CROMOS: A Cryogenic Near-Infrared, Multi-Object Spectrometer for the VLT

Abstract.

We discuss a cryogenic, multi-object near-infrared spectrometer as a second generation instrument for the VLT. The spectrometer combines 20 to 40 independent integral field units (IFUs), which can be positioned by a cryogenic robot over the entire unvignetted field of the VLT ($\lambda$ $\Delta\lambda\sim 4000$ and simultaneously covers the J-, H-, and K-bands with three HAWAII 2 detectors. The system is designed for operation both in seeing limited and MCAO modes. Its speed is approximately 3500 times greater than that of ISAAC and 60 times greater than NIRMOS (in H-band). The proposed instrument aims at a wide range of science, ranging from studies of galaxies/clusters in the high-z Universe (dynamics and star formation in $z>1$ galaxies, evolution of ellipticals, properties of distant, obscured far-IR and X-ray sources), to investigations of nearby starbursts, star clusters and properties of young low mass stars and brown dwarfs.