Effects of long-wavelength fluctuations in large galaxy surveys
In order to capture as much information as possible large galaxies surveys have been increasing their volume and redshift depth. To face this challenge theory has responded by making cosmological simulations of huge computational volumes with equally increasing numbers of dark matter particles and s...
| Autores: | , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2019 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/192262 |
| Acceso en línea: | http://hdl.handle.net/10261/192262 |
| Access Level: | acceso abierto |
| Palabra clave: | Cosmology: Large-scale structure Dark matter Galaxies: halos Methods: numerical |
| Sumario: | In order to capture as much information as possible large galaxies surveys have been increasing their volume and redshift depth. To face this challenge theory has responded by making cosmological simulations of huge computational volumes with equally increasing numbers of dark matter particles and supercomputing resources. Thus, it is taken for granted that the ideal situation is when a single computational box encompasses the whole volume of the observational survey, e.g. ∼50h−3Gpc3 for the DESI and Euclid surveys. Here we study the effects of missing long waves in a finite volume using several relevant statistics: the abundance of dark matter haloes, the probability distribution function (PDF), the correlation function and power spectrum, and covariance matrices. Finite volume effects can substantially modify the results if the computational volumes are less than ∼(500h−1Mpc)3. However, the effects become extremely small and practically can be ignored when the box size exceeds ∼1 Gpc3. We find that the average power spectra of dark matter fluctuations show remarkable lack of dependence on the computational box size with less than 0.1 per cent differences between 1 and 4h−1Gpc boxes. No measurable differences are expected for the halo mass functions for these volumes. The covariance matrices are scaled trivially with volume, and small corrections due to supersample modes can be added. We conclude that there is no need to make those extremely large simulations when a box size of 1−1.5h−1Gpc is sufficient to fulfil most of the survey science requirements.© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. |
|---|