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P. Morrissey (Caltech), GALEX Science Team
We present current performance results for the Galaxy Evolution Explorer (GALEX), a NASA mission that is performing a survey of the sky in two ultraviolet bands. The GALEX instrument comprises a 50 cm diameter modified Ritchey-Chretien telescope with imaging and objective-grism spectroscopic modes that feed a pair of large-format microchannel-plate-intensified, delay-line readout detectors. Simultaneous 2-color imaging of the large 1.2 degree field is achieved with an innovative optical system including a thin-film multilayer dichroic beamsplitter, which complements the bandpass-defining characteristics of a Lyman-alpha blocking filter and CsI cathode in the 23 nm-wide FUV band centered at 154 nm, in parallel with a red-blocking filter and CsTe cathode in the 80 nm-wide NUV band centered at 230 nm. Flight calibration based on the first year of observations has significantly improved the instrument performance, especially in the areas of astrometric accuracy and image resolution. GALEX continues to perform very well, meeting its requirements for resolution, efficiency, astrometry, bandpass definition and survey sensitivity. We describe the recent results and outline plans for further improvement.
GALEX (Galaxy Evolution Explorer) is a NASA Small Explorer, launched in April 2003. We gratefully acknowledge NASA's support for construction, operation, and science analysis for the GALEX mission.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.