Stars 1/2 - AA vs steal pos raiser

[JSampras1]

Unfortunately this guy just sat down, and i had 0 hands on him.

PokerStars 1/2 Hold'em (10 handed) Poker Stars Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Preflop: Hero is SB with A[img]/images/graemlins/spade.gif[/img], A[img]/images/graemlins/club.gif[/img]. CO posts a blind of $1.
<font color="#666666">6 folds</font>, <font color="#CC3333">CO (poster) raises</font>, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero 3-bets</font>, <font color="#666666">1 fold</font>, CO calls.

Flop: (7 SB) 5[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/spade.gif[/img], T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, CO calls.

Turn: (4.50 BB) 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">CO raises</font>, Hero ???

If this was a legit raise i would probably 3 bet, because unless he has 99 or TT I'm almost definately ahead. But since he raised in steal pos should i bet worried about some junk 2 pair, a set or a straight here? Since I have no reads, is this a reraise or just a call and then call down?