2014/11/30 by Geoffrey C. Bower, Adam Deller, Paul Demorest +12 · 2 citations
Physics and Astronomy · #Astrometry #Astrophysical Phenomena and Observations #Galactic Center #Millisecond pulsar #Position angle #Proper motion #Pulsar #Pulsars and Gravitational Waves Research #Radial velocity #Sagittarius A* #Scientific Research and Discoveries #Very Long Baseline Array #astro-ph.HE
paper · pdf · doi:10.1088/0004-637x/798/2/120
Arxiv submission has been updated based on published erratum. ICRF positions reported for the magnetar are correct as reported in the original paper but relative positions are adjusted by (+18.36, -32.0) mas. Tables 2 and 4 and Figure 1 have been updated accordingly. Proper motion, acceleration, and core shift values are unaffected. There are no changes in the interpretation of the results
openalex publication_date 2015/01/08 · arxiv created 2016/03/16 · arxiv updated 2016/03/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 −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 ≲ 500 km s −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.