Wavelength range: 145 - 655 µm
The spectral resolution plotted corresponds to the FWHM of the instrument line spread function for a monochromatic line from a point source. This plot is only representative; order selection and spectral resolution are provided by a chain of fixed and tunable Fabry-Perot filters, resulting in a variety of resolving power choices (TBD).
Incremental wavelength changes can be made on the fly in a stepped mode, enabling real-time imaging spectroscopy.
Error in velocity determination 10 km/sec (TBC) for unresolved lines
Wavelength setting accuracy corresponds to about 10% of the resolution, e.g. 20 km/s at R = 1500.
Free spectral range : several values possible, ~20 µm typical (TBD)
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SAFIRE sensitivity is shown for a monochromatic line from a point source, at the spectral resolution plotted on the previous page.
MDLF is the Òminimum detectable line fluxÓ, 4s in 15 minutes (900 seconds).
The plotted curve connects points at wavelengths where atmospheric transmission exceeds 80%. Where transmission is low, the MDLF will be much higher.
MDLF scales roughly as (S/N) /Ã t where t = net integration time
Minimum detectable continuum flux MDCF (4s, 15 minutes):
l = 100-300µm: ~ 0.5 Jy
l = 300-700µm: ~ 0.3 Jy
Calibration and setup overhead time is roughly 20%.
Line measurements in bright continuum sources may take longer to reach the same S/N.
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Beam size shown is the instrument FWHM size for nominal operating conditions.
Field of View = 160Ó x 320Ó
16 x 32 pixel array, 10Ó / pixel
SAFIRE FOV and beam size at l158 µm (C II) shown superimposed on visible image and C II map of face-on spiral galaxy M 83. Also shown is beam size for FIFI used on KAO to obtain the C II map. The latter is also the SAFIRE beam size at about l550 µm.
Notes: (1) Higher spectral resolution may be limited to a smaller FOV. (2) Plate scale changes are possible with added optics, to improve resolution at shorter wavelengths.
SOFIA and all first light focal-plane instruments are now in development. All sensitivity and resolution data are preliminary, and based on anticipated performance of the observatory and the instruments. Actual performance of the SOFIA telescope and instrument combination will be established after flight operations begin. Telescope performance is expected to be upgraded during the first two years, and instrument performance may be upgraded, or additional modes or capabilities may be added.
PERFORMANCE ESTIMATES GIVEN HERE ARE BASED ON DATA SUPPLIED BY THE INSTRUMENT TEAMS. A POINT OF CONTACT FOR EACH INSTRUMENT IS PROVIDED.
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