EDiFiSE: equalized and diffraction-limited field spectrographexperiment

摘要

We present EDiFiSE, a prototype instrument for the observation of high-contrast systems, combining an adaptive optics (AO) system and an equalized integral field unit (EIFU). The design of the AO system takes into account the statistical behaviour of the atmospheric turbulence structure at the Canary Islands (Spain) astronomical observatories: Roque de los Muchachos (ORM) on the island of La Palma and Teide observatory (OT) in Tenerife. The AO will have the capability of adapting to the prevailing turbulence conditions; in this sense, the EDiFiSE AO unit will be an 'adaptable' adaptive optics system. The corrected beam feeds an hexagonal integral field unit formed by 331 micro-lenslets, which focus the intensity distribution at the focal plane into 331 optical fibers. The central seven fibers of the bundle include variable attenuators for the equalization of these fibers output intensities, matching them to the dynamical range of the detector and reducing the optical cross talk inside the spectrograph. This technique, called equalized integral field spectroscopy (Arribas, Mediavilla & Fuensalida 1998), permits to obtain spectral and spatial information of the equalized object and its surroundings as well as accurate relative photometry and astrometry.