No one knows what ecto energy is. If they do, I didn't find it. But it's everywhere. People can harvest it, if they know how. It could be harmful or it could be completely benign. The Fentons actually cook with it, and eat food that was revived with it without any bad affects.
Whatever ecto is, it's versatile in ways nothing else should be, and it's always there somehow. And it attracts to the 'soul' of the dead like magnets if there's strong enough emotions, in my world.
It could be, it's not that different from what you call astral. It even makes super powers if the being knows how to use it right.