Propeller effect in the transient X-ray pulsar SMC X-2

Abstract

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 $\simeq 10^{39}$ down to several$\times 10^{34}$ erg/s. Moreover, we discovered its dramatic drop by a factor of more than 100 below the limiting value of $L_{\lim }\simeq 4\times 10^{36}$ 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 $B\simeq 3\times 10^{12}$ G, which is in agreement with independent results of the spectral analysis.

8 pages, 2 figures, accepted to ApJ

References in corpus (5)

• 4U 0115+63 from RXTE and INTEGRAL Data: Pulse Profile and Cyclotron Line Energy
• A Further Study of the Luminosity-Dependent Cyclotron Resonance Energies of the Binary X-ray Pulsar 4U0115+63 with RXTE
• The return to quiescence of Aql X-1 following the 2010 outburst
• Swift observations of SAX J1808.4-3658: monitoring the return to quiescence
• Detection of Cyclotron Resonance Scattering Feature in High Mass X-ray Binary Pulsar SMC X-2

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