This is the 8738th most frequent Russian word.
петербургского
"Of St. Petersburg"
In this sentence, 'Петербургского' is used as a possessive adjective related to 'университета', denoting that the university is located in or associated with Petersburg.
Архитектура Петербургского университета впечатляет своей красотой.
The architecture of the Petersburg University impresses with its beauty.
Here, 'Петербургского' describes 'художника', indicating that the artist is from Petersburg.
На выставке были представлены картины Петербургского художника.
Paintings by a Petersburg artist were displayed at the exhibition.
In this usage, 'Петербургского' modifies 'журналиста', specifying that the journalist originates from Petersburg.