Daily Image
25-04-2014
The first infrared fringes with MATISSE
| Submitter: | Felix Bettonvil |
| Description: | MATISSE, the mid-infrared interferometric spectrograph and imager for the VLTI, recently passed an important milestone by recording interferometric fringes in the lab for the very first time. MATISSE is an instrument that is designed to coherently combine the light of up to four telescopes of ESO's Very Large Telescope Interferometer (VLTI). The combined light is imaged on a detector, to form an interference pattern from which a high-resolution image of the observed source can be reconstructed. In this way, the VLTI with MATISSE emulates the aperture of a telescope with a diameter of up to 200m, giving a spatial resolution up to 5 milli-arcsec in the 2.8-5 and 8-13 micrometer wavelength bands. The spectral resolution is between 30 and 5000. With these characteristics, MATISSE is extremely well suited for the study of Young Stellar Objects (YSOs), extra-solar planets and Active galactic nuclei (AGNs), asymptotic giant branch stars (AGBs) and planetary nebulae. The NOVA/ASTRON Optical Infrared instrumentation group is responsible for building the Cold Optics Benches (COB) for MATISSE. The first COB unit, which operates in the 8-13 micrometer N-band, is currently at MPIA/Heidelberg were it is tested at its cryogenic working temperature. Last month, for the first time, the Aquarius detector recorded light from a test laser source at its working wavelength, with two spectral lines around 10.5 micrometer. The above image shows the interferometric fringe-patterns of the two laser lines. The cross-section of one is shown in the inset. The orange colour represents the thermal background. The white spots originate from the 10.5 micrometer test laser. The spatial direction is horizontal, and the dispersion direction is vertical. The two directions have different magnifications, in order to optimally match pixel size. The vertical bands on the left and right of the interferometric image contain photometric information for each telescope. In this experiment, the interferometric image is formed by combining 3 telescope beams. The spacing of the fringes of the interference pattern depends on the separation of the beams in the pupil plane. Note that the clear diffraction rings of the photometric laser spots give a first indication of the image quality. More information may be gleaned by clicking on "Archive" at the top of this webpage, and searching with the keyword "MATISSE". Or, alternatively, by means of the following link. |
| Copyright: | NOVA Optical Infrared Instrumentation group |
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