Does a manifold quotient group action need to be Hausdorff?

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If the group $G$ acts continuously on a manifold $M$, does $M/G$ need to be Hausdorff? I don't think it does, but i can't think of any counterexamples.

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$\newcommand{\Reals}{\mathbf{R}}$"Natural" examples include the multiplicative group of real numbers, $(\Reals^{\times}, \cdot)$, acting on:

  • The real line $M = \Reals$ by $g_{t}(x) = tx$. (The quotient is a two-point space; one point is closed, the other is open and dense.)

  • The punctured plane $M = \Reals^{2}\setminus\{(0,0)\}$ by $g_{t}(x, y) = (tx, \frac{1}{t}y)$. (The quotient is the line with two origins.)