Non-parametric reconstruction of interaction in the cosmic dark sector

The possibility of a nongravitational interaction between dark matter and dark energy is reconstructed using some recent data sets. The crucial aspect is that the interaction is not parametrized at the outset, but rather reconstructed directly from the data in a nonparametric way. The cosmic chronometer Hubble data, the Pantheon supernova compilation of CANDELS and CLASH Multi-Cycle Treasury programs obtained by the Hubble Space Telescope, and the baryon acoustic oscillation Hubble data are considered in this work. The widely accepted Gaussian process is used for the reconstruction. The results clearly indicate that a no-interaction scenario is definitely a possibility. Also, the interaction (if any) is not really significant at the present epoch. The direction of the flow of energy is clearly from dark energy to dark matter, which is consistent with the thermodynamic requirement.