SIMBAD references

1997A&A...323..781B - Astronomy and Astrophysics, volume 323, 781-788 (1997/7-3)

Stellar kinematics in the solar neighbourhood and the disc scale lengths of the Galaxy.


Abstract (from CDS):

A general dynamically consistent 2D flat distribution function is built to model the kinematics of neighbouring stars. Application leads to the measurement of a short galactic scale length Rρ between 1.7 and 2.9kpc and a locally decreasing rotation curve. This is in agreement with recent determinations based on kinematics and counts of distant stars. These results rule out the classical assumption that 2Rρ=Rσ or that σz(R)/σR(R) is constant when the vertical scale height hz(R) is assumed to be constant. We explain why the measured squared axis ratio of the velocity dispersions σv2u2 of disc stars is less than 1/2. This ratio has been claimed to be important evidence for the non-axisymmetry of the galactic disc. We show that this is not the case and that it may be simply explained with a realistic axisymmetric disc model if the circular velocity is locally declining or if there is a mismatch between the photometric and kinematic scale lengths.

Abstract Copyright:

Journal keyword(s): stars: kinematics - Galaxy: kinematics and dynamics - solar neighbourhood - Galaxy: structure

Simbad objects: 27

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