@article {39995,
	title = {A Bayesian approach for torque modelling of BeXRB pulsars with application to super-Eddington accretors},
	volume = {520},
	year = {2023},
	month = {2023/03/1},
	pages = {281 - 299},
	publisher = {OUP},
	abstract = {In this study, we present a method to estimate posterior distributions for standard accretion torque model parameters and binary orbital parameters for X-ray binaries using a nested sampling algorithm for Bayesian parameter estimation. We study the spin evolution of two Be X-ray binary systems in the Magellanic Clouds, RX J0520.5-6932 and RX J0209-7427, during major outbursts, in which they surpassed the Eddington limit. Moreover, we apply our method to the recently discovered Swift J0243.6+6124, the only known Galactic pulsating ultra-luminous X-ray source. This is an excellent candidate for studying the disc evolution at super-Eddington accretion rates, because its luminosity spans several orders of magnitude during its outburst, with a maximum L<SUB>X</SUB> that exceeded the Eddington limit by a factor of ~10. Our method, when applied to RX J0520.5-6932 and RX J0209-7427, is able to identify the more favourable torque model for each system, while yielding meaningful ranges for the NS and orbital parameters. Our analysis for Swift J0243.6+6124 illustrates that, contrary to the standard torque model predictions, the magnetospheric radius (R<SUB>m</SUB>) and the Alfv{\'e}n radius (R<SUB>A</SUB>) are not proportional to each other when surpassing the Eddington limit. Reported distance estimates of this source range between 5 and 7 kpc. Smaller distances require non-typical neutron star properties (i.e. mass and radius) and possibly lower radiative efficiency of the accretion column.},
	keywords = {Accretion, accretion discs, Astrophysics - High Energy Astrophysical Phenomena, pulsars: individual: RX J0520.5-6932, RX J0209-7427, Swift J0243.6+6124, X-rays: binaries},
	isbn = {0035-8711},
	url = {https://ui.adsabs.harvard.edu/abs/2023MNRAS.520..281K},
	author = {Karaferias, A. S. and Vasilopoulos, G. and Petropoulou, M. and Jenke, P. A. and Wilson-Hodge, C. A. and Malacaria, C.}
}
