Thought Provoking Nut Flush Draw Hand

[Doylestown]

PokerStars No-Limit Hold'em Tourney, Big Blind is t200 (9 handed) internettexasholdem.com

Button (t9625)
SB (t17110)
BB (t19323)
UTG (t5300)
UTG+1 (t9750)
MP1 (t4680)
Hero (t9825)
MP3 (t13853)
CO (t11295)

Preflop: Hero is MP2 with Q[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/heart.gif[/img].
<font color="#CC3333">UTG raises to t500</font>, <font color="#666666">2 folds</font>, Hero calls t500, <font color="#666666">3 folds</font>, SB calls t400, BB calls t300.

Flop: (t1900) 8[img]/images/graemlins/diamond.gif[/img], 6[img]/images/graemlins/heart.gif[/img], T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(4 players)</font>
SB checks, BB checks, <font color="#CC3333">UTG bets t1600</font>, Hero?

I'm quite confident that utg has an overpair here based on the smaller than normal raise and the strong flop lead. The 2 big stacks in the blinds checked and can still act behind.

What do I want to do here and why?