Question: What features are used to represent the salience and relative authority of entities?
Answer: Salience features positional features, occurrence frequency and the internal POS structure of the entity and the sentence it occurs in.
The relative authority of entity features:   comparative relevance of the news article to the different entities occurring in it.
Alternative answer: positional features, occurrence frequency, internal POS structure of the entity and the sentence it occurs in, relative entity frequency, centrality measures like PageRank