Check behind right play in this situation?

Villan is 39/11

Full Tilt No-Limit Hold'em, $0.50 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

saw flop|saw showdown

BB ($63.15)
UTG ($48.80)
UTG+1 ($12.45)
MP1 ($41.35)
MP2 ($95.50)
MP3 ($43)
Hero ($53.95)
Button ($28.25)
SB ($56.45)

Preflop: Hero is CO with Ahttp://www.flopturnriver.com/phpBB2/...miles/club.gif, 8http://www.flopturnriver.com/phpBB2/...miles/club.gif.
UTG raises to $1.25, 1 fold, MP1 calls $1.25, 2 folds, Hero calls $1.25, 3 folds.

Flop: ($4.50) 6http://www.flopturnriver.com/phpBB2/...es/diamond.gif, Ahttp://www.flopturnriver.com/phpBB2/...iles/spade.gif, 4http://www.flopturnriver.com/phpBB2/...iles/spade.gif (3 players)
UTG bets $4, MP1 folds, Hero calls $4.

Turn: ($12.50) 7http://www.flopturnriver.com/phpBB2/...es/diamond.gif (2 players)
UTG bets $7, Hero raises to $16.5, UTG calls $9.50.

River: ($45.50) 8http://www.flopturnriver.com/phpBB2/...es/diamond.gif (2 players)
UTG checks, Hero checks.

Final Pot: $45.50

Why you half-stacking off with a rag ace?

I don't believe he has a better A given what he has shown down in the past pretty much and thought I'd get him off with the turn raise.

I was pretty much going to c/f the river if he bet but once he checked I was considering value-betting...thinking over his possible holdings A5 was prime contender given the turn call but the backdoor flush may also of hit him and that's what I'm questioning.

The fact that someone plays a lot of shit doesn't exempt them form getting good cards.

Do you have a read that he doesn't have a better Ace here?

I don't get the turn raise, you value betting or bluffing?

Once he called I figured I was bluffing pretty much at that point, however the initial raise was because I thought I was ahead of his range here.

[EDIT]
The question here though isn't about the way I played the hand (if it were I'd have posted it in HH), it's about what to do given the way I played it.

Yes I sucked out, but given the river card gave me top two but also completed flush and straight draws is checking behind right here...is it one of those situations that only a better hand calls...what if he c/r's all-in if I bet, etc.

Would there ever be value betting this river?

You're up again Ax here almost always given the way UTG played the turn. He didn't want you to draw out cheap against him.

If you can make that read, the river is an easy bet. The board will freeze up weak players from re-raising.

Yeah, my main concern was that he was playing A5 most likely (Axd was less likely in my mind) and given that I had raised him on the turn, he was trying to give me enough rope to hang myself on the river.

If I do bet is it a push given stacks by that stage?..I guess it is since if I bet say $10 and he raises me the odds have to justify stacking off anyway here right?