name that face

This is a picture of one of the enigmatic (official adjective) faces of Bayon, one of the larger of the Angkor temples, housed in the Angkor Thom complex, built, I believe, by Jayavarman II in the 12th century. Where is the guidebook that will make me sound like a great authority on Angkorian history?

There are more than fifty of these faces, which are about two metres high, staring out from every tower and aspect of this huge temple. The first Angkor temples were built to Hindu gods; when the kings converted to Buddhism, so did the temples. No one is sure whose faces peer out of the Bayon temples. Does this face belong to the Buddha, to Shiva, or to Brahma? If you know the answer, tell me, and together we will rocket straight to the top of archaeology class.