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David Alonso edited this page Jan 16, 2017
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CoLoRe is a massively-paralallel code to generate fast mock observations of a number of cosmological observables based on generating approximate realizations of the matter density field.
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The code is currently able to generate the following observables:
- Source number counts: angular positions and redshifts (including redshift-space distortions) for a sample of discrete objects defined by a bias function and an average number density
- Weak galaxy lensing: the sources above can also be provided with ellipticities caused by the gravitational lensing effect of the intervening matter.
- Intensity mapping: sky maps at different frequencies containing the intensity of a line-emitting species integrated over angular pixels. The species is defined by a rest-frame frequency, a background emission temperature and a bias function.
- Lensing convergence: sky maps for the lensing convergence for sources at a given redshift (for an arbitrary number of redshifts). Source redshifts beyond the simulation box are supplemented with a random Gaussian realization corresponding to the fluctuations in the matter density for the redshift range not covered by the simulation.
- Integrated Sachs-Wolfe effect: sky maps for the ISW effect from a given redshift (for an arbitrary number of redshifts). Source redshifts beyond the simulation box are supplemented with a random Gaussian realization corresponding to the fluctuations in the matter density for the redshift range not covered by the simulation.
CoLoRe currently supports three different algorithms to generate the initial density field:
- Lognormal realizations: this method is based on performing a local transformation on a Gaussian density field that makes it positive everywhere. The details are given in section 4.1 of the documentation.
- 1LPT: first-order Lagrangian perturbation theory. In this case a Gaussian density field is related to the cosmic displacement field to first order in perturbation theory. The displaced tracer particles are then interpolated into a grid to produce a positive density field. Details in section 4.2 of the documentation.
- 2LPT: second-order Lagrangian perturbation theory. In this case the initial Gaussian field is related to the displacement to second order in perturbation theory. Details in section 4.3 of the documentation.
TO DO
TO DO