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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; ... Zuntz, J; + view all (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. 10.1093/mnras/stz1514. Green open access

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Abstract

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-Cℓ 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 Cℓ’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 Cℓ’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.

Type: Article
Title: Dark Energy Survey Year 1 results: measurement of the galaxy angular power spectrum
Open access status: An open access version is available from UCL Discovery
DOI: 10.1093/mnras/stz1514
Publisher version: https://doi.org/10.1093/mnras/stz1514
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: cosmology: observations, large-scale structure of Universe
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery.ucl.ac.uk/id/eprint/10077395
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