  We are building an image slicer integral field unit (IFU) to go on the IMACS
wide-field imaging spectrograph on the Magellan Baade Telescope at Las Campanas
Observatory, the Reformatting Optically-Sensitive IMACS Enhancement IFU, or
ROSIE IFU. The 50.4" x 53.5" field of view will be pre-sliced into four 12.6" x
53.5" subfields, and then each subfield will be divided into 21 0.6" x 53.5"
slices. The four main image slicers will produce four pseudo-slits spaced six
arcminutes apart across the IMACS f/2 camera field of view, providing a
wavelength coverage of 1800 Angstroms at a spectral resolution of 2000. Optics
are in-hand, the first image slicer is being aluminized, mounts are being
designed and fabricated, and software is being written. This IFU will enable
the efficient mapping of extended objects such as nebulae, galaxies, or
outflows, making it a powerful addition to IMACS.
