Bondi news in de Sitter space-time

Observations have shown that a model with a positive cosmological constant is more appropriate to describe our universe. The aim of this manuscript is to study the gravitational fields in de Sitter space-time. To achieve this goal, de Sitter metric is written in Bondi Sachs form and the Einstein equations are solved for this form of the metric in presence of $\Lambda$. On the other hand, a null tetrad is defined for the de Sitter metric and its form in Bondi gauge is obtained by using the general transformation. Then a new result for the Bondi news in de Sitter background is obtained, using the coordinate independent notion of Bondi news which was first presented by Penrose in 1963.