TY - JOUR
T1 - On the vertical equilibrium of the local Galactic disk and the search for disk dark matter
AU - Sánchez-Salcedo, F. J.
AU - Flynn, Chris
AU - Hidalgo-Gámez, A. M.
PY - 2011/4/20
Y1 - 2011/4/20
N2 - 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.
AB - 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.
KW - Galaxy: disk
KW - Galaxy: kinematics and dynamics
KW - Galaxy: structure
UR - http://www.scopus.com/inward/record.url?scp=79955642745&partnerID=8YFLogxK
U2 - 10.1088/2041-8205/731/2/L35
DO - 10.1088/2041-8205/731/2/L35
M3 - Artículo
SN - 2041-8205
VL - 731
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2 PART II
M1 - L35
ER -