Propeller effect in action in the ultraluminous accreting magnetar M82 X-2

TL;DR

This paper reports the first observational evidence of a magnetar-like magnetic field in an accreting neutron star, demonstrating the propeller effect in a pulsating ultra-luminous X-ray source in M82.

Contribution

It provides the first convincing observational evidence of a magnetar-like magnetic field in an accreting neutron star within a binary system.

Findings

Bimodal luminosity distribution with two peaks separated by a factor of 40

Detection of the propeller regime in an accreting pulsar

Estimate of the neutron star's magnetic field at ~10^14 G

Abstract

We present here the first convincing observational manifestation of a magnetar-like magnetic field in an accreting neutron star in binary system - the first pulsating ultra-luminous X-ray source X-2 in the galaxy M82. Using the Chandra X-ray observatory data we show that the source exhibit the bimodal distribution of the luminosity with two well-defined peaks separated by a factor of 40. This behaviour can be interpreted as the action of the "propeller regime" of accretion. The onset of the propeller in a 1.37 s pulsar at luminosity of ~$10^{40}$ erg/s implies the dipole component of the neutron star magnetic field of ~$10^{14}$ G.