Parameter study for hot spot trajectories around Sgr$A\ast$

Abstract

Intense flaring events in the near-infrared and X-ray wavebands of our Galactic Center have been the subject of research for decades. In recent years, the GRAVITY instrument of the Very Large Telescope captured the motion and polarimetric signature of such a flare in close proximity to the supermassive black hole. This study aims to investigate a broad parameter space for hot spot motion in the vicinity of Sgr$A\ast$ and reproduce the observed flaring behavior. To this end, we have developed a General Relativistic Radiative Transfer code and conducted a parameter study including both planar and ejected hot spot configurations around supermassive black holes. Super-Keplerian orbital frequencies are favored by circular equatorial, cylindrical and parabolic models, whereas conical hot spot trajectories provide a better fit for orbital frequencies below the Keplerian value. Additionally, a distant observer cannot effectively differentiate between Schwarzschild and Kerr black holes, as well as face-on orbits at different observation angles.

10 pages, 7 figures, 6 tables, accepted for publication in A&A

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Cited by in corpus (8)

• Hot-spots around Sagittarius A*: Joint fits to astrometry and polarimetry
• Magnetically arrested disk flux eruption events to describe SgrA* flares
• Forward Ray Tracing and Hot Spots in Kerr Spacetime
• Deep learning inference with the Event Horizon Telescope III. Zingularity results from the 2017 observations and predictions for future array expansions
• Observational signatures from higher-order images of moving hotspots in accretion disks
• Investigating non-Keplerian motion in flare events with astrometric data
• Sagittarius A* near-infrared flares polarization as a probe of space-time I: Non-rotating exotic compact objects
• Nonthermal hotspot orbiting the supermassive black hole Sgr A*