This is the 1190th most frequent Turkish word.
ulaşan
"Ulaşan" means "reaching" or "arriving."
Here, 'ulaşan' functions as a present participle used as an adjective, describing the letter as 'reaching to me'.
Bana ulaşan mektup çok duygusal bir içerik taşıyordu.
The letter that reached me contained very emotional content.
'Ulaşan' is used as a participle to describe 'bilgiler' as 'those reaching to the students'.
Öğretmenin verdiği bilgiler, öğrencilere tartışmalar sırasında ulaşan önemli bilgilerdi.
The information provided by the teacher was important information that reached the students during discussions.
In this sentence, 'ulaşan' is part of a phrase used to describe the group as 'the first to reach'.