This is the 13211th most frequent German word.
aufgegangen
"Aufgegangen" means "risen" or "opened" depending on context.
In this sentence, 'aufgegangen' is used to describe the event of the sun rising, a common literal utilization of the verb 'aufgehen'.
Die Sonne ist am Morgen aufgegangen.
The sun has risen in the morning.
Here, 'aufgegangen' is used metaphorically to signify the occurrence of an inspiration or realization.
Mir ist ein Licht aufgegangen.
I had an epiphany.
In this instance, 'aufgegangen' indicates that an object, the door, has opened, showing a physical and causative action.