Emir: The Gtc Nir Multi-Object Imager-Spectrograph

We present the final global design and performances of EMIR, the NIR multiobject spectrograph of the GTC, as well as the plan for its early scientific exploitation. EMIR, currently in the middle of its final phase, will be one of the first common user instruments for the GTC, the 10 meter telescope under construction by GRANTECAN at the Roque de los Muchachos Observatory (Canary Islands, Spain). EMIR is being built by a Consortium of Spanish and Fench institutes led by the IAC. EMIR is designed to realize one of the central goals of 10m class telescopes, allowing observers to obtain spectra for large numbers of faint sources in an time-efficient manner. EMIR is primarily designed to be operated as a MOS in the K band, but offers a wide range of observing anodes, which include imaging and spectroscopy, both long slit and multiobject, in the wavelength range 0.9 to 2.5 mu m. It is equipped with two innovative subsystems: a robotic reconfigurable multislit mask and dispersive elements formed by the combination of high quality diffraction grating and conventional prisms, both at the heart of the instrument. The present status of development, expected performances, schedule and plans for scientific exploitation are described and discussed. This project is mostly funded by GRANTECAN and the Plan Nacional de Astronomia y Astrofisica (National Plan for Astronomy and Astrophysics, Spain).