Polarimetry of near-infrared flares from Sagittarius A*

By A. Eckart, R. Schödel, L. Meyer, S. Trippe, T. Ott, R. Genzel. 2006

154 citations recorded by the source corpus.

Context. We report new polarization measurements of the variable near-infrared emission of the SgrA* counterpart associated with the massive 3–$4\times10^6$ $M_{\odot}$ Black Hole at the Galactic Center. Aims. We investigate the physical processes responsible for the variable emission from SgrA*. Methods. The observations have been carried out using the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope. Results. We find that the variable NIR emission of SgrA* is highly polarized and consists of a contribution of a non- or weakly polarized main flare with highly polarized sub-flares. The flare activity shows a possible quasi-periodicity of $20\pm3$ min consistent with previous observations. Conclusions. The highly variable and polarized emission supports that the NIR emission is non-thermal. The observations can be interpreted in a jet or temporary disk model. In the disk model the quasi-periodic flux density variations can be explained by spots on relativistic orbits around the central MBH. Alternative explanations for the high central mass concentration involving boson or fermion balls are increasingly unlikely.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/62c16524b6194c5b873347fe20324eb4bbf34661

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Citations in the corpus

The structure of the nuclear stellar cluster of the Milky Way (2006, methodology): “As for the orientation of the outflow, Eckart et al. (2006b) and Meyer et al. (2006b) note that the electric field vector during a NIR flare was oriented along 6.0 ± 1.0 0.19 ± 0.05 0.75±0.10 a Star counts on ISAAC image (see Fig.”
An X-Ray, Infrared, and Submillimeter Flare of Sagittarius A* (2007, methodology): “From campaigns between 2004 and 2006 there are approximately 52 hr of joint X-ray/submillimeter observations of Sgr A* yielding just one X-ray flare, the 2006 flare presented here (Eckart et al. 2006b; Yusef-Zadeh et al. 2006b; F. K. Baganoff et al., in preparation).”
Influence of Cosmic Repulsion and Magnetic Fields on Accretion Disks Rotating around Kerr Black Holes (2020, background): “5 [124], and the magnetic field in its vicinity is estimated to be B ∼ 10 G [125] but an increase by one order to 100 G is possible [86].”
DETECTING FLARING STRUCTURES IN SAGITTARIUS A* WITH HIGH-FREQUENCY VLBI (2008, background): “Claims of observed periodicity in IR and X-ray light curves (Bélanger et al. 2006; Meyer et al. 2006; Eckart et al. 2006) during Sgr A* flares, can potentially be explained in the context of hot spots orbiting the black hole at a few times RS.”
Measuring Distance and Properties of the Milky Way’s Central Supermassive Black Hole with Stellar Orbits (2008, background): “Periodicities on shorter timescales, such as the putative quasi-periodic oscillation (QPO) at 20 minutes (Genzel. et al. 2003a; Eckart et al. 2006; Bélanger et al. 2006) have been interpreted as arising from the innermost stable circular orbit of a spinning black hole.”
On the charge of the Galactic centre black hole (2018, unknown): “The constraints for the spin J• were inferred indirectly based on the variable total and polarized NIR emission (Eckart et al. 2006).”