2018A&A...618L..10G

Query : 2018A&A...618L..10G

2018A&A...618L..10G - Astronomy and Astrophysics, volume 618L10-10 (2018/1-0)

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

GRAVITY COLLABORATION, ABUTER R., AMORIM A., BAUBOCK M., BERGER J.P., BONNET H., BRANDNER W., CLENET Y., COUDE DU FORESTO V., DE ZEEUW P.T., DEEN C., DEXTER J., DUVERT G., ECKART A., EISENHAUER F., FORSTER SCHREIBER N.M., GARCIA P., GAO F., GENDRON E., GENZEL R., GILLESSEN S., GUAJARDO P., HABIBI M., HAUBOIS X., HENNING T., HIPPLER S., HORROBIN M., HUBER A., JIMENEZ-ROSALES A., JOCOU L., KERVELLA P., LACOUR S., LAPEYRERE V., LAZAREFF B., LE BOUQUIN J.-B., LENA P., LIPPA M., OTT T., PANDURO J., PAUMARD T., PERRAUT K., PERRIN G., PFUHL O., PLEWA P.M., RABIEN S., RODRIGUEZ-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. and YAZICI S.

Abstract (from CDS):

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.

Abstract Copyright: © ESO 2018

Journal keyword(s): Galaxy: center - black hole physics - gravitation - relativistic processes

VizieR on-line data: <Available at CDS (J/A+A/618/L10): avg.dat wais.dat pfuhl.dat>

CDS comments: Appendix A. Object R2 not identified.

Simbad objects: 11

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Number of rows : 11
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
2 GCIRS 7 LP* 17 45 39.987 -29 00 22.24           M2 388 0
3 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4970 3
4 GCIRS 16NW WR* 17 45 40.0451 -29 00 26.847           Ofpe/WN9 144 0
5 GCIRS 33E WR* 17 45 40.0941 -29 00 31.213           Ofpe/WN9 59 0
6 GCIRS 16C WR* 17 45 40.12 -29 00 27.6           Ofpe/WN9 197 1
7 GCIRS 16SW WR* 17 45 40.1245 -29 00 29.018           Ofpe/WN9 167 0
8 PSR J1745-2900 Psr 17 45 40.1640 -29 00 29.818           ~ 358 0
9 GCIRS 21 WR* 17 45 40.222 -29 00 30.85           WC9 104 0
10 GCIRS 1W Em* 17 45 40.442 -29 00 27.51           Be? 109 0
11 [EG97] S22 * ~ ~           ~ 9 0

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