### 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-C_{l} 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_{l}'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 χ^{2}. 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 deg^{2} and 0.6 < z < 1.0. We find that the DES Y1 data favour a model with BAO at the $2.6 σ C.L. However, the goodness of fit is somewhat poor, with χ^{2}/(d.o.f.) = 1.49. We identify a possible cause showing that using a theoretical covariance matrix obtained from C_{l}'s that are better adjusted to data results in an improved value of χ^{2}/(dof) = 1.36 which is similar to the value obtained with the real-space analysis. Our results correspond to a distance measurement of D_{A}(z_{eff} = 0.81)/r_{d} = 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.

Original language | English (US) |
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Pages (from-to) | 3870-3883 |

Number of pages | 14 |

Journal | Monthly Notices of the Royal Astronomical Society |

Volume | 487 |

Issue number | 3 |

DOIs | |

State | Published - 2019 |

### Keywords

- cosmology: observations
- large-scale structure of Universe

### ASJC Scopus subject areas

- Astronomy and Astrophysics
- Space and Planetary Science

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## Cite this

*Monthly Notices of the Royal Astronomical Society*,

*487*(3), 3870-3883. https://doi.org/10.1093/mnras/stz1514