Propeller effect in the transient X-ray pulsar SMC X-2
  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 $\simeq10^{39}$ down to several$\times10^{34}$ erg/s. Moreover, we discovered its dramatic drop by a factor of more than 100 below the limiting value of $L_{\rm lim}\simeq4\times10^{36}$ 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 $B\simeq3\times10^{12}$ G, which is in agreement with independent results of the spectral analysis. 
A.Lutovinov (1,2), S.Tsygankov (3), R.Krivonos (1), S.Molkov (1),   J.Poutanen (3,4) (1 - Space Research Institute, IKI, 2 -...
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