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1Current: Matt Richter (UCD), Mark McKelvey (Ames), Curtis DeWitt (UCD), Mike Case (UCD), Jeff Huang (Ames), Kristin Kulas (Ames), Robert McMurray (Ames), Damon Flansburg (Ames), Jeff Blair (Ames), Emmett Quigley (Ames), Reed Porter (Ames)

Past: Pete Zell (Ames), Andreas Seifahrt (UCD), John Reimer (Ames), Bala Balakrishnan (Ames), Dana Lynch (Ames), John Lacy (UT Austin), Doug Mar (UT Austin), Bill Moller (UT Austin)

Honorary (SOFIA): Melanie Clarke, Bill Vacca, Adwin BoogertFirst flights of EXES on SOFIA

Adapted from Scott Sandfords 2009 teletalk2OutlineMid-IR spectroscopy featuresatmospheric effectsImportance of high resolution About EXESSome highlightsFurther informationAdapted from Scott Sandfords 2009 teletalkAdapted from Scott Sandfords 2009 teletalk

3IR spectroscopy, particularly in the 2-40 m range, can detect and identify many molecular species since different molecules have different IR spectral fingerprintsMolecules seen with TEXESwithout dipole moments: H2, C2H2, CH4, CH3other molecules: H2O, HDO, HCN, NH3, SO2, CO, HNCO, OH, SiO, CS, C2H4, C2H6, C3H4, C4H2, C6H2, PH3, CH3DAdapted from Scott Sandfords 2009 teletalkmolecules in stars, planets, mass-loss regions (Fonfria et al), star forming regions (Knez, et al. 2009; Barentine & Lacy 2012)(T)EXES lowAdapted from Scott Sandfords 2009 teletalkArmed with the appropriate spectral resolutions, one can also distinguish between solids and gases

45.0Spitzer IRS HighISO SWS (about)JWST MIRI (about)NOTE: (T)EXES do not observe this full spectral region. IRS did not cover any of this region.Adapted from Scott Sandfords 2009 teletalkPoint out the resolving powers of Spitzer, ISO SWS (2000), MIRI (3000), (T)EXES low - high = 80,000, med ~15,000

SOFIA vs Mauna Kea5TEXES cutoff (optics)Atmospheric comparisonEXES cutoff (Si:As)Adapted from Scott Sandfords 2009 teletalkMention wavelength cut-off for TEXES6Advantage of EXES/SOFIAhigh spectral resolution at wavelengths inaccessible from ground

Comparison of transmission from SOFIA and Mauna Kea for some important moleculesH2OC2H2CH3CH4HCNSO2Effect of atmosphere in background limit (Mason et al 2008)

S/N T / ( (1-T) + e )0.5

where:T is atmospheric transmissione is system emissivity Adapted from Scott Sandfords 2009 teletalk7High Spectral ResolutionLine profile informationLimit confusionother source lineslines from atmosphereMaximize sensitivity for narrow lines

SOFIAMauna Kea100 km/s

PropaneRoe et al. 2003

40 km/sJaffe et al (2003) R~80,000Adapted from Scott Sandfords 2009 teletalkUpper Right is from [NeII] map of Mon R2 - histogram for data as observed. Dashed line is convolved with thermal broadening for ionized H.Lower Right shows propane detection from Titan - Strongest lines are not propane so would cause confusion. Lower Left shows model atmosphere near J=3-1 H2 line from Mauna Kea and from SOFIA. From ground, careful about Doppler shift. 8

Tau OrinoiseEXES/TEXES niche

Designed and built to emphasize high resolutionEvolution from J. Lacy work with Irshell, R=10,000 grating spectrographHigher resolving power than other mid-IR grating and FP instrumentsHigher sensitivity than FTS or HeterodyneJennings et al. 1986TEXES on IRTF: 4 minutes, R=80,000 1.20.6Adapted from Scott Sandfords 2009 teletalkFTS on 4m - R=50,000 and 4 hrs on alpha Ori, 6.4 hrs on alpha TauTEXES on IRTF in 2000 with R=80,000 and 3x spectral coverage. Note vertical scale. almost no noise.EXES/TEXES niche9

TEXES survey of IRC +10216 (Fonfria et al. 2008) 1 of 6 pages

zoom of upper leftProvide data unobtainable elsewhereComplement ALMA, GREAT on SOFIA, Herschelvibrational transitionsmolecules with no dipole momentAdapted from Scott Sandfords 2009 teletalkTEXES observations10Other Mid-IR Spectrographs

Adapted from Scott Sandfords 2009 teletalkNOTE that VISIR detector upgrade keeping it out of commission for next year.11Other Mid-IR Spectrographs

EXESozoneAdapted from Scott Sandfords 2009 teletalkTEXES is smaller due to atmosphere and detector.12Echelon grating40 long0.300 groove spacing0.131 grooves/mm84.2 degree incidence angle0.03 groove heightDiamond machined Al 6061Hyperfine Inc

0.30.3

Adapted from Scott Sandfords 2009 teletalk13DetectorsEXES10242 pixels25 mm per pixelOversampled0.38 km/s per pixel0.21 per pixel60 e- single sample readmatches size of high resolution orders ~19 mTEXES2562 pixelfocal reduced to 63 mm pixels0.97 km/s per pixel0.13 per pixel on Gemini30 e- single sample read (IRAC array)matches size of high resolution orders ~11 mBoth:Si:As Optimized for low background (space)shallow wells ~1.e5 e- for 40% transmission from ground)Same general guidelines as EXESAdapted from Scott Sandfords 2009 teletalk26Further informationFor EXES on SOFIAMatt Richter (PI): mjrichter@ucdavis.eduMark McKelvey (Co-I): mark.e.mckelvey@nasa.govCurtis DeWitt (postdoc): curtisdewitt@gmail.comhttp://irastro.physics.ucdavis.edu/exeswebsite still work in progressEXES exposure time calculator: http://irastro.physics.ucdavis.edu/exes/etcFor TEXES on Gemini/IRTFJohn Lacy (PI): lacy@astro.as.utexas.eduTommy Greathouse (solar system): tgreathouse@swri.eduMatt Richter (Galactic): mjrichter@ucdavis.eduAdapted from Scott Sandfords 2009 teletalk