We report the results of the monitoring campaign of the transient X-ray pulsar SMC X-2 performed with the Swift/XRT telescope over the period of 2015 September - 2016 January during the Type II outburst. During this event, the bolometric luminosity of the source ranged from ≃1039 down to several×1034 erg/s. Moreover, we discovered its dramatic drop by a factor of more than 100 below the limiting value of Llim≃4×1036 erg/s, which can be interpreted as a transition to the propeller regime. These measurements make SMC X-2 the sixth pulsating X-ray source where such a transition is observed and allow us to estimate the magnetic field of the neutron star in the system B≃3×1012 G, which is in agreement with independent results of the spectral analysis.
@article{arxiv.1607.03427,
title = {Propeller effect in the transient X-ray pulsar SMC X-2},
author = {A. Lutovinov and S. Tsygankov and R. Krivonos and S. Molkov and J. Poutanen},
journal= {arXiv preprint arXiv:1607.03427},
year = {2017}
}