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Grism Spectroscopy with FLITECAM Erin C. Smith (UCLA) Ian S. McLean (UCLA)
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FLITECAM 1- 5.5 micron NIR camera 1024x1024 InSb Aladdin III detector Optics cooled to ~ 80K with LN2 Detector controlled at 30K
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SOFIA
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8 arcminute circular FOV.43 arcsec/pixel (SOFIA).48 arcsec/pixel (Lick) Entrance aperture Slit mechanism Collimator Dual Filter Wheel Re-imaging optics Detector
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Why spectroscopy? Water Vapor monitor calibration –Resolve 2.5 micron water line (need R~1000) Allows low background, low water vapor spectroscopy in the thermal (3- 5.5 micron IR) –No spectral coverage by Spitzer at these wavelengths
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Science PAH features at 3.3 m Water ices 2.5-4.6 m Pa-a (1.87 m ) Br- (4.05 m )
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Grism Spectroscopy d d pupil X mm =d pupil /cos A A ii dd grism normal T m c = (n – 1) sin A R = 206265 (n – 1) d pupil tan A / D tel s arc, (max/min wavelength) = c +/- [(n – 1) d pix cos A / F cam m T] *N pix /2,
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KRS-5 N~2.4 Thalium bromo-iodide Manufactured by Zeiss- Jena –Can make grisms with T=651/n, up to 40 degrees
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Wavelength coverage
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Slit
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Lab testing Neon Argon lamps used to calibrate wavelength solutions Slit width found to be slightly larger than designed, narrow slit is 1.3”, wide slit is 2.35” wide R ~1700/900
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FLITECAM also mounts to the Shane 3 meter telescope at Lick Observatory Imaging mode commissioned October 2002 Spectroscopy mode was commissioned in June 2004
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DifferenceRAW C + K wide C + LM 69 Leo A0V star, for telluric standards High backgrounds at Lick require differences in thermal IR 1.872 2.346 2.756 3.467
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Gl406- (M5.5) Raw H band spectrum A-B spectrum High-res position B High res position A
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Data reduction
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NGC 7027
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Imaging & spectroscopy Switching between spectroscopy and imaging takes less than 20 seconds Using narrow band filters, we can make maps of spectral features, then use spectroscopy to investigate
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Aboard SOFIA
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