For refcode 1996AstL...22...71Z: Retrieve 24 NED objects in this reference. Please click here for ADS abstract
NED Abstract
Copyright by American Institute of Physics.
1996AstL...22...71Z
An Estimate of the Hubble Constant Using a Criterion for Gravitational
Stability of Gaseous Disks
A. V. Zasov and D. V. Bizyaev
Sternberg Astronomical Institute, Universitetskii pr 13, Moscow 119899
Russia
Receive May 26,1995; in final form, August 10,1995
AbstractA semiempirical method for determination of the Hubble constant
H_0_ using a criterion for the gravitational stability of the gaseous
disks of galaxies, proposed earlier by Zasov, is developed. The premise
is considered that at the distance R_H_ from the center of a galaxy at
which the azimuthally averaged surface densities of atomic ({sigma}_HI_)
and molecular ({sigma}_H_2__) hydrogen are equal, the total surface
density of gas ({sigma}_c_) is equal to or proportional to the critical
density ({sigma}_c_) for gravitational stability of the gaseous disk.
Since the estimate of {sigma}_c_ depends on the adopted distance to the
galaxy, this condition allows one to estimate the distance based on a
experimental determination of R_H_ and the shape of the rotation curve.
For five nearby spiral galaxies for which the distances are considered to
be known, the coefficient of proportionality {sigma}_g_/{sigma}_c_ at R =
R_H_ is found to be 1.)c_g_/10 km s^1^, where c_g_ is the dispersion
velocity for the clouds of gas. Estimates of the distances to 11 SbScd
field galaxies lead to the value H_0_ = 76 +/ 8 km s^1^ Mpc^1^ (with
allowance for motion toward Virgo). The mean distance to five galaxies
located at the periphery of the Virgo cluster is found to be 14.8 +/ 3
Mpc. The close correlation between R_H_ and the radius at which
{sigma}_g_ = {sigma}_c_ is evidence of the defining role of gravitational
instability in the formation of molecular gas in the disks of latetype
spiral galaxies.
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