2 / 2
When Academy Researchers enters, you may put an Aura card from your hand onto the battlefield attached to Academy Researchers.
You can't put an Aura card from your hand onto the battlefield this way if that Aura can't legally enchant Academy Researchers. For example, you can't put an Aura with "enchant land" or "enchant green creature" onto the battlefield attached to Academy Researchers (unless Academy Researchers somehow turned into a land or a green creature before the ability resolved).