On the vertical equilibrium of the local Galactic disk and the search for disk dark matter

Abstract

Estimates of the dynamical surface mass density at the solar Galactocentric distance are commonly derived assuming that the disk is in vertical equilibrium with the Galactic potential. This assumption has recently been called into question, based on the claim that the ratio between the kinetic and the gravitational energy in such solutions is a factor of 3 larger than required if Virial equilibrium is to hold. Here we show that this ratio between energies was overerestimated and that the disk solutions are likely to be in Virial equilibrium after all. We additionally demonstrate, using one-dimensional numerical simulations, that the disks are indeed in equilibrium. Hence, given the uncertainties, we find no reason to cast doubt on the steady-state solutions which are traditionally used to measure the matter density of the disk.

6 pages, 2 figures, accepted for publication in ApJ Letters

References in corpus (4)

• On the mass-to-light ratio of the local Galactic disc and the optical luminosity of the Galaxy
• Dark matter in the Milky Way, II. the HI gas distribution as a tracer of the gravitational potential
• No evidence for a dark matter disk within 4 kpc from the Galactic plane
• The Futile Search for Galactic Disk Dark Matter

Cited by in corpus (6)

• The Local Dark Matter Density
• Galactoseismology: Discovery of Vertical Waves in the Galactic Disk
• Thick disks of edge-on galaxies seen through the Spitzer Survey of Stellar Structure in Galaxies (S4G): Lair of missing baryons?
• Kinematical and chemical vertical structure of the Galactic thick disk II. A lack of dark matter in the solar neighborhood
• Evolution over time of the Milky Way's disc shape
• Limits on the local dark matter density