GHαFaS, 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˜15,000, and with a seeing-limited spatial resolution, GHαFaS will provide a new look at the

A new scanning Fabry-Perot system will soon be available at the Nasmyth focus of the 4.2 m William Herschel Telescope. It has been designed by the Laboratoire d'Astrophysique Expérimentale in Montréal and is being built in collaboration with astronomers at the Instituto de Astrofísica de Canarias. The instrument will see first light at the

We have analyzed the effects of gas on the disk-halo evolution in barred galaxies using N-body/SPH simulations. Our main focus has been the angular momentum (J)~redistribution mediated by the stellar bar and the subsequent evolution of the galactic disk. We find that the stellar bars in disks with 0-8 percent gas fraction are primarily affected by

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I use computer simulations to examine the evolution of close galaxy pair counts and the formation of galaxy clusters. I show that the evolution of the close pair fraction is much weaker than the strong evolution in the dark matter halo merger rate. I continue with a discussion of how galaxy cluster-sized dark matter halos are assembled. This result

We present here a simple approach to understanding the gas cloud mass distribution function by simulating formation and destruction of gas clouds and gas clumps in the interstellar medium. We include as relevant processes coagulation to form bigger clouds, as well as disruption by collisions and the removal of gas by collapse to form stars. We