GHαFaS:: Galaxy Hα Fabry-Perotsystem for the William!Herschel Telescope

GH alpha FAS, a new Fabry-Perot system, is now available at the William Herschel Telescope (WHT). It was mounted, for the first time, at the Nasmyth focus of the 4.2-m WHT on La Palma in 2007 July. Using modern technology, with a spectral resolution of the order R similar to 15, 000, and with a seeing-limited spatial resolution, GHaFAS will provide a new look at the H alpha-emitting gas over a 4.8' circular field in the nearby universe. Many science programs can be done on a 4.2-m class telescope in world-class seeing conditions with a scanning Fabry-Perot. Not only galaxies but H II regions, planetary nebulae, supernova remnants, and the diffuse interstellar medium are subjects for which unique data can be aquired rapidly. Astronomers from the Laboratoire d'Astrophysique Experimentale (LAE) in Montreal, the Laboratoire d'Astrophysique de Marseille (LAM-OAMP), and the Instituto de Astrofisica de Canarias (IAC), have inaugurated GHaFAS by studying in detail the dynamics of some nearby spiral galaxies. A robust set of state-of-the-art tools for reducing and analyzing the data cubes obtained with GHaFAS has also been developed.