Date Published:

November 1, 2014

Abstract:

Extraction of the Baryon Acoustic Oscillations (BAO) to per cent levelaccuracy is challenging and demands an understanding of many potentialsystematics to an accuracy well below 1 per cent, in order to ensurethat they do not combine significantly when compared to statisticalerror of the BAO measurement. Baryon Oscillation Spectroscopic Survey(BOSS) Data Release 11 (DR11) reaches a distance measurement with˜1 per cent statistical error and this prompts an extensive searchfor all possible sub-per cent level systematic errors which couldpreviously be safely ignored. In this paper, we analyse the potentialsystematics in BAO fitting methodology using mocks and data from BOSSDR10 and DR11. We demonstrate the robustness of the fiducial multipolefitting methodology to be at 0.1-0.2 per cent level with a wide range oftests in mock galaxy catalogues pre- and post-reconstruction. We alsofind the DR10 and DR11 data from BOSS to be robust against changes inmethodology at a similar level. This systematic error budget isincorporated into the BOSS DR10 and DR11 BAO measurements. Of the widerange of changes we have investigated, we find that when fittingpost-reconstructed data or mocks, the only change which has an effect>0.1 per cent on the best-fitting values of distance measurements isvarying the order of the polynomials to describe the broad-band terms(˜0.2 per cent). Finally, we compare an alternative methodologydenoted as Clustering Wedges with Multipoles, and find that it isconsistent with the standard approach.

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