Science Highlights from 4 Years of NIRSPEC on the Keck II Telescope

Abstract

NIRSPEC is the facility-class near-infrared spectrometer for the W.M. Keck Observatory. Commissioned from April August 1999, NIRSPEC has been used extensively and successfully over the last four years. In high-resolution mode (R ~ 20,000 30,000), NIRSPEC science includes studies of comets and solar system bodies, abundance studies in red giants, the kinematics of the population of stars near the Galactic Center, protostars and disks, low-mass spectroscopic binaries, brown dwarfs, galactic photo-dissociation regions and the study of extragalactic super clusters. NIRSPEC is an all-reflecting f/10 spectrograph with a 120mm collimated beam. A single echelle grating with ~22 l/mm is used in quasi-Littrow mode with an out-of-plane angle of 5 degrees. The collimator is an off-axis parabola and the camera is a three-mirror anastigmat. All of the optical components in the spectrometer chain are diamond-machined, post-polished aluminum mirrors with silver-coatings for high throughput. Spectral coverage from 0.95 5.5 mum is achieved with an ALADDIN III 1024 1024 InSb detector having a median dark current of ~0.2 e/s/pixel and a readout noise of ~25 electrons rms using 16 reads. NIRSPEC has a cryogenic image rotator, a set of fixed reflective slits and an independent slit-viewing camera with a field of view of 46" 46". Examples of high resolution spectra are described to illustrate performance.