We present a 0.2–10 keV 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 \pm 0.07 ) \times 10 ^ { 21 } atoms cm ^ { -2 } , a power-law index of 0.78 \pm 0.02 and a cut-off energy of 4.30 \pm 0.08 keV ( 68 % confidence errors ) , except at energies near \sim 1 keV where excess emission is present .
This can be modeled by a broad Gaussian line feature with an energy of 1.02 \pm 0.04 keV , a full width half-maximum of 0.47 \pm 0.07 keV and an equivalent width of 74 \pm ^ { 25 } _ { 11 } eV .
This result confirms earlier reports of line emission near 1 keV and shows the intensity and structure of the feature to be variable .