出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We study the energy dependent pulse profiles and phase resolved spectra of the high-mass X-ray binary pulsar 4U 0115+63 to investigate the role of cyclotron resonant scattering in the pulse profile formation. For this purpose, we exploit archival BeppoSAX and RXTE data taken during the bright phase of the giant outburst occurred in 1999. We find that the pulse profiles are significantly shifted and distorted at the energies corresponding to the cyclotron scattering absorption features. We develop a geometrical model of the column emission and pulse profile formation that explains this newly discovered phenomenon, finding that it can be modeled as an energy dependent angular beaming of the radiation emitted by the column. Data with higher S/N andmore sophisticated theoreticalmodelswill contribute significantly to the comprehension of the X-ray emission in the strong gravitational and radiative fields of accreting neutron stars.
