WMAP Data Research Articles

Anisotropic Inflationary Scenario Via Generalized Chaplygin Gas Model

We investigate generalized chaplygin gas for warm inflationary scenario in the context of locally rotationally symmetric Bianchi type I universe model. We assume two different cases of dissipative coefficient, i.e., constant as well as function of scalar field. We construct dynamical equations as well as a relationship between scalar and radiation energy densities under slow-roll approximation. We also derive slow-roll parameters, scalar and tensor power spectra, scalar spectral index, tensor to scalar ratio for analyzing inflationary background during high dissipative regime. We also use the WMAP7 data for the discussion of our parameters.

Preferred axis of CMB parity asymmetry in the masked maps

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.

Nonlinear electromagnetic fields as a source of universe acceleration

A model of nonlinear electromagnetic fields with a dimensional parameter [Formula: see text] is proposed. From PVLAS experiment the bound on the parameter [Formula: see text] was obtained. Electromagnetic fields are coupled with the gravitation field and we show that the universe accelerates due to nonlinear electromagnetic fields. The magnetic universe is considered and the stochastic magnetic field is a background. After inflation the universe decelerates and approaches to the radiation era. The range of the scale factor, when the causality of the model and a classical stability take place, was obtained. The spectral index, the tensor-to-scalar ratio, and the running of the spectral index were estimated which are in approximate agreement with the Planck, WMAP, and BICEP2 data.

Modified Chaplygin gas inspired inflationary model in braneworld scenario

We investigate the modified Chaplygin gas inspired inflationary regime in the brane-world framework in the presence of standard and tachyon scalar fields. We consider the intermediate inflationary scenario and construct the slow-roll parameters, e-folding numbers, spectral index, scalar and tensor power spectra, tensor to scalar ratio for both scalar field models. We develop the $n_{s} - \mathcal{N}$ and $r - \mathcal{N}$ planes and concluded that $n_{s}\simeq96^{+0.5}_{-0.5}$ and $r\leq0.0016$ for $\mathcal{N}\simeq60^{+5}_{-5}$ in both cases of scalar field models as well as for all values of $m$ . These constraints are consistent with observational data such as WMAP7, WMAP9 and Planck data.

Pion-like dark matter

We introduce the model of the light dark matter particles emerging as the pseudo-Goldstone bosons of spontaneously broken GDM=SU(N)⊗SU(N) to the unbroken HDM=SU(N) group. The associated fields transform linearly under HDM, but non-linearly under GDM/HDM and their number is equal to the number of broken generators of G/H group according to the Coleman-Wess-Zumino theorem. Those massless fields which acquire HDM breaking degenerate masses we call “dark mater pions” (DMP). We investigate the thermal history of DMP and solve the Boltzmann equations. We compare the results with the WMAP and PLANCK data as well as with the direct detection experiment results and constrain the model parameters.

Characterization of foreground emission on degree angular scales for CMBB-mode observations

We quantify the contamination from polarized diffuse Galactic synchrotron and thermal dust emissions to the B-modes of the CMB anisotropies on the degree angular scale, using data from the Planck and WMAP satellites. We compute power spectra of foreground polarized emissions in 352 circular sky patches located at Galactic latitude |b|>20{\deg}, each of which covering a fraction of the sky of about 1.5%. We make use of the spectral properties derived from Planck and WMAP data to extrapolate, in frequency, the amplitude of synchrotron and thermal dust B-modes spectra in the multipole bin centered at $\ell\simeq80$. In this way we estimate, for each analyzed region, the amplitude and frequency of the foreground minimum. We detect both dust and synchrotron signal, at degree angular scale and at 3 confidence level, in 28 regions. Here the minimum of the foreground emission is found at frequencies between 60 and 100 GHz with an amplitude,expressed in terms of the equivalent tensor-to-scalar ratio, r_FG, between ~0.06 and ~1. Some of these regions are located at high Galactic latitudes, in areas close to the ones which are being observed by sub-orbital experiments.In all the other sky patches, where synchrotron or dust B-modes are not detectable with the required confidence, we put upper limits on the minimum foreground contamination and find values of r_FG between ~0.05 and ~1.5, in the frequency range 60-90 GHz. Our results indicate that, with the current sensitivity at low frequency, it is not possible to exclude the presence of synchrotron contamination to CMB cosmological B-modes at the level requested to measure a gravitational waves signal with r~0.01, at frequency <100 GHz, anywhere. Therefore, more accurate data are essential in order to better characterize the synchrotron polarized component, and eventually, remove its contamination to CMB signal through foreground cleaning.

Dark matter implications of the WMAP-Planck Haze

Gamma rays and microwave observations of the Galactic Center and surrounding areas indicate the presence of anomalous emission, whose origin remains ambiguous. The possibility of dark matter annihilation explaining both signals through prompt emission at gamma rays and secondary emission at microwave frequencies from interactions of high-energy electrons produced in annihilation with the Galactic magnetic fields has attracted much interest in recent years. We investigate the dark matter interpretation of the Galactic Center gamma-ray excess by searching for the associated synchrotron emission in the WMAP and Planck microwave data. Considering various magnetic field and cosmic-ray propagation models, we predict the synchrotron emission due to dark matter annihilation in our Galaxy, and compare it with the WMAP and Planck data at 23–70 GHz. In addition to standard microwave foregrounds, we separately model the microwave counterpart to the Fermi Bubbles and the signal due to dark matter annihilation, and use component separation techniques to extract the signal associated with each template from the total emission. We confirm the presence of the Haze at the level of ≈7% of the total sky intensity at 23 GHz in our chosen region of interest, with a harder spectrum (I ∼ ν−0.8) than the synchrotron from regular cosmic-ray electrons. The data do not show a strong preference towards fitting the Haze by either the Bubbles or dark matter emission only. Inclusion of both components provides a better fit with a dark matter contribution to the Haze emission of ≈20% at 23 GHz, however, due to significant uncertainties in foreground modeling, we do not consider this a clear detection of a dark matter signal. We set robust upper limits on the annihilation cross section by ignoring foregrounds, and also report best-fit dark matter annihilation parameters obtained from a complete template analysis. We conclude that the WMAP and Planck data are consistent with a dark matter interpretation of the gamma-ray excess.

Fractality of Isotherms of the Cosmic Microwave Background Based on Data from the Planck Spacecraft

A system of isophotes of the cosmic microwave background (CMB) is constructed for several regions on the celestial sphere using data from the Planck spacecraft. The fractal dimensionality of the isotherms is estimated to be Dc ≈ 1.78 ± 0.03. Our results agree with earlier work based on the ILC charts with WMAP data. Our simulations confirm the previous conclusion that a similar dimensionality is obtained for a gaussian spectrum of initial perturbations.

Cosmic ray contributions to the WMAP polarization data on the cosmic microwave background

We have updated our analysis of the 9-year WMAP data using the collection of polarization maps looking for the presence of additional evidence for a finite ‘cosmic ray (CR) foreground’ for the cosmic microwave background (CMB). We have given special attention to high Galactic latitudes, where the recent BICEP2 findings were reported although very recent Planck data claims that dust is prevalent, thus nullifying the BICEP2 results. The method of examining the correlation with the observed gamma ray flux proposed in our earlier papers and applied to the polarization data shows that the foreground related to CRs is still observed even at high Galactic latitudes and conclusions about gravitational waves are not yet secure. Theory has it that there is important information about inflationary gravitational waves in the fine structure of the CMB polarization properties (polarization vector and angle) and it is necessary to examine further the conclusions that can be gained from studies of the CMB maps, in view of the disturbing foreground effects.

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

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

Hypothesis of the Hidden Multiverse Explains Dark Matter and Dark Energy

Analysis of WMAP and Planck spacecraft data has proved that we live in an invisible Multiverse, referred to as hidden, that has a quaternion structure. It explains the reason for the mutual invisibility of parallel universes contained in the hidden Multiverse. It is shown that the hidden Multiverse includes most likely twenty parallel universes from different dimensions, six of which are adjacent to our universe. Besides, edges of the hidden Multiverse are connected to other (from one to four) Multiverses, which are observable neither by electromagnetic nor by gravitational manifestations. The Multiverse described contains four matter-antimatter pairs, annihilation of which is prevented by relative spatial position of the universes. The experimental proof of existence of the hidden Multiverse is explained to be the phenomenon of dark matter and dark energy that correspond to other invisible parallel universes, except ours, included in the hidden Multiverse. General scientific principle of physical reality of imaginary numbers, refuting some of the statements of the existing version of the special theory of relativity, is a physical and mathematical foundation of the outlined conception of the hidden Multiverse. The article presents relativistic formulas of the theory of special relativity adjusted in accordance with the principle. It also offers appropriate interpretation of multidimensional space of the hidden Multiverse.

Possible evidence for Planck-scale resonant particle production during inflation from the CMB power spectrum

The power spectrum of the cosmic microwave background from both the Planck and WMAP data exhibits a slight dip in for multipoles in the range of l=10-30. We show that such a dip could be the result of resonant creation of a massive particle that couples to the inflaton field. For our best-fit models, epochs of resonant particle creation reenters the horizon at wave numbers of k* ~ 0.00011 (h/Mpc). The amplitude and location of these features correspond to the creation of a number of degenerate fermion species of mass ~ 15 times the planck mass during inflation with a coupling constant between the inflaton field and the created fermion species of near unity. Although the evidence is marginal, if this interpretation is correct, this could be one of the first observational hints of new physics at the Planck scale.

Search for features in the spectrum of primordial perturbations using Planck and other datasets

We reconstruct the power spectrum of primordial curvature perturbations by applying a well-validated non-parametric technique employing Tikhonov regularisation to the first data release from the Planck satellite. To improve the reconstruction on small spatial scales we include data from the ground-based ACT and SPT experiments, the WiggleZ galaxy redshift survey, the CFHTLenS tomographic weak lensing survey, and spectral analysis of the Lyman-α forest. The reconstructed scalar spectrum (assuming the standard ΛCDM cosmology) is not scale-free but has an infrared cutoff at k ≲ 5 × 10-4 Mpc-1 and several (2−3)σ features, of which two at wavenumber k/Mpc-1 0.0018 and 0.057 had been seen already in WMAP data. A higher significance feature at k ∼ 0.12 Mpc-1 is indicated by Planck data, but may be sensitive to the systematic uncertainty around multipole ℓ ∼ 1800 in the 217×217 GHz cross-spectrum. In any case accounting for the ‘look elsewhere’ effect decreases its global significance to ∼2σ.

Influence ofPlanckforeground masks in the large angular scale quadrant CMB asymmetry

The measured CMB angular distribution shows a great consistency with the LCDM model. However, isotropy violations were reported in CMB temperature maps of both WMAP and Planck data. We investigate the influence of different masks employed in the analysis of CMB angular distribution, in particular in the excess of power in the Southeastern quadrant (SEQ) and the lack of power in the Northeastern quadrant (NEQ). We compare the two-point correlation function (TPCF) computed for each quadrant of the CMB foreground-cleaned temperature maps to 1000 simulations generated assuming the LCDM best-fit power spectrum using four different masks. In addition to the quadrants, we computed the TPCF for circular regions in the map where the excess and lack of power are present. We also compare the effect of Galactic cuts in the TPCF calculations as compared to the simulations. We found consistent results for three masks, namely mask-rulerminimal, U73 and U66. The results indicate that the excess of power in the SEQ tends to vanish as the portion of the sky covered by the mask increases and the lack of power in the NEQ remains virtually unchanged. When UT78 mask is applied, the NEQ becomes no longer anomalous and the excess of power in the SEQ becomes the most significant one among the masks. Nevertheless, the asymmetry between the SEQ and NEQ is independent of the mask and it is in disagreement with the isotropic model with at least 95% C.L. We find that UT78 is in disagreement with the other analysed masks, specially considering the SEQ and the NEQ individual analysis. Most importantly, the use of UT78 washes out the anomaly in the NEQ. Furthermore, we found excess of kurtosis, compared with simulations, in the NEQ for the regions not masked by UT78 but masked by the other masks, indicating that the previous result could be due to non-removed residual foregrounds by UT78.

ASSOCIATIONS BETWEEN SMALL-SCALE STRUCTURE IN LOCAL GALACTIC NEUTRAL HYDROGEN AND IN THE COSMIC MICROWAVE BACKGROUND OBSERVED BYPLANCK

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

Constraints on the birth of the universe and origin of cosmic dark flow

We summarize three recent efforts to constrain the first few moments of cosmic creation before and during the epoch of inflation. We consider two means to explain a slight dip in the power spectrum of the cosmic microwave background for multipoles in the range of [Formula: see text] from both the Planck and WMAP data. We show that such a dip could be the result of resonant creation of a massive particle that couples to the inflaton field. For best-fit models, the epoch of resonant particle creation reenters the horizon at wave numbers of [Formula: see text]. The amplitude and location of these features correspond to the creation of a number of degenerate fermion species of mass [Formula: see text] during inflation where [Formula: see text] is the coupling constant between the inflaton field and the created fermion species. Alternatively, one can explain the existence of such a dip as due to a jump in the inflation generating potential. We show that such a jump can also resolve the excessively large dark flow predicted from the M-theory landscape. Finally, we summarize our efforts to quantify constraints on the cosmic dark flow from a new analysis of the Type Ia supernova distance-redshift relation.

THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS OF THE GALACTIC PLANE AT 43 AND 95 GHz

We present polarization observations of two Galactic plane fields centered on Galactic coordinates (l,b)=(0 deg,0 deg) and (329 deg, 0 deg) at Q- (43 GHz) and W-band (95 GHz), covering between 301 and 539 square degrees depending on frequency and field. These measurements were made with the QUIET instrument between 2008 October and 2010 December, and include a total of 1263 hours of observations. The resulting maps represent the deepest large-area Galactic polarization observations published to date at the relevant frequencies with instrumental rms noise varying between 1.8 and 2.8 uK deg, 2.3-6 times deeper than corresponding WMAP and Planck maps. The angular resolution is 27.3' and 12.8' FWHM at Q- and W-band, respectively. We find excellent agreement between the QUIET and WMAP maps over the entire fields, and no compelling evidence for significant residual instrumental systematic errors in either experiment, whereas the Planck 44 GHz map deviates from these in a manner consistent with reported systematic uncertainties for this channel. We combine QUIET and WMAP data to compute inverse-variance-weighted average maps, effectively retaining small angular scales from QUIET and large angular scales from WMAP. From these combined maps, we derive constraints on several important astrophysical quantities, including a robust detection of polarized synchrotron spectral index steepening of ~0.2 off the plane, as well as the Faraday rotation measure toward the Galactic center (RM=-4000 +/- 200 rad m^-2), all of which are consistent with previously published results. Both the raw QUIET and the co-added QUIET+WMAP maps are made publicly available together with all necessary ancillary information.

Microwave background correlations from dipole anisotropy modulation

Full-sky maps of the cosmic microwave background temperature reveal a 7% asymmetry of fluctuation power between two halves of the sky. A common phenomenological model for this asymmetry is an overall dipole modulation of statistically isotropic fluctuations, which produces particular off-diagonal correlations between multipole coefficients. We compute these correlations and construct corresponding estimators for the amplitude and direction of the dipole modulation. Applying these estimators to various cut-sky temperature maps from Planck and WMAP data shows consistency with a dipole modulation, differing from a null signal at 2.5$\sigma$, with an amplitude and direction consistent with previous fits based on the temperature fluctuation power. The signal is scale dependent, with a statistically significant amplitude at angular scales larger than 2 degrees. Future measurements of microwave background polarization and gravitational lensing can increase the significance of the signal. If the signal is not a statistical fluke in an isotropic Universe, it requires new physics beyond the standard model of cosmology.

Testing isotropy of cosmos with WMAP and PLANCK data

In recent years, there have been a large number of studies which support violation of statistical isotropy. Meanwhile, there are some studies which also found inconsistency. We use the power tensor method defined earlier in the literature to study the new CMBR data. The orientation of these three orthogonal vectors, as well as the power associated with each vector, contains information about possible violation of statistical isotropy. This information is encoded in two entropy measures, the power-entropy and alignment-entropy. We apply this method to WMAP 9-year and PLANCK data. Here, we also revisit the statistics to test high-[Formula: see text] anomaly reported in our earlier paper and find that the high degree of isotropy seen in earlier WMAP 5-year data is absent in the revised WMAP 9-year data.

Planckintermediate results

Any variation of the fundamental physical constants, and more particularly of the fine structure constant, $\alpha$, or of the mass of the electron, $m_e$, would affect the recombination history of the Universe and cause an imprint on the cosmic microwave background angular power spectra. We show that the Planck data allow one to improve the constraint on the time variation of the fine structure constant at redshift $z\sim 10^3$ by about a factor of 5 compared to WMAP data, as well as to break the degeneracy with the Hubble constant, $H_0$. In addition to $\alpha$, we can set a constraint on the variation of the mass of the electron, $m_{\rm e}$, and on the simultaneous variation of the two constants. We examine in detail the degeneracies between fundamental constants and the cosmological parameters, in order to compare the limits obtained from Planck and WMAP and to determine the constraining power gained by including other cosmological probes. We conclude that independent time variations of the fine structure constant and of the mass of the electron are constrained by Planck to ${\Delta\alpha}/{\alpha}= (3.6\pm 3.7)\times10^{-3}$ and ${\Delta m_{\rm e}}/{m_{\rm e}}= (4 \pm 11)\times10^{-3}$ at the 68% confidence level. We also investigate the possibility of a spatial variation of the fine structure constant. The relative amplitude of a dipolar spatial variation of $\alpha$ (corresponding to a gradient across our Hubble volume) is constrained to be $\delta\alpha/\alpha=(-2.4\pm 3.7)\times 10^{-2}$.