It's official! Strong evidence that Saggitarius A black hole exists in the center of our galaxy.
paper: [aanda.org]
abstract: We report the detection of continuous positional and polarization changes of the compact source SgrA* in high states (“flares&rdquo
of its variable nearinfrared
emission with the near-infrared GRAVITY-Very Large Telescope Interferometer (VLTI) beam-combining instrument. In three prominent
bright flares, the position centroids exhibit clockwise looped motion on the sky, on scales of typically 150 µas over a few tens of minutes, corresponding
to about 30% the speed of light. At the same time, the flares exhibit continuous rotation of the polarization angle, with about the same
45(±15) min period as that of the centroid motions. Modelling with relativistic ray tracing shows that these findings are all consistent with a near
face-on, circular orbit of a compact polarized “hot spot” of infrared synchrotron emission at approximately six to ten times the gravitational radius
of a black hole of 4 million solar masses. This corresponds to the region just outside the innermost, stable, prograde circular orbit (ISCO) of a
Schwarzschild–Kerr black hole, or near the retrograde ISCO of a highly spun-up Kerr hole. The polarization signature is consistent with orbital
motion in a strong poloidal magnetic field.
below is a picture: [eurekalert.org]
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5 comments
Feel free to reply to any comment by clicking the "Reply" button.Um, it has been widely believed that all spiral galaxies have black holes at their centres. Like an unfortunate Tootsie Pop. Neat to see some data, though. Thank you.
BiasedLemmings
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Nov 26, 2018
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