The Pattern Speed of the Galactic Bar

نویسنده

  • Walter Dehnen
چکیده

Most late-type stars in the solar neighborhood have velocities similar to the local standard of rest (LSR), but there is a clearly separated secondary component corresponding to a slower rotation and a mean outward motion. Detailed simulations of the response of a stellar disk to a central bar show that such a bi-modality is expected from outer-Lindblad resonant scattering. When constraining the run of the rotation curve by the proper motion of SgrA and the terminal gas velocities, the value observed for the rotation velocity separating the two components results in a value of (53± 3) km s kpc for the pattern speed of the bar, only weakly dependent on the precise values for R0 and bar angle φ. Subject headings: Galaxy: kinematics and dynamics — Galaxy: structure — solar neighborhood

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تاریخ انتشار 1999