arXiv subjects

A. Marcos-Caballero

Publications and source records attributed to A. Marcos-Caballero.

22 records · Page 2Linked to original sources

arXiv2013

A new model for NVSS galaxy catalogue using the redshift distribution and halo minimum mass

In the present paper we study the radio sources in the NRAO VLA SKY Survey (NVSS) analysing its power spectrum and galaxy distribution. There is a discrepancy between the theoretical models in the literature and the data at large scales. A new model for NVSS is proposed combining the power spectrum data from NVSS and the galaxy distribution from the Combined EIS-NVSS Survey Of Radio Sources (CENSORS). Taken into account these two data sets the differences in the power spectrum at large scales are reduced, but there is still some tension between the two data sets. Different models are compared using Bayesian evidence. A model for the galaxy distribution based on a gamma function provides a higher evidence against other models proposed in the literature. In addition, the effect of primordial non-Gaussianity has been also considered. The 2-sigma constraints on the local non-Gaussian f_NL parameter are -43 < f_NL < 142.

astro-ph.CO↗

arXiv2013

The Jubilee ISW Project I: simulated ISW and weak lensing maps and initial power spectra results

We present initial results from the Jubilee ISW project, which models the expected \LambdaCDM Integrated Sachs-Wolfe (ISW) effect in the Jubilee simulation. The simulation volume is (6 Gpc/h)^3, allowing power on very large-scales to be incorporated into the calculation. Haloes are resolved down to a mass of 1.5x10^12 M_sun/h, which allows us to derive a catalogue of mock Luminous Red Galaxies (LRGs) for cross-correlation analysis with the ISW signal. We find the ISW effect observed on a projected sky to grow stronger at late times with the evolution of the ISW power spectrum matching expectations from linear theory. Maps of the gravitational lensing effect, including the convergence and deflection fields, are calculated using the same potential as for the ISW. We calculate the redshift dependence of the ISW-LRG cross-correlation signal for a full sky survey with no noise considerations. For l < 30, the signal is strongest for lower redshift bins (z ~ 0.2 to 0.5), whereas for l > 30 the signal is best observed with surveys covering z ~ 0.6-1.0.

astro-ph.CO↗

arXiv2013

Integrated Sachs-Wolfe map recovery from NVSS and WMAP 7yr data

We present a map of the Cosmic Microwave Background (CMB) anisotropies induced by the late Integrated Sachs Wolfe effect. The map is constructed by combining the information of the WMAP 7-yr CMB data and the NRAO VLA Sky Survey (NVSS) through a linear filter. This combination improves the quality of the map that would be obtained using information only from the Large Scale Structure data. In order to apply the filter, a given cosmological model needs to be assumed. In particular, we consider the standard LCDM model. As a test of consistency, we show that the reconstructed map is in agreemet with the assumed model, which is also favoured against a scenario where no correlation between the CMB and NVSS catalogue is considered.

astro-ph.CO↗

arXiv2012

An optimal estimator for the CMB-LSS angular power spectrum and its application to WMAP and NVSS data

We use a Quadratic Maximum Likelihood (QML) method to estimate the angular power spectrum of the cross-correlation between cosmic microwave background and large scale structure maps as well as their individual auto-spectra. We describe our implementation of this method and demonstrate its accuracy on simulated maps. We apply this optimal estimator to WMAP 7-year and NRAO VLA Sky Survey (NVSS) data and explore the robustness of the angular power spectrum estimates obtained by the QML method. With the correction of the declination systematics in NVSS, we can safely use most of the information contained in this survey. We then make use of the angular power spectrum estimates obtained by the QML method to derive constraints on the dark energy critical density in a flat $Λ$CDM model by different likelihood prescriptions. When using just the cross-correlation between WMAP 7 year and NVSS maps with 1.8$^\circ$ resolution, the best-fit model has a cosmological constant of approximatively 70% of the total energy density, disfavouring an Einstein-de Sitter Universe at more than 2 $σ$ CL (confidence level).

astro-ph.CO↗