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Sagittarius A* (SgrA*) exhibits frequent flaring activity across theelectromagnetic spectrum. Signatures of an orbiting hot spot have beenidentified in the polarized millimeter wavelength light curves observed withALMA in 2017 immediately after an X-ray flare. The nature of these hot spotsremains uncertain. We expanded existing theoretical hot spot models created todescribe the Sgr~A* polarized emission at millimeter wavelengths. We sample theposterior space, identifying best-fitting parameters and characterizinguncertainties. Using the numerical radiative transfer code IPOLE we defined asemi-analytical model describing a ball of plasma orbiting Sgr~A*, threadedwith a magnetic field and emitting synchrotron radiation. We then explore theposterior space in the Bayesian framework of DYNESTY. We fitted the staticbackground emission separately, using a radiatively inefficient accretion flowmodel. We considered eight models with a varying level of complexity. Allmodels converge to realisations that fit the data, but two models, one withcooling and one with non-Keplerian motion, improve the fit significantly, whileadditionally matching the expected synchrotron cooling timescale and observedcircular polarization. Our models represent observational data well, and allowfor testing of the impact of various effects in a systematic manner. From ouranalysis we have inferred an inclination of $\sim150-160$ deg, corroboratingprevious estimates, a preferred period of $\sim$ $90$ minutes and an orbitalradius of $10.7 - 13.0$ gravitational radii. Our non-Keplerian models indicatea preference for an orbital velocity of $0.8-0.9$ times the Keplerian value.Lastly, our best models agree on a low dimensionless spin value ($a_* < 0.6$),however, the impact of spin on the corresponding light curves is subdominantwith respect to other parameters.

Fitting Sagittarius A* light curves with a hot spot model: Bayesian modeling of QU loops in millimeter band