Paper: astro-ph/9902247
From: Ortwin Gerhard <gerhard@astro.unibas.ch>
Date: Wed, 17 Feb 1999 19:49:02 GMT   (218kb)

Title: Dynamics of the Galaxy
Authors: Ortwin E. Gerhard (Astron.Inst., Univ.Basel, CH)
Comments: 15 pages, LaTeX, 5 figures, Fig.4 degraded. Invited review, to appear
  in `Galaxy Dynamics', ASP Conf.Ser., eds. D.Merritt, M.Valluri, J.Sellwood
Report-no: Astr.Inst.Basel Prep.Ser.122
\\
  Our Galaxy is a barred spiral. Recent work based on the COBE NIR data implies
a small bulge-bar and a disk with a short scale-length. The corotation radius
of the bar is in the range 3-4.5 kpc. The stellar density distribution beyond
the end of the bar appears to be perturbed strongly by the Galaxy's spiral
arms.
  Gas flow calculations in corresponding potentials provide a qualitative
explanation of many features observed in HI and CO lv-diagrams. These include
the 3-kpc-arm and the apparent four-armed spiral structure between corotation
and the solar radius.
  The mass of NIR-luminous matter is constrained by the terminal velocity
curve, the Oort limit, and the bulge microlensing observations, and this
implies that the Milky Way has a near-maximum disk and a dark halo with a large
core radius of ~ 15 kpc.
  However, we are still some way from a detailed quantitative model for the
large-scale dynamics of the Galaxy. I summarize a number of uncertainties as
well as how future work might resolve them.
\\ ( http://xxx.lanl.gov/abs/astro-ph/9902247 ,  218kb)
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