摘要：The hard X-ray transient sourceSwiftJ1845.7–0037 was discovered in 2012 bySwift/BAT. However, at that time, no dedicated observations of the source were performed. In October 2019, the source became active again, and X-ray pulsations with a period of ∼199 s were detected withSwift/XRT. This triggered follow-up observations withNuSTAR. Here, we report on the timing and spectral analysis of the source properties usingNuSTARandSwift/XRT. The main goal was to confirm pulsations and search for possible cyclotron lines in the broadband spectrum of the source to probe its magnetic field. Despite highly significant pulsations with period of 207.379(2) s being detected, no evidence for a cyclotron line was found in the spectrum of the source. We therefore discuss the strength of the magnetic field based on the source flux and the detection of the transition to the “cold-disc” accretion regime during the 2012 outburst. Our conclusion is that the source is most likely a highly magnetized neutron star withB ≳ 1013G at a large distance ofd ∼ 10 kpc. The latter is consistent with the nondetection of a cyclotron line in theNuSTARenergy band.
关键词：enaccretion, accretion disksmagnetic fieldsstars: individual: Swift J1845.7-0037X-rays: binaries
