Tunable Filter Capabilities for the CFHT and recent FaNTOmM results
Claude Carignan, Olivier Hernandez

Abstract: Fabry Perot (FP) interferometers are the spectrometers with the largest line-continuum contrast, their emission line detection power is thus greater than any other spectrograph. Very low order (p ~ 10 to p ~ 50) scanning FPs, commonly called Tunable Filters (TF), are instruments for which the central wavelength and the bandpass can be continuously tuned over a large wavelength range. They are ideal instruments to detect emission lines while scanning large redshifts volume up to the first light after reonization. In particular, their large monochromatic detection power increases considerably the hope to detect diffuse and extended Lyman alpha halos. A scanning FP (TF) is an integral field spectrograph which means that morphological information can be obtained at the same time than spectral information. Star formation and gas content are traced by the diagnostics given by the morphology combined with the line ratios., , It will be showed that in an era of 8-10m class telescopes, TF capalities on 4m class telescopes can be competitive when having access to large field-of-views (%3E 20 arcmins). Such instruments, being build at the moment for the WHT and the NTT, will be described. Finally, results already obtained at the CFHT with the FP system FaNTOmM will be presented.