Deadline day on Monday saw the Gunners release Aubameyang from his contract 18 months early.
He is expected to be unveiled at the Camp Nou this week.
An Arsenal statement on Tuesday night confirmed Aubameyang's exit: "We wish Auba all the best for the next chapter in his career and thank him for his contribution to the club."
He scored 92 goals in 163 games for the north London club and won the FA Cup in 2020.
For the match-winning moments
For the iconic celebrations
For making us smile
Thank you for everything, @Auba
— Arsenal (@Arsenal) February 1, 2022