Oral comunication
D. M. L. Castelão
Abstract
In this talk I will present the results of testing two types of UDM models: The generalized Chaplygin gas with a back-reaction effect and an UDM model with fast transition. Implemented in the Boltzmann code CLASS we test these models against weak lensing, CMB, SNe IA and BAO tests. In the second case, due to a unsmooth matter power spectrum caused by a speed of sound bigger than zero, the traditional sampling methods used in MCMC codes known as annealing methods, like Metropolis-Hastings, are not very efficient, resulting in long computation time and hard fine tuning of parameters. In this talk, I will present the results comparison obtained when using this sampling algorithm and a Nested Sampling algorithm, explain the second method and why it is considerably better. Then I will show the results of model comparison against ΛCDM and enumerate some topics in the line of work for UDM models to be tested with Euclid future data.
XXIX Encontro Nacional de Estudantes de Astronomia
Lisboa, Portugal
2019 September
