Aronian is in check and in a fork, but that's okay. He captured Carlsen's rook on c6 just a move ago, and this is payback. However, White's response wasn't the obvious one but 48. Kg4. Why not take the pawn on e5? Well, let's take a look : 48. Ke5 Nc6+ 49. Kf5 Nd4+ 50. Kg4 Kf8 51. Kh5 Nf3 52. Kh6. Okay, so White wins anyway but it is a longer process than Aronian's move. Let's go back to the game 48. Kg4 Nc6 49. Kh5 Kf8 50. Kh6 Ne7 51. Kh7 ( to take g8 from the Black king ) and Black resigned. 1-0. That's a pretty good choice considering this was a blitz game.