ON THE VERTICAL EQUILIBRIUM OF THE LOCAL GALACTIC DISK AND THE SEARCH FOR DISK DARK MATTER
- Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Apt. Postal 70 264, C.P. 04510, Mexico City (Mexico)
- Department of Physics and Astronomy, University of Sydney, NSW 2006 (Australia)
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 three larger than required if virial equilibrium is to hold. Here we show that this ratio between energies was overestimated 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.
- OSTI ID:
- 21562728
- Journal Information:
- Astrophysical Journal Letters, Vol. 731, Issue 2; Other Information: DOI: 10.1088/2041-8205/731/2/L35; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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