Development of the VIRUS Integral-Field Spectrograph

One of the major discoveries of the last years was the accelerated expansion of the universe through the measurement of distant supernovae (Nobel price in physics in 2011). The yet completely unknown source of this apparent "anti-gravity" was dubbed Dark Energy.

AIP is partner of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), which is one of several research projects worldwide, trying to measure the properties and effects of this mysterious energy. The project is led by the University of Texas at Austin and involves American, German and British institutes. HETDEX aims to detect up to 800.000 Lyman-alpha galaxies in a large volume of 9 cubic Giga parsec, (corresponding to redshifts between 2 and 4). The goal is to determine the typical distribution of galaxies within this space and to compare it with the tiny energy fluctuations in the early Universe.

The AIP team is significantly involved in the hardware development for the HETDEX instrument, called VIRUS. Based on a modular concept that features 150 spectrographs, connected by optical fibre-bundles to the 9m Hobby-Eberly Telescope (HET), VIRUS is a huge integral-field spectrograph that can record over 33.400 spectra in one exposure.

Within the partnership, the AIP team has built and delivered optical fibre bundle prototypes for both the 2.7m telescope and HET, which are used for the pilot survey at McDonald Observatory. In order to build the remaining integral-field units (IFUs), AIP is engaged in technology transfer with industrial partners, and has manufactured fibre bundles in small series production runs. In exchange for the IFU development and deliveries, AIP receives access to observing time over the operational lifetime of VIRUS and is scientifically involved in the HETDEX survey.

During the last years, the AIP participation was partly funded by the Leibniz competition.