AAS 203rd Meeting, January 2004
Session 96 GALEX I: The Mission and Early Type Galaxies
Oral, Wednesday, January 7, 2004, 10:00-11:30am, Centennial III

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[96.02] On-Orbit Performance of the Galaxy Evolution Explorer (GALEX)

P. Morrissey (CalTech), GALEX Science Team

We present the early on-orbit performance results for the Galaxy Evolution Explorer (GALEX), a NASA mission that launched on April 28 and 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. Simulataneous 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. Initial measurements demonstrate that GALEX is performing very well, meeting its requirements for resolution, efficiency, astrometry, bandpass definition and survey sensitivity. We describe the results from both ground test and flight for comparison.

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.

The author(s) of this abstract have provided an email address for comments about the abstract: patrick@srl.caltech.edu

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.