Does the gamma-ray binary LS I +61°303 harbor a magnetar? by Arthur G. Suvorov et al. on Wednesday 30 November

The high-mass X-ray binary LS I +61{\deg}303 is also cataloged as a gamma-ray

binary as a result of frequent outbursts at TeV photon energies. The system has

released two soft-gamma flares in the past, suggesting a magnetar

interpretation for the compact primary. This inference has recently gained

significant traction following the discovery of transient radio pulses,

detected in some orbital phases from the system, as the measured rotation and

tentative spin-down rates imply a polar magnetic field strength of $B_p \gtrsim

10^{14}\,\mbox{G}$ if the star is decelerating via magnetic dipole braking. In

this paper, we scrutinize magnetic field estimates for the primary in LS I

+61{\deg}303 by analyzing the compatibility of available data with the system's

accretion dynamics, spin evolution, age limits, gamma-ray emissions, and radio

pulsar activation. We find that the neutron star's age and spin evolution are

theoretically difficult to reconcile unless a strong propeller torque is in

operation. This torque could be responsible for the bulk of even the maximum

allowed spin-down, potentially weakening the inferred magnetic field by more

than an order of magnitude.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2210.09471v2