Error analysis in cross-correlation of sky maps: application to the ISW detection

Constraining cosmological parameters from measurements of the Integrated Sachs-Wolfe effect requires developing robust and accurate methods for computing statistical errors in the cross-correlation between maps. This paper presents a detailed comparison of such error estimation applied to the case of cross-correlation of Cosmic Microwave Background (CMB) and large-scale structure data. We compare theoretical models for error estimation with montecarlo simulations where both the galaxy and the CMB maps vary around a fiducial auto-correlation and cross-correlation model which agrees well with the current concordance LCDM cosmology. Our analysis compares estimators both in harmonic and configuration (or real) space, quantifies the accuracy of the error analysis and discuss the impact of partial sky survey area and the choice of input fiducial model on dark-energy constraints. We show that purely analytic approaches yield accurate errors even in surveys that cover only 10% of the sky and that parameter constraints strongly depend on the fiducial model employed. Alternatively, we discuss the advantages and limitations of error estimators that can be directly applied to data. In particular, we show that errors and covariances from the Jack-Knife method agree well with the theoretical approaches and simulations. We also introduce a novel method in real space that is computationally efficient and can be applied to real data and realistic survey geometries. Finally, we present a number of new findings and prescriptions that can be useful for analysis of real data and forecasts, and present a critical summary of the analyses done to date.Comment: submitted to MNRAS, 26 page

Demanda permanente e inversión privada en la teoría general: una investigación empírica

We empirically test some Keynes’ (and post Keynesians’) assertions relative to the multiplier-accelerator principle. By means of the nonlinear causality test proposed by Diks and Wolski (2016), we conclude that in the United States domestic private investment is driven by permanent demand. We explain that this result is consistent with Keynes’s principle of effective demand in the long run. We hope this paper helps consolidating the potential consensus among Keynesian, Kaleckian and Sraffian economists initiated by the work of Allain (2015)Analizamos empíricamente algunos postulados keynesianos (y post keynesianos) relativos a la interacción multiplicador-acelerador. Mediante el test de causalidad no lineal de Diks y Wolski (2016), sostenemos que en los Estados Unidos existe evidencia a favor de que la inversión privada doméstica es motorizada por la demanda permanente. Argumentamos que este resultado es consistente con el principio de la demanda efectiva en el largo plazo. Esperamos que este trabajo ayude a consolidar el potencial consenso entre economistas Keynesianos, Kaleckianos y Sraffianos que inició el trabajo de Allain (2015

Large-scale Bias and Efficient Generation of Initial Conditions for Non-Local Primordial Non-Gaussianity

We study the scale-dependence of halo bias in generic (non-local) primordial non-Gaussian (PNG) initial conditions of the type motivated by inflation, parametrized by an arbitrary quadratic kernel. We first show how to generate non-local PNG initial conditions with minimal overhead compared to local PNG models for a general class of primordial bispectra that can be written as linear combinations of separable templates. We run cosmological simulations for the local, and non-local equilateral and orthogonal models and present results on the scale-dependence of halo bias. We also derive a general formula for the Fourier-space bias using the peak-background split (PBS) in the context of the excursion set approach to halos and discuss the difference and similarities with the known corresponding result from local bias models. Our PBS bias formula generalizes previous results in the literature to include non-Markovian effects and non-universality of the mass function and are in better agreement with measurements in numerical simulations than previous results for a variety of halo masses, redshifts and halo definitions. We also derive for the first time quadratic bias results for arbitrary non-local PNG, and show that non-linear bias loops give small corrections at large-scales. The resulting well-behaved perturbation theory paves the way to constrain non-local PNG from measurements of the power spectrum and bispectrum in galaxy redshift surveys.Comment: 43 pages, 10 figures. v2: references added. 2LPT parallel code for generating non-local PNG initial conditions available at http://cosmo.nyu.edu/roman/2LP

The clustering of the SDSS main galaxy sample - II. Mock galaxy catalogues and a measurement of the growth of structure from redshift space distortions at z=0.15

Citation: Howlett, C., Ross, A. J., Samushia, L., Percival, W. J., & Manera, M. (2015). The clustering of the SDSS main galaxy sample - II. Mock galaxy catalogues and a measurement of the growth of structure from redshift space distortions at z=0.15. Monthly Notices of the Royal Astronomical Society, 449(1), 848-866. doi:10.1093/mnras/stu2693We measure redshift space distortions in the two-point correlation function of a sample of 63 163 spectroscopically identified galaxies with z < 0.2, an epoch where there are currently only limited measurements, from the Sloan Digital Sky Survey Data Release 7 main galaxy sample (MGS). Our sample, which we denote MGS, covers 6813 deg(2) with an effective redshift z(eff) = 0.15 and is described in our companion paper (Paper I), which concentrates on baryon acoustic oscillation (BAO) measurements. In order to validate the fitting methods used in both papers, and derive errors, we create and analyse 1000 mock catalogues using a new algorithm called PICOLA to generate accurate dark matter fields. Haloes are then selected using a friends-of-friends algorithm, and populated with galaxies using a halo-occupation distribution fitted to the data. Using errors derived from these mocks, we fit a model to the monopole and quadrupole moments of the MGS correlation function. If we assume no Alcock-Paczynski (AP) effect (valid at z = 0.15 for any smooth model of the expansion history), we measure the amplitude of the velocity field, f sigma(8), at z = 0.15 to be 0.49(-0.14)(+0.15) . We also measure f sigma(8) including the AP effect. This latter measurement can be freely combined with recent cosmic microwave background results to constrain the growth index of fluctuations, gamma Assuming a background Lambda cold dark matter cosmology and combining with current BAO data, we find gamma = 0.64 +/- 0.09, which is consistent with the prediction of general relativity (gamma approximate to 0.55), though with a slight preference for higher gamma and hence models with weaker gravitational interactions

Cross-correlation of WMAP 3rd year and the SDSS DR4 galaxy survey: new evidence for Dark Energy

We cross-correlate the third-year WMAP data with galaxy samples extracted from the SDSS DR4 (SDSS4) covering 13% of the sky, increasing by a factor of 3.7 the volume sampled in previous analyses. The new measurements confirm a positive cross-correlation with higher significance (total signal-to-noise of about 4.7). The correlation as a function of angular scale is well fitted by the integrated Sachs-Wolfe (ISW) effect for LCDM flat FRW models with a cosmological constant. The combined analysis of different samples gives Omega_L=0.80-0.85$(68$0.77-0.86$ (95% CL). We find similar best fit values for Omega_L for different galaxy samples with median redshifts of z ~0.3 and z ~0.5, indicating that the data scale with redshift as predicted by the LCDM cosmology (with equation of state parameter w=-1). This agreement is not trivial, but can not yet be used to break the degeneracy constraints in the w versus Omega_L plane using only the ISW data.Comment: 5 pages, final version to be published by MNRAS Let. Minor changes with some additional clarification on error analysis don

Do Patients with Bronchiectasis Have an Increased Risk of Developing Lung Cancer? A Systematic Review

Background: Initial evidence supports the hypothesis that patients with non-cystic fibrosis bronchiectasis (NCFB) have a higher risk of lung cancer. We systematically reviewed the available literature to define the characteristics of lung malignancies in patients with bronchiectasis and the characteristics of patients who develop bronchiectasis-associated lung cancer. Method: This study was performed based on the PRISMA guidelines. The review protocol was registered in PROSPERO. Results: The frequency rates of lung cancer in patients with NCFB ranged from 0.93% to 8.0%. The incidence rate was 3.96. Cancer more frequently occurred in the elderly and males. Three studies found an overall higher risk of developing lung cancer in the NCFB population compared to the non-bronchiectasis one, and adenocarcinoma was the most frequently reported histological type. The effect of the co-existence of NCFB and COPD was unclear. Conclusions: NCFB is associated with a higher risk of developing lung cancer than individuals without NCFB. This risk is higher for males, the elderly, and smokers, whereas concomitant COPD’s effect is unclear