed CMB and the “inverse lensing” potential. We demonstrate a fast implementation on simulated data, including noise and a sky cut, that uses a further acceleration based on a very mild approximation of the inverse lensing potential. We find that the resulting Markov Chain has short correlation lengths and excellent convergence properties, making it promising for applications to high-resolution CMB data sets in the future.
Multiple mapping conditioning for flames with partial premixing
Kronenburg, A.; Cleary, M.J.
2008-10-15
Fully closed multiple mapping conditioning (MMC) is used to model partially premixed flames in homogeneous, isotropic decaying turbulence where the partial premixing is caused by local extinction and reignition phenomena. Two reference variables that represent mixing and reaction progress, such as mixture fraction and sensible enthalpy, are used to emulate turbulent scalar fluctuations. Local extinction is achieved by a priori coupling between scalar dissipation and temperature fluctuations via a correlation function that is based on the conditionally averaged sensible enthalpy at stoichiometric composition. The proposed model provides closures for the joint PDF of mixture fraction and sensible enthalpy, for the conditional variance equation of a reactive scalar, and for the doubly conditioned dissipation terms. Model results are compared with DNS in three flame cases with varying levels of local extinction, up to global extinction. The joint PDF predicted by MMC is in fair agreement with DNS. It constitutes, however, a clear improvement over conventional models using preassumed distribution functions for the PDFs. The doubly conditioned dissipation terms are modeled well and the results for all major chemical species are in good agreement with DNS. Predictions for intermediate species are also satisfactory. (author)
[Cosmic Microwave Background (CMB) Anisotropies
NASA Technical Reports Server (NTRS)
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.
[Cosmic Microwave Background (CMB) Anisotropies
NASA Astrophysics Data System (ADS)
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.
Fergusson, J.R.; Liguori, M.; Shellard, E.P.S. E-mail: michele.liguori@pd.infn.it
2012-12-01
We use a separable mode expansion estimator with WMAP7 data to estimate the bispectrum for all the primary families of non-Gaussian models, including non-scaling feature (periodic) models, the flat (trans-Planckian) model, DBI and ghost inflation, as well as previously constrained simple cases. We review the late-time mode expansion estimator methodology which can be applied to any non-separable primordial and CMB bispectrum model, and we demonstrate how the method can be used to reconstruct the CMB bispectrum from an observational map. We extend the previous validation of the general estimator using local map simulations. We apply the estimator to the coadded WMAP 7-year V and W channel maps, reconstructing the WMAP bispectrum using l < 500 multipoles and n = 50 orthonormal 3D eigenmodes; both the mode expansion parameters and the reconstructed 3D WMAP bispectrum are plotted. We constrain all popular nearly scale-invariant models, ensuring that the theoretical bispectrum is well-described by a convergent mode expansion. Constraints from the local model f{sub NL} = 20.31±27.64 and the equilateral model f{sub NL} = 10.19±127.38 (F{sub NL} = 1.90±23.79) are consistent with previously published results. (Here, we use a nonlinearity parameter F{sub NL} normalised to the local case, to allow more direct comparison between different models.) Notable new constraints from our method include those for the constant model F{sub NL} = 7.82±24.57, the flat model F{sub NL} = 7.31±26.22, and warm inflation F{sub NL} = 2.10±25.83. We investigate feature models, which break scale invariance, surveying a wide parameter range for both the scale and phase (scanning for feature models with an effective period l* > 150). We find no significant evidence of non-Gaussianity for all cases well-described by the given eigenmodes. In the overall non-Gaussian analysis, we find one anomalous mode n = 33 with a 3.39σ amplitude which could give rise to an oscillatory model signal with l*
New Measurements of CMB Polarization with SPTpol
NASA Astrophysics Data System (ADS)
Henning, Jason; SPTpol Collaboration
2016-06-01
All-sky surveys of the primary temperature anisotropies of the Cosmic Microwave Background (CMB) are now cosmic variance limited on large to intermediate scales. To place tighter constraints on cosmology from CMB primary anisotropies we turn to measurements of CMB polarization. Not only is polarization another probe of ΛCDM cosmology, but secondary anisotropies are expected to have low polarized emission, which opens more of the so-called CMB damping tail to cosmological study. In this talk, we present new 150 GHz measurements of the CMB E-mode polarization auto-power and temperature-E-mode cross-power spectra from a 500 deg2 patch of sky observed with the SPTpol instrument, the second-generation receiver installed on the South Pole Telescope. Over a range of spherical harmonic multipoles 50 ≤ l < 10000 we detect 9 acoustic peaks in the E-mode spectrum. With these spectra we constrain ΛCDM cosmology independently from temperature-only measurements, and present new joint constraints with the Planck temperature auto-power spectrum. The CMB is also gravitationally lensed by large-scale structure. We use our high-fidelity map of E-mode polarization, in conjunction with SPTpol maps of B-mode polarization and temperature, to map the lensing potential of the CMB and measure its corresponding power spectrum. Finally, the CMB lensing potential can be combined with our E-mode map to estimate lensing B modes present in our field, which can be delensed to improve constraints on primordial B modes and the energy scale of inflation through the tensor-to-scalar ratio, r.
A neural-network based estimator to search for primordial non-Gaussianity in Planck CMB maps
NASA Astrophysics Data System (ADS)
Novaes, C. P.; Bernui, A.; Ferreira, I. S.; Wuensche, C. A.
2015-09-01
We present an upgraded combined estimator, based on Minkowski Functionals and Neural Networks, with excellent performance in detecting primordial non-Gaussianity in simulated maps that also contain a weighted mixture of Galactic contaminations, besides real pixel's noise from Planck cosmic microwave background radiation data. We rigorously test the efficiency of our estimator considering several plausible scenarios for residual non-Gaussianities in the foreground-cleaned Planck maps, with the intuition to optimize the training procedure of the Neural Network to discriminate between contaminations with primordial and secondary non-Gaussian signatures. We look for constraints of primordial local non-Gaussianity at large angular scales in the foreground-cleaned Planck maps. For the SMICA map we found fNL = 33 ± 23, at 1σ confidence level, in excellent agreement with the WMAP-9yr and Planck results. In addition, for the other three Planck maps we obtain similar constraints with values in the interval fNL in [33, 41], concomitant with the fact that these maps manifest distinct features in reported analyses, like having different pixel's noise intensities.
Cosmological parameter estimation: impact of CMB aberration
NASA Astrophysics Data System (ADS)
Catena, Riccardo; Notari, Alessio
2013-04-01
The peculiar motion of an observer with respect to the CMB rest frame induces an apparent deflection of the observed CMB photons, i.e. aberration, and a shift in their frequency, i.e. Doppler effect. Both effects distort the temperature multipoles alm's via a mixing matrix at any l. The common lore when performing a CMB based cosmological parameter estimation is to consider that Doppler affects only the l = 1 multipole, and neglect any other corrections. In this paper we reconsider the validity of this assumption, showing that it is actually not robust when sky cuts are included to model CMB foreground contaminations. Assuming a simple fiducial cosmological model with five parameters, we simulated CMB temperature maps of the sky in a WMAP-like and in a Planck-like experiment and added aberration and Doppler effects to the maps. We then analyzed with a MCMC in a Bayesian framework the maps with and without aberration and Doppler effects in order to assess the ability of reconstructing the parameters of the fiducial model. We find that, depending on the specific realization of the simulated data, the parameters can be biased up to one standard deviation for WMAP and almost two standard deviations for Planck. Therefore we conclude that in general it is not a solid assumption to neglect aberration in a CMB based cosmological parameter estimation.
Cosmological parameter estimation: impact of CMB aberration
Catena, Riccardo; Notari, Alessio E-mail: notari@ffn.ub.es
2013-04-01
The peculiar motion of an observer with respect to the CMB rest frame induces an apparent deflection of the observed CMB photons, i.e. aberration, and a shift in their frequency, i.e. Doppler effect. Both effects distort the temperature multipoles a{sub lm}'s via a mixing matrix at any l. The common lore when performing a CMB based cosmological parameter estimation is to consider that Doppler affects only the l = 1 multipole, and neglect any other corrections. In this paper we reconsider the validity of this assumption, showing that it is actually not robust when sky cuts are included to model CMB foreground contaminations. Assuming a simple fiducial cosmological model with five parameters, we simulated CMB temperature maps of the sky in a WMAP-like and in a Planck-like experiment and added aberration and Doppler effects to the maps. We then analyzed with a MCMC in a Bayesian framework the maps with and without aberration and Doppler effects in order to assess the ability of reconstructing the parameters of the fiducial model. We find that, depending on the specific realization of the simulated data, the parameters can be biased up to one standard deviation for WMAP and almost two standard deviations for Planck. Therefore we conclude that in general it is not a solid assumption to neglect aberration in a CMB based cosmological parameter estimation.
Bleem, L. E.; Becker, M. R.; Benson, B. A.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T.; Van Engelen, A.; Holder, G. P.; De Haan, T.; Dobbs, M. A.; Aird, K. A.; Armstrong, R.; Ashby, M. L. N.; Biesiadzinski, T.; Brodwin, M.; Busha, M. T.; Cho, H. M.; Desai, S.; Dore, O.; and others
2012-07-01
We compare cosmic microwave background lensing convergence maps derived from South Pole Telescope (SPT) data with galaxy survey data from the Blanco Cosmology Survey, WISE, and a new large Spitzer/IRAC field designed to overlap with the SPT survey. Using optical and infrared catalogs covering between 17 and 68 deg{sup 2} of sky, we detect a correlation between the SPT convergence maps and each of the galaxy density maps at >4{sigma}, with zero correlation robustly ruled out in all cases. The amplitude and shape of the cross-power spectra are in good agreement with theoretical expectations and the measured galaxy bias is consistent with previous work. The detections reported here utilize a small fraction of the full 2500 deg{sup 2} SPT survey data and serve as both a proof of principle of the technique and an illustration of the potential of this emerging cosmological probe.
Impact of secondary non-Gaussianities on the search for primordial non-Gaussianity with CMB maps
Serra, Paolo; Cooray, Asantha
2008-05-15
When constraining the primordial non-Gaussianity parameter f{sub NL} with cosmic microwave background anisotropy maps, the bias resulting from the covariance between primordial non-Gaussianity and secondary non-Gaussianities to the estimator of f{sub NL} is generally assumed to be negligible. We show that this assumption may not hold when attempting to measure the primordial non-Gaussianity out to angular scales below a few tens arcminutes with an experiment like Planck, especially if the primordial non-Gaussianity parameter is around the minimum detectability level with f{sub NL} between 5 and 10. In the future, it will be necessary to jointly estimate the combined primordial and secondary contributions to the cosmic microwave background bispectrum and establish f{sub NL} by properly accounting for the confusion from secondary non-Gaussianiti0008.
NASA Astrophysics Data System (ADS)
Richards, P. L.
This paper describes the status of four CMB cosmology experiments which are currently being developed by the Berkeley group. These include the APEXSZ and South Pole Telescope searches for clusters of galaxies using the Sunyaev-Zeldovich effect and the Polar Bear and EBEX CMB polarization anisotropy experiments. These experiments exploit new detector technologies with Superconducting TES bolometers and frequency domain output multiplexing, which has been developed at Berkeley.
Direct cortical mapping via solving partial differential equations on implicit surfaces.
Shi, Yonggang; Thompson, Paul M; Dinov, Ivo; Osher, Stanley; Toga, Arthur W
2007-06-01
In this paper, we propose a novel approach for cortical mapping that computes a direct map between two cortical surfaces while satisfying constraints on sulcal landmark curves. By computing the map directly, we can avoid conventional intermediate parameterizations and help simplify the cortical mapping process. The direct map in our method is formulated as the minimizer of a flexible variational energy under landmark constraints. The energy can include both a harmonic term to ensure smoothness of the map and general data terms for the matching of geometric features. Starting from a properly designed initial map, we compute the map iteratively by solving a partial differential equation (PDE) defined on the source cortical surface. For numerical implementation, a set of adaptive numerical schemes are developed to extend the technique of solving PDEs on implicit surfaces such that landmark constraints are enforced. In our experiments, we show the flexibility of the direct mapping approach by computing smooth maps following landmark constraints from two different energies. We also quantitatively compare the metric preserving property of the direct mapping method with a parametric mapping method on a group of 30 subjects. Finally, we demonstrate the direct mapping method in the brain mapping applications of atlas construction and variability analysis. PMID:17379568
CMB cold spot from inflationary feature scattering
NASA Astrophysics Data System (ADS)
Wang, Yi; Ma, Yin-Zhe
2016-05-01
We propose a "feature-scattering" mechanism to explain the cosmic microwave background cold spot seen from WMAP and Planck maps. If there are hidden features in the potential of multi-field inflation, the inflationary trajectory can be scattered by such features. The scattering is controlled by the amount of isocurvature fluctuations, and thus can be considered as a mechanism to convert isocurvature fluctuations into curvature fluctuations. This mechanism predicts localized cold spots (instead of hot ones) on the CMB. In addition, it may also bridge a connection between the cold spot and a dip on the CMB power spectrum at ℓ ∼ 20.
The partial captivity condition for U(1) extensions of expanding maps on the circle
NASA Astrophysics Data System (ADS)
Nakano, Yushi; Tsujii, Masato; Wittsten, Jens
2016-07-01
This paper concerns the compact group extension f:T2→T2,f(x,s)=(E(x),s+τ(x) mod 1) of an expanding map E:{{{S}}1}\\to {{{S}}1} . The dynamics of f and its stochastic perturbations have previously been studied under the so-called partial captivity condition. Here we prove a supplementary result that shows that partial captivity is a \\mathscr{C}r generic condition on τ, once we fix E.
Large-Angle Anomalies in the CMB
Copi, Craig J.; Huterer, Dragan; Schwarz, Dominik J.; Starkman, Glenn D.
2010-01-01
We review the recently found large-scale anomalies in the maps of temperature anisotropies in the cosmic microwave background. These include alignments of the largest modes of CMB anisotropy with each other and with geometry and direction of motion of the solar ssystem, and the unusually low power at these largest scales. We discuss these findings in relation to expectation from standard inflationary cosmology, their statistical significance, the tools to study them, and the various attempts to explain them.
Low-ℓ CMB analysis and inpainting
NASA Astrophysics Data System (ADS)
Starck, J.-L.; Fadili, M. J.; Rassat, A.
2013-02-01
Reconstructing the cosmic microwave background (CMB) in the Galactic plane is extremely difficult due to the dominant foreground emissions such as dust, free-free or synchrotron. For cosmological studies, the standard approach consists in masking this area where the reconstruction is insufficient. This leads to difficulties for the statistical analysis of the CMB map, especially at very large scales (to study for instance the low quadrupole, integrated Sachs Wolfe effect, axis of evil, etc.). We investigate how well some inpainting techniques can recover the low-ℓ spherical harmonic coefficients. We introduce three new inpainting techniques based on three different kinds of priors: sparsity, energy, and isotropy, which we compare. We show that sparsity and energy priors can lead to extremely high-quality reconstruction, within 1% of the cosmic variance for a mask with a sky coverage larger than 80%.
CMB component separation in the pixel domain
Doroshkevich, A.; Verkhodanov, O.
2011-02-15
We show that the popular internal linear combination approach is unstable with respect to division of the observed map pixels to a set of 'homogeneous' subsamples. For various choices of such subsamples we can obtain a restored CMB signal with amplitudes ranging from zero to the amplitude of the observed signal. We propose an approach which allows us to obtain corrected estimates of the CMB power spectrum C{sub l} at l{<=}30 and provides results similar to WMAP for larger l. Using this approach, we eliminate some anomalies of the WMAP results. In particular, our estimate of the quadrupole is consistent with the theoretically expected one. The effect of the 'axis of evil' is suppressed, and the symmetry of the north and south galactic hemispheres increases. These results can change estimates of quadrupole polarization and the redshift of reionization of the Universe. We also propose a new simple approach which can improve the WMAP estimates of the high l power spectrum.
Status of CMB Observations in 2015
NASA Astrophysics Data System (ADS)
Bucher, Martin
2016-07-01
The 2.725 K cosmic microwave background has played a key role in the development of modern cosmology by providing a solid observational foundation for constraining possible theories of what happened at very large redshifts and theoretical speculation reaching back almost to the would-be big bang initial singularity. After recounting some of the lesser known history of this area, I summarize the current observational situation and also discuss some exciting challenges that lie ahead: the search for B modes, the precision mapping of the CMB gravitational lensing potential, and the ultra-precise characterization of the CMB frequency spectrum, which would allow the exploitation of spectral distortions to probe new physics.
General parity-odd CMB bispectrum estimation
Shiraishi, Maresuke; Liguori, Michele; Fergusson, James R. E-mail: michele.liguori@pd.infn.it
2014-05-01
We develop a methodology for estimating parity-odd bispectra in the cosmic microwave background (CMB). This is achieved through the extension of the original separable modal methodology to parity-odd bispectrum domains (ℓ{sub 1}+ℓ{sub 2}+ℓ{sub 3} = odd). Through numerical tests of the parity-odd modal decomposition with some theoretical bispectrum templates, we verify that the parity-odd modal methodology can successfully reproduce the CMB bispectrum, without numerical instabilities. We also present simulated non-Gaussian maps produced by modal-decomposed parity-odd bispectra, and show the consistency with the exact results. Our new methodology is applicable to all types of parity-odd temperature and polarization bispectra.
POLARBEAR CMB Polarization Experiment
NASA Astrophysics Data System (ADS)
Nishino, H.; Ade, P.; Akiba, Y.; Anthony, A.; Arnold, K.; Barron, D.; Boettger, D.; Borrill, J.; Chapmann, S.; Chinone, Y.; Dobbs, M. A.; Errard, J.; Fabbian, G.; Feng, C.; Flanigan, D.; Fuller, G.; Ghribi, A.; Grainger, W.; Halverson, N.; Hasegawa, M.; Hattori, K.; Hazumi, M.; Holzapfel, W. L.; Howard, J.; Hyland, P.; Inoue, Y.; Jaffe, A.; Jaehnig, G.; Kaneko, Y.; Katayama, N.; Keating, B.; Kermish, Z.; Kimura, N.; Kisner, T.; Lee, A. T.; Le Jeune, M.; Linder, E.; Lungu, M.; Matsuda, F.; Matsumura, T.; Miller, N. J.; Morii, H.; Moyerman, S.; Myers, M. J.; O'Brient, R.; Okamura, T.; Paar, H.; Peloton, J.; Quealy, E.; Reichardt, C. L.; Richards, P. L.; Ross, C.; Shimizu, A.; Shimon, M.; Shimmin, C.; Sholl, M.; Siritanasak, P.; Spieler, H.; Stebor, N.; Steinbach, B.; Stompor, R.; Suzuki, A.; Suzuki, J.; Tanaka, K.; Tomaru, T.; Tucker, C.; Yadav, A.; Zahn, O.
POLARBEAR is a ground-based experiment in the Atacama desert in hile, measuring the polarization of the Cosmic Microwave Background (CMB) radiation. One of the science goals of POLARBEAR is to detect the B-mode polarization pattern of the CMB produced by primordial gravitational waves from the epoch of inflation. The detection of the B-mode polarization provides strong evidence for inflationary cosmological models. POLARBEAR is expected to reach a sensitivity to the tensor-to-scalar ratio r = 0.025 at 95% confidence level, using the data from two years of observation. With a beam size of 3.5 arcminutes, POLARBEAR is also sensitive to B-mode polarization signals at small-angular scales produced by weak gravitational lensing of large-scale structure. POLARBEAR is expected to provide a constraint on the sum of neutrino masses because of their effect on the large-scale structure. POLARBEAR was deployed in late 2011 and started observing in early 2012 at 150 GHz with an array of 1,274 polarization sensitive antenna-coupled Transition Edge Sensor (TES) bolometers. The current status of the POLARBEAR experiment is reported.
Principal components of CMB non-Gaussianity
NASA Astrophysics Data System (ADS)
Regan, Donough; Munshi, Dipak
2015-04-01
The skew-spectrum statistic introduced by Munshi & Heavens has recently been used in studies of non-Gaussianity from diverse cosmological data sets including the detection of primary and secondary non-Gaussianity of cosmic microwave background (CMB) radiation. Extending previous work, focused on independent estimation, here we deal with the question of joint estimation of multiple skew-spectra from the same or correlated data sets. We consider the optimum skew-spectra for various models of primordial non-Gaussianity as well as secondary bispectra that originate from the cross-correlation of secondaries and lensing of CMB: coupling of lensing with the Integrated Sachs-Wolfe effect, coupling of lensing with thermal Sunyaev-Zeldovich, as well as from unresolved point sources. For joint estimation of various types of non-Gaussianity, we use the principal component analysis (PCA) to construct the linear combinations of amplitudes of various models of non-Gaussianity, e.g. f^loc_NL,f^eq_NL,f^ortho_NL that can be estimated from CMB maps. We describe how the bias induced in the estimation of primordial non-Gaussianity due to secondary non-Gaussianity may be evaluated for arbitrary primordial models using a PCA analysis. The PCA approach allows one to infer approximate (but generally accurate) constraints using CMB data sets on any reasonably smooth model by use of a look-up table and performing a simple computation. This principle is validated by computing constraints on the Dirac-Born-Infeld bispectrum using a PCA analysis of the standard templates.
CMB all-scale blackbody distortions induced by linearizing temperature
NASA Astrophysics Data System (ADS)
Notari, Alessio; Quartin, Miguel
2016-08-01
Cosmic microwave background (CMB) experiments, such as WMAP and Planck, measure intensity anisotropies and build maps using a linearized formula for relating them to the temperature blackbody fluctuations. However, this procedure also generates a signal in the maps in the form of y -type distortions which is degenerate with the thermal Sunyaev Zel'dovich (tSZ) effect. These are small effects that arise at second order in the temperature fluctuations not from primordial physics but from such a limitation of the map-making procedure. They constitute a contaminant for measurements of our peculiar velocity, the tSZ and primordial y -distortions. They can nevertheless be well modeled and accounted for. We show that the distortions arise from a leakage of the CMB dipole into the y -channel which couples to all multipoles, mostly affecting the range ℓ≲400 . This should be visible in Planck's y -maps with an estimated signal-to-noise ratio of about 12. We note however that such frequency-dependent terms carry no new information on the nature of the CMB dipole. This implies that the real significance of Planck's Doppler coupling measurements is actually lower than reported by the collaboration. Finally, we quantify the level of contamination in tSZ and primordial y -type distortions and show that it is above the sensitivity of proposed next-generation CMB experiments.
NASA Astrophysics Data System (ADS)
Rathaus, Ben; Itzhaki, Nissan
2012-05-01
We study the CMB lensing signature of a pre-inationary particle (PIP), assuming it is responsible for the giant rings anomaly that was found recently in the WMAP data. Simulating Planck-like data we find that generically the CMB lensing signal to noise ratio associated with such a PIP is quite small and it would be difficult to cross correlate the temperature giant rings with the CMB lensing signal. However, if the pre-inationary particle is also responsible for the bulk flow measured from the local large scale structure, which happens to point roughly at the same direction as the giant rings, then the CMB lensing signal to noise ratio is fairly significant.
Amplifier arrays for CMB polarization
NASA Technical Reports Server (NTRS)
Gaier, Todd; Lawrence, Charles R.; Seiffert, Michael D.; Wells, Mary M.; Kangaslahti, Pekka; Dawson, Douglas
2003-01-01
Cryogenic low noise amplifier technology has been successfully used in the study of the cosmic microwave background (CMB). MMIC (Monolithic Millimeter wave Integrated Circuit) technology makes the mass production of coherent detection receivers feasible.
CMB hemispherical asymmetry: long mode modulation and non-Gaussianity
Namjoo, Mohammad Hossein; Baghram, Shant; Firouzjahi, Hassan; Abolhasani, Ali Akbar E-mail: abolhasani@ipm.ir E-mail: firouz@ipm.ir
2014-08-01
The observed hemispherical asymmetry in CMB map can be explained by modulation from a long wavelength super horizon mode which non-linearly couples to the CMB modes. We address the criticism in [1] about the role of non-Gaussianities in squeezed and equilateral configurations in generating hemispherical asymmetry from the long mode modulation. We stress that the modulation is sensitive to the non-Gaussianity in the squeezed limit. In addition, we demonstrate the validity of our approach in providing a consistency condition relating the amplitude of dipole asymmetry to f{sub NL} in the squeezed limit.
Parker, G.F.; Roberts, D.B.
1996-04-01
Inbred Drosophila melanogaster stocks were surveyed for {alpha}-glucosidases with nondenaturing gel electrophoresis using a fluorogenic substrate to stain the gels. The glucosidase most active under these conditions is polymorphic. We established that the polymorphism is genetic in origin and that the glucosidase was not likely to be a previously characterized enzyme. The gene encoding the enzyme was mapped cytogenetically to 33 A1-2- 33A8-B1, confirming that this is an enzyme not yet reported in D. melanogaster. The enzyme was partially purified by elution from nondenaturing gels, which enable us to establish that it has optimal activity at pH 6 and interacts most strongly with {alpha}- 1 -4 glucosides. A developmental and tissue survey suggested that this enzyme could have a purely digestive role or be involved in carbohydrate metabolism inside the organism. We propose that this enzyme is involved in either starch digestion or glycogen metabolism. 37 refs., 6 figs., 1 tab.
Dynamics of Hollow Atom Formation in Intense X-Ray Pulses Probed by Partial Covariance Mapping
NASA Astrophysics Data System (ADS)
Frasinski, L. J.; Zhaunerchyk, V.; Mucke, M.; Squibb, R. J.; Siano, M.; Eland, J. H. D.; Linusson, P.; v. d. Meulen, P.; Salén, P.; Thomas, R. D.; Larsson, M.; Foucar, L.; Ullrich, J.; Motomura, K.; Mondal, S.; Ueda, K.; Osipov, T.; Fang, L.; Murphy, B. F.; Berrah, N.; Bostedt, C.; Bozek, J. D.; Schorb, S.; Messerschmidt, M.; Glownia, J. M.; Cryan, J. P.; Coffee, R. N.; Takahashi, O.; Wada, S.; Piancastelli, M. N.; Richter, R.; Prince, K. C.; Feifel, R.
2013-08-01
When exposed to ultraintense x-radiation sources such as free electron lasers (FELs) the innermost electronic shell can efficiently be emptied, creating a transient hollow atom or molecule. Understanding the femtosecond dynamics of such systems is fundamental to achieving atomic resolution in flash diffraction imaging of noncrystallized complex biological samples. We demonstrate the capacity of a correlation method called “partial covariance mapping” to probe the electron dynamics of neon atoms exposed to intense 8 fs pulses of 1062 eV photons. A complete picture of ionization processes competing in hollow atom formation and decay is visualized with unprecedented ease and the map reveals hitherto unobserved nonlinear sequences of photoionization and Auger events. The technique is particularly well suited to the high counting rate inherent in FEL experiments.
Singh, Sachin Kumar; Sethi, Sachin; Aravamudhan, Sriram; Krüger, Marcus; Grabher, Clemens
2013-01-01
Neutrophil granulocytes are pivotal cells within the first line of host defense of the innate immune system. In this study, we have used a gel-based LC-MS/MS approach to explore the proteome of primary marrow neutrophils from adult zebrafish. The identified proteins originated from all major cellular compartments. Gene ontology analysis revealed significant association of proteins with different immune-related network and pathway maps. 75% of proteins identified in neutrophils were identified in neutrophils only when compared to neutrophil-free brain tissue. Moreover, cross-species comparison with human peripheral blood neutrophils showed partial conservation of immune-related proteins between human and zebrafish. This study provides the first zebrafish neutrophil proteome and may serve as a valuable resource for an understanding of neutrophil biology and innate immunity. PMID:24019943
Galactic dust polarized emission at high latitudes and CMB polarization
NASA Astrophysics Data System (ADS)
Prunet, S.; Sethi, S. K.; Bouchet, F. R.; Miville-Deschenes, M.-A.
1998-11-01
With recent instrumental advances, it might become possible to measure the polarization of the Cosmic Microwave Background (CMB), e.g. by future space missions like MAP and Planck Surveyor. In this paper, we estimate the dust polarized emission in our galaxy which is the major foreground to cope with for measuring the CMB polarization in the Wien part of CMB spectrum. We model the dust polarized emission in the galaxy using the three-dimensional HI maps of the Leiden/Dwingeloo survey at high galactic latitudes. We use the fact that the dust emission, for a wide range of wavelengths, has a tight correlation with the HI emission maps of this survey (Boulanger et al. 1996). Assuming the dust grains to be oblate with axis ratio =~ 2/3, which recent studies support, we determine the intrinsic dust polarized emissivity. The distribution of magnetic field with respect to the dust grain distribution is quite uncertain, we thus consider three extreme cases: (1) The magnetic field is aligned with the major axis of the dust structure, (2) the magnetic field has a random direction in the plane perpendicular to the direction of major axis of the dust structure, and (3) the magnetic field is unidirectional throughout. We further assume, as recent observations and theoretical analyses support, that the dust grains align with the magnetic field independently of its strength. The polarization reduction factor from misalignment of the direction of polarization from the plane of the sky and the differential polarization along a line of sight is calculated using these maps, to construct two-dimensional maps of dust polarized emission. We calculate the angular power spectrum of dust polarized emission from these maps and cast it in variables which allow a direct comparison with the polarized component of the CMB. Our results, at frequencies =~ 100 GHz, suggest that: (a) This foreground contamination is smaller than the scalar-induced polarization of the CMB at l ga 200 while the tensor
Measuring the CMB Dipole at 11 GHz—for cheap!
NASA Astrophysics Data System (ADS)
Markowitz, Aaron; Harrison, S.; Karkare, K. S.; Kimbert, R.; Kovac, J. M.
2014-01-01
We report the design of a telescope capable of making mK-sensitivity maps of the microwave sky, with potential to map large-scale structure of the CMB and galaxy, within the budget of a classroom or amateur astronomer. This project modifies a telescope designed by Harvard’s advanced undergraduate astrophysics lab course, with the goal of improving sensitivity enough to detect the CMB dipole. The telescope’s design allows replication of the experiment within the resources of most similar undergraduate laboratory research courses. We use a low-noise block (LNB) receiver and a bandpass filter to amplify radiation near 10.7 GHz and remove RFI, and we rotate the telescope at constant angular velocity and elevation to provide coverage of the entire visible sky over 24 hours. Before modifications, the telescope accurately measured the isotropic CMB temperature, but interference and 1/f noise limited detection of isotropies in the microwave signal. With current modifications, the telescope can collect data continuously for over 24 hours, and produce maps used to constrain galactic and CMB signals.
CMB temperature bispectrum induced by cosmic strings
NASA Astrophysics Data System (ADS)
Hindmarsh, Mark; Ringeval, Christophe; Suyama, Teruaki
2009-10-01
The cosmic microwave background (CMB) bispectrum of the temperature anisotropies induced by a network of cosmic strings is derived for small angular scales, under the assumption that the principal cause of temperature fluctuations is the Gott-Kaiser-Stebbins effect. We provide analytical expressions for all isosceles triangle configurations in Fourier space. Their overall amplitude is amplified as the inverse cube of the angle and diverges for flat triangles. The isosceles configurations generically lead to a negative bispectrum with a power-law decay ℓ-6 for large multipole ℓ. However, collapsed triangles are found to be associated with a positive bispectrum whereas the squeezed triangles still exhibit negative values. We then compare our analytical estimates to a direct computation of the bispectrum from a set of 300 statistically independent temperature maps obtained from Nambu-Goto cosmic string simulations in a Friedmann-Lemaître-Robertson-Walker universe. We find good agreement for the overall amplitude, the power-law behavior, and the angle dependency of the various triangle configurations. At ℓ˜500 the cosmic string Gott-Kaiser-Stebbins effect contributes approximately the same equilateral CMB bispectrum amplitude as an inflationary model with |fNLloc|≃103, if the strings contribute about 10% of the temperature power spectrum at ℓ=10. Current bounds on fNL are not derived using cosmic string bispectrum templates, and so our fNL estimate cannot be used to derive bounds on strings. However it does suggest that string bispectrum templates should be included in the search of CMB non-Gaussianities.
CMB temperature bispectrum induced by cosmic strings
Hindmarsh, Mark; Ringeval, Christophe; Suyama, Teruaki
2009-10-15
The cosmic microwave background (CMB) bispectrum of the temperature anisotropies induced by a network of cosmic strings is derived for small angular scales, under the assumption that the principal cause of temperature fluctuations is the Gott-Kaiser-Stebbins effect. We provide analytical expressions for all isosceles triangle configurations in Fourier space. Their overall amplitude is amplified as the inverse cube of the angle and diverges for flat triangles. The isosceles configurations generically lead to a negative bispectrum with a power-law decay l{sup -6} for large multipole l. However, collapsed triangles are found to be associated with a positive bispectrum whereas the squeezed triangles still exhibit negative values. We then compare our analytical estimates to a direct computation of the bispectrum from a set of 300 statistically independent temperature maps obtained from Nambu-Goto cosmic string simulations in a Friedmann-Lemaitre-Robertson-Walker universe. We find good agreement for the overall amplitude, the power-law behavior, and the angle dependency of the various triangle configurations. At l{approx}500 the cosmic string Gott-Kaiser-Stebbins effect contributes approximately the same equilateral CMB bispectrum amplitude as an inflationary model with |f{sub NL}{sup loc}|{approx_equal}10{sup 3}, if the strings contribute about 10% of the temperature power spectrum at l=10. Current bounds on f{sub NL} are not derived using cosmic string bispectrum templates, and so our f{sub NL} estimate cannot be used to derive bounds on strings. However it does suggest that string bispectrum templates should be included in the search of CMB non-Gaussianities.
Probing Inflation with CMB Polarization
Baumann, Daniel; Jackson, Mark G.; Adshead, Peter; Easther, Richard; Amblard, Alexandre; Cooray, Asantha; Ashoorioon, Amjad; Watson, Scott; Bartolo, Nicola; Matarrese, Sabino; Bean, Rachel; Beltran, Maria; Dvorkin, Cora; Bernardis, Francesco de; Melchiorri, Alessandro; Pagano, Luca; Bird, Simeon; Peiris, Hiranya V.; Chen Xingang; Hertzberg, Mark P.
2009-06-09
We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes of the physics of inflation. We focus on the prospects for using CMB measurements to differentiate various inflationary mechanisms. In particular, a detection of primordial B-mode polarization would demonstrate that inflation occurred at a very high energy scale, and that the inflaton traversed a super-Planckian distance in field space. We explain how such a detection or constraint would illuminate aspects of physics at the Planck scale. Moreover, CMB measurements can constrain the scale-dependence and non-Gaussianity of the primordial fluctuations and limit the possibility of a significant isocurvature contribution. Each such limit provides crucial information on the underlying inflationary dynamics. Finally, we quantify these considerations by presenting forecasts for the sensitivities of a future satellite experiment to the inflationary parameters.
Bolometeric detector arrays for CMB polarimetry
NASA Technical Reports Server (NTRS)
Kuo, C. L.; Bock, J. J.; Day, P.; Goldin, A.; Golwala, S.; Holmes, W.; Irwin, K.; Kenyon, M.; Lange, A. E.; LeDuc, H. G.; Rossinot, P.; Sterb, J.; Vayonakis, A.; Wang, G.; Yun, M.; Zmuidzinas, J.
2005-01-01
We describe the development of antenna coupled bolometers for CMB polarization experiments. The necessary components of a bolometric CMB polarimeter - a beam forming element, a band defining filter, and detectors - are all fabricated on a silicon chip with photolithography.
ERIC Educational Resources Information Center
Lindsen, Job P.; de Jong, Ritske
2010-01-01
Lien, Ruthruff, Remington, & Johnston (2005) reported residual switch cost differences between stimulus-response (S-R) pairs and proposed the partial-mapping preparation (PMP) hypothesis, which states that advance preparation will typically be limited to a subset of S-R pairs because of structural capacity limitations, to account for these…
Amiba Observation of CMB Anisotropies
NASA Astrophysics Data System (ADS)
Ng, Kin-Wang
2003-03-01
The Array for Microwave Background Anisotropies (AMiBA), a 13-element dual-channel 85-105 GHz interferometer array with full polarization capabilities, is being built to search for high redshift clusters of galaxies via the Sunyaev-Zel'dovich effect as well as to probe the polarization properties of the cosmic microwave background (CMB). We discuss several important issues in the observation of the CMB anisotropies such as observing strategy, l space resolution and mosaicing, optimal estimation of the power spectra, and ground pickup removal.
Genetic dissection of heterosis using epistatic association mapping in a partial NCII mating design
Wen, Jia; Zhao, Xinwang; Wu, Guorong; Xiang, Dan; Liu, Qing; Bu, Su-Hong; Yi, Can; Song, Qijian; Dunwell, Jim M.; Tu, Jinxing; Zhang, Tianzhen; Zhang, Yuan-Ming
2015-01-01
Heterosis refers to the phenomenon in which an F1 hybrid exhibits enhanced growth or agronomic performance. However, previous theoretical studies on heterosis have been based on bi-parental segregating populations instead of F1 hybrids. To understand the genetic basis of heterosis, here we used a subset of F1 hybrids, named a partial North Carolina II design, to perform association mapping for dependent variables: original trait value, general combining ability (GCA), specific combining ability (SCA) and mid-parental heterosis (MPH). Our models jointly fitted all the additive, dominance and epistatic effects. The analyses resulted in several important findings: 1) Main components are additive and additive-by-additive effects for GCA and dominance-related effects for SCA and MPH, and additive-by-dominant effect for MPH was partly identified as additive effect; 2) the ranking of factors affecting heterosis was dominance > dominance-by-dominance > over-dominance > complete dominance; and 3) increasing the proportion of F1 hybrids in the population could significantly increase the power to detect dominance-related effects, and slightly reduce the power to detect additive and additive-by-additive effects. Analyses of cotton and rapeseed datasets showed that more additive-by-additive QTL were detected from GCA than from trait phenotype, and fewer QTL were from MPH than from other dependent variables. PMID:26679476
Genomic mapping of phosphorothioates reveals partial modification of short consensus sequences
Cao, Bo; Chen, Chao; DeMott, Michael S.; Cheng, Qiuxiang; Clark, Tyson A.; Xiong, Xiaolin; Zheng, Xiaoqing; Butty, Vincent; Levine, Stuart S.; Yuan, George; Boitano, Matthew; Luong, Khai; Song, Yi; Zhou, Xiufen; Deng, Zixin; Turner, Stephen W.; Korlach, Jonas; You, Delin; Wang, Lianrong; Chen, Shi; Dedon, Peter C.
2015-01-01
Bacterial phosphorothioate (PT) DNA modifications are incorporated by Dnd proteins A-E and often function with DndF-H as a restriction-modification (R-M) system, as in Escherichia coli B7A. However, bacteria such as Vibrio cyclitrophicus FF75 lack dndF-H, which points to other PT functions. To better understand PT biology, we report two novel, orthogonal technologies to map PTs across the genomes of B7A and FF75 with >90% agreement: real-time (SMRT) sequencing and deep sequencing of iodine-induced cleavage at PT (ICDS). In B7A, we detect PT on both strands of GpsAAC/GpsTTC motifs, but with only 18% of 40,701 possible sites modified. In contrast, PT in FF75 occurs as a single-strand modification at CpsCA, again with only 14% of 160,541 sites modified. Single-molecule analysis indicates that modification could be partial at any particular genomic site even with active restriction by DndF-H, with direct interaction of modification proteins with GAAC/GTTC sites demonstrated with oligonucleotides. These results point to highly unusual target selection by PT modification proteins and rule out known R-M mechanisms. PMID:24899568
CMB component separation in the pixel domain
NASA Astrophysics Data System (ADS)
Doroshkevich, A.; Verkhodanov, O.
2011-02-01
We show that the popular internal linear combination approach is unstable with respect to division of the observed map pixels to a set of “homogeneous” subsamples. For various choices of such subsamples we can obtain a restored CMB signal with amplitudes ranging from zero to the amplitude of the observed signal. We propose an approach which allows us to obtain corrected estimates of the CMB power spectrum Cℓ at ℓ≤30 and provides results similar to WMAP for larger ℓ. Using this approach, we eliminate some anomalies of the WMAP results. In particular, our estimate of the quadrupole is consistent with the theoretically expected one. The effect of the “axis of evil” is suppressed, and the symmetry of the north and south galactic hemispheres increases. These results can change estimates of quadrupole polarization and the redshift of reionization of the Universe. We also propose a new simple approach which can improve the WMAP estimates of the high ℓ power spectrum.
Probing cosmic strings with satellite CMB measurements
Jeong, E.; Baccigalupi, Carlo; Smoot, G.F. E-mail: bacci@sissa.it
2010-09-01
We study the problem of searching for cosmic string signal patterns in the present high resolution and high sensitivity observations of the Cosmic Microwave Background (CMB). This article discusses a technique capable of recognizing Kaiser-Stebbins effect signatures in total intensity anisotropy maps from isolated strings. We derive the statistical distributions of null detections from purely Gaussian fluctuations and instrumental performances of the operating satellites, and show that the biggest factor that produces confusion is represented by the acoustic oscillation features of the scale comparable to the size of horizon at recombination. Simulations show that the distribution of null detections converges to a χ{sup 2} distribution, with detectability threshold at 99% confidence level corresponding to a string induced step signal with an amplitude of about 100 μK which corresponds to a limit of roughly Gμ ∼ 1.5 × 10{sup −6}. We implement simulations for deriving the statistics of spurious detections caused by extra-Galactic and Galactic foregrounds. For diffuse Galactic foregrounds, which represents the dominant source of contamination, we construct sky masks outlining the available region of the sky where the Galactic confusion is sub-dominant, specializing our analysis to the case represented by the frequency coverage and nominal sensitivity and resolution of the Planck experiment. As for other CMB measurements, the maximum available area, corresponding to 7%, is reached where the foreground emission is expected to be minimum, in the 70–100 GHz interval.
Reionization and CMB non-Gaussianity
NASA Astrophysics Data System (ADS)
Munshi, D.; Corasaniti, P. S.; Coles, P.; Heavens, A.; Pandolfi, S.
2014-08-01
We show how cross-correlating a high-redshift external tracer field, such as the 21-cm neutral hydrogen distribution and product maps involving cosmic microwave background (CMB) temperature and polarization fields, that probe mixed bispectrum involving these fields, can help to determine the reionization history of the Universe, beyond what can be achieved from cross-spectrum analysis. Taking clues from recent studies for the detection of primordial non-Gaussianity, we develop a set of estimators that can study reionization using a power spectrum associated with the bispectrum (or skew-spectrum). We use the matched filtering inherent in this method to investigate different reionization histories. We check to what extent they can be used to rule out various models of reionization and study cross-contamination from different sources such as the lensing of the CMB. The estimators can be fine-tuned to optimize study of a specific reionization history. We consider three different types of tracers in our study, namely: proto-galaxies; 21-cm maps of neutral hydrogen; and quasars. We also consider four alternative models of reionization. We find that the cumulative signal-to-noise ratio (S/N) for detection at ℓmax = 2000 can reach O(70) for cosmic variance limited all-sky experiments. Combining 100 GHz, 143 GHz and 217 GHz channels of the Planck experiment, we find that the S/N lies in the range O(5)-O(35). The S/N depends on the specific choice of a tracer field, and multiple tracers can be effectively used to map out the entire reionization history with reasonable S/N. Contamination from weak lensing is investigated and found to be negligible, and the effects of Thomson scattering from patchy reionization are also considered.
Advanced Antenna-Coupled Superconducting Detector Arrays for CMB Polarimetry
NASA Astrophysics Data System (ADS)
Bock, James
2014-01-01
We are developing high-sensitivity millimeter-wave detector arrays for measuring the polarization of the cosmic microwave background (CMB). This development is directed to advance the technology readiness of the Inflation Probe mission in NASA's Physics of the Cosmos program. The Inflation Probe is a fourth-generation CMB satellite that will measure the polarization of the CMB to astrophysical limits, characterizing the inflationary polarization signal, mapping large-scale structure based on polarization induced by gravitational lensing, and mapping Galactic magnetic fields through measurements of polarized dust emission. The inflationary polarization signal is produced by a background of gravitational waves from the epoch of inflation, an exponential expansion of space-time in the early universe, with an amplitude that depends on the physical mechanism producing inflation. The inflationary polarization signal may be distinguished by its unique 'B-mode' vector properties from polarization from the density variations that predominantly source CMB temperature anisotropy. Mission concepts for the Inflation Probe are being developed in the US, Europe and Japan. The arrays are based on planar antennas that provide integral beam collimation, polarization analysis, and spectral band definition in a compact lithographed format that eliminates discrete fore-optics such as lenses and feedhorns. The antennas are coupled to transition-edge superconducting bolometers, read out with multiplexed SQUID current amplifiers. The superconducting sensors and readouts developed in this program share common technologies with NASA X-ray and FIR detector applications. Our program targets developments required for space observations, and we discuss our technical progress over the past two years and plans for future development. We are incorporating arrays into active sub-orbital and ground-based experiments, which advance technology readiness while producing state of the art CMB
Interacted QTL Mapping in Partial NCII Design Provides Evidences for Breeding by Design
Yi, Can; Wen, Jia; Jinxing, Tu; Zhang, Yuan Ming
2015-01-01
The utilization of heterosis in rice, maize and rapeseed has revolutionized crop production. Although elite hybrid cultivars are mainly derived from the F1 crosses between two groups of parents, named NCII mating design, little has been known about the methodology of how interacted effects influence quantitative trait performance in the population. To bridge genetic analysis with hybrid breeding, here we integrated an interacted QTL mapping approach with breeding by design in partial NCII mating design. All the potential main and interacted effects were included in one full model. If the number of the effects is huge, bulked segregant analysis were used to test which effects were associated with the trait. All the selected effects were further shrunk by empirical Bayesian, so significant effects could be identified. A series of Monte Carlo simulations was performed to validate the new method. Furthermore, all the significant effects were used to calculate genotypic values of all the missing F1 hybrids, and all these F1 phenotypic or genotypic values were used to predict elite parents and parental combinations. Finally, the new method was adopted to dissect the genetic foundation of oil content in 441 rapeseed parents and 284 F1 hybrids. As a result, 8 main-effect QTL and 37 interacted QTL were found and used to predict 10 elite restorer lines, 10 elite sterile lines and 10 elite parental crosses. Similar results across various methods and in previous studies and a high correlation coefficient (0.76) between the predicted and observed phenotypes validated the proposed method in this study. PMID:25822501
Interacted QTL mapping in partial NCII design provides evidences for breeding by design.
Bu, Su Hong; Zhao, Xinwang; Xinwang, Zhao; Yi, Can; Wen, Jia; Tu, Jinxing; Jinxing, Tu; Zhang, Yuan Ming
2015-01-01
The utilization of heterosis in rice, maize and rapeseed has revolutionized crop production. Although elite hybrid cultivars are mainly derived from the F1 crosses between two groups of parents, named NCII mating design, little has been known about the methodology of how interacted effects influence quantitative trait performance in the population. To bridge genetic analysis with hybrid breeding, here we integrated an interacted QTL mapping approach with breeding by design in partial NCII mating design. All the potential main and interacted effects were included in one full model. If the number of the effects is huge, bulked segregant analysis were used to test which effects were associated with the trait. All the selected effects were further shrunk by empirical Bayesian, so significant effects could be identified. A series of Monte Carlo simulations was performed to validate the new method. Furthermore, all the significant effects were used to calculate genotypic values of all the missing F1 hybrids, and all these F1 phenotypic or genotypic values were used to predict elite parents and parental combinations. Finally, the new method was adopted to dissect the genetic foundation of oil content in 441 rapeseed parents and 284 F1 hybrids. As a result, 8 main-effect QTL and 37 interacted QTL were found and used to predict 10 elite restorer lines, 10 elite sterile lines and 10 elite parental crosses. Similar results across various methods and in previous studies and a high correlation coefficient (0.76) between the predicted and observed phenotypes validated the proposed method in this study. PMID:25822501
What will we learn from the CMB?
Dodelson, S.
1997-10-01
Within the next decade, experiments measuring the anisotropies in the cosmic microwave background (CMB) will add greatly to our knowledge of the universe. There are dozens of experiments scheduled to take data over the next several years, capped by the satellite missions of NASA (MAP) and ESA (PLANCK). What will we learn from these experiments? I argue that the potential pay-off is immense: We are quite likely to determine cosmological parameters to unprecedented accuracy. This will provide key information about the theory of structure formation and even about the physics behind inflation. If the experiments succeed, can anything spoil this pay-off? I focus on three possible spoilers - foregrounds, reionization, and defect models - and argue that we have every reason to be optimistic.
Cross-correlation analysis of CMB with foregrounds for residuals
NASA Astrophysics Data System (ADS)
Aluri, Pavan K.; Rath, Pranati K.
2016-06-01
In this paper, we try to probe whether a clean cosmic microwave background (CMB) map obtained from the raw satellite data using a cleaning procedure is sufficiently clean. Specifically, we study if there are any foreground residuals still present in the cleaned data using a cross-correlation statistic. Residual contamination is expected to be present, primarily, in the Galactic plane due to the high emission from our own Galaxy. A foreground mask is applied conventionally to avoid biases in the estimated quantities of interest due to foreground leakage. Here, we map foreground residuals, if present, in the unmasked region i.e. outside a CMB analysis mask. Further locally extended foreground-contaminated regions, found eventually, are studied to understand them better. The few contaminated regions thus identified may be used to slightly extend the available masks to make them more stringent.
How accurately can suborbital experiments measure the CMB?
Oliveira-Costa, Angelica de; Tegmark, Max; Devlin, Mark J.; Page, Lyman; Miller, Amber D.; Netterfield, C. Barth; Xu Yongzhong
2005-02-15
Great efforts are currently being channeled into ground- and balloon-based CMB experiments, mainly to explore polarization and anisotropy on small angular scales. To optimize instrumental design and assess experimental prospects, it is important to understand in detail the atmosphere-related systematic errors that limit the science achievable with new instruments. As a step in this direction, we spatially compare the 648 square degree ground- and balloon-based QMASK map with the atmosphere-free WMAP map, finding beautiful agreement on all angular scales where both are sensitive. Although much work remains on quantifying atmospheric effects on CMB experiments, this is a reassuring quantitative assessment of the power of the state-of-the-art fast-Fourier-transform- and matrix-based mapmaking techniques that have been used for QMASK and virtually all subsequent experiments.
CMB: polarization and temperature waves from spatially limited cosmological structures
NASA Astrophysics Data System (ADS)
Baccigalupi, Carlo
1999-05-01
The most known inflationary model leaves traces in the form of Gaussian scale-invariant perturbations. It univoquely marks the CMB angular power spectrum. However, high energy physics may be more complicated and may leave other (and richer) traces, in the form of non-Gaussian scale-dependent perturbations. In this work we change our mind to the second issue. Instead of the CMB angular power spectrum only, we predict the temperature and polarization anisotropies from single well shaped spatially limited structures. These are generally characterized by some symmetries, and here we concentrate on the spherical ones. The treatment developed allows to express the anisotropy pattern as a function of (i) the geometrical coordinates of the particular structure under investigation, including its position relative to the last scattering surface, and (ii) the photon propagation direction n̂. Due to the wave-like behavior of the relevant equations, the general phenomenology that turns out is that for a localized initial inhomogeneity, the corresponding CMB perturbation propagates beyond the initial size, generating waves traveling outward with the sound velocity cs, and reaching the size of the sound horizon at the time we are examinating it. This behavior is a common feature of both the pure temperature and polarization anisotropies. The natural test of these computations will be the comparison with the observational data from the forthcoming high resolution CMB maps from the Planck mission.
Can CMB Experiments Find Planet Nine?
NASA Astrophysics Data System (ADS)
Kohler, Susanna
2016-04-01
authors propose that CMB experiments with high enough resolution (~5m telescopes and larger) could have the ability to detect Planet Nine!Theres one major catch: how can we differentiate between Planet Nine and the ~4000 foreground asteroids that are brighter than 30 mJy at millimeter wavelengths?Cowan and collaborators argue that this can be done using a combination of asteroid databases and parallax measurements. The authors calculate that Planet Nine should move roughly a few arcseconds per day, mostly due to parallax. In comparison, asteroids will move ~10 arcminutes per day in a combination of proper motion and parallax an order of magnitude faster than Planet Nine.Resolution ConstraintsTo hunt down Planet Nine, we therefore need telescopes that can not only resolve a 30 mJy point source, but can also resolve an annual parallax motion of ~5 arcminutes per year.The authors demonstrate that several current and planned CMB experiments have the resolution and ability to detect Planet Nine, provided that they map large swatches of the sky and return to the same regions every few months. These experiments include CCAT, the South Pole Telescope, the Atacama Cosmology Telescope, CMB-S4, and even possibly Planck.With the astronomical community coming together to brainstormwaysto trackdown this elusive possible planet, the use of CMB experiments is an intriguing option. And even if Planet Nine is discovered by other means, measuring its heat signaturewillteach usmore about the internal workings of giant planets.CitationNicolas B. Cowan et al 2016 ApJ 822 L2. doi:10.3847/2041-8205/822/1/L2
Early Universe with CMB polarization
NASA Astrophysics Data System (ADS)
Souradeep, Tarun
2011-12-01
The Universe is the grandest conceivable scale on which the human mind can strive to understand nature. The amazing aspect of cosmology, the branch of science that attempts to understand the origin and evolution of the Universe, is that it is largely comprehensible by applying the same basic laws of physics that we use for other branches of physics. The observed cosmic microwave background (CMB) is understood by applying the basic laws of radiative processes and transfer, masterfully covered in the classic text by S. Chandrasekhar, in the cosmological context. In addition to the now widely acclaimed temperature anisotropy, there is also linear polarization information imprinted on the observed Cosmic Microwave background. CMB polarization already has addressed, and promises to do a lot more to unravel the deepest fundamental queries about physics operating close to the origin of the Universe.
Planned CMB Satellite Mission Overview
NASA Astrophysics Data System (ADS)
Lee, Adrian
2016-03-01
I will summarize space missions that are in the planning stage to measure the polarized spatial fluctuations of the cosmic microwave background (CMB). Space missions are complementary to ground-based observatories. First, the absence of atmospheric emission results in a wider range of frequencies that can be observed, which in turn improves removal of galactic foreground emission. Second, the stable observations possible from space give high-fidelity measurements at angular scales of tens of degrees where inflation theory predicts a peak in the B-mode angular power spectrum. Robust detection of both this ``reionization'' peak and the ``recombination'' peak at degree angular scales will give the most convincing case that the fingerprints of inflation have been detected. CMB polarization space missions in the planning stage include CORE+, LiteBIRD, and PIXIE. Science goals for all these missions include the detection and characterization of inflation and the characterization of the reionization epoch. CORE+ and LiteBIRD are imaging telescopes with sub-Kelvin superconducting focal-plane detector arrays with several thousand detectors. PIXIE is a two-beam differential spectrometer that will measure the Planck spectrum of the CMB in addition to searching for inflation.
Probing gravity at large scales through CMB lensing
NASA Astrophysics Data System (ADS)
Pullen, Anthony R.; Alam, Shadab; Ho, Shirley
2015-06-01
We describe a methodology to probe gravity with the cosmic microwave background (CMB) lensing convergence κ, specifically by measuring EG, the ratio of the Laplacian of the gravitational scalar potential difference to the velocity divergence. Using CMB lensing instead of galaxy-galaxy lensing avoids intrinsic alignments while also lacking a hard limit on the lens redshift and significant uncertainties in the source plane. We model EG for general relativity and modified gravity, finding that EG for f(R) gravity should be scale dependent due to the scale dependence of the growth rate f. Next, we construct an estimator for EG in terms of the galaxy-CMB lensing and galaxy clustering angular power spectra, along with the redshift-space distortion parameter β. We also forecast statistical errors for EG from the current Planck CMB lensing map and the spectroscopic galaxy and quasar samples from the Sloan Digital Sky Survey Data Release 11, being 9 per cent with galaxies and 8 per cent when quasars are included. We also find that upcoming spectroscopic and photometric surveys, combined with the final Planck lensing map, can measure precisely the redshift- and scale dependence of EG out to redshifts z = 2 and higher, with photometric surveys having an advantage due to their high number densities. Advanced ACTPol's lensing map will increase the EG sensitivity even further. Finally, we find that Advanced ACTPol cross-correlated with spectroscopic (photometric) surveys can differentiate between general relativity and f(R) gravity at the level of 3σ (13σ). Performing a <1 per cent measurement of EG requires a 10 per cent precision in β from Euclid or Large Synoptic Survey Telescope, currently achievable with a spectroscopic survey but difficult with only a photometric survey.
Tularosa Basin Play Fairway Analysis: Partial Basin and Range Heat and Zones of Critical Stress Maps
Adam Brandt
2015-11-15
Interpolated maps of heat flow, temperature gradient, and quartz geothermometers are included as TIF files. Zones of critical stress map is also included as a TIF file. The zones are given a 5km diameter buffer. The study area is only a part of the Basin and Range, but it does includes the Tularosa Basin.
Non-Gaussianity and CMB aberration and Doppler
Catena, Riccardo; Liguori, Michele; Renzi, Alessandro; Notari, Alessio E-mail: michele.liguori@pd.infn.it E-mail: arenzi@pd.infn.it
2013-09-01
The peculiar motion of an observer with respect to the CMB rest frame induces a deflection in the arrival direction of the observed photons (also known as CMB aberration) and a Doppler shift in the measured photon frequencies. As a consequence, aberration and Doppler effects induce non trivial correlations between the harmonic coefficients of the observed CMB temperature maps. In this paper we investigate whether these correlations generate a bias on non-Gaussianity estimators f{sub NL}. We perform this analysis simulating a large number of temperature maps with Planck-like resolution (lmax = 2000) as different realizations of the same cosmological fiducial model (WMAP7yr). We then add to these maps aberration and Doppler effects employing a modified version of the HEALPix code. We finally evaluate a generalization of the Komatsu, Spergel and Wandelt non-Gaussianity estimator for all the simulated maps, both when peculiar velocity effects have been considered and when these phenomena have been neglected. Using the value v/c = 1.23 × 10{sup −3} for our peculiar velocity, we found that the aberration/Doppler induced non-Gaussian signal is at most of about half of the cosmic variance σ for f{sub NL} both in a full-sky and in a cut-sky experimental configuration, for local, equilateral and orthogonal estimators. We conclude therefore that when estimating f{sub NL} it is safe to ignore aberration and Doppler effects if the primordial map is already Gaussian. More work is necessary however to assess whether a map which contains non-Gaussianity can be significantly distorted by a peculiar velocity.
Optimal constraint on g{sub NL} from CMB
Sekiguchi, Toyokazu; Sugiyama, Naoshi E-mail: naoshi@nagoya-u.jp
2013-09-01
An optimal method to constrain the non-linearity parameter g{sub NL} of the local-type non-Gaussianity from CMB data is proposed. Our optimal estimator for g{sub NL} is separable and can be efficiently computed in real space. Combining the exact filtering of CMB maps with the full covariance matrix, our method allows us to extract cosmological information from observed data as much as possible and obtain a tighter constraint on g{sub NL} than previous studies. Applying our method to the WMAP 9-year data, we obtain the constraint g{sub NL} = (−3.3±2.2) × 10{sup 5}, which is a few times tighter than previous ones. We also make a forecast for PLANCK data by using the Fisher matrix analysis.
NASA Astrophysics Data System (ADS)
Liu, Guo-Chin; Ichiki, Kiyotomo; Tashiro, Hiroyuki; Sugiyama, Naoshi
2016-07-01
Scattering of cosmic microwave background (CMB) radiation in galaxy clusters induces polarization signals determined by the quadrupole anisotropy in the photon distribution at the location of clusters. This `remote quadrupole' derived from the measurements of the induced polarization in galaxy clusters provides an opportunity to reconstruct local CMB temperature anisotropies. In this Letter, we develop an algorithm of the reconstruction through the estimation of the underlying primordial gravitational potential, which is the origin of the CMB temperature and polarization fluctuations and CMB induced polarization in galaxy clusters. We found a nice reconstruction for the quadrupole and octopole components of the CMB temperature anisotropies with the assistance of the CMB induced polarization signals. The reconstruction can be an important consistency test on the puzzles of CMB anomalies, especially for the low-quadrupole and axis-of-evil problems reported in Wilkinson Microwave Anisotropy Probe and Planck data.
Nonlinear electrodynamics and CMB polarization
Cuesta, Herman J. Mosquera; Lambiase, G. E-mail: lambiase@sa.infn.it
2011-03-01
Recently WMAP and BOOMERanG experiments have set stringent constraints on the polarization angle of photons propagating in an expanding universe: Δα = (−2.4±1.9)°. The polarization of the Cosmic Microwave Background radiation (CMB) is reviewed in the context of nonlinear electrodynamics (NLED). We compute the polarization angle of photons propagating in a cosmological background with planar symmetry. For this purpose, we use the Pagels-Tomboulis (PT) Lagrangian density describing NLED, which has the form L ∼ (X/Λ{sup 4}){sup δ−1} X, where X = ¼F{sub αβ}F{sup αβ}, and δ the parameter featuring the non-Maxwellian character of the PT nonlinear description of the electromagnetic interaction. After looking at the polarization components in the plane orthogonal to the (x)-direction of propagation of the CMB photons, the polarization angle is defined in terms of the eccentricity of the universe, a geometrical property whose evolution on cosmic time (from the last scattering surface to the present) is constrained by the strength of magnetic fields over extragalactic distances.
Genetic dissection of heterosis using epistatic QTL mapping in partial NCII mating design
Technology Transfer Automated Retrieval System (TEKTRAN)
Heterosis refers to the phenomenon in which hybrid F1 exhibits enhanced growth or agronomic performance. However, theoretical studies on the genetic basis of heterosis were based on bi-parental segregation populations instead of multiple-parental hybrid F1 populations. In simulation study, we mapped...
Circular polarization of the CMB: Foregrounds and detection prospects
NASA Astrophysics Data System (ADS)
King, Soma; Lubin, Philip
2016-07-01
The cosmic microwave background (CMB) is one of the finest probes of cosmology. Its all-sky temperature and linear polarization fluctuations have been measured precisely at a level of δ T /TCMB˜10-6 . In contrast, circular polarization (C P ) of the CMB has not been precisely explored. The current upper limit on the C P of the CMB is at a level of δ V /TCMB˜10-4 and is limited on large scales. Some of the cosmologically important sources which can induce a C P in the CMB include early Universe symmetry breaking, a primordial magnetic field, galaxy clusters, and Pop III stars (also known as the first stars). Among these sources, Pop III stars are expected to induce the strongest signal with levels strongly dependent on the frequency of observation and on the number, Np, of the Pop III stars per halo. Optimistically, a C P signal in the CMB resulting from the Pop III stars could be at a level of δ V /TCMB˜2 ×10-7 in scales of 1° at 10 GHz, which is much smaller than the currently existing upper limits on the C P measurements. Primary foregrounds in the cosmological C P detection will come from the galactic synchrotron emission, which is naturally (intrinsically) circularly polarized. We use data-driven models of the galactic magnetic field, thermal electron density, and relativistic electron density to simulate all-sky maps of the galactic C P . This work also points out that the galactic C P levels are important below 50 GHz and is an important factor for telescopes aiming to detect primordial B modes using C P as a systematic rejection channel. In this paper, we focus on a SNR evaluation for the detectability of the Pop III induced C P signal in the CMB. We find that a SNR higher than unity is achievable, for example, with a 10 m telescope and an observation time of 20 months at 10 GHz, if Np≥100 . We also find that, if frequency of observation and resolution of the beam is appropriately chosen, a SNR higher than unity is possible with Np≥10 and
Spin-SILC: CMB polarisation component separation with spin wavelets
NASA Astrophysics Data System (ADS)
Rogers, Keir K.; Peiris, Hiranya V.; Leistedt, Boris; McEwen, Jason D.; Pontzen, Andrew
2016-08-01
We present Spin-SILC, a new foreground component separation method that accurately extracts the cosmic microwave background (CMB) polarisation E and B modes from raw multifrequency Stokes Q and U measurements of the microwave sky. Spin-SILC is an internal linear combination method that uses spin wavelets to analyse the spin-2 polarisation signal P = Q + iU. The wavelets are additionally directional (non-axisymmetric). This allows different morphologies of signals to be separated and therefore the cleaning algorithm is localised using an additional domain of information. The advantage of spin wavelets over standard scalar wavelets is to simultaneously and self-consistently probe scales and directions in the polarisation signal P = Q + iU and in the underlying E and B modes, therefore providing the ability to perform component separation and E-B decomposition concurrently for the first time. We test Spin-SILC on full-mission Planck simulations and data and show the capacity to correctly recover the underlying cosmological E and B modes. We also demonstrate a strong consistency of our CMB maps with those derived from existing component separation methods. Spin-SILC can be combined with the pseudo- and pure E-B spin wavelet estimators presented in a companion paper to reliably extract the cosmological signal in the presence of complicated sky cuts and noise. Therefore, it will provide a computationally-efficient method to accurately extract the CMB E and B modes for future polarisation experiments.
Lübberstedt, T; Klein, D; Melchinger, A E
1998-12-01
ABSTRACT We mapped and characterized quantitative trait loci (QTL) for partial resistance to Puccinia sorghi and investigated consistency across different European flint maize populations. Four independent populations, containing 280 F(3) lines (AxB(I)), 120 F(5) lines (AxB(II)), 131 F(4) lines (AxC), and 133 F(4) lines (CxD) were produced from four European elite flint inbreds (A, B, C, and D) and genotyped at 89, 151, 104, and 122 restriction fragment length polymorphism marker loci, respectively. All F(n) lines were evaluated in field trials with two replications in three or five (AxB(I)) environments. Genotypic variance was highly significant for rust ratings in all populations, and heritabilities exceeded 0.64. Between 4 and 13 QTL were detected in individual populations using composite interval mapping, explaining between 33 and 71% of the phenotypic variance. Twenty QTL were distributed over all ten chromosomes, without preference to chromosomes 3, 4, 6, and 10, which harbor qualitatively acting Rp loci. In most cases, gene action was additive or partially dominant. Four pairs of QTL displayed significant digenic epistatic interactions, and QTL-environment interactions were observed frequently. Approximately half of the QTL were consistent between AxB(I) and AxB(II) or AxC and CxD; fewer were consistent between AxB(I) and AxC or CxD. In European flint maize germ plasm, conventional selection for partial rust resistance seems to be more promising than marker-assisted selection. PMID:18944835
Spectral Distortions of the CMB Dipole
NASA Astrophysics Data System (ADS)
Balashev, S. A.; Kholupenko, E. E.; Chluba, J.; Ivanchik, A. V.; Varshalovich, D. A.
2015-09-01
We consider the distortions of the cosmic microwave background (CMB) dipole anisotropy related to primordial recombination radiation (PRR) and primordial y- and μ-distortions. The signals arise due to our motion relative to the CMB restframe and appear as a frequency-dependent distortion of the CMB temperature dipole. To leading order, the expected relative distortion of the CMB dipole does not depend on the particular observation directions and reaches the level of 10-6 for the PRR- and μ-distortions and 10-5 for the y-distortion in the frequency range 1-700 GHz. The temperature differences arising from the dipole anisotropy of the relic CMB distortions depend on the observation directions. For mutually opposite directions, collinear to the CMB dipole axis, the temperature differences due to the PRR- and μ-dipole anisotropy attain values {{Δ }}T≃ 10 {nK} in the considered range. The temperature difference arising from the y-dipole anisotropy may reach values of up to 1 μ {{K}}. The key features of the considered effect are as follow: (i) an observation of the effect does not require absolute calibration; (ii) patches of sky with minimal foreground contamination can be chosen. Future measurements of the CMB dipole distortion thus will provide an alternative method for direct detection of the PRR-, y-, and μ-distortions. The y-distortion dipole may be detectable with PIXIE at a few standard deviations.
CMB source apportionment during REVEAL
Lowenthal, D.H.; Gertler, A.W.; Wittorff, D.; Sakiyama, S.
1997-01-01
Source contributions to PM{sub 2.5} aerosol measured at Chilliwack and Pitt Meadows in the Lower Fraser Valley, B.C., Canada, during the REVEAL study, were estimated using chemical mass balance (CMB) receptor modeling. ON average, motor vehicles accounted for 34 and 43% of PM{sub 2.5} at Chilliwack and Pitt Meadows, respectively. Secondary sulfate and secondary nitrate were the next most significant PM{sub 2.5} components, accounting for 25 and 27%, respectively, at Chilliwack, and 27 and 12%, respectively, at Pitt Meadows. Geological material accounted for 3 and 5% of PM{sub 2.5} at Chilliwack and Pitt Meadows, respectively. A significant contribution of wood smoke was estimated for both sites: 8% at Chilliwack and 9% at Pitt Meadows.
Disformal transformations on the CMB
NASA Astrophysics Data System (ADS)
Burrage, Clare; Cespedes, Sebastian; Davis, Anne-Christine
2016-08-01
In this work we study the role of disformal transformation on cosmological backgrounds and its relation to the speed of sound for tensor modes. A speed different from one for tensor modes can arise in several contexts, such as Galileons theories or massive gravity, nevertheless the speed is very constrained to be one by observations of gravitational wave emission. It has been shown that in inflation a disformal transformation allows to set the speed for tensor modes to one without making changes to the curvature power spectrum. Here we show that this invariance does not hold when considering the CMB anisotropy power spectrum. It turns out that the after doing the transformation there is an imprint on the acoustic peaks and the diffusion damping. This has interesting consequences; here we explore quartic galileon theories which allow a modified speed for tensor modes. For these theories the transformation can be used to constraint the parameter space in different regimes.
Statistical aspect of trait mapping using a dense set of markers: A partial review
Dupuis, J.
1996-12-31
This paper presents a review of statistical methods used to locate trait loci using maps of markers spanning the whole genome. Such maps are becoming readily available and can be especially useful in mapping traits that are non Mendelian. Genome-wide search for a trait locus is often called a {open_quotes}global search{close_quotes}. Global search methods include, but are not restricted to, identifying disease susceptibility genes using affected relative pairs, finding quantitative trait loci in experimental organisms and locating quantitative trait loci in humans. For human linkage, we concentrate on methods using pairs of affected relatives rather than pedigree analysis. We begin in the next section with a review of work on the use of affected pairs of relatives to identify gene loci that increase susceptibility to a particular disease. We first review Risch`s 1990 series of papers. Risch`s method can be used to search the entire genome for such susceptibility genes. Using Risch`s idea Elston explored the issue of how many pairs and markers are necessary to reach a certain probability of detecting a locus if there exists one. He proposed a more economical two stage design that uses few markers at the first stage but adds markers around the {open_quotes}promising{close_quotes} area of the genome at the second stage. However, Risch and Elston do not use multipoint linkage analysis, which takes into account all markers at once (rather than one at a time) in the calculation of the test statistic. Such multipoint methods for affected relatives have been developed by Feingold and Feingold et al. The last authors` multipoint method is based on a continuous specification of identity by descent between the affected relatives but can also be used for a set of linked markers spanning the genome. A brief description of their method and treatment of more complex issues such as combining relative pairs is included. 29 refs., 4 tabs.
Search for primordial symmetry breakings in CMB
NASA Astrophysics Data System (ADS)
Shiraishi, Maresuke
2016-06-01
There are possibilities to violate symmetries (e.g. parity and rotational invariance) in the primordial cosmological fluctuations. Such symmetry breakings can imprint very rich signatures in late-time phenomena, which may be possible to observe. Especially, Cosmic Microwave Background (CMB) will change its face drastically, corresponding to the symmetry-breaking types, since the harmonic-space representation is very sensitive to the statistical, spin and angular dependences of cosmological perturbations. Here, we discuss (1) general responses of CMB to the symmetry breakings, (2) some theoretical models creating interesting CMB signatures, and (3) aspects of the estimation from observational data.
Generation of circular polarization of the CMB
NASA Astrophysics Data System (ADS)
Zarei, M.; Bavarsad, E.; Haghighat, M.; Mohammadi, R.; Motie, I.; Rezaei, Z.
2010-04-01
According to the standard cosmology, near the last scattering surface, the photons scattered via Compton scattering are just linearly polarized and then the primordial circular polarization of the cosmic microwave background (CMB) photons is zero. In this work we show that CMB polarization acquires a small degree of circular polarization when a background magnetic field is considered or the quantum electrodynamic sector of standard model is extended by Lorentz-noninvariant operators as well as noncommutativity. The existence of circular polarization for the CMB radiation may be verified during future observation programs, and it represents a possible new channel for investigating new physics effects.
Albarracin, R; Robles, G; Martinez-Tarifa, J M; Ardila-Rey, J
2015-09-01
Partial discharges measurement is one of the most useful tools for condition monitoring of high-voltage (HV) equipment. These phenomena can be measured on-line in radiofrequency (RF) with sensors such as the Vivaldi antenna, used in this paper, which improves the signal-to-noise ratio by rejecting FM and low-frequency TV bands. Additionally, the power ratios (PR), a signal-processing technique based on the power distribution of the incoming signals in frequency bands, are used to characterize different sources of PD and electromagnetic noise (EMN). The calculation of the time length of the pulses is introduced to separate signals where the PR alone do not give a conclusive solution. Thus, if several EM sources could be previously calibrated, it is possible to detect pulses corresponding to PD activity. PMID:25997372
A CMB foreground study in WMAP data: Extragalactic point sources and zodiacal light emission
NASA Astrophysics Data System (ADS)
Chen, Xi
The Cosmic Microwave Background (CMB) radiation is the remnant heat from the Big Bang. It serves as a primary tool to understand the global properties, content and evolution of the universe. Since 2001, NASA's Wilkinson Microwave Anisotropy Probe (WMAP) satellite has been napping the full sky anisotropy with unprecedented accuracy, precision and reliability. The CMB angular power spectrum calculated from the WMAP full sky maps not only enables accurate testing of cosmological models, but also places significant constraints on model parameters. The CMB signal in the WMAP sky maps is contaminated by microwave emission from the Milky Way and from extragalactic sources. Therefore, in order to use the maps reliably for cosmological studies, the foreground signals must be well understood and removed from the maps. This thesis focuses on the separation of two foreground contaminants from the WMAP maps: extragalactic point sources and zodiacal light emission. Extragalactic point sources constitute the most important foreground on small angular scales. Various methods have been applied to the WMAP single frequency maps to extract sources. However, due to the limited angular resolution of WMAP, it is possible to confuse positive CMB excursions with point sources or miss sources that are embedded in negative CMB fluctuations. We present a novel CMB-free source finding technique that utilizes the spectrum difference of point sources and CMB to form internal linear combinations of multifrequency maps to suppress the CMB and better reveal sources. When applied to the WMAP 41, 64 and 94 GHz maps, this technique has not only enabled detection of sources that are previously cataloged by independent methods, but also allowed disclosure of new sources. Without the noise contribution from the CMB, this method responds rapidly with the integration time. The number of detections varies as 0( t 0.72 in the two-band search and 0( t 0.70 in the three-band search from one year to five years
Measuring the Polarized CMB with ACT
NASA Astrophysics Data System (ADS)
Staggs, Suzanne
2016-06-01
The Atacama Cosmology Telescope is a special-purpose 6m telescope designed for cosmic microwave background (CMB) measurements at arcminute resolution. We will describe recent results using the second-generation camera called ACTPol. The camera comprises three sets of optics and detectors. Two operate at 150 GHz, and the third is the first multichroic detector array deployed for the CMB. The latter operates at 90 and 150 GHz.
Polarized cosmic microwave background map recovery with sparse component separation
NASA Astrophysics Data System (ADS)
Bobin, J.; Sureau, F.; Starck, J.-L.
2015-11-01
The polarization modes of the cosmological microwave background are an invaluable source of information for cosmology and a unique window to probe the energy scale of inflation. Extracting this information from microwave surveys requires distinguishing between foreground emissions and the cosmological signal, which means solving a component separation problem. Component separation techniques have been widely studied for the recovery of cosmic microwave background (CMB) temperature anisotropies, but very rarely for the polarization modes. In this case, most component separation techniques make use of second-order statistics to distinguish between the various components. More recent methods, which instead emphasize the sparsity of the components in the wavelet domain, have been shown to provide low-foreground, full-sky estimates of the CMB temperature anisotropies. Building on sparsity, we here introduce a new component separation technique dubbed the polarized generalized morphological component analysis (PolGMCA), which refines previous work to specifically work on the estimation of the polarized CMB maps: i) it benefits from a recently introduced sparsity-based mechanism to cope with partially correlated components; ii) it builds upon estimator aggregation techniques to further yield a better noise contamination/non-Gaussian foreground residual trade-off. The PolGMCA algorithm is evaluated on simulations of full-sky polarized microwave sky simulations using the Planck Sky Model (PSM). The simulations show that the proposed method achieves a precise recovery of the CMB map in polarization with low-noise and foreground contamination residuals. It provides improvements over standard methods, especially on the Galactic center, where estimating the CMB is challenging.
Dai, Xuan; Reading, Mike; Craig, Duncan Q M
2009-04-01
The use of nanothermal analysis for mapping amorphous and crystalline lactose at a nanoscale is explored. Compressed tablets of amorphous and crystalline lactose (alone and mixed) were prepared and localised thermomechanical analysis (L-TMA) performed using micro- and nanothermal analysis in a addition to single point variable temperature pull-off force measurements. L-TMA was shown to be able to identify the different materials at a nanoscale via measurement of the thermal events associated with the amorphous and crystalline regions, while pull off force measurements showed that the adhesion of the amorphous material increased on approaching the T(g). Imaging was performed isothermally using topographic and pulsed force mode (PFM) measurements; both approaches were capable of discriminating two regions which L-TMA conformed to correspond to the two materials. In addition, force volume imaging (FVI) is suggested as a further approach to mapping the surfaces. We demonstrate that performing heated tip PFM measurements at a temperature close to the T(g) allows greater discrimination between the two regions. We therefore suggest that the nanothermal approach allows both characterisation and imaging of partially amorphous surfaces, and also demonstrate that heated tip imaging allows greater discrimination between crystalline and amorphous materials than is possible using ambient studies. PMID:18752293
The BRAIN CMB polarization experiment
NASA Astrophysics Data System (ADS)
Polenta, G.; Ade, P. A. R.; Bartlett, J.; Bréelle, E.; Conversi, L.; de Bernardis, P.; Dufour, C.; Gervasi, M.; Giard, M.; Giordano, C.; Giraud-Heraud, Y.; Maffei, B.; Masi, S.; Nati, F.; Orlando, A.; Peterzen, S.; Piacentini, F.; Piat, M.; Piccirillo, L.; Pisano, G.; Pons, R.; Rosset, C.; Savini, G.; Sironi, G.; Tartari, A.; Veneziani, M.; Zannoni, M.
2007-03-01
In the standard cosmological scenario tensor perturbations of the metric produce a rotational component in the Cosmic Microwave Background polarization, called B-modes. The expected signal is of the order of ˜0.1 μK, well beyond the sensitivity of current experiments. In this paper, we introduce the BRAIN experiment, a bolometric interferometer devoted to measure the B-modes polarization of the CMB from Concordia station in Antarctica. This experiment will take advantage of both high sensitivity of bolometer arrays and low level of systematic effects of interferometers. We report the results obtained during the first campaign we carried out this austral summer at Dome-C. Using a pathfinder experiment, we demonstrated that a cryocooler based cryogenic system can work in such environmental conditions. We also carried out preliminary observations of the atmospheric emission at 145 GHz from Dome-C, and during the next campaign we'll extend the measurements to all the Stokes parameters I, Q, U, V all over the winter.
The CMB modulation from inflation
Lyth, David H.
2013-08-01
Erickcek, Kamionkowski and Carroll proposed in 2008 that the dipole modulation of the CMB could be due to a very large scale perturbation of the field φ causing the primordial curvature perturbation. We repeat their calculation using weaker assumptions and the current data. If φ is the inflaton of any single-field inflation with the attractor behaviour, the asymmetry is almost certainly too small. If instead φ is any curvaton-type field (ie. one with the canonical kinetic term and a negligible effect during inflation) the asymmetry can agree with observation if |f{sub NL}| in the equilateral configuration is ≅ 10 for k{sup −1} = 1Gpc and ∼<3 for k{sup −1} = 1Mpc. An f{sub NL} with these properties can apparently be obtained from the curvaton with an axionic potential. Within any specific curvaton-type model, the function f{sub NL}(k{sub 1},k{sub 2},k{sub 3}) required to generate the asymmetry would be determined, and could perhaps already be confirmed or ruled out using existing Planck or WMAP data.
Quantifying the Effect of Component Covariances in CMB Extraction from Multi-frequency Data
NASA Technical Reports Server (NTRS)
Phillips, Nicholas G.
2008-01-01
Linear combination methods provide a global method for component separation of multi-frequency data. We present such a method that allows for consideration of possible covariances between the desired cosmic microwave background signal and various foreground signals that are also present. We also recover information on the foregrounds including the number of foregrounds, their spectra and templates. In all this, the covariances, which we would only expect to vanish 'in the mean' are included as parameters expressing the fundamental uncertainty due to this type of cosmic variance. When we make the reasonable assumption that the CMB is Gaussian, we can compute both a mean recovered CMB map and also an RMS error map, The mean map coincides with WMAP's Internal Linear Combination map.
Planck 2013 results. XXIII. Isotropy and statistics of the CMB
NASA Astrophysics Data System (ADS)
Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Bartolo, N.; Battaner, E.; Battye, R.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R. C.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Couchot, F.; Coulais, A.; Crill, B. P.; Cruz, M.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Fantaye, Y.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Frommert, M.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Hansen, M.; Hanson, D.; Harrison, D. L.; Helou, G.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kim, J.; Kisner, T. S.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leahy, J. P.; Leonardi, R.; Leroy, C.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Mangilli, A.; Marinucci, D.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McEwen, J. D.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mikkelsen, K.; Mitra, S.; Miville-Deschênes, M.-A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Peiris, H. V.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pogosyan, D.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Racine, B.; Räth, C.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rotti, A.; Roudier, G.; Rubiño-Martín, J. A.; Ruiz-Granados, B.; Rusholme, B.; Sandri, M.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Souradeep, T.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutter, P.; 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.; Türler, M.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Varis, J.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; White, M.; Wilkinson, A.; Yvon, D.; Zacchei, A.; Zonca, A.
2014-11-01
The two fundamental assumptions of the standard cosmological model - that the initial fluctuations are statistically isotropic and Gaussian - are rigorously tested using maps of the cosmic microwave background (CMB) anisotropy from the Planck satellite. The detailed results are based on studies of four independent estimates of the CMB that are compared to simulations using a fiducial ΛCDM model and incorporating essential aspects of the Planck measurement process. Deviations from isotropy have been found and demonstrated to be robust against component separation algorithm, mask choice, and frequency dependence. Many of these anomalies were previously observed in the WMAP data, and are now confirmed at similar levels of significance (about 3σ). However, we find little evidence of non-Gaussianity, with the exception of a few statistical signatures that seem to be associated with specific anomalies. In particular, we find that the quadrupole-octopole alignment is also connected to a low observed variance in the CMB signal. A power asymmetry is now found to persist on scales corresponding to about ℓ = 600 and can be described in the low-ℓ regime by a phenomenological dipole modulation model. However, any primordial power asymmetry is strongly scale-dependent and does not extend toarbitrarily small angular scales. Finally, it is plausible that some of these features may be reflected in the angular power spectrum of the data, which shows a deficit of power on similar scales. Indeed, when the power spectra of two hemispheres defined by a preferred direction are considered separately, one shows evidence of a deficit in power, while its opposite contains oscillations between odd and even modes that may be related to the parity violation and phase correlations also detected in the data. Although these analyses represent a step forward in building an understanding of the anomalies, a satisfactory explanation based on physically motivated models is still lacking.
Planck CMB anomalies: astrophysical and cosmological secondary effects and the curse of masking
Rassat, A.; Starck, J.-L.; Paykari, P.; Sureau, F.; Bobin, J. E-mail: jstarck@cea.fr E-mail: florent.sureau@cea.fr
2014-08-01
Large-scale anomalies have been reported in CMB data with both WMAP and Planck data. These could be due to foreground residuals and or systematic effects, though their confirmation with Planck data suggests they are not due to a problem in the WMAP or Planck pipelines. If these anomalies are in fact primordial, then understanding their origin is fundamental to either validate the standard model of cosmology or to explore new physics. We investigate three other possible issues: 1) the trade-off between minimising systematics due to foreground contamination (with a conservative mask) and minimising systematics due to masking, 2) astrophysical secondary effects (the kinetic Doppler quadrupole and kinetic Sunyaev-Zel'dovich effect), and 3) secondary cosmological signals (the integrated Sachs-Wolfe effect). We address the masking issue by considering new procedures that use both WMAP and Planck to produce higher quality full-sky maps using the sparsity methodology (LGMCA maps). We show the impact of masking is dominant over that of residual foregrounds, and the LGMCA full-sky maps can be used without further processing to study anomalies. We consider four official Planck PR1 and two LGMCA CMB maps. Analysis of the observed CMB maps shows that only the low quadrupole and quadrupole-octopole alignment seem significant, but that the planar octopole, Axis of Evil, mirror parity and cold spot are not significant in nearly all maps considered. After subtraction of astrophysical and cosmological secondary effects, only the low quadrupole may still be considered anomalous, meaning the significance of only one anomaly is affected by secondary effect subtraction out of six anomalies considered. In the spirit of reproducible research all reconstructed maps and codes will be made available for download here http://www.cosmostat.org/anomaliesCMB.html.
NASA Astrophysics Data System (ADS)
Meerburg, P. Daniel; Meyers, Joel; van Engelen, Alexander; Ali-Haïmoud, Yacine
2016-06-01
We study the degree to which the cosmic microwave background (CMB) can be used to constrain primordial non-Gaussianity involving one tensor and two scalar fluctuations, focusing on the correlation of one polarization B mode with two temperature modes. In the simplest models of inflation, the tensor-scalar-scalar primordial bispectrum is nonvanishing and is of the same order in slow-roll parameters as the scalar-scalar-scalar bispectrum. We calculate the ⟨B T T ⟩ correlation arising from a primordial tensor-scalar-scalar bispectrum, and show that constraints from an experiment like CMB-Stage IV using this observable are more than an order of magnitude better than those on the same primordial coupling obtained from temperature measurements alone. We argue that B -mode non-Gaussianity opens up an as-yet-unexplored window into the early Universe, demonstrating that significant information on primordial physics remains to be harvested from CMB anisotropies.
CMB μ distortion from primordial gravitational waves
Ota, Atsuhisa; Yamaguchi, Masahide; Takahashi, Tomo; Tashiro, Hiroyuki E-mail: tomot@cc.saga-u.ac.jp E-mail: gucci@phys.titech.ac.jp
2014-10-01
We propose a new mechanism of generating the μ distortion in cosmic microwave background (CMB) originated from primordial gravitational waves. Such μ distortion is generated by the damping of the temperature anisotropies through the Thomson scattering, even on scales larger than that of Silk damping. This mechanism is in sharp contrast with that from the primordial curvature (scalar) perturbations, in which the temperature anisotropies mainly decay by Silk damping effects. We estimate the size of the μ distortion from the new mechanism, which can be used to constrain the amplitude of primordial gravitational waves on smaller scales independently from the CMB anisotropies, giving more wide-range constraint on their spectral index by combining the amplitude from the CMB anisotropies.
Kasanda, Simon Muya; Moodley, Kavilan E-mail: moodleyk41@ukzn.ac.za
2014-12-01
We forecast how current (PLANCK) and future (PRISM) cosmic microwave background (CMB) experiments constrain the adiabatic mode and its admixtures with primordial isocurvature modes. The forecasts are based on measurements of the reconstructed CMB lensing potential and lensing-induced CMB B-mode polarization anisotropies in combination with the CMB temperature and E-mode polarization anisotropies. We first study the characteristic features of the CMB temperature, polarization and lensing spectra for adiabatic and isocurvature modes. We then consider how information from the CMB lensing potential and B-mode polarization induced by lensing can improve constraints on an admixture of adiabatic and three correlated isocurvature modes. We find that the CMB lensing spectrum improves constraints on isocurvature modes by at most 10% for the PLANCK and PRISM experiments. The limited improvement is a result of the low amplitude of isocurvature lensing spectra and cancellations between these spectra that render them only slightly detectable. There is a larger gain from using the lensing-induced B-mode polarization spectrum measured by PRISM. In this case constraints on isocurvature mode amplitudes improve by as much as 40% relative to the CMB temperature and E-mode polarization constraints. The addition of both lensing and lensing-induced B-mode polarization information constrains isocurvature mode amplitudes at the few percent level or better. In the case of admixtures of the adiabatic mode with one or two correlated isocurvature modes we find that constraints at the percent level or better are possible. We investigate the dependence of our results to various assumptions in our analysis, such as the inclusion of dark energy parameters, the CMB temperature-lensing correlation, and the presence of primordial tensor modes, and find that these assumptions do not significantly change our main results.
Future detectability of gravitational-wave induced lensing from high-sensitivity CMB experiments
NASA Astrophysics Data System (ADS)
Namikawa, Toshiya; Yamauchi, Daisuke; Taruya, Atsushi
2015-02-01
We discuss the future detectability of gravitational-wave induced lensing from high-sensitivity cosmic microwave background (CMB) experiments. Gravitational waves can induce a rotational component of the weak-lensing deflection angle, usually referred to as the curl mode, which would be imprinted on the CMB maps. Using the technique of reconstructing lensing signals involved in CMB maps, this curl mode can be measured in an unbiased manner, offering an independent confirmation of the gravitational waves complementary to B-mode polarization experiments. Based on the Fisher matrix analysis, we first show that with the noise levels necessary to confirm the consistency relation for the primordial gravitational waves, the future CMB experiments will be able to detect the gravitational-wave induced lensing signals. For a tensor-to-scalar ratio of r ≲0.1 , even if the consistency relation is difficult to confirm with a high significance, the gravitational-wave induced lensing will be detected at more than 3 σ significance level. Further, we point out that high-sensitivity experiments will be also powerful to constrain the gravitational waves generated after the recombination epoch. Compared to the B-mode polarization, the curl mode is particularly sensitive to gravitational waves generated at low redshifts (z ≲10 ) with a low frequency (k ≲1 0-3 Mpc-1 ), and it could give a much tighter constraint on their energy density ΩGW by more than 3 orders of magnitude.
Large scale CMB anomalies from thawing cosmic strings
NASA Astrophysics Data System (ADS)
Ringeval, Christophe; Yamauchi, Daisuke; Yokoyama, Jun'ichi; Bouchet, François R.
2016-02-01
Cosmic strings formed during inflation are expected to be either diluted over super-Hubble distances, i.e., invisible today, or to have crossed our past light cone very recently. We discuss the latter situation in which a few strings imprint their signature in the Cosmic Microwave Background (CMB) Anisotropies after recombination. Being almost frozen in the Hubble flow, these strings are quasi static and evade almost all of the previously derived constraints on their tension while being able to source large scale anisotropies in the CMB sky. Using a local variance estimator on thousand of numerically simulated Nambu-Goto all sky maps, we compute the expected signal and show that it can mimic a dipole modulation at large angular scales while being negligible at small angles. Interestingly, such a scenario generically produces one cold spot from the thawing of a cosmic string loop. Mixed with anisotropies of inflationary origin, we find that a few strings of tension GU = Script O(1) × 10-6 match the amplitude of the dipole modulation reported in the Planck satellite measurements and could be at the origin of other large scale anomalies.
Extreme data compression for the CMB
NASA Astrophysics Data System (ADS)
Zablocki, Alan; Dodelson, Scott
2016-04-01
We apply the Karhunen-Loéve methods to cosmic microwave background (CMB) data sets, and show that we can recover the input cosmology and obtain the marginalized likelihoods in Λ cold dark matter cosmologies in under a minute, much faster than Markov chain Monte Carlo methods. This is achieved by forming a linear combination of the power spectra at each multipole l , and solving a system of simultaneous equations such that the Fisher matrix is locally unchanged. Instead of carrying out a full likelihood evaluation over the whole parameter space, we need evaluate the likelihood only for the parameter of interest, with the data compression effectively marginalizing over all other parameters. The weighting vectors contain insight about the physical effects of the parameters on the CMB anisotropy power spectrum Cl . The shape and amplitude of these vectors give an intuitive feel for the physics of the CMB, the sensitivity of the observed spectrum to cosmological parameters, and the relative sensitivity of different experiments to cosmological parameters. We test this method on exact theory Cl as well as on a Wilkinson Microwave Anisotropy Probe (WMAP)-like CMB data set generated from a random realization of a fiducial cosmology, comparing the compression results to those from a full likelihood analysis using CosmoMC. After showing that the method works, we apply it to the temperature power spectrum from the WMAP seven-year data release, and discuss the successes and limitations of our method as applied to a real data set.
Weak lensing of the primary CMB bispectrum
Cooray, Asantha; Sarkar, Devdeep; Serra, Paolo
2008-06-15
The bispectrum of cosmic microwave background (CMB) anisotropies is a well-known probe of the non-Gaussianity of primordial perturbations. Just as the intervening large-scale structure modifies the CMB angular power spectrum through weak gravitational lensing, the CMB primary bispectrum generated at the last scattering surface is also modified by lensing. We discuss the lensing modification to the CMB bispectrum and show that lensing leads to an overall decrease in the amplitude of the primary bispectrum at multipoles of interest between 100 and 2000 through additional smoothing introduced by lensing. Since weak lensing is not accounted for in current estimators of the primordial non-Gaussianity parameter, the existing measurements of f{sub NL} of the local model with WMAP out to l{sub max}{approx}750 is biased low by about 6%. For a high resolution experiment such as Planck, the lensing modification to the bispectrum must be properly included when attempting to estimate the primordial non-Gaussianity or the bias will be at the level of 30%. For Planck, weak lensing increases the minimum detectable value for the non-Gaussianity parameter of the local type f{sub NL} to 7 from the previous estimate of about 5 without lensing. The minimum detectable value of f{sub NL} for a cosmic variance limited experiment is also increased from less than 3 to {approx}5.
NASA Astrophysics Data System (ADS)
Catena, Riccardo; Notari, Alessio
2013-07-01
The peculiar motion of an observer with respect to the CMB rest frame induces an apparent deflection of the observed CMB photons, i.e. aberration, and a shift in their frequency, i.e. Doppler effect. Both effects distort the temperature multipoles alm's via a mixing matrix at any l. The common lore when performing a CMB based cosmological parameter estimation is to consider that Doppler affects only the l = 1 multipole, and neglect any other corrections. In ref. [1] we checked the validity of this assumption in parameter estimation for a Planck-like angular resolution, both for a full-sky ideal experiment and also when sky cuts are included to model CMB foreground contaminations with a sky fraction similar to the Planck satellite. The result to this analysis was that aberration and Doppler have a sizable impact on a CMB based parameter estimation. In this erratum we correct an error made in ref. [1] when comparing pseudo angular power spectra computed in the CMB rest frame with the ones measured by a moving observer. Properly comparing the two spectra we find now that although the corrections to the Cl due to aberration and Doppler are larger than the cosmic variance at l > 1000 and potentially important, the resulting bias on the parameters is negligible for Planck.
Detection of thermal SZ-CMB lensing cross-correlation in Planck nominal mission data
Hill, J. Colin; Spergel, David N. E-mail: dns@astro.princeton.edu
2014-02-01
The nominal mission maps from the Planck satellite contain a wealth of information about secondary anisotropies in the cosmic microwave background (CMB), including those induced by the thermal Sunyaev-Zel'dovich (tSZ) effect and gravitational lensing. As both the tSZ and CMB lensing signals trace the large-scale matter density field, the anisotropies sourced by these processes are expected to be correlated. We report the first detection of this cross-correlation signal, which we measure at 6.2σ significance using the Planck data. We take advantage of Planck's multifrequency coverage to construct a tSZ map using internal linear combination techniques, which we subsequently cross-correlate with the publicly-released Planck CMB lensing potential map. The cross-correlation is subject to contamination from the cosmic infrared background (CIB), which is known to correlate strongly with CMB lensing. We correct for this contamination via cross-correlating our tSZ map with the Planck 857 GHz map and confirm the robustness of our measurement using several null tests. We interpret the signal using halo model calculations, which indicate that the tSZ-CMB lensing cross-correlation is a unique probe of the physics of intracluster gas in high-redshift, low-mass groups and clusters. Our results are consistent with extrapolations of existing gas physics models to this previously unexplored regime and show clear evidence for contributions from both the one- and two-halo terms, but no statistically significant evidence for contributions from diffuse, unbound gas outside of collapsed halos. We also show that the amplitude of the signal depends rather sensitively on the amplitude of fluctuations (σ{sub 8}) and the matter density (Ω{sub m}), scaling as σ{sub 8}{sup 6.1}Ω{sub m}{sup 1.5} at ℓ = 1000. We constrain the degenerate combination σ{sub 8}(Ω{sub m}/0.282){sup 0.26} = 0.824±0.029, a result that is in less tension with primordial CMB constraints than some recent t
Applications of the Gaussian kinematic formula to CMB data analysis
NASA Astrophysics Data System (ADS)
Fantaye, Yabebal; Marinucci, Domenico; Hansen, Frode; Maino, Davide
2015-03-01
The Gaussian kinematic formula (GKF) [R. J. Adler and J. E. Taylor, Random Fields and Geometry (Springer, New York, 2007).] is an extremely powerful tool allowing for explicit analytic predictions of expected values of Minkowski functionals under realistic experimental conditions for cosmological data collections. In this paper, we implement Minkowski functionals on multipoles and needlet components of CMB fields, thus allowing a better control of cosmic variance and extraction of information on both harmonic and real domains; we then exploit the GKF to provide their expected values on spherical maps, in the presence of arbitrary sky masks, and under non-Gaussian circumstances. All our results are validated by numerical experiments, which show a perfect agreement between theoretical predictions and Monte Carlo simulations.
First measurement of the cross-correlation of CMB lensing and galaxy lensing
NASA Astrophysics Data System (ADS)
Hand, Nick; Leauthaud, Alexie; Das, Sudeep; Sherwin, Blake D.; Addison, Graeme E.; Bond, J. Richard; Calabrese, Erminia; Charbonnier, Aldée; Devlin, Mark J.; Dunkley, Joanna; Erben, Thomas; Hajian, Amir; Halpern, Mark; Harnois-Déraps, Joachim; Heymans, Catherine; Hildebrandt, Hendrik; Hincks, Adam D.; Kneib, Jean-Paul; Kosowsky, Arthur; Makler, Martin; Miller, Lance; Moodley, Kavilan; Moraes, Bruno; Niemack, Michael D.; Page, Lyman A.; Partridge, Bruce; Sehgal, Neelima; Shan, Huanyuan; Sievers, Jonathan L.; Spergel, David N.; Staggs, Suzanne T.; Switzer, Eric R.; Taylor, James E.; Van Waerbeke, Ludovic; Welker, Charlotte; Wollack, Edward J.
2015-03-01
We measure the cross-correlation of cosmic microwave background (CMB) lensing convergence maps derived from Atacama Cosmology Telescope data with galaxy lensing convergence maps as measured by the Canada-France-Hawaii Telescope Stripe 82 Survey. The CMB-galaxy lensing cross power spectrum is measured for the first time with a significance of 4.2 σ , which corresponds to a 12% constraint on the amplitude of density fluctuations at redshifts ˜0.9 . With upcoming improved lensing data, this novel type of measurement will become a powerful cosmological probe, providing a precise measurement of the mass distribution at intermediate redshifts and serving as a calibrator for systematic biases in weak lensing measurements.
Secondary anisotropies in CMB, skew-spectra and Minkowski Functionals
NASA Astrophysics Data System (ADS)
Munshi, Dipak; Coles, Peter; Heavens, Alan
2013-01-01
Secondary contributions to the anisotropy of the cosmic microwave background (CMB), such as the integrated Sachs-Wolfe (ISW) effect, the thermal Sunyaev-Zel'dovich (tSZ) effect, and the effect of gravitational lensing, have distinctive non-Gaussian signatures, and full descriptions therefore require information beyond that contained in their power spectra. The Minkowski Functionals (MF) are well-known as tools for quantifying any departure from Gaussianity and are affected by noise and other sources of confusion in a different way from the usual methods based on higher-order moments or polyspectra, thus providing complementary tools for CMB analysis and cross-validation of results. In this paper we use the recently introduced skew-spectra associated with the MFs to probe the topology of CMB maps to probe the secondary non-Gaussianity as a function of beam smoothing in order to separate various contributions. We devise estimators for these spectra in the presence of realistic observational masks and present expressions for their covariance as a function of instrumental noise. Specific results are derived for the mixed ISW-lensing and tSZ-lensing bispectra as well as contamination due to point sources for noise levels that correspond to the Planck (143 GHz channel) and Experimental Probe of Inflationary Cosmology (EPIC; 150 GHz channel) experiments. The cumulative signal-to-noise ratio (S/N) for one-point generalized skewness parameters can reach an order of O(10) for Planck and two orders of magnitude higher forEPIC, i.e. O(10^3). We also find that these three skew-spectra are correlated, having correlation coefficients r ˜ 0.5-1.0; higher l modes are more strongly correlated. Although the values of S/N increase with decreasing noise, the triplets of skew-spectra that determine the MFs become more correlated; the S/N of lensing-induced skew-spectra are smaller compared to that of a frequency-cleaned tSZ map.
NASA Astrophysics Data System (ADS)
Bonavera, L.; Barreiro, R. B.; Marcos-Caballero, A.; Vielva, P.
2016-06-01
In this work we present a method to extract the signal induced by the integrated Sachs-Wolfe (ISW) effect in the cosmic microwave background (CMB). It makes use of the Linear Covariance-Based filter introduced by Barreiro et al., and combines CMB data with any number of large-scale structure (LSS) surveys and lensing information. It also exploits CMB polarization to reduce cosmic variance. The performance of the method has been thoroughly tested with simulations taking into account the impact of non-ideal conditions such as incomplete sky coverage or the presence of noise. In particular, three galaxy surveys are simulated, whose redshift distributions peak at low (z ≃ 0.3), intermediate (z ≃ 0.6) and high redshift (z ≃ 0.9). The contribution of each of the considered data sets as well as the effect of a mask and noise in the reconstructed ISW map is studied in detail. When combining all the considered data sets (CMB temperature and polarization, the three galaxy surveys and the lensing map), the proposed filter successfully reconstructs a map of the weak ISW signal, finding a perfect correlation with the input signal for the ideal case and around 80 per cent, on average, in the presence of noise and incomplete sky coverage. We find that including CMB polarization improves the correlation between input and reconstruction although only at a small level. Nonetheless, given the weakness of the ISW signal, even modest improvements can be of importance. In particular, in realistic situations, in which less information is available from the LSS tracers, the effect of including polarization is larger. For instance, for the case in which the ISW signal is recovered from CMB plus only one survey, and taking into account the presence of noise and incomplete sky coverage, the improvement in the correlation coefficient can be as large as 10 per cent.
CMB lensing and primordial non-Gaussianity
Hanson, Duncan; Smith, Kendrick M.; Challinor, Anthony; Liguori, Michele
2009-10-15
We study the effects of gravitational lensing on the estimation of non-Gaussianity from the bispectrum of the CMB temperature anisotropies. We find that the effect of lensing on the bispectrum may qualitatively be described as a smoothing of the acoustic features analogous to the temperature power spectrum. In contrast to previous results, for a Planck-like experiment which is cosmic-variance limited to l{sub max}=2000, we find that lensing causes no significant degradation of our ability to constrain the non-Gaussianity amplitude f{sub NL} for both local and equilateral configurations, provided that the biases due to the cross correlation between the lensing potential and the integrated-Sachs-Wolfe contribution to the CMB temperature are adequately understood. With numerical simulations, we also verify that low-order Taylor approximations to the lensed bispectrum and integrated-Sachs-Wolfe-lensing biases are accurate.
Constraining fundamental physics with future CMB experiments
Galli, Silvia; Martinelli, Matteo; Melchiorri, Alessandro; Pagano, Luca; Sherwin, Blake D.; Spergel, David N.
2010-12-15
The Planck experiment will soon provide a very accurate measurement of cosmic microwave background anisotropies. This will let cosmologists determine most of the cosmological parameters with unprecedented accuracy. Future experiments will improve and complement the Planck data with better angular resolution and better polarization sensitivity. This unexplored region of the CMB power spectrum contains information on many parameters of interest, including neutrino mass, the number of relativistic particles at recombination, the primordial helium abundance, and the injection of additional ionizing photons by dark matter self-annihilation. We review the imprint of each parameter on the CMB and forecast the constraints achievable by future experiments by performing a Monte Carlo analysis on synthetic realizations of simulated data. We find that next generation satellite missions such as CMBPol could provide valuable constraints with a precision close to that expected in current and near future laboratory experiments. Finally, we discuss the implications of this intersection between cosmology and fundamental physics.
Valkenburg, Wessel
2009-06-01
It has been argued that the Swiss-Cheese cosmology can mimic Dark Energy, when it comes to the observed luminosity distance-redshift relation. Besides the fact that this effect tends to disappear on average over random directions, we show in this work that based on the Rees-Sciama effect on the cosmic microwave background (CMB), the Swiss-Cheese model can be ruled out if all holes have a radius larger than about 35 Mpc. We also show that for smaller holes, the CMB is not observably affected, and that the small holes can still mimic Dark Energy, albeit in special directions, as opposed to previous conclusions in the literature. However, in this limit, the probability of looking in a special direction where the luminosity of supernovae is sufficiently supressed becomes very small, at least in the case of a lattice of spherical holes considered in this paper.
CMB Polarization Detector Operating Parameter Optimization
NASA Astrophysics Data System (ADS)
Randle, Kirsten; Chuss, David; Rostem, Karwan; Wollack, Ed
2015-04-01
Examining the polarization of the Cosmic Microwave Background (CMB) provides the only known way to probe the physics of inflation in the early universe. Gravitational waves produced during inflation are posited to produce a telltale pattern of polarization on the CMB and if measured would provide both tangible evidence for inflation along with a measurement of inflation's energy scale. Leading the effort to detect and measure this phenomenon, Goddard Space Flight Center has been developing high-efficiency detectors. In order to optimize signal-to-noise ratios, sources like the atmosphere and the instrumentation must be considered. In this work we examine operating parameters of these detectors such as optical power loading and photon noise. SPS Summer Internship at NASA Goddard Spaceflight Center.
Reconciling the local void with the CMB
Nadathur, Seshadri; Sarkar, Subir
2011-03-15
In the standard cosmological model, the dimming of distant Type Ia supernovae is explained by invoking the existence of repulsive ''dark energy'' which is causing the Hubble expansion to accelerate. However, this may be an artifact of interpreting the data in an (oversimplified) homogeneous model universe. In the simplest inhomogeneous model which fits the SNe Ia Hubble diagram without dark energy, we are located close to the center of a void modeled by a Lemaitre-Tolman-Bondi metric. It has been claimed that such models cannot fit the cosmic microwave background (CMB) and other cosmological data. This is, however, based on the assumption of a scale-free spectrum for the primordial density perturbation. An alternative physically motivated form for the spectrum enables a good fit to both SNe Ia (Constitution/Union2) and CMB (WMAP 7-yr) data, and to the locally measured Hubble parameter. Constraints from baryon acoustic oscillations and primordial nucleosynthesis are also satisfied.
Pre-inflationary relics in the CMB?
NASA Astrophysics Data System (ADS)
Gruppuso, A.; Kitazawa, N.; Mandolesi, N.; Natoli, P.; Sagnotti, A.
2016-03-01
String Theory and Supergravity allow, in principle, to follow the transition of the inflaton from pre-inflationary fast roll to slow roll. This introduces an infrared depression in the primordial power spectrum that might have left an imprint in the CMB anisotropy, if it occurred at accessible wavelengths. We model the effect extending Λ CDM with a scale Δ related to the infrared depression and explore the constraints allowed by PLANCK 2015 data, employing also more conservative, wider Galactic masks in the low resolution CMB likelihood. In an extended mask with fsky = 39 %, we thus find Δ =(0.351 ± 0.114) × 10-3Mpc-1, at 99.4% confidence level, to be compared with a nearby value at 88.5% with the standard fsky = 94 % mask. With about 64 e-folds of inflation, these values for Δ would translate into primordial energy scales O(1014) GeV.
New constraints on inflation from the CMB
NASA Astrophysics Data System (ADS)
Kinney, William H.; Melchiorri, Alessandro; Riotto, Antonio
2001-10-01
The recent data from the Boomerang and MAXIMA-1 balloon flights have marked the beginning of the precision era of Cosmic Microwave Background anisotropy (CMB) measurements. We discuss the observational constraints from the current CMB anisotropy measurements on the simplest inflation models, characterized by a single scalar field φ, in the parameter space consisting of scalar spectral index nS and tensor/scalar ratio r. The data are consistent with the simplest assumption of a scale invariant power spectrum, but the specific error contours in the r-n plane depend on prior assumptions, particularly the baryon density of the universe and the reionization history. Models with significant ``red'' tilt (n<1) and appreciable tensor fluctuations are disfavored in all cases. .
The Next Generation Ground-based CMB experiment, CMB-S4
NASA Astrophysics Data System (ADS)
Carlstrom, John E.; CMB-S4 Collaboration
2016-06-01
This talk will review the goals and status of the community planning for the next generation ground-based CMB experiment, CMB-S4. Following the detection of CMB polarization in 2002, the current generation of ground-based experiments each fielding of order 1000 superconducting detectors (Stage II experiments) have led to the first detection of the much fainter lensing B-mode polarization signal and the most stringent constraints on the level of the B-mode signal from inflationary gravitational waves. We can expect significant advances in the next few years as the ongoing ground-based experiments deploy of order 10,000 detectors (Stage III). The CMB community is now planning an ambitious next generation (Stage IV) ground-based program with order of 500,000 detectors, CMB-S4, to achieve critical threshold crossing goals of 1) detecting or ruling out large field inflationary models, 2) determining the effective number and masses of the neutrinos, and 3) providing precision constraints on dark energy through its impact on structure formation.
Suppressing CMB low multipoles with ISW effect
Das, Santanu; Souradeep, Tarun E-mail: tarun@iucaa.ernet.in
2014-02-01
Recent results of Planck data reveal that the power [1,2] in the low multipoles of the CMB angular power spectrum, approximately up to l = 30, is significantly lower than the theoretically predicted in the best fit ΛCDM model. There are different known physical effects that can affect the power at low multipoles, such as features in the primordial power spectrum (PPS) in some models of inflation and ISW effect. In this paper we investigate the possibility of invoking the Integrated Sachs-Wolfe (ISW) effect to explain the power deficit at low multipoles. The ISW effect that originates from the late time expansion history of the universe is rich in possibilities given the limited understanding of the origin of dark energy (DE). It is a common understanding that the ISW effect adds to the power at the low multipoles of the CMB angular power spectrum. In this paper we carry out an analytic study to show that there are some expansion histories in which the ISW effect, instead of adding power, provides negative contribution to the power at low multipoles. Guided by the analytic study, we present examples of the features required in the late time expansion history of the universe that could explain the power deficiency through the ISW effect. We also show that an ISW origin of power deficiency is consistent, at present, with other cosmological observations that probe the expansion history such as distance modulus, matter power spectrum and the evolution of cluster number count. We also show that the ISW effect may be distinguished from power deficit originating from features in the PPS using the measurements of the CMB polarization spectrum at low multipoles expected from Planck. We conclude that the power at low multipoles of the CMB anisotropy could well be closely linked to Dark Energy puzzle in cosmology and this observation could be actually pointing to richer phenomenology of DE beyond the cosmological constant Λ.
Transfer matrices for magnetized CMB anisotropies
Giovannini, Massimo
2006-05-15
Large-scale magnetic fields can affect scalar cosmological perturbations whose evolution is described in the conformally Newtonian gauge and within the tight coupling approximation. The magnetized curvature perturbations present after matter-radiation equality (and prior to decoupling) are computed in terms of an appropriate transfer matrix allowing a general estimate of the Sachs-Wolfe plateau. From the observation that CMB initial conditions should be (predominantly) adiabatic, the contribution of the magnetic field intensity can be constrained.
Extreme data compression for the CMB
Zablocki, Alan; Dodelson, Scott
2016-04-28
We apply the Karhunen-Loéve methods to cosmic microwave background (CMB) data sets, and show that we can recover the input cosmology and obtain the marginalized likelihoods in Λ cold dark matter cosmologies in under a minute, much faster than Markov chain Monte Carlo methods. This is achieved by forming a linear combination of the power spectra at each multipole l, and solving a system of simultaneous equations such that the Fisher matrix is locally unchanged. Instead of carrying out a full likelihood evaluation over the whole parameter space, we need evaluate the likelihood only for the parameter of interest, with themore » data compression effectively marginalizing over all other parameters. The weighting vectors contain insight about the physical effects of the parameters on the CMB anisotropy power spectrum Cl. The shape and amplitude of these vectors give an intuitive feel for the physics of the CMB, the sensitivity of the observed spectrum to cosmological parameters, and the relative sensitivity of different experiments to cosmological parameters. We test this method on exact theory Cl as well as on a Wilkinson Microwave Anisotropy Probe (WMAP)-like CMB data set generated from a random realization of a fiducial cosmology, comparing the compression results to those from a full likelihood analysis using CosmoMC. Furthermore, after showing that the method works, we apply it to the temperature power spectrum from the WMAP seven-year data release, and discuss the successes and limitations of our method as applied to a real data set.« less
Pietrobon, Davide; Amblard, Alexandre; Cooray, Asantha; Balbi, Amedeo; Cabella, Paolo; Marinucci, Domenico
2008-11-15
We apply spherical needlets to the Wilkinson Microwave Anisotropy Probe 5-year cosmic microwave background (CMB) data set, to search for imprints of nonisotropic features in the CMB sky. We use the needlets' localization properties to resolve peculiar features in the CMB sky and to study how these features contribute to the anisotropy power spectrum of the CMB. In addition to the now well-known 'cold spot' of the CMB map in the southern hemisphere, we also find two hot spots at greater than 99% confidence level, again in the southern hemisphere and closer to the Galactic plane. While the cold spot contributes to the anisotropy power spectrum in the multipoles between l=6 to l=33, the hot spots are found to be dominating the anisotropy power in the range between l=6 and l=18. Masking both the cold and the two hot spots results in a reduction by about 15% in the amplitude of the angular power spectrum of CMB around l=10. The resulting changes to the cosmological parameters when the power spectrum is estimated masking these features (in addition to the WMAP team's KQ85 mask) are within the 1{sigma} errors published with the WMAP mask only. We also study the asymmetry between the angular power spectra evaluated on the northern and southern hemispheres. When the features detected by needlets are masked, we find that the difference in the power, measured in terms of the anisotropy variance between l=4 and l=18, is reduced by a factor 2. We make available a mask related to needlet features for more detailed studies on asymmetries in the CMB anisotropy sky.
Planck CMB Anomalies: Astrophysical and Cosmological Secondary Effects and the Curse of Masking
NASA Astrophysics Data System (ADS)
Rassat, Anais
2016-07-01
Large-scale anomalies have been reported in CMB data with both WMAP and Planck data. These could be due to foreground residuals and or systematic effects, though their confirmation with Planck data suggests they are not due to a problem in the WMAP or Planck pipelines. If these anomalies are in fact primordial, then understanding their origin is fundamental to either validate the standard model of cosmology or to explore new physics. We investigate three other possible issues: 1) the trade-off between minimising systematics due to foreground contamination (with a conservative mask) and minimising systematics due to masking, 2) astrophysical secondary effects (the kinetic Doppler quadrupole and kinetic Sunyaev-Zel'dovich effect), and 3) secondary cosmological signals (the integrated Sachs-Wolfe effect). We address the masking issue by considering new procedures that use both WMAP and Planck to produce higher quality full-sky maps using the sparsity methodology (LGMCA maps). We show the impact of masking is dominant over that of residual foregrounds, and the LGMCA full-sky maps can be used without further processing to study anomalies. We consider four official Planck PR1 and two LGMCA CMB maps. Analysis of the observed CMB maps shows that only the low quadrupole and quadrupole-octopole alignment seem significant, but that the planar octopole, Axis of Evil, mirror parity and cold spot are not significant in nearly all maps considered. After subtraction of astrophysical and cosmological secondary effects, only the low quadrupole may still be considered anomalous, meaning the significance of only one anomaly is affected by secondary effect subtraction out of six anomalies considered. In the spirit of reproducible research all reconstructed maps and codes are available online.
The theoretical agenda in CMB research.
NASA Astrophysics Data System (ADS)
Bond, J. R.
The terrain that theorists cover in this CMB golden age is described. The author ponders early universe physics in quest of the fluctuation generator. He extolls the virtues of inflation and defects. He transports fields, matter and radiation into the linear (primary anisotropies) and nonlinear (secondary anisotropies) regimes. The author validates the linear codes to deliver accurate predictions for experimentalists to shoot at. He struggles at the computing edge to push the nonlinear simulations from only illustrative to fully predictive. He is now phenomenologists, optimizing statistical techniques for extrating truths and their errors from current and future experiments. He begins to clean foregrounds. He joins CMB experimental teams. He combines the CMB with large scale structure, galaxy and other cosmological observations in search of current concordance. The brave use all topical data. Others carefully craft their prior probabilities to downweight data sets. The author is always unbiased. He declares theories sick, dead, ugly. Sometimes he cures them, resurrect them, rarely beautify them. The goal is to understand how all cosmic structure we see arose and what the Universe is made of, and to use this to discover the laws of ultrahigh energy physics.
Phases of new physics in the CMB
NASA Astrophysics Data System (ADS)
Baumann, Daniel; Green, Daniel; Meyers, Joel; Wallisch, Benjamin
2016-01-01
Fluctuations in the cosmic neutrino background are known to produce a phase shift in the acoustic peaks of the cosmic microwave background. It is through the sensitivity to this effect that the recent CMB data has provided a robust detection of free-streaming neutrinos. In this paper, we revisit the phase shift of the CMB anisotropy spectrum as a probe of new physics. The phase shift is particularly interesting because its physical origin is strongly constrained by the analytic properties of the Green's function of the gravitational potential. For adiabatic fluctuations, a phase shift requires modes that propagate faster than the speed of fluctuations in the photon-baryon plasma. This possibility is realized by free-streaming relativistic particles, such as neutrinos or other forms of dark radiation. Alternatively, a phase shift can arise from isocurvature fluctuations. We present simple models to illustrate each of these effects. We then provide observational constraints from the Planck temperature and polarization data on additional forms of radiation. We also forecast the capabilities of future CMB Stage IV experiments. Whenever possible, we give analytic interpretations of our results.
What is the distance to the CMB?
Clarkson, Chris; Umeh, Obinna; Maartens, Roy; Durrer, Ruth E-mail: umeobinna@gmail.com E-mail: Ruth.Durrer@unige.ch
2014-11-01
The success of precision cosmology depends not only on accurate observations, but also on the theoretical model --- which must be understood to at least the same level of precision. Subtle relativistic effects can lead to biased measurements if they are neglected. One such effect gives a systematic shift in the distance-redshift relation away from its background value, due to the non-linear relativistic conservation of total photon flux. We also show directly how this shift follows from a fully relativistic analysis of the geodesic deviation equation. We derive the expectation value of the shift using second-order perturbations about a concordance background, and show that the distance to last scattering is increased by 1%. We argue that neglecting this shift could lead to a significant bias in the background cosmological parameters, because it alters the meaning of the background model. A naive adjustment of CMB parameter estimation if this shift is really a correction to the background would raise the H{sub 0} value inferred from the CMB by 5%, potentially removing the tension with local measurements of H{sub 0}. Other CMB parameters which depend on the distance would also be shifted by ∼ 1σ when combined with local H{sub 0} data. While our estimations rely on a simplistic analysis, they nevertheless illustrate that accurately defining the background model in terms of the expectation values of observables is critical when we aim to determine the model parameters at the sub-percent level.
Probing neutrino masses with CMB lensing extraction
NASA Astrophysics Data System (ADS)
Lesgourgues, Julien; Perotto, Laurence; Pastor, Sergio; Piat, Michel
2006-02-01
We evaluate the ability of future cosmic microwave background (CMB) experiments to measure the power spectrum of large scale structure using quadratic estimators of the weak lensing deflection field. We calculate the sensitivity of upcoming CMB experiments such as BICEP, QUaD, BRAIN, ClOVER and Planck to the nonzero total neutrino mass Mν indicated by current neutrino oscillation data. We find that these experiments greatly benefit from lensing extraction techniques, improving their one-sigma sensitivity to Mν by a factor of order four. The combination of data from Planck and the SAMPAN mini-satellite project would lead to σ(Mν)˜0.1 eV, while a value as small as σ(Mν)˜0.035 eV is within the reach of a space mission based on bolometers with a passively cooled 3 4 m aperture telescope, representative of the most ambitious projects currently under investigation. We show that our results are robust not only considering possible difficulties in subtracting astrophysical foregrounds from the primary CMB signal but also when the minimal cosmological model (Λ Mixed Dark Matter) is generalized in order to include a possible scalar tilt running, a constant equation-of-state parameter for the dark energy and/or extra relativistic degrees of freedom.
NASA Astrophysics Data System (ADS)
de Bernardis, P.
DomeC is likely to be the best site in the world for mm and sub-mm observations. In this paper we focus on what can be done from DomeC to investigate the detailed properties of the Cosmic Microwave Background (CMB). Two experiment typologies are particularly promising: precision measurements of the polarization of the CMB, to confirm the presence of an inflation phase in the very early universe, and high resolution measurements of the Sunyaev-Zeldovich effect (SZE) in clusters of galaxies, which can be used to investigate dark energy and dark matter in the Universe. Several important teams are currently carrying out experiments of the first kind; DomeC is the location of the BRAIN experiment, which uses bolometric interferometry as the tool to produce sensitive measurements with low systematic effects, and certainly orthogonal to the systematic effects of all other instruments currently developed to this purpose. DomeC will be an ideal location for a large dish telescope for mm and sub-mm measurements. In addition to cutting-edge sub-mm science, a telescope complementing SPT (in size and/or in frequency) will be ideal for special CMB observation, like the detection of non-Gaussian features, the measurement of relativistic effects in SZE, the measurement of the SZE resulting from the decay products of super-symmetric dark matter in selected clusters.
CMB as a Probe of New Physics and Old Times
NASA Astrophysics Data System (ADS)
Gluscevic, Vera
Cosmic birefringence (CB)---a rotation of photon-polarization plane in vacuum---is a generic signature of new scalar fields that could provide dark energy. Previously, WMAP observations excluded a uniform CB-rotation angle larger than a degree. In this thesis, we develop a minimum-variance--estimator formalism for reconstructing direction-dependent rotation from full-sky CMB maps, and forecast more than an order-of-magnitude improvement in sensitivity with incoming Planck data and future satellite missions. Next, we perform the first analysis of WMAP-7 data to look for rotation-angle anisotropies and report null detection of the rotation-angle power-spectrum multipoles below L=512, constraining quadrupole amplitude of a scale-invariant power to less than one degree. We further explore the use of a cross-correlation between CMB temperature and the rotation for detecting the CB signal, for different quintessence models. We find that it may improve sensitivity in case of marginal detection, and provide an empirical handle for distinguishing details of new physics indicated by CB. We then consider other parity-violating physics beyond standard models---in particular, a chiral inflationary-gravitational-wave background. We show that WMAP has no constraining power, while a cosmic-variance--limited experiment would be capable of detecting only a large parity violation. In case of a strong detection of EB/TB correlations, CB can be readily distinguished from chiral gravity waves. We next adopt our CB analysis to investigate patchy screening of the CMB, driven by inhomogeneities during the Epoch of Reionization (EoR). We constrain a toy model of reionization with WMAP-7 data, and show that data from Planck should start approaching interesting portions of the EoR parameter space and can be used to exclude reionization tomographies with large ionized bubbles. In light of the upcoming data from low-frequency radio observations of the redshifted 21-cm line from the EoR, we
Unavoidable CMB Spectral Features and Blackbody Photosphere of Our Universe
NASA Astrophysics Data System (ADS)
Sunyaev, Rashid A.; Khatri, Rishi
2015-01-01
Spectral features in the CMB energy spectrum contain a wealth of information about the physical processes in the early Universe, z ≲ 2 × 106. The CMB spectral distortions are complementary to all other probes of cosmology. In fact, most of the information contained in the CMB spectrum is inaccessible by any other means. This review outlines the main physics behind the spectral features in the CMB throughout the history of the Universe, concentrating on the distortions which are inevitable and must be present at a level observable by the next generation of proposed CMB experiments. The spectral distortions considered here include spectral features from cosmological recombination, resonant scattering of CMB by metals during reionization which allows us to measure their abundances, y-type distortions during and after reionization and μ-type and i-type (intermediate between μ and y) distortions created at redshifts z ≳ 1.5 × 104.
Planck 2013 results. XV. CMB power spectra and likelihood
NASA Astrophysics Data System (ADS)
Planck Collaboration; Ade, P. A. R.; Aghanim, N.; 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.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Gaier, T. C.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Hanson, D.; 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.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jewell, J.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kiiveri, K.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Laureijs, R. J.; Lawrence, C. R.; Le Jeune, M.; Leach, S.; Leahy, J. P.; Leonardi, R.; León-Tavares, J.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; Lindholm, V.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Marinucci, D.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Menegoni, E.; Mennella, A.; Migliaccio, M.; Millea, M.; Mitra, S.; Miville-Deschênes, M.-A.; Molinari, D.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; O'Dwyer, I. J.; Orieux, F.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Paykari, P.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Rahlin, A.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ringeval, C.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Sanselme, L.; Santos, D.; Savini, G.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; 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.; Türler, M.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Varis, J.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; White, M.; White, S. D. M.; Yvon, D.; Zacchei, A.; Zonca, A.
2014-11-01
This paper presents the Planck 2013 likelihood, a complete statistical description of the two-point correlation function of the CMB temperature fluctuations that accounts for all known relevant uncertainties, both instrumental and astrophysical in nature. We use this likelihood to derive our best estimate of the CMB angular power spectrum from Planck over three decades in multipole moment, ℓ, covering 2 ≤ ℓ ≤ 2500. The main source of uncertainty at ℓ ≲ 1500 is cosmic variance. Uncertainties in small-scale foreground modelling and instrumental noise dominate the error budget at higher ℓs. For ℓ < 50, our likelihood exploits all Planck frequency channels from 30 to 353 GHz, separating the cosmological CMB signal from diffuse Galactic foregrounds through a physically motivated Bayesian component separation technique. At ℓ ≥ 50, we employ a correlated Gaussian likelihood approximation based on a fine-grained set of angular cross-spectra derived from multiple detector combinations between the 100, 143, and 217 GHz frequency channels, marginalising over power spectrum foreground templates. We validate our likelihood through an extensive suite of consistency tests, and assess the impact of residual foreground and instrumental uncertainties on the final cosmological parameters. We find good internal agreement among the high-ℓ cross-spectra with residuals below a few μK2 at ℓ ≲ 1000, in agreement with estimated calibration uncertainties. We compare our results with foreground-cleaned CMB maps derived from all Planck frequencies, as well as with cross-spectra derived from the 70 GHz Planck map, and find broad agreement in terms of spectrum residuals and cosmological parameters. We further show that the best-fit ΛCDM cosmology is in excellent agreement with preliminary PlanckEE and TE polarisation spectra. We find that the standard ΛCDM cosmology is well constrained by Planck from the measurements at ℓ ≲ 1500. One specific example is the
Kuroyanagi, Sachiko; Gordon, Christopher; Silk, Joseph; Sugiyama, Naoshi
2010-04-15
We study how direct detection of the inflationary gravitational wave background constrains inflationary parameters and complements CMB polarization measurements. The error ellipsoids calculated using the Fisher information matrix approach with Planck and the direct detection experiment, Big Bang Observer (BBO), show different directions of parameter degeneracy, and the degeneracy is broken when they are combined. For a slow-roll parametrization, we show that BBO could significantly improve the constraints on the tensor-to-scalar ratio compared with Planck alone. We also look at a quadratic and a natural inflation model. In both cases, if the temperature of reheating is also treated as a free parameter, then the addition of BBO can significantly improve the error bars. In the case of natural inflation, we find that the addition of BBO could even partially improve the error bars of a cosmic variance-limited CMB experiment.
NASA Astrophysics Data System (ADS)
Krauss, Lawrence M.
1995-01-01
The Table of Contents for the book is as follows: * Preface * I. The Experimental Situation Two Years After COBE: Anisotropies, and the CMB Power Spectrum * COBE DMR Data, Signal and Noise: Color Plates * CMB Two Years After the COBE Discovery of Anisotropies * Comparison of Spectral Index Determinations * Two-Point Correlations in the COBE-DMR Two-Year Anisotropy Maps * A Preliminary Analysis of UCSB's South Pole 1993-94 Results * CMB Anisotropy Measurements During the Fourth Flight of MAX * Observations of the Anisotropy in the Cosmic Microwave Background by the Firs, SK93, and MSAM-I Experiments * The Python Microwave Background Anisotropy Experiment * II. Theoretical Implications and Cosmology: The Early Universe, Large Scale Structure and Dark Matter * Testing Inflationary Cosmology and Measuring Cosmological Parameters Using the Cosmic Microwave Background * Inflation Confronts the CMB: An Analysis Including the Effects of Foreground * Testing Inflation with MSAM, MAX Tenerife and COBE * CMBR Anisotropy Due to Gravitational Radiation in Inflationary Cosmologies * Black Holes From Blue Spectra * Cosmic Microwave Background Anisotropies and the Geometry of the Universe * Ω and Cosmic Microwave Background Anisotropies * CDM Cosmogony in an Open Universe * Cosmic Microwave Background Radiation Anisotropy Induced by Cosmic Strings * Temperature Anisotropies in a Universe with Global Defects * The Nature Versus Nurture of Anisotropies * The Existence of Baryons at z = 1000 * Polarization-Temperature Correlations in the Microwave Background * III. Related Issues: BBN Limits on ΩB, and Comparing Theoretical Predictions and Observations * Big Bang Nucleosynthesis and ΩB: A Guide for CMB Interpreters * Quoting Experimental Information
NASA Astrophysics Data System (ADS)
Mangilli, A.; Wandelt, B.; Elsner, F.; Liguori, M.
2013-07-01
We present the tools to optimally extract the lensing-integrated Sachs Wolfe (L-ISW) bispectrum signal from future cosmic microwave background (CMB) data. We implemented two different methods to simulate the non-Gaussian CMB maps with the L-ISW signal: a non-perturbative method based on the FLINTS lensing code and the separable mode-expansion method. We implemented the Komatsu, Spergel, and Wandelt (KSW) optimal estimator analysis for the L-ISW bispectrum and tested it on the non-Gaussian simulations for realistic CMB experimental settings with an inhomogeneous sky coverage. We show that the estimator approaches the Cramer-Rao bound and that Wiener filtering the L-ISW simulations slightly improves the estimate of fNLL-ISW by ≤ 10%. For a realistic CMB experimental setting that accounts for anisotropic noise and masked sky, we show that the linear term of the estimator is highly correlated to the cubic term and it is necessary to recover the signal and the optimal error bars. We also show that the L-ISW bispectrum, if not correctly accounted for, yields an underestimation of the fNLlocal error bars of ≃ 4%. A joint analysis of the non-Gaussian shapes and/or L-ISW template subtraction is needed to recover unbiased results of the primordial non-Gaussian signal from ongoing and future CMB experiments.
ERIC Educational Resources Information Center
Kinney, Douglas M.; McIntosh, Willard L.
1979-01-01
The area of geological mapping in the United States in 1978 increased greatly over that reported in 1977; state geological maps were added for California, Idaho, Nevada, and Alaska last year. (Author/BB)
What do we learn from the CMB observations?
Rubakov, V. A.; Vlasov, A. D.
2012-09-15
We give an account, at nonexpert and quantitative level, of physics behind the CMB temperature anisotropy and polarization and their peculiar features. We discuss, in particular, how cosmological parameters are determined from the CMB measurements and their combinations with other observations. We emphasize that CMB is the major source of information on the primordial density perturbations and, possibly, gravitational waves, and discuss the implication for our understanding of the extremely early Universe.
Lowe, Iago; Jankuloski, Ljupcho; Chao, Shiaoman; Chen, Xianming; See, Deven; Dubcovsky, Jorge
2016-01-01
A mapping population of 186 recombinant inbred lines developed from a cross between UC1110, an adapted California spring wheat, and PI610750, a synthetic derivative from CIMMYT’s wide-cross program, was evaluated for its response to current California races of stripe rust (Puccinia striiformis f. sp. tritici) in replicated field trials over four seasons (2007–2010) in the northern Sacramento Valley. A genetic map was constructed consisting of 1,493 polymorphic probes (SSRs, DArTs, and ESTs) mapped to 559 unique loci; and QTL analysis revealed the presence of four stripe rust resistance QTL segregating in this population, two from UC1110 (on chromosomes 3BS and 2BS) and two from PI610750 (5AL and 2AS). The two QTL of largest effects (on 3BS and 5AL) were validated in independent populations and their intervals narrowed to 2.5 cM and 4.7 cM, respectively. The 3BS QTL was shown, by allelism test and genotype, to carry a gene different from the Yr30/Sr2 complex. Mapped position also suggests that the 3BS QTL is associated with a gene different from either Yrns-B1 or YrRub, two stripe rust resistance genes mapped to this region in other studies. The 5AL QTL carries a previously unreported partial stripe rust resistance gene, designated here as Yr48. This paper discusses the individual contributions to resistance of these four QTL, their epistatic interactions, and their potential in durable resistance breeding strategies based on combinations of partial resistance genes. PMID:21455722
ACTPol: Overview of a next-generation polarization-sensitive CMB observatory in Chile
NASA Astrophysics Data System (ADS)
McMahon, Jeff
2013-04-01
ACTPol is a new polarization sensitive receiver on the six-meter Atacama Cosmology Telescope which is surveying the Chilean sky and will produce deep maps of the polarization, temperature, and lensing of the Cosmic Microwave Background (CMB) in two frequency bands centered near 90 and 150 GHz. These measurements will improve constraints on inflation, neutrino properties, curvature, the primordial helium abundance, and dark energy. Cross correlating the ACTPol maps with optical surveys accessible from Chile will significantly amplify these constraints. In this talk I provide an overview of the project inclduing discussions of the instrument, science goals, and status of ACTPol.
Technology Transfer Automated Retrieval System (TEKTRAN)
Phytophthora root and stem rot is one of the most yield-limiting diseases of soybean [Glycine max (L.) Merr], caused by the oomycete Phytophthora sojae. Partial resistance is controlled by several genes and, compared to single gene (Rps gene) resistance to P. sojae, places less selection pressure on...
Technology Transfer Automated Retrieval System (TEKTRAN)
White mold, caused by the fungus Sclerotinia sclerotiorum (Lib.) de Bary, is a devastating disease in common bean (Phaseolus vulgaris L.). Resistance to this pathogen can be due to physiological or avoidance mechanisms. We sought to characterize the partial physiological resistance exhibited by ‘Xa...
CMB statistical anisotropy from noncommutative gravitational waves
Shiraishi, Maresuke; Ricciardone, Angelo; Mota, David F.; Arroja, Frederico E-mail: d.f.mota@astro.uio.no E-mail: arroja@pd.infn.it
2014-07-01
Primordial statistical anisotropy is a key indicator to investigate early Universe models and has been probed by the cosmic microwave background (CMB) anisotropies. In this paper, we examine tensor-mode CMB fluctuations generated from anisotropic gravitational waves, parametrised by P{sub h}(k) = P{sub h}{sup (0)}(k) [ 1 + ∑{sub LM} f{sub L}(k) g{sub LM} Y{sub LM} ( k-circumflex )], where P{sub h}{sup (0)}(k) is the usual scale-invariant power spectrum. Such anisotropic tensor fluctuations may arise from an inflationary model with noncommutativity of fields. It is verified that in this model, an isotropic component and a quadrupole asymmetry with f{sub 0}(k) = f{sub 2}(k) ∝ k{sup -2} are created and hence highly red-tilted off-diagonal components arise in the CMB power spectra, namely ℓ{sub 2} = ℓ{sub 1} ± 2 in TT, TE, EE and BB, and ℓ{sub 2} = ℓ{sub 1} ± 1 in TB and EB. We find that B-mode polarisation is more sensitive to such signals than temperature and E-mode polarisation due to the smallness of large-scale cosmic variance and we can potentially measure g{sub 00} = 30 and g{sub 2M} = 58 at 68% CL in a cosmic-variance-limited experiment. Such a level of signal may be measured in a PRISM like experiment, while the instrumental noise contaminates it in the Planck experiment. These results imply that it is impossible to measure the noncommutative parameter if it is small enough for the perturbative treatment to be valid. Our formalism and methodology for dealing with the CMB tensor statistical anisotropy are general and straightforwardly applicable to other early Universe models.
When can preheating affect the CMB?
NASA Astrophysics Data System (ADS)
Tsujikawa, Shinji; Bassett, Bruce A.
2002-05-01
We discuss the principles governing the selection of inflationary models for which preheating can affect the CMB. This is a (fairly small) subset of those models which have nonnegligible entropy/isocurvature perturbations on large scales during inflation. We study new models which belong to this class-two-field inflation with negative nonminimal coupling and hybrid/double/supernatural inflation models where the tachyonic growth of entropy perturbations can lead to the variation of the curvature perturbation, /R, on super-Hubble scales. Finally, we present evidence against recent claims for the variation of /R in the absence of substantial super-Hubble entropy perturbations.
Technology Transfer Automated Retrieval System (TEKTRAN)
Phytophthora root rot (PRR) caused by Phytophthora sojae Kaufm. & Gerd. and flooding can limit growth and productivity, of soybean [Glycine max (L.) Merr.], especially on poorly drained soils. The primary objective of this research project was to map quantitative trait loci (QTL) associated with f...
The U.S. Environmental Protection Agency's Office of Research and Development have mapped and interpreted landscape-scale (i.e., broad scale) ecological metrics among watersheds in the upper White River watershed, producing the first geospatial models of water quality vulnerabili...
The U.S. Environmental Protection Agency¿s Office of Research and Development have mapped and interpreted landscape-scale (i.e., broad scale) ecological metrics among watersheds in the upper White River watershed, producing the first geospatial models of water quality vulnerabili...
CMB spectral distortions and energy release in the early universe
NASA Astrophysics Data System (ADS)
Tashiro, Hiroyuki
2014-06-01
Measuring the spectral deviation of the cosmic microwave background (CMB) from the blackbody spectrum has become a focus of attention as a probe of the thermal history of the Universe. It has been more than 20 years since COBE/FIRAS's measurement, which showed excellent agreement between the CMB spectrum and a perfect blackbody spectrum. Significant developments in the technology since then have allowed us to improve the sensitivity of the absolute spectrum measurement by a factor of {˜ }10^4. Therefore, the physics related to the generation of CMB spectral distortions should now be investigated in greater detail. To probe the physics in the early universe and to open an observational window for new physics, various energy release mechanisms both in and beyond standard cosmology need to be studied. In this paper, we provide a review of the physics of CMB distortions and the energy release that creates CMB distortions in the early universe.
Detecting the cosmological neutrino background in the CMB
NASA Astrophysics Data System (ADS)
Sellentin, Elena; Durrer, Ruth
2015-09-01
Three relativistic particles in addition to the photon are detected in the cosmic microwave background (CMB). In the standard model of cosmology, these are interpreted as the three neutrino species. However, at the time of CMB decoupling, neutrinos are not only relativistic but they are also free-streaming. Here we investigate whether the CMB is sensitive to this defining feature of neutrinos, or whether the CMB data allow us to replace neutrinos with a relativistic fluid. We show that free-streaming particles are preferred over a relativistic perfect fluid with Δ χ2≃21 . We then study the possibility to replace the neutrinos by a viscous fluid and find that also a relativistic viscous fluid with either the standard values ceff2=cvis2=1 /3 or best-fit values for ceff2 and cvis2 has Δ χ2≃20 and thus cannot provide a good fit to present CMB data either.
Testing distance duality with CMB anisotropies
NASA Astrophysics Data System (ADS)
Räsänen, Syksy; Väliviita, Jussi; Kosonen, Ville
2016-04-01
We constrain deviations of the form T propto (1+z)1+epsilon from the standard redshift-temperature relation, corresponding to modifying distance duality as DL = (1+z)2(1+epsilon) DA. We consider a consistent model, in which both the background and perturbation equations are changed. For this purpose, we introduce a species of dark radiation particles to which photon energy density is transferred, and assume epsilon >= 0. The Planck 2015 release high multipole temperature plus low multipole data give the limit epsilon < 4.5 × 10-3 at 95% C.L. The main obstacle to improving this CMB-only result is strong degeneracy between epsilon and the physical matter densities ωb and ωc. A constraint on deuterium abundance improves the limit to epsilon < 1.8 × 10-3. Adding the Planck high-multipole CMB polarisation and BAO data leads to a small improvement; with this maximal dataset we obtain epsilon < 1.3 × 10-3. This dataset constrains the present dark radiation energy density to at most 12% of the total photon plus dark radiation density. Finally, we discuss the degeneracy between dark radiation and the effective number of relativistic species Neff, and consider the impact of dark radiation perturbations and allowing epsilon < 0 on the results.
Magnetized CMB observables: A dedicated numerical approach
Giovannini, Massimo; Kunze, Kerstin E.
2008-03-15
Large-scale magnetic fields affect the scalar modes of the geometry whose ultimate effect is to determine the anisotropies of the cosmic microwave background (CMB in what follows). For the first time, a consistent numerical approach to the magnetized CMB anisotropies is pursued with the aim of assessing the angular power spectra of temperature and polarization when the scalar modes of the geometry and a stochastic background of inhomogeneous magnetic fields are simultaneously present in the plasma. The effects related to the magnetized nature of the plasma are taken into account both at the level of the dynamical equations and at the level of the initial conditions of the Einstein-Boltzmann hierarchy. The temperature and polarization observables are exploited to infer the peculiar signatures of a pre-equality magnetic field. Using the extrapolated best fit to the three-year WMAP (Wilkinson Microwave Anisotropy Probe) data the increase and distortions of the first seven peaks in the temperature autocorrelations are monitored for different values of the regularized magnetic field intensity and for the physical range of spectral indices. Similar analyses are also conducted for the first few anticorrelation (and corrrelation) peaks of the temperature-polarization power spectra. Possible interesting degeneracies and stimulating perspectives are pointed out and explored.
Smoothed Quantum Fluctuations and CMB Observations
NASA Astrophysics Data System (ADS)
Mielczarek, Jakub; Kamionka, Michał
2012-10-01
In this paper, we investigate power spectrum of a smoothed scalar field. The smoothing leads to regularization of the UV divergences and can be related with the internal structure of the considered field or the space itself. We perform Gaussian smoothing to the quantum fluctuations generated during the phase of cosmic inflation. We study whether this effect can be probed observationally and conclude that the modifications of the power spectrum due to the smoothing on the Planck scale are negligible and far beyond the observational abilities. Subsequently, we investigate whether smoothing in any other form can be probed observationally. We introduce phenomenological smoothing factor e-k2σ2 to the inflationary spectrum and investigate its effects on the spectrum of CMB anisotropies and polarization. We show that smoothing can lead to suppression of high multipoles in the spectrum of the CMB. Based on seven years observations of WMAP satellite we indicate that the present scale of high multipoles suppression is constrained by σ < 3.19 Mpc (95% CL). This corresponds to the constraint σ < 100 μm at the end of inflation. Despite this value is far above the Planck scale, other processes of smoothing can be possibly studied with this constraint, as decoherence or diffusion of primordial perturbations.
Punctuated inflation and the low CMB multipoles
Jain, Rajeev Kumar; Sriramkumar, L.; Chingangbam, Pravabati; Gong, Jinn-Ouk; Souradeep, Tarun E-mail: prava@kias.re.kr E-mail: sriram@hri.res.in
2009-01-15
We investigate inflationary scenarios driven by a class of potentials which are similar in form to those that arise in certain minimal supersymmetric extensions of the standard model. We find that these potentials allow a brief period of departure from inflation sandwiched between two stages of slow roll inflation. We show that such a background behavior leads to a step like feature in the scalar power spectrum. We set the scales such that the drop in the power spectrum occurs at a length scale that corresponds to the Hubble radius today - a feature that seems necessary to explain the lower power observed in the quadrupole moment of the Cosmic Microwave Background (CMB) anisotropies. We perform a Markov Chain Monte Carlo analysis to determine the values of the model parameters that provide the best fit to the recent WMAP 5-year data for the CMB angular power spectrum. We find that an inflationary spectrum with a suppression of power at large scales that we obtain leads to a much better fit (with just one extra parameter, {chi}{sub eff}{sup 2} improves by 6.62) of the observed data when compared to the best fit reference {Lambda}CDM model with a featureless, power law, primordial spectrum.
Testing distance duality with CMB anisotropies
NASA Astrophysics Data System (ADS)
Räsänen, Syksy; Väliviita, Jussi; Kosonen, Ville
2016-04-01
We constrain deviations of the form T propto (1+z)1+epsilon from the standard redshift-temperature relation, corresponding to modifying distance duality as DL = (1+z)2(1+epsilon) DA. We consider a consistent model, in which both the background and perturbation equations are changed. For this purpose, we introduce a species of dark radiation particles to which photon energy density is transferred, and assume epsilon >= 0. The Planck 2015 release high multipole temperature plus low multipole data give the limit epsilon < 4.5 × 10‑3 at 95% C.L. The main obstacle to improving this CMB-only result is strong degeneracy between epsilon and the physical matter densities ωb and ωc. A constraint on deuterium abundance improves the limit to epsilon < 1.8 × 10‑3. Adding the Planck high-multipole CMB polarisation and BAO data leads to a small improvement; with this maximal dataset we obtain epsilon < 1.3 × 10‑3. This dataset constrains the present dark radiation energy density to at most 12% of the total photon plus dark radiation density. Finally, we discuss the degeneracy between dark radiation and the effective number of relativistic species Neff, and consider the impact of dark radiation perturbations and allowing epsilon < 0 on the results.
Mapping matter jointly with CMB lensing and Large Scale Structure
NASA Astrophysics Data System (ADS)
Huffenberger, Kevin; Maldonado, Felipe; Rotti, Aditya
2015-04-01
In the near future, Stage III and Stage IV Cosmic Microwave Background experiments will measure to high precision the lensing distortions that trace matter fluctuations in the universe. On a similar timescale, WFIRST, EUCLID, DESI, LSST, and other surveys will provide galaxy redshift information, imaging, and cosmic shear data over large regions of the sky. Taking a holistic, Bayesian approach to combine datasets, we seek to understand keenly the statistical properties of joint estimates of the matter distribution and its correlations, including their non-Gaussian likelihoods.
Mapping matter jointly with CMB lensing and Large Scale Structure
NASA Astrophysics Data System (ADS)
Huffenberger, Kevin; Rotti, Aditya; Maldonado, Felipe
2016-01-01
In the near future, Stage III and Stage IV Cosmic Microwave Background experiments will measure to high precision the lensing distortions that trace matter fluctuations in the universe. On a similar timescale DES, HSC, WFIRST, EUCLID, DESI, LSST, and other surveys will provide galaxy redshift information, imaging, and cosmic shear data over large regions of the sky. Taking a holistic, Bayesian approach to combine datasets, we seek to understand the statistical properties of joint estimates of the matter distribution and its correlations, including their non-Gaussian likelihoods.
Constraining gravity at the largest scales through CMB lensing and galaxy velocities
NASA Astrophysics Data System (ADS)
Pullen, Anthony R.; Alam, Shadab; He, Siyu; Ho, Shirley
2016-08-01
We demonstrate a new method to constrain gravity on the largest cosmological scales by combining measurements of cosmic microwave background (CMB) lensing and the galaxy velocity field. EG is a statistic, constructed from a gravitational lensing tracer and a measure of velocities such as redshift-space distortions (RSD), that can discriminate between gravity models while being independent of clustering bias and σ8. While traditionally, the lensing field for EG has been probed through galaxy lensing, CMB lensing has been proposed as a more robust tracer of the lensing field for EG at higher redshifts while avoiding intrinsic alignments. We perform the largest-scale measurement of EG ever, up to 150 Mpc h-1, by cross-correlating the Planck CMB lensing map with the Sloan Digital Sky Survey III (SDSS-III) CMASS galaxy sample and combining this with our measurement of the CMASS auto-power spectrum and the RSD parameter β. We report EG(z = 0.57) = 0.243 ± 0.060 (stat) ± 0.013 (sys), a measurement in tension with the general relativity (GR) prediction at a level of 2.6σ. Note that our EG measurement deviates from GR only at scales greater than 80 Mpc h-1, scales which have not been probed by previous EG tests. Upcoming surveys, which will provide an order-of-magnitude reduction in statistical errors, can significantly constrain alternative gravity models when combined with better control of systematics.
NASA Astrophysics Data System (ADS)
Velpuri, N.; Senay, G. B.
2011-12-01
Information on the variability in surface water is critical to understand the impact of climate change and global water cycle. Surface water features such as lakes, or reservoirs can affect local weather and regional climate. Hence, there is a widespread demand for accurate and quantitative global observations of surface water variability. Satellite imagery provides a direct way to monitor variations in surface water. However, estimating accurate surface area from satellite imagery can be a problem due to clouds. Hence, the use of optical imagery for operational implementation has been a challenge for monitoring variations in surface water. In this research, a semi-empirical lake level (SELL) model is developed to derive lake/reservoir water levels from partially covered satellite imagery. SRTM elevation combined with bathymetry was used to derive the relationships between lake depth vs. surface area and shore line (L). Using these relationships, lake level/depth (D) was estimated from the surface area (A) and/or shore line (L) delineated from Landsat and MODIS data. The SELL model was applied on Lake Turkana, one of the rift valley lakes in East Africa. First, Lake Turkana water levels were delineated using cloud-free or partially clouded Landsat and MODIS imagery over 1993-2009 and 2002-2009 time periods respectively. Historic lake depths were derived using 1972-1992 Landsat imagery. Lake depths delineated using this approach were validated using TOPEX/Poseidon/Jason satellite altimetry data. It was found that lake depths derived using SELL model matched reasonably well with the satellite altimetry data. The approach presented in this research can be used to (a) simulate lake water level variations in data scarce regions (b) increase the frequency of observation in regions where cloud cover is a problem (c) operationally monitor lake water levels in ungauged basins (d) derive historic lake level information using satellite data.
Primordial gravitational waves measurements and anisotropies of CMB polarization rotation
NASA Astrophysics Data System (ADS)
Li, Si-Yu; Xia, Jun-Qing; Li, Mingzhe; Li, Hong; Zhang, Xinmin
2015-12-01
Searching for the signal of primordial gravitational waves in the B-modes (BB) power spectrum is one of the key scientific aims of the cosmic microwave background (CMB) polarization experiments. However, this could be easily contaminated by several foreground issues, such as the interstellar dust grains and the galactic cyclotron electrons. In this paper we study another mechanism, the cosmic birefringence, which can be introduced by a CPT-violating interaction between CMB photons and an external scalar field. Such kind of interaction could give rise to the rotation of the linear polarization state of CMB photons, and consequently induce the CMB BB power spectrum, which could mimic the signal of primordial gravitational waves at large scales. With the recently released polarization data of BICEP2 and the joint analysis data of BICEP2/Keck Array and Planck, we perform a global fitting analysis on constraining the tensor-to-scalar ratio r by considering the polarization rotation angle [ α (n ˆ)] which can be separated into a background isotropic part [ α bar ] and a small anisotropic part [ Δα (n ˆ)]. Since the data of BICEP2 and Keck Array experiments have already been corrected by using the "self-calibration" method, here we mainly focus on the effects from the anisotropies of CMB polarization rotation angle. We find that including Δα (n ˆ) in the analysis could slightly weaken the constraints on the tensor-to-scalar ratio r, when using current CMB polarization measurements. We also simulate the mock CMB data with the BICEP3-like sensitivity. Very interestingly, we find that if the effects of the anisotropic polarization rotation angle could not be taken into account properly in the analysis, the constraints on r will be dramatically biased. This implies that we need to break the degeneracy between the anisotropies of the CMB polarization rotation angle and the CMB primordial tensor perturbations, in order to measure the signal of primordial gravitational
CMB temperature trispectrum of cosmic strings
NASA Astrophysics Data System (ADS)
Hindmarsh, Mark; Ringeval, Christophe; Suyama, Teruaki
2010-03-01
We provide an analytical expression for the trispectrum of the cosmic microwave background (CMB) temperature anisotropies induced by cosmic strings. Our result is derived for the small angular scales under the assumption that the temperature anisotropy is induced by the Gott-Kaiser-Stebbins effect. The trispectrum is predicted to decay with a noninteger power-law exponent ℓ-ρ with 6<ρ<7, depending on the string microstructure, and thus on the string model. For Nambu-Goto strings, this exponent is related to the string mean square velocity and the loop distribution function. We then explore two classes of wave number configuration in Fourier space, the kite and trapezium quadrilaterals. The trispectrum can be of any sign and appears to be strongly enhanced for all squeezed quadrilaterals.
Reionization history and CMB parameter estimation
Dizgah, Azadeh Moradinezhad; Kinney, William H.; Gnedin, Nickolay Y. E-mail: gnedin@fnal.edu
2013-05-01
We study how uncertainty in the reionization history of the universe affects estimates of other cosmological parameters from the Cosmic Microwave Background. We analyze WMAP7 data and synthetic Planck-quality data generated using a realistic scenario for the reionization history of the universe obtained from high-resolution numerical simulation. We perform parameter estimation using a simple sudden reionization approximation, and using the Principal Component Analysis (PCA) technique proposed by Mortonson and Hu. We reach two main conclusions: (1) Adopting a simple sudden reionization model does not introduce measurable bias into values for other parameters, indicating that detailed modeling of reionization is not necessary for the purpose of parameter estimation from future CMB data sets such as Planck. (2) PCA analysis does not allow accurate reconstruction of the actual reionization history of the universe in a realistic case.
Observed parity-odd CMB temperature bispectrum
Shiraishi, Maresuke; Liguori, Michele; Fergusson, James R. E-mail: michele.liguori@pd.infn.it
2015-01-01
Parity-odd non-Gaussianities create a variety of temperature bispectra in the cosmic microwave background (CMB), defined in the domain: ℓ{sub 1} + ℓ{sub 2} + ℓ{sub 3} = odd. These models are yet unconstrained in the literature, that so far focused exclusively on the more common parity-even scenarios. In this work, we provide the first experimental constraints on parity-odd bispectrum signals in WMAP 9-year temperature data, using a separable modal parity-odd estimator. Comparing theoretical bispectrum templates to the observed bispectrum, we place constraints on the so-called nonlineality parameters of parity-odd tensor non-Gaussianities predicted by several Early Universe models. Our technique also generates a model-independent, smoothed reconstruction of the bispectrum of the data for parity-odd configurations.
CMB non-gaussianity from vector fields
Peloso, Marco
2014-01-01
The Planck satellite has recently measured the CMB temperature anisotropies with unprecedented accuracy, and it has provided strong bounds on primordial non-gaussianity. Such bounds constrain models of inflation, and mechanisms that produce the primordial perturbations. We discuss the non-gaussian signatures from the interactions of the inflation φ with spin-1 fields. We study the two different cases in which the inflaton is (i) a pseudo-scalar field with a (φ)/(fa) F·F interaction with a vector field, and (ii) a scalar field with a f (φ)F² interaction. In the first case we obtain the strong limit f{sub a} ≥ 10¹⁶GeV on the decay constant. In the second case, specific choices of the function f (φ) can lead to a non-gaussianity with a characteristic shape not encountered in standard models of scalar field inflation, and which has also been constrained by Planck.
CMB temperature trispectrum of cosmic strings
Hindmarsh, Mark; Ringeval, Christophe; Suyama, Teruaki
2010-03-15
We provide an analytical expression for the trispectrum of the cosmic microwave background (CMB) temperature anisotropies induced by cosmic strings. Our result is derived for the small angular scales under the assumption that the temperature anisotropy is induced by the Gott-Kaiser-Stebbins effect. The trispectrum is predicted to decay with a noninteger power-law exponent l{sup -{rho}}with 6<{rho}<7, depending on the string microstructure, and thus on the string model. For Nambu-Goto strings, this exponent is related to the string mean square velocity and the loop distribution function. We then explore two classes of wave number configuration in Fourier space, the kite and trapezium quadrilaterals. The trispectrum can be of any sign and appears to be strongly enhanced for all squeezed quadrilaterals.
The full squeezed CMB bispectrum from inflation
Lewis, Antony
2012-06-01
The small-scale CMB temperature we observe on the sky is modulated by perturbations that were super-horizon at recombination, giving differential focussing and lensing that generate a non-zero bispectrum even for single-field inflation where local physics is identical. Understanding this signal is important for primordial non-Gaussianity studies and also parameter constraints from the CMB lensing bispectrum signal. Because of cancellations individual effects can appear larger or smaller than they are in total, so a full analysis may be required to avoid biases. I relate angular scales on the sky to physical scales at recombination using the optical equations, and give full-sky results for the large-scale adiabatic temperature bispectrum from Ricci focussing (expansion of the ray bundle), Weyl lensing (convergence and shear), and temperature redshift modulations of small-scale power. The δN expansion of the beam is described by the constant temperature 3-curvature, and gives a nearly-observable version of the consistency relation prediction from single-field inflation. I give approximate arguments to quantify the likely importance of dynamical effects, and argue that they can be neglected for modulation scales l∼<100, which is sufficient for lensing studies and also allows robust tests of local primordial non-Gaussianity using only the large-scale modulation modes. For accurate numerical results early and late-time ISW effects must be accounted for, though I confirm that the late-time non-linear Rees-Sciama contribution is negligible compared to other more important complications. The total corresponds to f{sub NL} ∼ 7 for Planck-like temperature constraints and f{sub NL} ∼ 11 for cosmic-variance limited data to l{sub max} = 2000. Temperature lensing bispectrum estimates are affected at the 0.2σ level by Ricci focussing, and up to 0.5σ with polarization.
SU(2,CMB), the nature of light and accelerated cosmological expansion
NASA Astrophysics Data System (ADS)
Hofmann, Ralf
2006-09-01
We present quantitative and qualitative arguments in favor of the claim that, within the present cosmological epoch, the U(1)Y factor in the Standard Model is an effective manifestation of SU(2) pure gauge dynamics of Yang-Mills scale Λ ˜ 10-4 eV. Results for the pressure and the energy density in the deconfining phase of this theory, obtained in a nonperturbative and analytical way, support this connection in view of large-angle features inherent in the map of the CMB tempera- ture fluctuations and temperature-polarization cross correlations. Dedicated to Pierre van Baal with best wishes for a soon recuperation.
Future of Colombo Airport (CMB) as an Airline Hub
NASA Technical Reports Server (NTRS)
Jayalath, J. T. D.; Bandara, J. M. S. J.
2001-01-01
Aviation throughout the world has seen profound changes within the last two decades. Today more and more airports are looking for hub operations. However, as the success of hub operation would depend on a number of parameters such as geographic location, route network, facilities available, passengers' acceptance etc., not all airports would be able to operate as successful hubs. This paper investigates the possibility for (he Bandaranayake international airport, Colombo, Sri Lanka (CMB) to emerge as a hub airport in the South Asian region. It is found that CMB is situated in a geographically advantageous position in the region with respect to the airline route network. Comparison of travel distances between CMB and prominent O-D pairs and evaluation of airline schedules at relevant established hub airports indicates that CMB could operate as a directional hub serving the South Asian market if the number of destinations with daily flights could be increased.
NASA Astrophysics Data System (ADS)
Deschamps, F.; Yin, Y.; Tackley, P. J.
2013-12-01
A variety of seismic observations, including tomographic models, indicate that the lowermost mantle is strongly heterogeneous. Seismic observations further support a thermo-chemical origin for the large scale heterogeneities. In particular, the large low-shear wave velocity provinces (LLSVP) observed by global tomographic images are better explained by a combination of thermal and chemical anomalies. Despite the accuracy of seismic information, uncertainties and trade-off still prevent the determination of a detailed lower mantle thermo-chemical structure. For instance, the nature of chemical heterogeneities and the exact role played by the post-perovskite phase transition are still debated. Additional constraints are needed to discriminate between the possible models of structure and dynamics of the lower mantle. Here, we consider two potential additional constraints, the electrical conductivity and the dynamic topography at the core-mantle boundary (CMB). Unlike density and seismic velocities, electrical conductivity increases with temperature. In addition, it strongly varies with the iron and silicate content. Using appropriate mineral physics data, we calculated a 3D distribution of electrical conductivity in lower mantle from the thermo-chemical structure inferred by probabilistic tomography, which maps iron and silicate excess in the LLSVP. In the lowermost mantle, we observe a belt of high conductivity, with maximum values around 20 S/m located in the LLSVP. Such a belt may trigger electric currents in the lowermost mantle and induce magnetic field variations with period of one year or more. It may thus be seen by global models of electrical conductivity. Unfortunately, such models do not sample yet regions deeper than 2000 km. A second, independent constraint we explored is the dynamic topography at the CMB. We used stagYY to calculate the dynamic topography associated with several models of thermo-chemical convection, and observe strong differences
CMB8: New software for chemical mass balance receptor modeling
Lewis, C.W.
1997-12-31
The Chemical Mass Balance (CMB) method for receptor modeling of ambient air pollutants has been in use for over two decades. over the past year the U.S. Environmental Protection Agency`s Office of Research and Development and Office of Air Quality Planning and standards have jointly sponsored the development of a new generation of CMB software, CMB8. Developmental work has been performed by the Desert Research Institute, Reno, NV. Changes embodied in CMB8 include (1) switch from a DOS-based to a Windows-based environment, (2) increased attention to volatile organic compounds (VOC) applications, (3) correction of some flaws in the previous version (CMB7), (4) more options for input and output data formats, (5) addition of a more accurate least squares computational algorithm, (6) a new treatment of source collinearity, (7) multiple defaults for sources and fitting species, and (8) choice of fitting criteria. Details of the changes and the procedure for obtaining CMB8 are given.
Effects of Rayleigh scattering on the CMB and cosmic structure
NASA Astrophysics Data System (ADS)
Alipour, Elham; Sigurdson, Kris; Hirata, Christopher M.
2015-04-01
During and after recombination, in addition to Thomson scattering with free electrons, photons also couple to neutral hydrogen and helium atoms through Rayleigh scattering. This coupling influences both cosmic microwave background (CMB) anisotropies and the distribution of matter in the Universe. The frequency dependence of the Rayleigh cross section breaks the thermal nature of CMB temperature and polarization anisotropies and effectively doubles the number of variables needed to describe CMB intensity and polarization statistics, while the additional atomic coupling changes the matter distribution and the lensing of the CMB. We introduce a new method to capture the effects of Rayleigh scattering on cosmological power spectra. Rayleigh scattering modifies CMB temperature and polarization anisotropies at the ˜1 % level at 35 GHz (scaling ∝ν4 ), and modifies matter correlations by as much as ˜0.3 %. We show the Rayleigh signal, especially the cross-spectra between the thermal (Rayleigh) E -polarization and Rayleigh (thermal) intensity signal, may be detectable with future CMB missions even in the presence of foregrounds, and how this new information might help to better constrain the cosmological parameters.
Large angular scale CMB anisotropy from an excited initial mode
NASA Astrophysics Data System (ADS)
Sojasi, A.; Mohsenzadeh, M.; Yusofi, E.
2016-07-01
According to inflationary cosmology, the CMB anisotropy gives an opportunity to test predictions of new physics hypotheses. The initial state of quantum fluctuations is one of the important options at high energy scale, as it can affect observables such as the CMB power spectrum. In this study a quasi-de Sitter inflationary background with approximate de Sitter mode function built over the Bunch-Davies mode is applied to investigate the scale-dependency of the CMB anisotropy. The recent Planck constraint on spectral index motivated us to examine the effect of a new excited mode function (instead of pure de Sitter mode) on the CMB anisotropy at large angular scales. In so doing, it is found that the angular scale-invariance in the CMB temperature fluctuations is broken and in the limit ℓ < 200 a tiny deviation appears. Also, it is shown that the power spectrum of CMB anisotropy is dependent on a free parameter with mass dimension H << M * < M p and on the slow-roll parameter ɛ. Supported by the Islamic Azad University, Rasht Branch, Rasht, Iran
Cosmology from CMB polarization with POLARBEAR and the Simons Array
NASA Astrophysics Data System (ADS)
Barron, Darcy; POLARBEAR Collaboration
2016-01-01
POLARBEAR is a cosmic microwave background (CMB) polarization experiment located in the Atacama desert in Chile. The science goals of the POLARBEAR project are to do a deep search for CMB B-mode polarization created by inflationary gravitational waves, as well as characterize the CMB B-mode signal from gravitational lensing. POLARBEAR-1 started observations in 2012. The POLARBEAR team has published results from its first season of observations on a small fraction of the sky, including a measurement of a non-zero B-mode polarization angular power spectrum at sub-degree scales, where the dominant signal is gravitational lensing of the CMB. Improving these measurements requires precision characterization of the CMB polarization signal over large fractions of the sky, at multiple frequencies. To achieve these goals, POLARBEAR has begun expanding to include an additional two 3.5 meter telescopes with multi-chroic receivers, known as the Simons Array. With high sensitivity and large sky coverage, the Simons Array will create a detailed survey of B-mode polarization, and its spectral information will be used to extract the CMB signal from astrophysical foregrounds. The Simons Array data will place strong constraints on the sum of the neutrino masses, when combined with data from the next generation of baryon acoustic oscillation measurements. We present the status of this funded instrument and its expected capabilities.
Symmetry of the CMB sky as a new test of its statistical isotropy. Non cosmological octupole?
Naselsky, P.; Hansen, M.; Kim, J. E-mail: kirstejn@nbi.dk
2011-09-01
In this article we propose a novel test for statistical anisotropy of the CMB ΔT( n-circumflex = (θ,φ)). The test is based on the fact, that the Galactic foregrounds have a remarkably strong symmetry with respect to their antipodal points with respect to the Galactic plane, while the cosmological signal should not be symmetric or asymmetric under these transitions. We have applied the test for the octupole component of the WMAP ILC 7 map, by looking at a{sub 3,1} and a{sub 3,3}, and their ratio to a{sub 3,2} both for real and imaginary values. We find abnormal symmetry of the octupole component at the level of 0.58%, compared to Monte Carlo simulations. By using the analysis of the phases of the octupole we found remarkably strong cross-correlations between the phases of the kinematic dipole and the ILC 7 octupole, in full agreement with previous results. We further test the multipole range 2 < l < 100, by investigating the ratio between the l+m = even and l+m = odd parts of power spectra. We compare the results to simulations of a Gaussian random sky, and find significant departure from the statistically isotropic and homogeneous case, for a very broad range of multipoles. We found that for the most prominent peaks of our estimator, the phases of the corresponding harmonics are coherent with phases of the octupole. We believe, our test would be very useful for detections of various types of residuals of the foreground and systematic effects at a very broad range of multipoles 2 ≤ l ≤ 1500−3000 for the forthcoming PLANCK CMB map, before any conclusions about primordial non-Gaussianity and statistical anisotropy of the CMB.
Bolejko, Krzysztof
2011-02-01
The standard analysis of the CMB data assumes that the distance to the last scattering surface can be calculated using the distance-redshift relation as in the Friedmann model. However, in the inhomogeneous universe, even if (δρ) = 0, the distance relation is not the same as in the unperturbed universe. This can be of serious consequences as a change of distance affects the mapping of CMB temperature fluctuations into the angular power spectrum C{sub l}. In addition, if the change of distance is relatively uniform no new temperature fluctuations are generated. It is therefore a different effect than the lensing or ISW effects which introduce additional CMB anisotropies. This paper shows that the accuracy of the CMB analysis can be impaired by the accuracy of calculation of the distance within the cosmological models. Since this effect has not been fully explored before, to test how the inhomogeneities affect the distance-redshift relation, several methods are examined: the Dyer-Roeder relation, lensing approximation, and non-linear Swiss-Cheese model. In all cases, the distance to the last scattering surface is different than when homogeneity is assumed. The difference can be as low as 1% and as high as 80%. An usual change of the distance is around 20–30%. Since the distance to the last scattering surface is set by the position of the CMB peaks, in order to have a good fit, the distance needs to be adjusted. After correcting the distance, the cosmological parameters change. Therefore, a not properly estimated distance to the last scattering surface can be a major source of systematics. This paper shows that if inhomogeneities are taken into account when calculating the distance then models with positive spatial curvature and with Ω{sub Λ} ∼ 0.8−0.9 are preferred.
Calabrese, Erminia; Smidt, Joseph; Amblard, Alexandre; Cooray, Asantha; Serra, Paolo; Melchiorri, Alessandro; Heavens, Alan; Munshi, Dipak
2010-02-15
We measure the skewness power spectrum of the CMB anisotropies optimized for a detection of the secondary bispectrum generated by the correlation of the CMB lensing potential with integrated Sachs-Wolfe effect and the Sunyaev-Zel'dovich effect. The covariance of our measurements is generated by Monte Carlo simulations of Gaussian CMB fields with noise properties consistent with WMAP 5-year data. When interpreting multifrequency measurements we also take into account the confusion resulting from unresolved radio point sources. We analyze Q, V and W-band WMAP 5-year raw and foreground-cleaned maps using the KQ75 mask out to l{sub max}=600. We find no significant evidence for a nonzero non-Gaussian signal from the lensing-secondary correlation in all three bands and we constrain the overall amplitude of the cross-power spectrum between CMB lensing potential and the sum of SZ and ISW fluctuations to be 0.42{+-}0.86 and 1.19{+-}0.86 in combined V and W-band raw and foreground-cleaned maps provided by the WMAP team, respectively. The point-source amplitude at the bispectrum level measured with this skewness power spectrum is higher than previous measurements of point-source non-Gaussianity. We also consider an analysis where we also account for the primordial non-Gaussianity in addition to lensing-secondary bispectrum and point sources. The focus of this paper is on secondary anisotropies. Consequently the estimator is not optimized for primordial non-Gaussianity and the limit we find on local non-Gaussianity from the foreground-cleaned V+W maps is f{sub NL}=-13{+-}62, when marginalized over point sources and lensing-ISW/SZ contributions to the total bispectrum.
CMB seen through random Swiss Cheese
NASA Astrophysics Data System (ADS)
Lavinto, Mikko; Räsänen, Syksy
2015-10-01
We consider a Swiss Cheese model with a random arrangement of Lemaȋtre-Tolman-Bondi holes in ΛCDM cheese. We study two kinds of holes with radius rb=50 h-1 Mpc, with either an underdense or an overdense centre, called the open and closed case, respectively. We calculate the effect of the holes on the temperature, angular diameter distance and, for the first time in Swiss Cheese models, shear of the CMB . We quantify the systematic shift of the mean and the statistical scatter, and calculate the power spectra. In the open case, the temperature power spectrum is three orders of magnitude below the linear ISW spectrum. It is sensitive to the details of the hole, in the closed case the amplitude is two orders of magnitude smaller. In contrast, the power spectra of the distance and shear are more robust, and agree with perturbation theory and previous Swiss Cheese results. We do not find a statistically significant mean shift in the sky average of the angular diameter distance, and obtain the 95% limit |Δ DA/bar DA|lesssim 10-4. We consider the argument that areas of spherical surfaces are nearly unaffected by perturbations, which is often invoked in light propagation calculations. The closed case is consistent with this at 1σ, whereas in the open case the probability is only 1.4%.
NASA Astrophysics Data System (ADS)
Schwarz, Dominik J.; Copi, Craig J.; Huterer, Dragan; Starkman, Glenn D.
2016-09-01
Several unexpected features have been observed in the microwave sky at large angular scales, both by WMAP and by Planck. Among those features is a lack of both variance and correlation on the largest angular scales, alignment of the lowest multipole moments with one another and with the motion and geometry of the solar system, a hemispherical power asymmetry or dipolar power modulation, a preference for odd parity modes and an unexpectedly large cold spot in the Southern hemisphere. The individual p-values of the significance of these features are in the per mille to per cent level, when compared to the expectations of the best-fit inflationary ΛCDM model. Some pairs of those features are demonstrably uncorrelated, increasing their combined statistical significance and indicating a significant detection of CMB features at angular scales larger than a few degrees on top of the standard model. Despite numerous detailed investigations, we still lack a clear understanding of these large-scale features, which seem to imply a violation of statistical isotropy and scale invariance of inflationary perturbations. In this contribution we present a critical analysis of our current understanding and discuss several ideas of how to make further progress.
The CMB bispectrum in the squeezed limit
Creminelli, Paolo; Pitrou, Cyril; Vernizzi, Filippo E-mail: cyril.pitrou@gmail.com
2011-11-01
The CMB bispectrum generated by second-order effects at recombination can be calculated analytically when one of the three modes has a wavelength much longer than the other two and is outside the horizon at recombination. This was pointed out in [1] and here we correct their results. We derive a simple formula for the bispectrum, f{sub NL}{sup loc} = −(1/6+cos 2θ)⋅(1−1/2⋅dln (l{sub S}{sup 2}C{sub S})/dln l{sub S}), where C{sub S} is the short scale spectrum and θ the relative orientation between the long and the short modes. This formula is exact and takes into account all effects at recombination, including recombination-lensing, but neglects all late-time effects such as ISW-lensing. The induced bispectrum in the squeezed limit is small and will negligibly contaminate the Planck search for a local primordial signal: this will be biased only by f{sub NL}{sup loc} ≈ −0.4. The above analytic formula includes the primordial non-Gaussianity of any single-field model. It also represents a consistency check for second-order Boltzmann codes: we find substantial agreement with the current version of the CMBquick code.
CMB anisotropies from a gradient mode
NASA Astrophysics Data System (ADS)
Mirbabayi, Mehrdad; Zaldarriaga, Matias
2015-03-01
A linear gradient mode must have no observable dynamical effect on short distance physics. We confirm this by showing that if there was such a gradient mode extending across the whole observable Universe, it would not cause any hemispherical asymmetry in the power of CMB anisotropies, as long as Maldacena's consistency condition is satisfied. To study the effect of the long wavelength mode on short wavelength modes, we generalize the existing second order Sachs-Wolfe formula in the squeezed limit to include a gradient in the long mode and to account for the change in the location of the last scattering surface induced by this mode. Next, we consider effects that are of second order in the long mode. A gradient mode Φ = qṡx generated in Single-field inflation is shown to induce an observable quadrupole moment. For instance, in a matter-dominated model it is equal to Q = 5(qṡx)2/18. This quadrupole can be canceled by superposition of a quadratic perturbation. The result is shown to be a nonlinear extension of Weinberg's adiabatic modes: a long-wavelength physical mode which looks locally like a coordinate transformation.
CMB constraints on cosmic strings and superstrings
NASA Astrophysics Data System (ADS)
Charnock, Tom; Avgoustidis, Anastasios; Copeland, Edmund J.; Moss, Adam
2016-06-01
We present the first complete Markov chain Monte Carlo analysis of cosmological models with evolving cosmic (super)string networks, using the unconnected segment model in the unequal-time correlator formalism. For ordinary cosmic string networks, we derive joint constraints on Λ cold dark matter (CDM) and string network parameters, namely the string tension G μ , the loop-chopping efficiency cr, and the string wiggliness α . For cosmic superstrings, we obtain joint constraints on the fundamental string tension G μF, the string coupling gs, the self-interaction coefficient cs, and the volume of compact extra dimensions w . This constitutes the most comprehensive CMB analysis of Λ CDM cosmology+strings to date. For ordinary cosmic string networks our updated constraint on the string tension, obtained using Planck2015 temperature and polarization data, is G μ <1.1 ×10-7 in relativistic units, while for cosmic superstrings our constraint on the fundamental string tension after marginalizing over gs, cs, and w is G μF<2.8 ×10-8.
Can residuals of the solar system foreground explain low multipole anomalies of the CMB?
Hansen, M.; Kim, J.; Frejsel, A.M.; Ramazanov, S.; Naselsky, P.; Zhao, W.; Burigana, C. E-mail: jkim@nbi.dk E-mail: sabir_ra@nbi.dk E-mail: wzhao7@nbi.ku.dk
2012-10-01
The low multipole anomalies of the Cosmic Microwave Background has received much attention during the last few years. It is still not ascertained whether these anomalies are indeed primordial or the result of systematics or foregrounds. An example of a foreground, which could generate some non-Gaussian and statistically anisotropic features at low multipole range, is the very symmetric Kuiper Belt in the outer solar system. In this paper, expanding upon the methods presented in [1], we investigate the contributions from the Kuiper Belt objects (KBO) to the WMAP ILC 7 map, whereby we can minimize the contrast in power between even and odd multipoles in the CMB, discussed in [2,3]. We submit our KBO de-correlated CMB signal to several tests, to analyze its validity, and find that incorporation of the KBO emission can decrease the quadrupole-octupole alignment and parity asymmetry problems, provided that the KBO signals has a non-cosmological dipole modulation, associated with the statistical anisotropy of the ILC 7 map. Additionally, we show that the amplitude of the dipole modulation, within a 2σ interval, is in agreement with the corresponding amplitudes, discussed in [4].
CMB polarization features from inflation versus reionization
Mortonson, Michael J.; Dvorkin, Cora; Peiris, Hiranya V.; Hu, Wayne
2009-05-15
The angular power spectrum of the cosmic microwave background temperature anisotropy observed by WMAP has an anomalous dip at l{approx}20 and a bump at l{approx}40. One explanation for this structure is the presence of features in the primordial curvature power spectrum, possibly caused by a step in the inflationary potential. The detection of these features is only marginally significant from temperature data alone. However, the inflationary feature hypothesis predicts a specific shape for the E-mode polarization power spectrum with a structure similar to that observed in temperature at l{approx}20-40. Measurement of the CMB polarization on few-degree scales can therefore be used as a consistency check of the hypothesis. The Planck satellite has the statistical sensitivity to confirm or rule out the model that best fits the temperature features with 3{sigma} significance, assuming all other parameters are known. With a cosmic variance limited experiment, this significance improves to 8{sigma}. For tests of inflationary models that can explain both the dip and the bump in temperature, the primary source of uncertainty is confusion with polarization features created by a complex reionization history, which, at most, reduces the significance to 2.5{sigma} for Planck and 5{sigma}-6{sigma} for an ideal experiment. Smoothing of the polarization spectrum by a large tensor component only slightly reduces the ability of polarization to test for inflationary features, as does requiring that polarization is consistent with the observed temperature spectrum, given the expected low level of TE correlation on few-degree scales. If polarized foregrounds can be adequately subtracted, Planck will supply valuable evidence for or against features in the primordial power spectrum. A future high-sensitivity polarization satellite would enable a decisive test of the feature hypothesis and provide complementary information about the shape of a possible step in the inflationary potential.
CMB polarization features from inflation versus reionization
NASA Astrophysics Data System (ADS)
Mortonson, Michael J.; Dvorkin, Cora; Peiris, Hiranya V.; Hu, Wayne
2009-05-01
The angular power spectrum of the cosmic microwave background temperature anisotropy observed by WMAP has an anomalous dip at ℓ˜20 and a bump at ℓ˜40. One explanation for this structure is the presence of features in the primordial curvature power spectrum, possibly caused by a step in the inflationary potential. The detection of these features is only marginally significant from temperature data alone. However, the inflationary feature hypothesis predicts a specific shape for the E-mode polarization power spectrum with a structure similar to that observed in temperature at ℓ˜20-40. Measurement of the CMB polarization on few-degree scales can therefore be used as a consistency check of the hypothesis. The Planck satellite has the statistical sensitivity to confirm or rule out the model that best fits the temperature features with 3σ significance, assuming all other parameters are known. With a cosmic variance limited experiment, this significance improves to 8σ. For tests of inflationary models that can explain both the dip and the bump in temperature, the primary source of uncertainty is confusion with polarization features created by a complex reionization history, which, at most, reduces the significance to 2.5σ for Planck and 5σ-6σ for an ideal experiment. Smoothing of the polarization spectrum by a large tensor component only slightly reduces the ability of polarization to test for inflationary features, as does requiring that polarization is consistent with the observed temperature spectrum, given the expected low level of TE correlation on few-degree scales. If polarized foregrounds can be adequately subtracted, Planck will supply valuable evidence for or against features in the primordial power spectrum. A future high-sensitivity polarization satellite would enable a decisive test of the feature hypothesis and provide complementary information about the shape of a possible step in the inflationary potential.
External priors for the next generation of CMB experiments
NASA Astrophysics Data System (ADS)
Manzotti, Alessandro; Dodelson, Scott; Park, Youngsoo
2016-03-01
Planned cosmic microwave background (CMB) experiments will improve what we know about neutrino physics, inflation, and dark energy. The low level of noise, together with improved angular resolution, will increase the signal-to-noise ratio of the CMB polarized data as well as the reconstructed lensing potential of large scale structure. Projected constraints on cosmological parameters are tight, but these can be improved even further with information from external experiments. Here, we examine quantitatively the extent to which external priors can lead to improvement in projected constraints from a CMB-Stage IV (S4) experiment on neutrino and dark energy properties. We find that CMB S4 constraints on neutrino mass could be strongly enhanced by external constraints on the cold dark matter density Ωch2 and the Hubble constant H0. If polarization on the largest scales (ℓ<50 ) will not be measured, an external prior on the primordial amplitude As or the optical depth τ will also be important. A CMB constraint on the number of relativistic degrees of freedom, Neff, will benefit from an external prior on the spectral index ns and the baryon energy density Ωbh2. Finally, an external prior on H0 will help constrain the dark energy equation of state (w ).
Measurements of the CMB temperature at z=0.89
NASA Astrophysics Data System (ADS)
Muller, Sebastien; Curran, Steve; Beelen, Alexandre; Aalto, Susanne; Combes, Francoise; Guelin, Michel; Black, John Harry; Horellou, Cathy
2011-04-01
The Cosmic Microwave Background (CMB) is one of the strongest pillars of the Big Bang theory. Determining the CMB temperature at high redshift has considerable interest to probe the T_CMB-z law and test decaying dark energy models. Our recent ATCA 7 mm spectral line survey toward the z=0.89 molecular absorber located in front of the lensed quasar PKS1830-211 has allowed us to detect a collection of about 30 different molecular species and to derive rotation temperatures of some of them toward one image of the quasar. Averaging these rotation temperatures, we obtain a value of 5.2 pm 0.3 K, consistent with the value T_CMB=5.14 K from standard cosmology. We now propose to strengthen this result by determining the rotation temperatures of a set of molecules toward the second lensed image, projected on the other side of the absorbing galaxy bulge, in a completely independent line of sight. We will therefore obtain a new, independent and presumably more robust measurement of T_CMB at z=0.89. A total of 8 hours of observations is requested in order to conduct the multi-transition analysis in the 7 mm and 3 mm bands.
Rayleigh scattering: blue sky thinking for future CMB observations
Lewis, Antony
2013-08-01
Rayleigh scattering from neutral hydrogen during and shortly after recombination causes the CMB anisotropies to be significantly frequency dependent at high frequencies. This may be detectable with Planck, and would be a strong signal in any future space-based CMB missions. The later peak of the Rayleigh visibility compared to Thomson scattering gives an increased large-scale CMB polarization signal that is a greater than 4% effect for observed frequencies ν ∼> 500GHz. There is a similar magnitude suppression on small scales from additional damping. Due to strong correlation between the Rayleigh and primary signal, measurement of the Rayleigh component is limited by noise and foregrounds, not cosmic variance of the primary CMB, and should observable over a wide range of angular scales at frequencies 200GHz ∼< ν ∼< 800GHz. I give new numerical calculations of the temperature and polarization power spectra, and show that future CMB missions could measure the temperature Rayleigh cross-spectrum at high precision, detect the polarization from Rayleigh scattering, and also accurately determine the cross-spectra between the Rayleigh temperature signal and primary polarization. The Rayleigh scattering signal may provide a powerful consistency check on recombination physics. In principle it can be used to measure additional horizon-scale primordial perturbation modes at recombination, and distinguish a significant tensor mode B-polarization signal from gravitational lensing at the power spectrum level.
External priors for the next generation of CMB experiments
Manzotti, Alessandro; Dodelson, Scott; Park, Youngsoo
2015-12-08
Planned cosmic microwave background (CMB) experiments can dramatically improve what we know about neutrino physics, inflation, and dark energy. The low level of noise, together with improved angular resolution, will increase the signal to noise of the CMB polarized signal as well as the reconstructed lensing potential of high redshift large scale structure. Projected constraints on cosmological parameters are extremely tight, but these can be improved even further with information from external experiments. Here, we examine quantitatively the extent to which external priors can lead to improvement in projected constraints from a CMB-Stage IV (S4) experiment on neutrino and dark energy properties. We find that CMB S4 constraints on neutrino mass could be strongly enhanced by external constraints on the cold dark matter density $\\Omega_{c}h^{2}$ and the Hubble constant $H_{0}$. If polarization on the largest scales ($\\ell<50$) will not be measured, an external prior on the primordial amplitude $A_{s}$ or the optical depth $\\tau$ will also be important. A CMB constraint on the number of relativistic degrees of freedom, $N_{\\rm eff}$, will benefit from an external prior on the spectral index $n_{s}$ and the baryon energy density $\\Omega_{b}h^{2}$. Finally, an external prior on $H_{0}$ will help constrain the dark energy equation of state ($w$).
NASA Astrophysics Data System (ADS)
Crill, Brendan
2015-08-01
The joint analysis of 150 GHz polarized maps from BICEP2 and Keck Array at 150 GHz with Planck data at 353 GHzallowed the removal of Galactic dust contamination from the measurement of lensed B-modes in the deep (57 nK deg)BICEP2/Keck maps as well as setting an upper limit on the primordial gravitational wave background from inflation. We present this analysis, describe prospects for polarized foreground cleaning of future suborbitalmeasurements of CMB, and additionally describe Planck's measurements of the spatial correlation of polarizedemission from synchrotron and dust at high galactic latitude, which complicates the removal of Galactic foregrounds at the foregroundminimum of 70-100 GHz.
Impact of point source clustering on cosmological parameters with CMB anisotropies
Serra, Paolo; Cooray, Asantha; Amblard, Alexandre; Pagano, Luca; Melchiorri, Alessandro
2008-08-15
The faint radio point sources that are unresolved in cosmic microwave background (CMB) anisotropy maps are likely to be a biased tracer of the large-scale structure dark matter distribution. While the shot-noise contribution to the angular power spectrum of unresolved radio point sources is included either when optimally constructing the CMB angular power spectrum, as with WMAP data, or when extracting cosmological parameters, we suggest that clustering part of the point source power spectrum should also be included. This is especially necessary at high frequencies above 150 GHz, where the clustering of far-IR sources is expected to dominate the shot-noise level of the angular power spectrum at tens of arcminute angular scales of both radio and sub-mm sources. We make an estimate of source clustering of unresolved radio sources in both WMAP and ACBAR, and marginalize over the amplitude of source clustering in each CMB data set when model fitting for cosmological parameters. For the combination of WMAP 5-year data and ACBAR, we find that the spectral index changes from the value of 0.963{+-}0.014 to 0.959{+-}0.014 (at 68% C.L.) when the clustering power spectrum of point sources is included in model fits. While we find that the differences are marginal with and without source clustering in current data, it may be necessary to account for source clustering with future data sets such as Planck, especially to properly model fit anisotropies at arcminute angular scales. If clustering is not accounted and point sources are modeled with a shot noise only out to l{approx}2000, the spectral index will be biased by about 1.5{sigma}.
Optimized Large-scale CMB Likelihood and Quadratic Maximum Likelihood Power Spectrum Estimation
NASA Astrophysics Data System (ADS)
Gjerløw, E.; Colombo, L. P. L.; Eriksen, H. K.; Górski, K. M.; Gruppuso, A.; Jewell, J. B.; Plaszczynski, S.; Wehus, I. K.
2015-11-01
We revisit the problem of exact cosmic microwave background (CMB) likelihood and power spectrum estimation with the goal of minimizing computational costs through linear compression. This idea was originally proposed for CMB purposes by Tegmark et al., and here we develop it into a fully functioning computational framework for large-scale polarization analysis, adopting WMAP as a working example. We compare five different linear bases (pixel space, harmonic space, noise covariance eigenvectors, signal-to-noise covariance eigenvectors, and signal-plus-noise covariance eigenvectors) in terms of compression efficiency, and find that the computationally most efficient basis is the signal-to-noise eigenvector basis, which is closely related to the Karhunen-Loeve and Principal Component transforms, in agreement with previous suggestions. For this basis, the information in 6836 unmasked WMAP sky map pixels can be compressed into a smaller set of 3102 modes, with a maximum error increase of any single multipole of 3.8% at ℓ ≤ 32 and a maximum shift in the mean values of a joint distribution of an amplitude-tilt model of 0.006σ. This compression reduces the computational cost of a single likelihood evaluation by a factor of 5, from 38 to 7.5 CPU seconds, and it also results in a more robust likelihood by implicitly regularizing nearly degenerate modes. Finally, we use the same compression framework to formulate a numerically stable and computationally efficient variation of the Quadratic Maximum Likelihood implementation, which requires less than 3 GB of memory and 2 CPU minutes per iteration for ℓ ≤ 32, rendering low-ℓ QML CMB power spectrum analysis fully tractable on a standard laptop.
Constraining gravity at the largest scales through CMB lensing and galaxy velocities
NASA Astrophysics Data System (ADS)
Pullen, Anthony R.; Alam, Shadab; He, Siyu; Ho, Shirley
2016-08-01
We demonstrate a new method to constrain gravity on the largest cosmological scales by combining measurements of cosmic microwave background (CMB) lensing and the galaxy velocity field. $E_G$ is a statistic, constructed from a gravitational lensing tracer and a measure of velocities such as redshift-space distortions (RSD), that can discriminate between gravity models while being independent of clustering bias and $\\sigma_8$. While traditionally, the lensing field for $E_G$ has been probed through galaxy lensing, CMB lensing has been proposed as a more robust tracer of the lensing field for $E_G$ at higher redshifts while avoiding intrinsic alignments. We perform the largest-scale measurement of $E_G$ ever, up to 150 Mpc/$h$, by cross-correlating the Planck CMB lensing map with the Sloan Digital Sky Survey III (SDSS-III) CMASS galaxy sample and combining this with our measurement of the CMASS auto-power spectrum and the RSD parameter $\\beta$. We report $E_G(z=0.57)=0.243\\pm0.060$ (stat) $\\pm0.013$ (sys), a measurement in tension with the general relativity prediction at a level of 2.6$\\sigma$. Note that our $E_G$ measurement deviates from GR only at scales greater than 80 Mpc/$h$, scales which have not been probed by previous $E_G$ tests. Upcoming surveys, which will provide an order-of-magnitude reduction in statistical errors, can significantly constrain alternative gravity models when combined with better control of systematics.
Effect of intermediate Minkowskian evolution on CMB bispectrum
Mironov, S.A.; Rubakov, V.A.; Ramazanov, S.R. E-mail: Sabir.Ramazanov@ulb.ac.be
2014-04-01
We consider a non-inflationary early Universe scenario in which relevant scalar perturbations get frozen out at some point, but then are defrosted and follow a long nearly Minkowskian evolution before the hot era. This intermediate stage leaves specific imprint on the CMB 3-point function, largely independent of details of microscopic physics. In particular, the CMB bispectrum undergoes oscillations in the multipole l space with roughly constant amplitude. The latter is in contrast to the oscillatory bispectrum enhanced in the flattened triangle limit, as predicted by inflation with non-Bunch-Davies vacuum. Given this and other peculiar features of the bispectrum, stringent constraints imposed by the Planck data may not apply. The CMB 3-point function is suppressed by the inverse duration squared of the Minkowskian evolution, but can be of observable size for relatively short intermediate Minkowskian stage.
TESTING CPT SYMMETRY WITH CURRENT AND FUTURE CMB MEASUREMENTS
Li, Si-Yu; Zhang, Xinmin; Xia, Jun-Qing; Li, Hong; Li, Mingzhe
2015-02-01
In this paper, we use the current and future cosmic microwave background (CMB) experiments to test the Charge-Parity-Time Reversal (CPT) symmetry. We consider a CPT-violating interaction in the photon sector L{sub cs}∼p{sub μ}A{sub ν} F-tilde {sup μν}, which gives rise to a rotation of the polarization vectors of the propagating CMB photons. By combining the 9 yr WMAP, BOOMERanG 2003, and BICEP1 observations, we obtain the current constraint on the isotropic rotation angle α-bar =−2.12±1.14 (1σ), indicating that the significance of the CPT violation is about 2σ. Here, we particularly take the systematic errors of CMB measurements into account. Then, we study the effects of the anisotropies of the rotation angle [Δα( n-hat )] on the CMB polarization power spectra in detail. Due to the small effects, the current CMB polarization data cannot constrain the related parameters very well. We obtain the 95% C.L. upper limit of the variance of the anisotropies of the rotation angle C {sup α}(0) < 0.035 from all of the CMB data sets. More interestingly, including the anisotropies of rotation angle could lower the best-fit value of r and relax the tension on the constraints of r between BICEP2 and Planck. Finally, we investigate the capabilities of future Planck polarization measurements on α-bar and Δα( n-hat ). Benefited from the high precision of Planck data, the constraints of the rotation angle can be significantly improved.
Testing CPT Symmetry with Current and Future CMB Measurements
NASA Astrophysics Data System (ADS)
Li, Si-Yu; Xia, Jun-Qing; Li, Mingzhe; Li, Hong; Zhang, Xinmin
2015-02-01
In this paper, we use the current and future cosmic microwave background (CMB) experiments to test the Charge-Parity-Time Reversal (CPT) symmetry. We consider a CPT-violating interaction in the photon sector {L}_cs˜ p_μ A_ν \\tilde{F}μ ν , which gives rise to a rotation of the polarization vectors of the propagating CMB photons. By combining the 9 yr WMAP, BOOMERanG 2003, and BICEP1 observations, we obtain the current constraint on the isotropic rotation angle \\bar{α } = -2.12 +/- 1.14 (1σ), indicating that the significance of the CPT violation is about 2σ. Here, we particularly take the systematic errors of CMB measurements into account. Then, we study the effects of the anisotropies of the rotation angle [Δ {α }({\\hat{n}})] on the CMB polarization power spectra in detail. Due to the small effects, the current CMB polarization data cannot constrain the related parameters very well. We obtain the 95% C.L. upper limit of the variance of the anisotropies of the rotation angle C α(0) < 0.035 from all of the CMB data sets. More interestingly, including the anisotropies of rotation angle could lower the best-fit value of r and relax the tension on the constraints of r between BICEP2 and Planck. Finally, we investigate the capabilities of future Planck polarization measurements on \\bar{α } and Δ {α }({\\hat{n}}). Benefited from the high precision of Planck data, the constraints of the rotation angle can be significantly improved.
Understanding the origin of CMB constraints on dark energy
NASA Astrophysics Data System (ADS)
Jassal, H. K.; Bagla, J. S.; Padmanabhan, T.
2010-07-01
We study the observational constraints of cosmic microwave background (CMB) temperature and polarization anisotropies on models of dark energy, with special focus on models with variation in properties of dark energy with time. We demonstrate that the key constraint from CMB observations arises from the location of acoustic peaks. An additional constraint arises from the limits on ΩNR from the relative amplitudes of acoustic peaks. Further, we show that the distance to the last scattering surface is not how the CMB observations constrain the combination of parameters for models of dark energy. We also use constraints from supernova observations and show that unlike the gold and silver samples, the Supernova Legacy Survey (SNLS) sample prefers a region of parameter space that has a significant overlap with the region preferred by the CMB observations. This is a verification of a conjecture made by us in an earlier work. We discuss combined constraints from Wilkinson Microwave Anisotropy Probe 5-yr and SNLS observations. We find that models with w ~= - 1 are preferred for models with a constant equation-of-state parameters. In case of models with a time-varying dark energy, we show that constraints on evolution of dark energy density are almost independent of the type of variation assumed for the equation-of-state parameter. This makes it easy to get approximate constraints from CMB observations on arbitrary models of dark energy. Constraints on models with a time-varying dark energy are predominantly due to CMB observations, with supernova constraints playing only a marginal role.
Observing the CMB with the AMiBA
NASA Astrophysics Data System (ADS)
Subrahmanyan, R.
I discuss the capabilities and limitations of the AMiBA for imaging CMB anisotropies. Michael Kesteven (ATNF-CSIRO) has proposed drift-scanning as an observing strategy for measuring and rejecting any instrumental response that the close-packed interferometers may have to the local environment. The advantages of mosaic imaging CMB anisotropies using a co-mounted interferometric array in a drift-scanning observing mode are discussed. A particular case of mosaic imaging a sky strip using a two-element AMiBA prototype interferometer is considered and the signal-to-noise ratio in the measurement of sky anisotropy using this observing strategy is analysed.
Scale-dependent CMB asymmetry from primordial configuration
Kohri, Kazunori; Lin, Chia-Min; Matsuda, Tomohiro E-mail: lin@chuo-u.ac.jp
2014-08-01
We demonstrate that a topological defect can explain the hemispherical power asymmetry of the CMB. The first point is that a defect configuration, which already exists prior to inflation, can source asymmetry of the CMB. The second point is that modulation mechanisms, such as the curvaton and other modulation mechanisms, can explain scale-dependence of the asymmetry. Using a simple analysis of the δ N formalism, we show models in which scale-dependent hemispherical power asymmetry is explained by primordial configuration of a defect.
Reconciling CMB and structure growth measurements with dark energy interactions
NASA Astrophysics Data System (ADS)
Pourtsidou, Alkistis; Tram, Thomas
2016-08-01
We study a coupled quintessence model with pure momentum exchange and present the effects of such an interaction on the cosmic microwave background (CMB) and matter power spectrum. For a wide range of negative values of the coupling parameter β structure growth is suppressed and the model can reconcile the tension between cosmic microwave background observations and structure growth inferred from cluster counts. We find that this model is as good as Λ CDM for CMB and baryon acoustic oscillation data, while the addition of cluster data makes the model strongly preferred, improving the best-fit χ2 value by more than 16.
The Kolmogorov-Smirnov test for the CMB
Frommert, Mona; Durrer, Ruth; Michaud, Jérôme E-mail: Ruth.Durrer@unige.ch
2012-01-01
We investigate the statistics of the cosmic microwave background using the Kolmogorov-Smirnov test. We show that, when we correctly de-correlate the data, the partition function of the Kolmogorov stochasticity parameter is compatible with the Kolmogorov distribution and, contrary to previous claims, the CMB data are compatible with Gaussian fluctuations with the correlation function given by standard ΛCDM. We then use the Kolmogorov-Smirnov test to derive upper bounds on residual point source power in the CMB, and indicate the promise of this statistics for further datasets, especially Planck, to search for deviations from Gaussianity and for detecting point sources and Galactic foregrounds.
Loop quantum cosmology, non-Gaussianity, and CMB power asymmetry
NASA Astrophysics Data System (ADS)
Agullo, Ivan
2015-09-01
We argue that the anomalous power asymmetry observed in the cosmic microwave background (CMB) may have originated in a cosmic bounce preceding inflation. In loop quantum cosmology (LQC), the big bang singularity is generically replaced by a bounce due to quantum gravitational effects. We compute the spectrum of inflationary non-Gaussianity and show that strong correlation between observable scales and modes with longer (superhorizon) wavelength arise as a consequence of the evolution of perturbations across the LQC bounce. These correlations are strongly scale dependent and induce a dipole-dominated modulation on large angular scales in the CMB, in agreement with observations.
Nonisotropy in the CMB power spectrum in single field inflation
Donoghue, John F.; Dutta, Koushik; Ross, Andreas
2009-07-15
Contaldi et al.[C. R. Contaldi, M. Peloso, L. Kofman, and A. Linde, J. Cosmol. Astropart. Phys. 07 (2003) 002] have suggested that an initial period of kinetic energy domination in single field inflation may explain the lack of CMB power at large angular scales. We note that in this situation it is natural that there also be a spatial gradient in the initial value of the inflaton field, and that this can provide a spatial asymmetry in the observed CMB power spectrum, manifest at low values of l. We investigate the nature of this asymmetry and comment on its relation to possible anomalies at low l.
NASA Astrophysics Data System (ADS)
Errard, Josquin; Feeney, Stephen M.; Peiris, Hiranya V.; Jaffe, Andrew H.
2016-03-01
Recent results from the BICEP, Keck Array and Planck Collaborations demonstrate that Galactic foregrounds are an unavoidable obstacle in the search for evidence of inflationary gravitational waves in the cosmic microwave background (CMB) polarization. Beyond the foregrounds, the effect of lensing by intervening large-scale structure further obscures all but the strongest inflationary signals permitted by current data. With a plethora of ongoing and upcoming experiments aiming to measure these signatures, careful and self-consistent consideration of experiments' foreground- and lensing-removal capabilities is critical in obtaining credible forecasts of their performance. We investigate the capabilities of instruments such as Advanced ACTPol, BICEP3 and Keck Array, CLASS, EBEX10K, PIPER, Simons Array, SPT-3G and SPIDER, and projects as COrE+, LiteBIRD-ext, PIXIE and Stage IV, to clean contamination due to polarized synchrotron and dust from raw multi-frequency data, and remove lensing from the resulting co-added CMB maps (either using iterative CMB-only techniques or through cross-correlation with external data). Incorporating these effects, we present forecasts for the constraining power of these experiments in terms of inflationary physics, the neutrino sector, and dark energy parameters. Made publicly available through an online interface, this tool enables the next generation of CMB experiments to foreground-proof their designs, optimize their frequency coverage to maximize scientific output, and determine where cross-experimental collaboration would be most beneficial. We find that analyzing data from ground, balloon and space instruments in complementary combinations can significantly improve component separation performance, delensing, and cosmological constraints over individual datasets. In particular, we find that a combination of post-2020 ground- and space-based experiments could achieve constraints such as σ(r)~1.3×10-4, σ(nt)~0.03, σ( ns )~1.8×10
Exploring two-spin internal linear combinations for the recovery of the CMB polarization
NASA Astrophysics Data System (ADS)
Fernández-Cobos, R.; Marcos-Caballero, A.; Vielva, P.; Martínez-González, E.; Barreiro, R. B.
2016-06-01
We present a methodology to recover cosmic microwave background (CMB) polarization in which the quantity P = Q + iU is linearly combined at different frequencies using complex coefficients. This is the most general linear combination of the Q and U Stokes parameters which preserves the physical coherence of the residual contribution on the CMB estimation. The approach is applied to the internal linear combination (ILC) and the internal template fitting (ITF) methodologies. The variance of P of the resulting map is minimized to compute the coefficients of the linear combination. One of the key aspects of this procedure is that it serves to account for a global frequency-dependent shift of the polarization phase. Although in the standard case, in which no global E-B transference depending on frequency is expected in the foreground components, minimizing <|P|2> is similar to minimizing
The shape of CMB temperature and polarization peaks on the sphere
NASA Astrophysics Data System (ADS)
Marcos-Caballero, A.; Fernández-Cobos, R.; Martínez-González, E.; Vielva, P.
2016-04-01
We present a theoretical study of CMB temperature peaks, including its effect over the polarization field, and allowing nonzero eccentricity. The formalism is developed in harmonic space and using the covariant derivative on the sphere, which guarantees that the expressions obtained are completely valid at large scales (i.e., no flat approximation). The expected patterns induced by the peak, either in temperature or polarization, are calculated, as well as their covariances. It is found that the eccentricity introduces a quadrupolar dependence in the peak shape, which is proportional to a complex bias parameter bepsilon, characterizing the peak asymmetry and orientation. In addition, the one-point statistics of the variables defining the peak on the sphere is reviewed, finding some differences with respect to the flat case for large peaks. Finally, we present a mechanism to simulate constrained CMB maps with a particular peak on the field, which is an interesting tool for analysing the statistical properties of the peaks present in the data.
Scodeller, Sandro; Hansen, Frode K. E-mail: frodekh@astro.uio.no
2012-12-20
In Scodeller et al., a new and extended point source catalog obtained from the Wilkinson Microwave Anisotropy Probe (WMAP) seven-year data was presented. It includes most of the sources included in the standard WMAP seven-year point source catalogs as well as a large number of new detections. Here, we study the effects on the estimated CMB power spectrum when taking the newly detected point sources into consideration. We create point source masks for all the 2102 sources that we detected as well as a smaller one for the 665 sources detected in the Q, V, and W bands. We also create WMAP7 maps with point sources subtracted in order to compare with the spectrum obtained with source masks. The extended point source masks and point source cleaned WMAP7 maps are made publicly available. Using the proper residual correction, we find that the CMB power spectrum obtained from the point source cleaned map without any source mask is fully consistent with the spectrum obtained from the masked map. We further find that the spectrum obtained masking all 2102 sources is consistent with the results obtained using the standard WMAP seven-year point source mask (KQ85y7). We also verify that the removal of point sources does not introduce any skewness.
CHEMICAL MASS BALANCE MODEL: EPA-CMB8.2
The Chemical Mass Balance (CMB) method has been a popular approach for receptor modeling of ambient air pollutants for over two decades. For the past few years the U.S. Environmental Protection Agency's Office of Research and Development (ORD) and Office of Air Quality Plannin...
CMB constraint on dark matter annihilation after Planck 2015
NASA Astrophysics Data System (ADS)
Kawasaki, Masahiro; Nakayama, Kazunori; Sekiguchi, Toyokazu
2016-05-01
We update the constraint on the dark matter annihilation cross section by using the recent measurements of the CMB anisotropy by the Planck satellite. We fully calculate the cascade of dark matter annihilation products and their effects on ionization, heating and excitation of the hydrogen, hence do not rely on any assumption on the energy fractions that cause these effects.
Dipole modulation in tensor modes: signatures in CMB polarization
NASA Astrophysics Data System (ADS)
Zarei, Moslem
2015-06-01
In this work we consider a dipole asymmetry in tensor modes and study the effects of this asymmetry on the angular power spectra of CMB. We derive analytical expressions for the and in the presence of such dipole modulation in tensor modes for . We also discuss on the amplitude of modulation term and show that the is considerably modified due to this term.
Joint Bayesian Component Separation and CMB Power Spectrum Estimation
NASA Technical Reports Server (NTRS)
Eriksen, H. K.; Jewell, J. B.; Dickinson, C.; Banday, A. J.; Gorski, K. M.; Lawrence, C. R.
2008-01-01
We describe and implement an exact, flexible, and computationally efficient algorithm for joint component separation and CMB power spectrum estimation, building on a Gibbs sampling framework. Two essential new features are (1) conditional sampling of foreground spectral parameters and (2) joint sampling of all amplitude-type degrees of freedom (e.g., CMB, foreground pixel amplitudes, and global template amplitudes) given spectral parameters. Given a parametric model of the foreground signals, we estimate efficiently and accurately the exact joint foreground- CMB posterior distribution and, therefore, all marginal distributions such as the CMB power spectrum or foreground spectral index posteriors. The main limitation of the current implementation is the requirement of identical beam responses at all frequencies, which restricts the analysis to the lowest resolution of a given experiment. We outline a future generalization to multiresolution observations. To verify the method, we analyze simple models and compare the results to analytical predictions. We then analyze a realistic simulation with properties similar to the 3 yr WMAP data, downgraded to a common resolution of 3 deg FWHM. The results from the actual 3 yr WMAP temperature analysis are presented in a companion Letter.
CMB ISW-lensing bispectrum from cosmic strings
NASA Astrophysics Data System (ADS)
Yamauchi, Daisuke; Sendouda, Yuuiti; Takahashi, Keitaro
2014-02-01
We study the effect of weak lensing by cosmic (super-)strings on the higher-order statistics of the cosmic microwave background (CMB). A cosmic string segment is expected to cause weak lensing as well as an integrated Sachs-Wolfe (ISW) effect, the so-called Gott-Kaiser-Stebbins (GKS) effect, to the CMB temperature fluctuation, which are thus naturally cross-correlated. We point out that, in the presence of such a correlation, yet another kind of the post-recombination CMB temperature bispectra, the ISW-lensing bispectra, will arise in the form of products of the auto- and cross-power spectra. We first present an analytic method to calculate the autocorrelation of the temperature fluctuations induced by the strings, and the cross-correlation between the temperature fluctuation and the lensing potential both due to the string network. In our formulation, the evolution of the string network is assumed to be characterized by the simple analytic model, the velocity-dependent one scale model, and the intercommutation probability is properly incorporated in order to characterize the possible superstringy nature. Furthermore, the obtained power spectra are dominated by the Poisson-distributed string segments, whose correlations are assumed to satisfy the simple relations. We then estimate the signal-to-noise ratios of the string-induced ISW-lensing bispectra and discuss the detectability of such CMB signals from the cosmic string network. It is found that in the case of the smaller string tension, Gμ << 10-7, the ISW-lensing bispectrum induced by a cosmic string network can constrain the string-model parameters even more tightly than the purely GKS-induced bispectrum in the ongoing and future CMB observations on small scales.
CMB ISW-lensing bispectrum from cosmic strings
Yamauchi, Daisuke; Sendouda, Yuuiti; Takahashi, Keitaro E-mail: sendouda@cc.hirosaki-u.ac.jp
2014-02-01
We study the effect of weak lensing by cosmic (super-)strings on the higher-order statistics of the cosmic microwave background (CMB). A cosmic string segment is expected to cause weak lensing as well as an integrated Sachs-Wolfe (ISW) effect, the so-called Gott-Kaiser-Stebbins (GKS) effect, to the CMB temperature fluctuation, which are thus naturally cross-correlated. We point out that, in the presence of such a correlation, yet another kind of the post-recombination CMB temperature bispectra, the ISW-lensing bispectra, will arise in the form of products of the auto- and cross-power spectra. We first present an analytic method to calculate the autocorrelation of the temperature fluctuations induced by the strings, and the cross-correlation between the temperature fluctuation and the lensing potential both due to the string network. In our formulation, the evolution of the string network is assumed to be characterized by the simple analytic model, the velocity-dependent one scale model, and the intercommutation probability is properly incorporated in order to characterize the possible superstringy nature. Furthermore, the obtained power spectra are dominated by the Poisson-distributed string segments, whose correlations are assumed to satisfy the simple relations. We then estimate the signal-to-noise ratios of the string-induced ISW-lensing bispectra and discuss the detectability of such CMB signals from the cosmic string network. It is found that in the case of the smaller string tension, Gμ << 10{sup -7}, the ISW-lensing bispectrum induced by a cosmic string network can constrain the string-model parameters even more tightly than the purely GKS-induced bispectrum in the ongoing and future CMB observations on small scales.
Vallinotto, Alberto
2011-01-01
The measurement of Baryon Acoustic Oscillations through the 21-cm intensity mapping technique at redshift z {<=} 4 has the potential to tightly constrain the evolution of dark energy. Crucial to this experimental effort is the determination of the biasing relation connecting fluctuations in the density of neutral hydrogen (HI) with the ones of the underlying dark matter field. In this work I show how the HI bias relevant to these 21-cm intensity mapping experiments can successfully be measured by cross-correlating their signal with the lensing signal obtained from CMB observations. In particular I show that combining CMB lensing maps from Planck with 21-cm field measurements carried out with an instrument similar to the Cylindrical Radio Telescope, this cross-correlation signal can be detected with a signal-to-noise (S/N) ratio of more than 5. Breaking down the signal arising from different redshift bins of thickness {Delta}z = 0.1, this signal leads to constraining the large scale neutral hydrogen bias and its evolution to 4{sigma} level.
Preliminary DMR measurements of the CMB isotropy
NASA Technical Reports Server (NTRS)
Smoot, G. F.; Bennett, C. L.; Kogut, A.; Aymon, J.; Backus, C.; De Amici, G.; Galuk, K.; Jackson, P. D.; Keegstra, P.; Rokke, L.
1991-01-01
The COBE Differential Microwave Radiometers (DMR) instrument has produced preliminary full-sky maps at frequencies 31.5, 53, and 90 GHz. The redundant channels and matched beams at three frequencies distinguish the DMR from previous large-scale surveys. Galactic emission is seen unambiguously at all three frequencies. The only large-scale anisotropy detected in the cosmic microwave background is the dipole anisotropy. There is no clear evidence for any other large-angular-scale feature in the maps. Without correcting for any systematic effects, we are able to place limits DeltaT/T sub 0 less than 3 x 10 exp -5 for the rms quadrupole amplitude, DeltaT/T sub 0 less than 4 x 10 exp -5 for monochromatic fluctuations, and DeltaT/T sub 0 less than 4 x 10 exp -5 for Gaussian fluctuations (all limits are 95 percent C.L. with TO = 2.735 K). The data limit DeltaT/T sub 0 less than 10 exp -4 for any feature larger than 7 deg. We briefly review the DMR and discuss some implications of these results in cosmology.
Testing the CMB Quenching for High-Redshift Radio Galaxies
NASA Astrophysics Data System (ADS)
Wu, Jianfeng; Gallo, Elena
2016-04-01
The identification of a dozen of high-redshift (z > 4) blazars implies that a much larger population of powerful, but mis-aligned jetted AGNs already exists in the early Universe. However, this parent population remains elusive, although they are expected to be within the sensitivity threshold of modern wide-field radio surveys. One appealing mechanism is that the CMB photons upscatter the diffuse synchrotron radio emission in the lobes to the X-ray band. In this scenario, the lobes will turn into luminous X-ray sources. We analyzed the extended X-ray emission around several radio galaxies at z~4 and constructed their broad-band spectral energy distributions (SEDs). Modeling their SEDs will test this CMB quenching scenario for high-redshift radio galaxies.
Probing early-universe phase transitions with CMB spectral distortions
NASA Astrophysics Data System (ADS)
Amin, Mustafa A.; Grin, Daniel
2014-10-01
Global, symmetry-breaking phase transitions in the early universe can generate scaling seed networks which lead to metric perturbations. The acoustic waves in the photon-baryon plasma sourced by these metric perturbations, when Silk damped, generate spectral distortions of the cosmic microwave background (CMB). In this work, the chemical potential distortion (μ ) due to scaling seed networks is computed and the accompanying Compton y -type distortion is estimated. The specific model of choice is the O (N ) nonlinear σ -model for N ≫1 , but the results remain the same order of magnitude for other scaling seeds. If CMB anisotropy constraints to the O (N ) model are saturated, the resulting chemical potential distortion μ ≲2 ×1 0-9 .
Superconducting Coplanar Switch and Phase Shifter for CMB Applications
NASA Astrophysics Data System (ADS)
Bordier, G.; Cammilleri, V. D.; Belier, B.; Bleurvacq, N.; Gadot, F.; Ghribi, A.; Piat, M.; Tartari, A.; Zanonni, M.
2016-08-01
The next generations of cosmic microwave background (CMB) instruments will be dedicated to the detection and characterization of CMB B-modes. To measure this tiny signal, instruments need to control and minimize systematics. Signal modulation is one way to achieve such a control. A new generation of focal planes will include the entire detection chain. In this context, we present a superconducting coplanar switch driven by DC current. It consists of a superconducting microbridge which commutes between its on (superconducting) and off (normal metal) states, depending on the amplitude of the injected current compared to the critical current. If the current injected inside the bridge is lower than the critical current, the phase of the signal passing through the bridge is tunable. A first prototype of this component working as a switch and as a phase shifter at 10 GHz has been made. The principle, the setup, and the first measurements made at 4 K will be shown.
Nonisotropy in the CMB power spectrum in single field inflation
NASA Astrophysics Data System (ADS)
Donoghue, John F.; Dutta, Koushik; Ross, Andreas
2009-07-01
Contaldi et al. [C. R. Contaldi, M. Peloso, L. Kofman, and A. Linde, J. Cosmol. Astropart. Phys.1475-7516 07 (2003) 00210.1088/1475-7516/2003/07/002] have suggested that an initial period of kinetic energy domination in single field inflation may explain the lack of CMB power at large angular scales. We note that in this situation it is natural that there also be a spatial gradient in the initial value of the inflaton field, and that this can provide a spatial asymmetry in the observed CMB power spectrum, manifest at low values of ℓ. We investigate the nature of this asymmetry and comment on its relation to possible anomalies at low ℓ.
Antenna-coupled TES bolometer arrays for CMB polarimetry
NASA Astrophysics Data System (ADS)
Kuo, C. L.; Bock, J. J.; Bonetti, J. A.; Brevik, J.; Chattopadhyay, G.; Day, P. K.; Golwala, S.; Kenyon, M.; Lange, A. E.; LeDuc, H. G.; Nguyen, H.; Ogburn, R. W.; Orlando, A.; Transgrud, A.; Turner, A.; Wang, G.; Zmuidzinas, J.
2008-07-01
We describe the design and performance of polarization selective antenna-coupled TES arrays that will be used in several upcoming Cosmic Microwave Background (CMB) experiments: SPIDER, BICEP-2/SPUD. The fully lithographic polarimeter arrays utilize planar phased-antennas for collimation (F/4 beam) and microstrip filters for band definition (25% bandwidth). These devices demonstrate high optical efficiency, excellent beam shapes, and well-defined spectral bands. The dual-polarization antennas provide well-matched beams and low cross polarization response, both important for high-fidelity polarization measurements. These devices have so far been developed for the 100 GHz and 150 GHz bands, two premier millimeter-wave atmospheric windows for CMB observations. In the near future, the flexible microstrip-coupled architecture can provide photon noise-limited detection for the entire frequency range of the CMBPOL mission. This paper is a summary of the progress we have made since the 2006 SPIE meeting in Orlando, FL.
CMB dipole asymmetry from a fast roll phase
Mazumdar, Anupam; Wang, Lingfei
2013-10-01
The observed CMB (cosmic microwave background) dipole asymmetry cannot be explained by a single field model of inflation - it inevitably requires more than one field where one of the fields is responsible for amplifying the super-Hubble fluctuations beyond the pivot scale. Furthermore the current constraints on f{sub NL} and τ{sub NL} require that such an amplification cannot produce large non-Gaussianity. In this paper we propose a model to explain this dipole asymmetry from a spectator field, which is responsible for generating all the curvature perturbations, but has a temporary fast roll phase before the Hubble exit of the pivot scale. The current data prefers spectator scenario because it leaves no isocurvature perturbations. The spectator model will also satisfy the well-known constraints arising from quasars, and the quadrupole and octupole of the CMB.
High altitude measurements of fluctuations in the CMB
Davies, R.D. )
1990-01-15
The detection of fluctuations in the primordial CMB emission requires long integrations on limited areas of the sky; such extensive observations are best made from the ground on (high) dry sites. A current programme of measurements is described covering the frequency range 5 to 32 GHz using equipment at Teide Observatory, Tenerife, and in Antarctica. A bolometer system is under development for observations in the range 100 to 300 GHz to be made on Mauna Kea.
Relic vector field and CMB large scale anomalies
Chen, Xingang; Wang, Yi E-mail: yw366@cam.ac.uk
2014-10-01
We study the most general effects of relic vector fields on the inflationary background and density perturbations. Such effects are observable if the number of inflationary e-folds is close to the minimum requirement to solve the horizon problem. We show that this can potentially explain two CMB large scale anomalies: the quadrupole-octopole alignment and the quadrupole power suppression. We discuss its effect on the parity anomaly. We also provide analytical template for more detailed data comparison.
Conformal invariance, dark energy, and CMB non-gaussianity
Antoniadis, Ignatios; Mazur, Pawel O.; Mottola, Emil E-mail: mazur@physics.sc.edu
2012-09-01
In addition to simple scale invariance, a universe dominated by dark energy naturally gives rise to correlation functions possessing full conformal invariance. This is due to the mathematical isomorphism between the conformal group of certain three dimensional slices of de Sitter space and the de Sitter isometry group SO(4,1). In the standard homogeneous, isotropic cosmological model in which primordial density perturbations are generated during a long vacuum energy dominated de Sitter phase, the embedding of flat spatial R{sup 3} sections in de Sitter space induces a conformal invariant perturbation spectrum and definite prediction for the shape of the non-Gaussian CMB bispectrum. In the case in which the density fluctuations are generated instead on the de Sitter horizon, conformal invariance of the S{sup 2} horizon embedding implies a different but also quite definite prediction for the angular correlations of CMB non-Gaussianity on the sky. Each of these forms for the bispectrum is intrinsic to the symmetries of de Sitter space, and in that sense, independent of specific model assumptions. Each is different from the predictions of single field slow roll inflation models, which rely on the breaking of de Sitter invariance. We propose a quantum origin for the CMB fluctuations in the scalar gravitational sector from the conformal anomaly that could give rise to these non-Gaussianities without a slow roll inflaton field, and argue that conformal invariance also leads to the expectation for the relation n{sub S}−1 = n{sub T} between the spectral indices of the scalar and tensor power spectrum. Confirmation of this prediction or detection of non-Gaussian correlations in the CMB of one of the bispectral shape functions predicted by conformal invariance can be used both to establish the physical origins of primordial density fluctuations, and distinguish between different dynamical models of cosmological vacuum dark energy.
Conformal invariance, dark energy, and CMB non-gaussianity
NASA Astrophysics Data System (ADS)
Antoniadis, Ignatios; Mazur, Pawel O.; Mottola, Emil
2012-09-01
In addition to simple scale invariance, a universe dominated by dark energy naturally gives rise to correlation functions possessing full conformal invariance. This is due to the mathematical isomorphism between the conformal group of certain three dimensional slices of de Sitter space and the de Sitter isometry group SO(4,1). In the standard homogeneous, isotropic cosmological model in which primordial density perturbations are generated during a long vacuum energy dominated de Sitter phase, the embedding of flat spatial Bbb R3 sections in de Sitter space induces a conformal invariant perturbation spectrum and definite prediction for the shape of the non-Gaussian CMB bispectrum. In the case in which the density fluctuations are generated instead on the de Sitter horizon, conformal invariance of the Bbb S2 horizon embedding implies a different but also quite definite prediction for the angular correlations of CMB non-Gaussianity on the sky. Each of these forms for the bispectrum is intrinsic to the symmetries of de Sitter space, and in that sense, independent of specific model assumptions. Each is different from the predictions of single field slow roll inflation models, which rely on the breaking of de Sitter invariance. We propose a quantum origin for the CMB fluctuations in the scalar gravitational sector from the conformal anomaly that could give rise to these non-Gaussianities without a slow roll inflaton field, and argue that conformal invariance also leads to the expectation for the relation nS-1 = nT between the spectral indices of the scalar and tensor power spectrum. Confirmation of this prediction or detection of non-Gaussian correlations in the CMB of one of the bispectral shape functions predicted by conformal invariance can be used both to establish the physical origins of primordial density fluctuations, and distinguish between different dynamical models of cosmological vacuum dark energy.
Testing inflation and curvaton scenarios with CMB distortions
NASA Astrophysics Data System (ADS)
Clesse, Sébastien; Garbrecht, Björn; Zhu, Yi
2014-10-01
Prior to recombination, Silk damping causes the dissipation of energy from acoustic waves into the monopole of the Cosmic Microwave Background (CMB), resulting in spectral distortions. These can be used to probe the primordial scalar power spectrum on smaller scales than it is possible with CMB anisotropies. An enhancement of power on these scales is nevertheless required for the resulting distortions to be detectable by future experiments like PIXIE. In this paper, we examine all 49 single-field inflation models listed by Martin et al. in the Encyclopaedia Inflationaris [1] and find that only one of these may lead to a detectable level of distortions in a tuned region of its parameter space, namely the original hybrid model. Three effective multi-field scenarios are also studied: with softly and suddenly turning trajectories, and with a mild waterfall trajectory. Softly turning trajectories do not induce distortions at any detectable level, whereas a sudden turn in the field space or a mild waterfall trajectory predicts a peak (plus damped oscillations in the sudden turn case) in the scalar power spectrum, which can lead to an observable amount of CMB distortions. Finally, another scenario leading to potentially detectable distortions involves a curvaton whose blue spectrum is subdominant on CMB angular scales and overtakes the inflaton spectrum on smaller scales. In this case however, we show that the bounds from ultra compact minihaloes are not satisfied. Expectations for an ultimate PRISM-class experiment characterized by an improvement in sensitivity by a factor of ten are discussed for some models.
Khatri, Rishi; Sunyaev, Rashid A. E-mail: sunyaev@mpa-garching.mpg.de
2013-06-01
Silk damping at redshifts 1.5 × 10{sup 4}∼
Cosmological avatars of the landscape. II. CMB and LSS signatures
Holman, R.; Mersini-Houghton, L.; Takahashi, T.
2008-03-15
This is the second paper in the series that confronts predictions of a model of the landscape with cosmological observations. We show here how the modifications of the Friedmann equation due to the decohering effects of long wavelength modes on the wave function of the Universe defined on the landscape leave unique signatures on the CMB spectra and large scale structure (LSS). We show that the effect of the string corrections is to suppress {sigma}{sub 8} and the CMB temperature-temperature (TT) spectrum at large angles, thereby bringing WMAP and SDSS data for {sigma}{sub 8} into agreement. We find interesting features imprinted on the matter power spectrum P(k): power is suppressed at large scales indicating the possibility of primordial voids competing with the integrated Sachs-Wolfe effect. Furthermore, power is enhanced at structure and substructure scales, k{approx_equal}10{sup -2-0}h Mpc{sup -1}. Our smoking gun for discriminating this proposal from others with similar CMB and LSS predictions comes from correlations between cosmic shear and temperature anisotropies, which here indicate a noninflationary channel of contribution to LSS, with unique ringing features of nonlocal entanglement displayed at structure and substructure scales.
Novel Calibration System with Sparse Wires for CMB Polarization Receivers
NASA Astrophysics Data System (ADS)
Tajima, O.; Nguyen, H.; Bischoff, C.; Brizius, A.; Buder, I.; Kusaka, A.
2012-06-01
A curl competent (also known as B-modes) in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate "simultaneously" all detectors on the large focal plane. We developed a novel calibration system that rotates a large "sparse" grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature photons from the wire surface. Since the detector has a finite beam size, the observed signal is convolved with the beam property. The intensity of the of the calibrator is reasonable (a few Kelvin or less) compared to sky temperature for typical observing conditions (˜10 K). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.
CMB lensing and primordial squeezed non-gaussianity
Pearson, Ruth; Lewis, Antony; Regan, Donough E-mail: antony@cosmologist.info
2012-03-01
Squeezed primordial non-Gaussianity can strongly constrain early-universe physics, but it can only be observed on the CMB after it has been gravitationally lensed. We give a new simple non-perturbative prescription for accurately calculating the effect of lensing on any squeezed primordial bispectrum shape, and test it with simulations. We give the generalization to polarization bispectra, and discuss the effect of lensing on the trispectrum. We explain why neglecting the lensing smoothing effect does not significantly bias estimators of local primordial non-Gaussianity, even though the change in shape can be ∼>10%. We also show how τ{sub NL} trispectrum estimators can be well approximated by much simpler CMB temperature modulation estimators, and hence that there is potentially a ∼ 10–30% bias due to very large-scale lensing modes, depending on the range of modulation scales included. Including dipole sky modulations can halve the τ{sub NL} error bar if kinematic effects can be subtracted using known properties of the CMB temperature dipole. Lensing effects on the g{sub NL} trispectrum are small compared to the error bar. In appendices we give the general result for lensing of any primordial bispectrum, and show how any full-sky squeezed bispectrum can be decomposed into orthogonal modes of distinct angular dependence.
Novel calibration system with sparse wires for CMB polarization receivers
Tajima, O.; Nguyen, H.; Bischoff, C.; Brizius, A.; Buder, I.; Kusaka, A. /Chicago U., KICP
2011-07-01
B-modes in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate 'simultaneously' all detectors on the large focal plane. We developed a novel calibration system that rotates a large 'sparse' grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature from the wire surface. Since the detector has a finite beam size, the observed signal is smeared according to the beam property. The resulting smeared polarized radiation has a reasonable intensity (a few Kelvin or less) compared to the sky temperature ({approx}10 K observing condition). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.
The binned bispectrum estimator: template-based and non-parametric CMB non-Gaussianity searches
NASA Astrophysics Data System (ADS)
Bucher, Martin; Racine, Benjamin; van Tent, Bartjan
2016-05-01
We describe the details of the binned bispectrum estimator as used for the official 2013 and 2015 analyses of the temperature and polarization CMB maps from the ESA Planck satellite. The defining aspect of this estimator is the determination of a map bispectrum (3-point correlation function) that has been binned in harmonic space. For a parametric determination of the non-Gaussianity in the map (the so-called fNL parameters), one takes the inner product of this binned bispectrum with theoretically motivated templates. However, as a complementary approach one can also smooth the binned bispectrum using a variable smoothing scale in order to suppress noise and make coherent features stand out above the noise. This allows one to look in a model-independent way for any statistically significant bispectral signal. This approach is useful for characterizing the bispectral shape of the galactic foreground emission, for which a theoretical prediction of the bispectral anisotropy is lacking, and for detecting a serendipitous primordial signal, for which a theoretical template has not yet been put forth. Both the template-based and the non-parametric approaches are described in this paper.
A FOREGROUND-CLEANED COSMIC MICROWAVE BACKGROUND MAP FROM NON-GAUSSIANITY MEASUREMENT
Saha, Rajib
2011-10-01
In this Letter, we present a new method to estimate a foreground-cleaned cosmic microwave background (CMB) map at a resolution of 1{sup 0} by minimizing the non-Gaussian properties of the cleaned map which arise dominantly due to diffuse foreground emission components from the Milky Way. We employ simple kurtosis statistic as the measure of non-Gaussian properties and perform a linear combination of five frequency maps provided by the Wilkinson Microwave Anisotropy Probe (WMAP) in its seven-year data release in such a way that the cleaned map has a minimum kurtosis which leads to a non-Gaussianity-minimized, foreground-cleaned CMB map. We validate the method by performing Monte Carlo simulations. To minimize any residual foreground contamination from the cleaned map we flag out the region near the galactic plane based upon results from simulations. Outside the masked region our new estimate of the CMB map matches well with the WMAP's Internal Linear Combination (ILC) map. A simple pseudo-C{sub l} -based CMB TT power spectrum derived from the non-Gaussianity minimized map reproduces the earlier results of WMAP's power spectrum. An important advantage of the method is that it does not introduce any negative bias in angular power spectrum in the low multipole regime, unlike usual ILC method. Comparing our results with the previously published results we argue that CMB results are robust with respect to specific foreground removal algorithms employed.
Breaking CMB degeneracy in dark energy through LSS
NASA Astrophysics Data System (ADS)
Lee, Seokcheon
2016-03-01
The cosmic microwave background (CMB) and large-scale structure (LSS) are complementary probes in the investigatation of the early and late time Universe. After the current accomplishment of the high accuracies of CMB measurements, accompanying precision cosmology from LSS data is emphasized. We investigate the dynamical dark energy (DE) models which can produce the same CMB angular power spectra as that of the Λ CDM model with less than a sub-percent level accuracy. If one adopts the dynamical DE models using the so-called Chevallier-Polarski-Linder (CPL) parametrization, ω equiv ω 0 + ω a(1-a), then one obtains models (ω 0,ω a) = (-0.8,-0.767),(-0.9,-0.375), (-1.1,0.355), (-1.2,0.688) named M8, M9, M11, and M12, respectively. The differences of the growth rate, f, which is related to the redshift-space distortions (RSD) between different DE models and the Λ CDM model are about 0.2 % only at z = 0. The difference of f between M8 (M9, M11, M12) and the Λ CDM model becomes maximum at z ˜eq 0.25 with -2.4 (-1.2, 1.2, 2.5) %. This is a scale-independent quantity. One can investigate the one-loop correction of the matter power spectrum of each model using the standard perturbation theory in order to probe the scale-dependent quantity in the quasi-linear regime (i.e. k le 0.4 {h^{-1} Mpc}). The differences in the matter power spectra including the one-loop correction between M8 (M9, M11, M12) and the Λ CDM model for the k= 0.4 {h^{-1} Mpc} scale are 1.8 (0.9, 1.2, 3.0) % at z=0, 3.0 (1.6, 1.9, 4.2) % at z=0.5, and 3.2 (1.7, 2.0, 4.5) % at z=1.0. The larger departure from -1 of ω 0, the larger the difference in the power spectrum. Thus, one should use both the RSD and the quasi-linear observable in order to discriminate a viable DE model among a slew of the models which are degenerate in CMB. Also we obtain the lower limit on ω 0> -1.5 from the CMB acoustic peaks and this will provide a useful limitation on phantom models.