Details

Autor(en) / Beteiligte

• Abuter, R.
• Amorim, A.
• Bauböck, M.
• Berger, J. P.
• Bonnet, H.
• Brandner, W.
• Clénet, Y.
• Coudé du Foresto, V.
• de Zeeuw, P. T.
• Deen, C.
• Dexter, J.
• Duvert, G.
• Eckart, A.
• Eisenhauer, F.
• Förster Schreiber, N. M.
• Garcia, P.
• Gao, F.
• Gendron, E.
• Genzel, R.
• Gillessen, S.
• Guajardo, P.
• Habibi, M.
• Haubois, X.
• Henning, Th
• Hippler, S.
• Horrobin, M.
• Huber, A.
• Jiménez-Rosales, A.
• Jocou, L.
• Kervella, P.
• Lacour, S.
• Lapeyrère, V.
• Lazareff, B.
• Le Bouquin, J.-B.
• Léna, P.
• Lippa, M.
• Ott, T.
• Panduro, J.
• Paumard, T.
• Perraut, K.
• Perrin, G.
• Pfuhl, O.
• Plewa, P. M.
• Rabien, S.
• Rodríguez-Coira, G.
• Rousset, G.
• Sternberg, A.
• Straub, O.
• Straubmeier, C.
• Sturm, E.
• Tacconi, L. J.
• Vincent, F.
• von Fellenberg, S.
• Waisberg, I.
• Widmann, F.
• Wieprecht, E.
• Wiezorrek, E.
• Woillez, J.
• Yazici, S.

Titel

Detection of orbital motions near the last stable circular orbit of the massive black hole SgrA

Ist Teil von

• Astronomy and astrophysics (Berlin), 2018-10, Vol.618, p.L10

Ort / Verlag

EDP Sciences

Erscheinungsjahr

2018

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• We report the detection of continuous positional and polarization changes of the compact source SgrA* in high states (“flares”) of its variable near-infrared 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.