Ghana midfielder Partey was expected to stay at Atletico Madrid for another season but Arsenal completed a shock deal on deadline day after meeting his £45m release clause.
The 27-year-old made 188 appearances for Atletico, helping the Spanish club win the Europa League and reach a Champions League final.
Partey received rave reviews after helping Arsenal beat Europa League rivals Rapid Vienna on his full debut and Aubameyang has paid tribute to his new team-mate.
‘Thomas has been great since joining the club,’ Aubameyang told Arsenal’s official matchday programme. ‘He has integrated so well in the squad.
‘He is kind, calm and smiley. On the pitch, we have seen already seen what he will bring us in matches.
‘He is so strong physically but yet so good on the ball as well. We didn’t really have a profile like this in our squad before.
‘In terms of ball progression, beating the press, going forward, he will be very important for us.
‘My family is from Gabon but I also have some roots in Ghana where Thomas is from so we are family too!
Arteta described Partey’s performance against Vienna as ‘fantastic’ but insisted there was ‘more to come’ from the midfielder.
The Gunners boss said: ‘I think he held the midfield by himself in the second half when we were a little bit more open.
‘He started to take more chances attacking certain spaces with some players. I think he was fantastic and there is much more to come from him.’
Arsenal return to Premier League action on Sunday, with Brendan Rodgers’ Leicester City travelling to north London.
The Gunners are currently fifth in the Premier League, having won three and lost two matches so far this season.