1997A&A...323L..29K

We present a 0.2-10keV spectrum of the low-mass X-ray binary Cygnus X-2 obtained using the Low Energy Concentrator Spectrometer on-board BeppoSAX. The spectrum can be described by a cut-off power-law model with absorption of (2.28±0.07)x10²¹atoms/cm², a power-law index of 0.78±0.02 and a cut-off energy of 4.30±0.08keV (68% confidence errors), except at energies near ∼1keV where excess emission is present. This can be modeled by a broad Gaussian line feature with an energy of 1.02±0.04keV, a full width half-maximum of 0.47±0.07keV and an equivalent width of 74±²⁵₁₁eV. This result confirms earlier reports of line emission near 1keV and shows the intensity and structure of the feature to be variable.