VIRUS-W: an integral field unit spectrograph dedicated to the study of spiral galaxy bulges

We present the design, layout and performance estimates for a fiber based Integral Field Unit spectrograph. This instrument is built for flexible use at different telescopes, and in particular for the new 2m telescope on Mount Wendelstein in the Bavarian Alps. Based on the VIRUS spectrograph for the HETDEX experiment, the proposed instrument will have a fiber head consisting of 267 optical fibers. The large angular field of view of 150×75 arcseconds will allow full coverage of the bulge regions of most local late type galaxies in one or two pointings. Realized by the usage of VPH gratings, a R ≈ 2500 and a R ≈ 6800 mode with 850Å and 515Å wavelength coverage will be dedicated to the study of stellar populations and kinematics of late type galaxy bulges.