Jimenez-Rosales, A., Dexter, J., Widmann, F., Bauboeck, M., Abuter, R., Amorim, A., Berger, J. P., Bonnet, H., Brandner, W., Clenet, Y., de Zeeuw, P. T., Eckart, A., Eisenhauer, F., Schreiber, N. M. Foerster, Garcia, P., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Heissel, G., Henning, T., Hippler, S., Horrobin, M., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V, Le Bouquin, J-B, Lena, P., Nowak, M., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pfuhl, O., Rodriguez-Coira, G., Shangguan, J., Scheithauer, S., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., von Fellenberg, S., Waisberg, I, Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S. and Zins, G. (2020). Dynamically important magnetic fields near the event horizon of Sgr A*. Astron. Astrophys., 643. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

Full text not available from this repository.

Abstract

We study the time-variable linear polarisation of Sgr A* during a bright near-infrared flare observed with the GRAVITY instrument on July 28, 2018. Motivated by the time evolution of both the observed astrometric and polarimetric signatures, we interpret the data in terms of the polarised emission of a compact region (hotspot) orbiting a black hole in a fixed, background magnetic field geometry. We calculated a grid of general relativistic ray-tracing models, created mock observations by simulating the instrumental response, and compared predicted polarimetric quantities directly to the measurements. We take into account an improved instrument calibration that now includes the instrument's response as a function of time, and we explore a variety of idealised magnetic field configurations. We find that the linear polarisation angle rotates during the flare, which is consistent with previous results. The hotspot model can explain the observed evolution of the linear polarisation. In order to match the astrometric period of this flare, the near horizon magnetic field is required to have a significant poloidal component, which is associated with strong and dynamically important fields. The observed linear polarisation fraction of similar or equal to 30% is smaller than the one predicted by our model (similar or equal to 50%). The emission is likely beam depolarised, indicating that the flaring emission region resolves the magnetic field structure close to the black hole.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Jimenez-Rosales, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Dexter, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Widmann, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Bauboeck, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Abuter, R.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Amorim, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Berger, J. P.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Bonnet, H.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Brandner, W.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Clenet, Y.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
de Zeeuw, P. T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Eckart, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Eisenhauer, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Schreiber, N. M. FoersterUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Garcia, P.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Gao, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Gendron, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Genzel, R.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Gillessen, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Habibi, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Haubois, X.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Heissel, G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Henning, T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Hippler, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Horrobin, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Jochum, L.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Jocou, L.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Kaufer, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Kervella, P.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Lacour, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Lapeyrere, VUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Le Bouquin, J-BUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Lena, P.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Nowak, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Ott, T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Paumard, T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Perraut, K.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Perrin, G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Pfuhl, O.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Rodriguez-Coira, G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Shangguan, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Scheithauer, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Stadler, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Straub, O.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Straubmeier, C.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Sturm, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Tacconi, L. J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Vincent, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
von Fellenberg, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Waisberg, IUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wieprecht, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wiezorrek, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Woillez, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Yazici, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Zins, G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-312285
DOI: 10.1051/0004-6361/202038283
Journal or Publication Title: Astron. Astrophys.
Volume: 643
Date: 2020
Publisher: EDP SCIENCES S A
Place of Publication: LES ULIS CEDEX A
ISSN: 1432-0746
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
SUPERMASSIVE BLACK-HOLE; NEAR-INFRARED FLARES; X-RAY FLARE; ACCRETION FLOW; YOUNG STARS; VARIABILITY; EMISSION; RADIO; MILKY; POLARIZATIONMultiple languages
Astronomy & AstrophysicsMultiple languages
URI: http://kups.ub.uni-koeln.de/id/eprint/31228

Downloads

Downloads per month over past year

Altmetric

Export

Actions (login required)

View Item View Item