Semi-blind Analysis of Uncertainties in Recombination Histoy
Farhang, Marzieh (CITA)

The standard model for recombination history, describing how the universe transitioned from an ionized to a neutral state, is a basic assumption for modeling the CMB sky which is to be compared to data to measure the cosmological parameters. The current model is fairly well explored and understood in the realm of standard physical processes relevant at the epoch of recombination. However, there is the possibility that some processes beyond the standard scenario, such as energy injection by annihilating dark matter, have also shaped the recombination history, which, if ignored, could lead to biases in the measurement of cosmological parameters. Moreover, studying these potential deviations could hint to some unknown physics playing role at that epoch. In this work we perform a semi-blind analysis of the uncertainties in the recombination model by constructing patterns which are maximally informative about the perturbations in the ionization history based on simulated CMB data. We demonstrate how the inclusion of these modes affect the measurements of other cosmological parameters. We also show how to achieve the model best explained by data through an iterative approach if deviations from the standard scenario is detected by real data.