A Possible Cyclotron Feature of the Gamma-Ray Binary 4FGL J1405.1–6119

Abstract

Abstract We reanalyzed the X-ray observations of the γ-ray binary candidate 4FGL J1405.1−6119 using the XMM-Newton observations. In the X-ray spectra, we find a weak absorption feature around 2 keV in the XMM-Newton observations, which could be the cyclotron resonant scattering feature (CRSF) or so called cyclotron line of the possible neutron star (NS) in the binary. The line energy of the CRSF is ∼2 keV, implying that the magnetic field on the surface of the NS is about B ≈ 1011 G or B ≈ 1014 G depending on the cyclotron line being generated by electron or proton, respectively. This suggest that 4FGL J1405.1−6119 hosts a weakly magnetized NS or a magnetar.