Confirmation of the presence of a CRSF in the NICER spectrum of X 1822-371

• DOI: 10.48550/arxiv.2401.03698
• Publication Date: 2024-01-01
• Authors: R. Iaria; T. Di Salvo; A. Anitra; C. Miceli; F. Barra; W. Leone; L. Burderi; A. Sanna; A. Riggio
• Keywords: Eddington luminosity

X 1822-371 is an eclipsing binary system with a period close to 5.57 hr and orbital derivative $\dot{P}_{\rm orb}$ of 1.42(3)$\times 10^{-10}$ s s$^{-1}$. The extremely high value its compatible super-Eddington mass transfer rate from the companion star and, consequently, intrinsic luminosity at Eddington limit. source also X-ray pulsar, it shows spin frequency 1.69 Hz in spin-up phase $7.4 \times 10^{-12}$ Assuming limit, neutron magnetic field strength $B = 8 10^{10}$ G estimated. However, direct measure $B$ could be obtained observing CRSF energy spectrum. Analysis \textit{XMM-Newton} data suggested presence cyclotron line 0.73 keV, estimated $B=(8.8 \pm 0.3) G. Here we analyze 0.3-50 keV broadband spectrum combining 0.3-10 NICER 4.5-50 \textit{NuSTAR} investigate absorption complex continuum emission confirms 0.66 keV. modeled Comptonized component, thermal component associated accretion disk truncated magnetospheric radius 105 km reflection blurred by relativistic effects. We confirm inferring NS (7.9\pm 0.5) suggesting that originates columns.