Detection and Velocities of Hα Emission Regions in Stephan's Quintet

Abstract

We present observations of Hα emission of Stephan's Quintet obtained with a scanning Fabry-Perot interferometer and samplings of ~11 km s^-1 and ~1". Our observations show an intragroup arclike feature formed of bright Hα knots and diffuse gas distributed along tidal tails associated with NGC 7318B and possibly also NGC 7318A. New velocities for 23 emitting regions detected along the Hα structure are presented. South of NGC 7318B, along a path covering ~12 h^-1_75 kpc, H II regions with velocities ranging from 5540 to 6700 km s^-1 are detected, suggesting that two or more overlapping tidal tails and/or a bow-shock region may have been formed through several interaction events within the group.