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Paper: Secular Component of Apparent Proper Motion of QSOs Induced by Gravitational Lens of the Galaxy
Volume: 289, The Proceedings of the IAU 8th Asian-Pacific Regional Meeting, Volume I
Page: 461
Authors: Ohnishi, K.; Hosokawa, M.; Fukushima, T.
Abstract: The observed position of QSOs may vary due to the gravitational deflection by foreground objects. This effect is eminent in the direction of the Galactic Center. To measure the distance to the Galactic Center with the relative error of a few %, in addition to the astrometric microlensing by individual stars in the Galaxy, we have to consider the macro lens effect, the collective gravitational deflection by the core and the bulge of the Galaxy. This effect is important because it has a secular component. Its magnitude is 0.4 micro arcsecond/yr in the case of internal motion of QSOs by the core and reaches 0.6 micro arcsecond/yr in the case of the collective motion produced by both the core and the bulge. The measurement of these effects will provide us valuable information on the density and mass function of the Galactic Center.
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