Dark Energy Survey Year 1 results: measurement of the galaxy angular power spectrum

Camacho, H, Kokron, N, Andrade-Oliveira, F, Rosenfeld, R, Lima, M, Lacasa, F, Sobreira, F, da Costa, L N, Avila, S, Chan, K C, Crocce, M, Ross, A J, Troja, A, García-Bellido, J, Romer, A K, DES Collaboration, and others, (2019) Dark Energy Survey Year 1 results: measurement of the galaxy angular power spectrum. Monthly Notices of the Royal Astronomical Society, 487 (3). pp. 3870-3883. ISSN 0035-8711

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We use data from the first-year observations of the DES collaboration to measure the galaxy angular power spectrum (APS), and search for its BAO feature. We test our methodology in a sample of 1800 DES Y1-like mock catalogues. We use the pseudo-C method to estimate the APS and the mock catalogues to estimate its covariance matrix. We use templates to model the measured spectra and estimate template parameters firstly from the C’s of the mocks using two different methods, a maximum likelihood estimator and a Markov Chain Monte Carlo, finding consistent results with a good reduced χ2. Robustness tests are performed to estimate the impact of different choices of settings used in our analysis. Finally, we apply our method to a galaxy sample constructed from DES Y1 data specifically for LSS studies. This catalogue comprises galaxies within an effective area of 1318 deg2 and 0.6 < z < 1.0. We find that the DES Y1 data favour a model with BAO at the 2.6σ C.L. However, the goodness of fit is somewhat poor, with χ2/(d.o.f.) = 1.49. We identify a possible cause showing that using a theoretical covariance matrix obtained from C ’s that are better adjusted to data results in an improved value of χ2/(dof) = 1.36 which is similar to the value obtained with the real-space analysis. Our results correspond to a distance measurement of DA (zeff = 0.81)/rd = 10.65 ± 0.49, consistent with the main DES BAO findings. This is a companion paper to the main DES BAO article showing the details of the harmonic space analysis.

Item Type: Article
Keywords: cosmology: observations, large-scale structure of Universe
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QB Astronomy
Depositing User: Amelia Redman
Date Deposited: 13 Sep 2019 12:03
Last Modified: 13 Sep 2019 12:03
URI: http://sro.sussex.ac.uk/id/eprint/85702

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