Astronomers estimated the existence of the local supercluster of galaxies.

Literal

Astronomers [subject-が] local super-galaxy-cluster [possessive-の] existence [object-を] estimated.

天文学者 'astronomers.' 局部超銀河団 'local supercluster' — a technical astronomy term. 推定する 'to estimate, to infer.' A scientific news sentence — straightforward and factual.