2026ApJ...996...49M

We present the high-resolution X-ray spectrum of the Z-source Cygnus X-2, obtained with the X-Ray Imaging and Spectroscopy Mission (XRISM). The observations have enabled a precise characterization of the Fe-K emission lines from the accretion disk corona (ADC) and a possible detection of an ultrafast outflow. The ADC component has at least two distinct regions. The Fe-K emission lines are remarkably broad, with a velocity dispersion of ${\sigma }_{v}=230{0}_{-700}^{+900}$ km s^–1. This can be larger than what was observed in previous Chandra observations (1120 ± 870 km s^–1) and recent XRISM observations of the similar Z-source GX 340+0 (360-800 km s^–1). Furthermore, we marginally detect a blueshifted absorption feature, which we identify as either Fe XXVI or Fe XXV, with outflow velocities of -0.29c or -0.26c, respectively. The mass loss rate is $\dot{M}\sim 1{0}^{-8}{M}_{\odot }\,{{\rm{yr}}}^{-1}$. Our findings suggest that the ADC in Cyg X-2 has a kinematically active environment with a high degree of turbulence and kinetic energy.