Revisiting the Dark Matter - Comet Shower Connection
  We revisit the question of whether the observed periodicity of comet impacts
on Earth is consistent with Solar oscillation about the Galactic midplane and
spiral arm crossings, here in the context of dissipative dark matter models.
Consider whether a hypothetical thin dark disk, a signature of these models, is
necessary to give the right periodicity, and whether such a dark disk is
allowed given kinematic and other observational constraints on the Galaxy's
gravitational potential, taking into account recent updates of these limits
based on the vertical epicyclic oscillations of the tracer populations. Our
analysis contains updated parameters for the Galactic disk, a self-consistent
gravitational potential under the Poisson-Jeans equations, and includes prior
probabilities from local stellar kinematics and the distribution of Milky Way
interstellar gas. Moreover, our analysis also includes radial oscillations and
Galactic spiral arm crossings. We find a dark disk explanation for the comet
periodicity to be 10 times more likely than a constant average rate model.
Moreover, we find that spiral arm crossing is necessary to correctly predict
the date of the Chicxulub crater dated to 66 My ago.
