Multi-resolution internal template cleaning: An application to the Wilkinson Microwave Anisotropy Probe 7-yr polarization data

Cosmic microwave background (CMB) radiation data obtained by different experiments contain, besides the desired signal, a superposition of microwave sky contributions. We present a fast and robust method, using a wavelet decomposition on the sphere, to recover the CMB signal from microwave maps. An application to \textit{WMAP} polarization data is presented, showing its good performance particularly in very polluted regions of the sky. The applied wavelet has the advantages of requiring little computational time in its calculations, being adapted to the \textit{HEALPix} pixelization scheme, and offering the possibility of multi-resolution analysis. The decomposition is implemented as part of a fully internal template fitting method, minimizing the variance of the resulting map at each scale. Using a $\chi^2$ characterization of the noise, we find that the residuals of the cleaned maps are compatible with those expected from the instrumental noise. The maps are also comparable to those obtained from the \textit{WMAP} team, but in our case we do not make use of external data sets. In addition, at low resolution, our cleaned maps present a lower level of noise. The E-mode power spectrum $C_{\ell}^{EE}$ is computed at high and low resolution; and a cross power spectrum $C_{\ell}^{TE}$ is also calculated from the foreground reduced maps of temperature given by \textit{WMAP} and our cleaned maps of polarization at high resolution. These spectra are consistent with the power spectra supplied by the \textit{WMAP} team. We detect the E-mode acoustic peak at $\ell \sim 400$, as predicted by the standard $\Lambda CDM$ model. The B-mode power spectrum $C_{\ell}^{BB}$ is compatible with zero.Comment: 8 pages, 6 figures. Some changes have been done from the original manuscript. This paper is accepted by MNRA

Wilkinson Microwave Anisotropy Probe 7-yr constraints on fNL with a fast wavelet estimator

A new method to constrain the local non-linear coupling parameter fNL based on a fast wavelet decomposition is presented. Using a multiresolution wavelet adapted to the HEALPix pixelization, we have developed a method that is 10^2 times faster than previous estimators based on isotropic wavelets and 10^3 faster than the KSW bispectrum estimator, at the resolution of the Wilkinson Microwave Anisotropy Probe (WMAP) data. The method has been applied to the WMAP 7-yr V+W combined map, imposing constraints on fNL of -69 < fNL < 65 at the 95 per cent CL. This result has been obtained after correcting for the contribution of the residual point sources which has been estimated to be fNL = 7 +/- 6. In addition, a Gaussianity analysis of the data has been carried out using the third order moments of the wavelet coefficients, finding consistency with Gaussianity. Although the constrainsts imposed on fNL are less stringent than those found with optimal estimators, we believe that a very fast method, as the one proposed in this work, can be very useful, especially bearing in mind the large amount of data that will be provided by future experiments, such as the Planck satellite. Moreover, the localisation of wavelets allows one to carry out analyses on different regions of the sky. As an application, we have separately analysed the two hemispheres defined by the dipolar modulation proposed by Hoftuft et al. (2009). We do not find any significant asymmetry regarding the estimated value of fNL in those hemispheres.Comment: 8 pages, 5 figures. Submitted and Accepted for publication in MNRA

Incidental changes in orthographic processing in the native language as a function of learning a new language late in life

Acquiring a second alphabetic language also entails learning a new set of orthographic rules and specific patterns of grapheme combinations (namely, the orthotactics). The present longitudinal study aims to investigate whether orthotactic sensitivity changes over the course of a second language learning programme. To this end, a group of Spanish monolingual old adults completed a Basque language learning course. They were tested in different moments with a language decision task that included pseudowords that could be Basque-marked, Spanish-marked or neutral. Results showed that the markedness effect varied as a function of second language acquisition, showing that learning a second language changes the sensitivity not only to the orthographic patterns of the newly acquired language, but to those of the native language too. These results demonstrate that the orthographic representations of the native language are not static and that experience with a second language boosts markedness perception in the first language

Constraints on fNL from Wilkinson Microwave Anisotropy Probe 7-year data using a neural network classifier

We present a multi-class neural network (NN) classifier as a method to measure nonGaussianity, characterised by the local non-linear coupling parameter fNL, in maps of the cosmic microwave background (CMB) radiation. The classifier is trained on simulated non-Gaussian CMB maps with a range of known fNL values by providing it with wavelet coefficients of the maps; we consider both the HealPix (HW) wavelet and the spherical Mexican hat wavelet (SMHW). When applied to simulated test maps, the NN classfier produces results in very good agreement with those obtained using standard chi2 minimization. The standard deviations of the fNL estimates for WMAPlike simulations were {\sigma} = 22 and {\sigma} = 33 for the SMHW and the HW, respectively, which are extremely close to those obtained using classical statistical methods in Curto et al. and Casaponsa et al. Moreover, the NN classifier does not require the inversion of a large covariance matrix, thus avoiding any need to regularise the matrix when it is not directly invertible, and is considerably faster.Comment: Accepted for publication in MNRAS, 9 pages, 5 figures, 1 tabl

Size magnification as a complement to Cosmic Shear

We investigate the extent to which cosmic size magnification may be used to com- plement cosmic shear in weak gravitational lensing surveys, with a view to obtaining high-precision estimates of cosmological parameters. Using simulated galaxy images, we find that size estimation can be an excellent complement, finding that unbiased estimation of the convergence field is possible with galaxies with angular sizes larger than the point-spread function (PSF) and signal-to-noise ratio in excess of 10. The statistical power is similar to, but not quite as good as, cosmic shear, and it is subject to different systematic effects. Application to ground-based data will be challeng- ing, with relatively large empirical corrections required to account for with biases for galaxies which are smaller than the PSF, but for space-based data with 0.1 arcsecond resolution, the size distribution of galaxies brighter than i=24 is ideal for accurate estimation of cosmic size magnification.Comment: 11 pages, 11 figures, accepted by MNRA

The QUIJOTE experiment: project overview and first results

QUIJOTE (Q-U-I JOint TEnerife) is a new polarimeter aimed to characterize the polarization of the Cosmic Microwave Background and other Galactic and extragalactic signals at medium and large angular scales in the frequency range 10-40 GHz. The multi-frequency (10-20~GHz) instrument, mounted on the first QUIJOTE telescope, saw first light on November 2012 from the Teide Observatory (2400~m a.s.l). During 2014 the second telescope has been installed at this observatory. A second instrument at 30~GHz will be ready for commissioning at this telescope during summer 2015, and a third additional instrument at 40~GHz is now being developed. These instruments will have nominal sensitivities to detect the B-mode polarization due to the primordial gravitational-wave component if the tensor-to-scalar ratio is larger than r=0.05.Comment: To appear in "Highlights of Spanish Astrophysics VIII", Proceedings of the XI Scientific Meeting of the Spanish Astronomical Society, Teruel, Spain (2014

On the optimality of the spherical Mexican hat wavelet estimator for the primordial non-Gaussianity

We study the spherical Mexican hat wavelet (SMHW) as a detector of primordial non-Gaussianity of the local type on the Cosmic Microwave Background (CMB) anisotropies. For this purpose we define third order statistics based on the wavelet coefficient maps and the original map. We find the dependence of these statistics in terms of the non-linear coupling parameter fnl and the bispectrum of this type of non-Gaussianity. We compare the analytical values for these statistics with the results obtained with non-Gaussian simulations for an ideal full-sky CMB experiment without noise. We study the power of this method to detect fnl, i. e. the variance of this parameter, and compare it with the variance obtained from the primary bispectrum for the same experiment. Finally we apply our wavelet based estimator on WMAP-like maps with incomplete sky and inhomogeneous noise and compare with the optimal bispectrum estimator. The results show that the wavelet cubic statistics are as efficient as the bispectrum as optimal detectors of this type of primordial non-Gaussianity.Comment: 10 pages, 9 figures, 1 table. Minor revision, references added, accepted for publication in MNRA

QUIJOTE scientific results - III. Microwave spectrum of intensity and polarization in the Taurus Molecular Cloud complex and L1527

ABSTRACT: We present new intensity and polarization observations of the Taurus Molecular Cloud (TMC) region in the frequency range 10–20 GHz with the multifrequency instrument (MFI) mounted on the first telescope of the Q-U-I-JOint TEnerife (QUIJOTE) experiment. From the combination of the QUIJOTE data with the WMAP 9-yr data release, the Planck second data release, the DIRBE maps, and ancillary data, we detect an anomalous microwave emission (AME) component with flux density SAME,peak = 43.0 ± 7.9 Jy in the TMC and SAME,peak = 10.7 ± 2.7 Jy in the dark cloud nebula L1527, which is part of the TMC. In the TMC the diffuse AME emission peaks around a frequency of 19 GHz, compared with an emission peak about a frequency of 25 GHz in L1527. In the TMC, the best constraint on the level of AME polarization is obtained at the Planck channel of 28.4 GHz, with an upper limit πAME < 4.2 per cent (95 per cent C.L.), which reduces to πAME < 3.8 per cent (95 per cent C.L.) if the intensity of all the free–free, synchrotron and thermal dust components are negligible at this frequency. The same analysis in L1527 leads to πAME < 5.3 per cent (95 per cent C.L.) or πAME < 4.5 per cent (95 per cent C.L.) under the same assumption. We find that in the TMC and L1527 on average about 80 per cent of the H II gas should be mixed with thermal dust. Our analysis shows how the QUIJOTE-MFI 10–20 GHz data provide key information to properly separate the synchrotron, free–free, and AME components.This work has been partially funded by the Spanish Ministry of Economy and Competitiveness (MINECO) under the projects AYA2007-68058-C03-01, AYA2010-21766-C03-02, AYA2012-39475-C02-01, AYA2014-60438-P: ESP2015- 70646.C2-1-R, AYA2015-64508-P and the Consolider-Ingenio project CSD2010-00064 (EPI: Exploring the Physics of Inflation)