show/hide this revision's text 2 added 88 characters in body

This is more of a comment than an answer. Any simplectic manifold with an effective circle action preserving the form is an example. So any smooth projective toric variety is an example of a manifold with an effective circle action preserving a volume form.

Edit: I forgot to say what the volume is: it's the top power of the symplectic form.

show/hide this revision's text 1

This is more of a comment than an answer. Any simplectic manifold with an effective circle action preserving the form is an example. So any smooth projective toric variety is an example of a manifold with an effective circle action preserving a volume form.