Describing variations of the Fisher-matrix across parameter space

• Verfasst von: Schäfer, Björn Malte [VerfasserIn]
• Verfasst von: Reischke, Robert [VerfasserIn]
• Titel: Describing variations of the Fisher-matrix across parameter space
• Verf.angabe: Björn Malte Schäfer and Robert Reischke
• Umfang: 9 S.
• Fussnoten: Gesehen am 06.11.2016
• Titel Quelle: Enthalten in: Royal Astronomical Society: Monthly notices of the Royal Astronomical Society
• Jahr Quelle: 2016
• Band/Heft Quelle: 460(2016), 3, S. 3398-3406
• ISSN Quelle: 1365-2966
• DOI: doi:10.1093/mnras/stw1221
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1565013387

Abstract

Forecasts in cosmology, both with Monte Carlo Markov-chain methods and with the Fisher-matrix formalism, depend on the choice of the fiducial model because both the signal strength of any observable and the model non-linearities linking observables to cosmological parameters vary in the general case. In this paper we propose a method for extrapolating Fisher-forecasts across the space of cosmological parameters by constructing a suitable basis. We demonstrate the validity of our method with constraints on a standard dark energy model extrapolated from a ΛCDM-model, as can be expected from two-bin weak lensing tomography with an Euclid-like survey, in the parameter pairs (Ωm, σ8), (Ωm, w0) and (w0, wa). Our numerical results include very accurate extrapolations across a wide range of cosmological parameters in terms of shape, size and orientation of the parameter likelihood, and a decomposition of the change of the likelihood contours into modes, which are straightforward to interpret in a geometrical way. We find that in particular the variation of the dark energy figure of merit is well captured by our formalism.