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95444 |
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|a Bower, Geoffrey C.
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|a Haystack Observatory
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|a Doeleman, Sheperd Samuel
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|a Deller, Adam
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|a Demorest, Paul
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|a Brunthaler, Andreas
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|a Falcke, Heino
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|a Moscibrodzka, Monika
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|a O'Leary, Ryan M.
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|a Eatough, Ralph P.
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|a Kramer, Michael
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|a Lee, K. J.
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|a Spitler, Laura
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|a Desvignes, Gregory
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|a Rushton, Anthony P.
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|a Reid, Mark J.
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|a Doeleman, Sheperd Samuel
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|a THE PROPER MOTION OF THE GALACTIC CENTER PULSAR RELATIVE TO SAGITTARIUS A*
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|b IOP Publishing,
|c 2015-02-20T16:40:23Z.
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|z Get fulltext
|u http://hdl.handle.net/1721.1/95444
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|a We measure the proper motion of the pulsar PSR J1745-2900 relative to the Galactic center massive black hole, Sgr A*, using the Very Long Baseline Array (VLBA). The pulsar has a transverse velocity of 236 ± 11 km s[superscript -1] at position angle 22 ± 2 deg east of north at a projected separation of 0.097 pc from Sgr A*. Given the unknown radial velocity, this transverse velocity measurement does not conclusively prove that the pulsar is bound to Sgr A*; however, the probability of chance alignment is very small. We do show that the velocity and position are consistent with a bound orbit originating in the clockwise disk of massive stars orbiting Sgr A* and a natal velocity kick of [< over ~] 500 km s[superscript -1]. An origin among the isotropic stellar cluster is possible but less probable. If the pulsar remains radio-bright, multiyear astrometry of PSR J1745-2900 can detect its acceleration and determine the full three-dimensional orbit. We also demonstrate that PSR J1745-2900 exhibits the same angular broadening as Sgr A* over a wavelength range of 3.6 cm to 0.7 cm, further confirming that the two sources share the same interstellar scattering properties. Finally, we place the first limits on the presence of a wavelength-dependent shift in the position of Sgr A*, i.e., the core shift, one of the expected properties of optically thick jet emission. Our results for PSR J1745-2900 support the hypothesis that Galactic center pulsars will originate from the stellar disk and deepen the mystery regarding the small number of detected Galactic center pulsars.
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|a en_US
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|a Article
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|t The Astrophysical Journal
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