Self-consistent Dynamical Models of the Galactic Bar
**Previous
abstract** **Next
abstract**

**Session 66 -- Galactic Center**
*Oral presentation, Tuesday, 10, 1995, 2:00pm - 3:30pm*

## [66.01D] Self-consistent Dynamical Models of the Galactic Bar

*HongSheng Zhao (Columbia University)*

I present a self-consistent stellar dynamical model for the bar of our
Galaxy. The model fits the density profile fits the COBE light
distribution, the observed solid body stllar rotation curve, the
fall-off of minor axis velocity dispersion and the velocity ellipsoid
at Baade's window. The fully self-consistent model was constructed
using quadratic programming to assign weights to several thousand
orbits running in a rotating bar potential. This model is {\sl the
first} self-consistent rapidly rotating bar model built using an
extension of Schwarzchild's orbit technique. The bar is smooth in
phase space with the direct boxy orbits being the dominant orbit
family. I have explored the range of models consist with current data
and can suggest future observations that will distinguish between
models. These techniques can easily be applied to external bulges and
galactic nuclei.

We also use the self-consistent bar to build {\sl a microlensing
model} for the Galactic Bulge. Comparing with the OGLE observations,
we find that the observed large optical depth and long microlensing
event duration towards the Bulge are consistent with a $2\times
10^{10}M\odot$ bar elongated along our line-of-sight and with lenses
being ordinary stars; the model predicts 5-7 events with typical time
scale of 20 days for the OGLE.

The thesis results also include finding a very general family of {\sl
analytical density-potential pairs} for bulges and nuclei of general
shape and radial profile. Most of the well-known spherical
density-potential pairs are its special cases, including the
$\eta$-models by Tremaine et al. (1994), Plummer model, the Perfect
Sphere model, the modified Hubble profile. We demonstrate its
application to study dynamics of both spherical and non-spherical
systems.

**Tuesday
program listing**