7/2/2015Richter - UC Davis1 EXES, the echelon-cross-echelle spectrograph for SOFIA Matthew J. Richter (UC Davis) with Mark McKelvey (NASA Ames Research Center) Andreas Seifahrt (UC Davis) special notice to John Lacy, UT Austin

7/2/2015Richter - UC Davis2 SOFIA -SOFIA is 747 with 2.5m aperture 6-8 hour flights at ,000 feet PWV 5-10 micron first science in Impact of SOFIA for mid-IR new spectral windows large instruments (600 kg) -EXES is PI instrument collaborative proposals

EXES and SOFIA 7/2/2015Richter - UC Davis Wavelength [µm] Spectral resolution HIPO FLITECAM FORCAST HAWC GREAT CASIMIR FIFI LS EXES

7/2/2015Richter - UC Davis4 Atmospheric comparison SOFIA vs Mauna Kea

7/2/2015Richter - UC Davis5 EXES -High spectral resolution, mid- IR, grating spectrograph Operates between 4.5 and 28  m R =100,000 (3 km/s) at 10  m - 0.7% spectral coverage with 15” long slit (depending on telescope) - medium (R=10,000) and low (R=3000) modes available pixel Si:As IBC detector designed for space backgrounds -Preparing for ground-based telescope proposal for 2010B fly on SOFIA in 2013 Forward

-measure weak lines -measure features in crowded regions -Resolve disk radii -Separate multiple velocity components 7/2/2015Richter - UC Davis6 Propane on Titan Roe et al Propane Importance of High Spectral Resolution

-Complements Spitzer (Herschel, JWST, ALMA) more later -Reduce impact of telluric features 7/2/2015Richter - UC Davis7 SOFIAMauna Kea ±100 km/s

0.3” Echelon Grating 7/2/2015Richter - UC Davis8 40 inches long 0.3 inch groove spacing grooves / mm Diamond machined Al inch groove height 84.3 degree angle of incidence

Selected Science Potential of EXES -Solar System mapping Martian disk in CH 4 SO 2 on Io H 2 O, CO 2, and other molecules in comets -Star formation regions H 2 O rotational and vibrational lines in circumstellar disks pre-biotic molecules in absorption 7/2/2015Richter - UC Davis9

Spitzer IRS Spectrum of a Typical T Tauri Star S/N  250 [NeII], other atomic lines and molecular bands Carr & Najita (2008)

7/2/ H 2 O Rotational Emission Line Resolved Gemini/TEXES R=100,000 Water emission resolved: 90 km/s FWHM From r = AU Carr, Najita, Richter, Lacy, Knez, etc. 13  m

Molecular absorption toward a low-mass PMS star -Spitzer found molecular band absorption toward a T Tauri star with IR companion C 2 H 2, HCN, CO 2 (T=550 K for HCN) Absorption against mid-IR continuum - star or disk 7/2/2015 Courtesy IRS GTOs

Molecular absorption toward a low-mass PMS star 7/2/2015Richter - UC Davis13 Molecular lines resolved with TEXES (R=80,000)  warm gas  asymmetric lines  offset from cloud velocity  probes origin (disk,wind, infall) Other molecules without strong, overlapping bands also detected e.g. NH 3

IRC (Fonfria et al. 2008) 7/2/2015Richter - UC Davis14 1 of 6 panels

IRC (Fonfria et al. 2008) 7/2/2015Richter - UC Davis15 1 of 6 panels

7/2/2015Richter - UC Davis16 Slit stepping observations provide data cube (spatial, spatial, spectral) Sky subtraction comes from edge of scan [NeII] map of the Galactic Center region

pixel array on long term loan from NASA intermediate step toward MIRI arrays for JWST -Designed for space backgrounds very low read noise: ~30 e - shallow well (roughly linear up to 100,000 e - ) EXES detector 7/2/2015Richter - UC Davis17

EXES C 2 H 2 Q-branch spectrum Pixels Q(1 ) Q(3 ) Q(5 ) Q(7 ) Q(8 ) Q(9 ) Q(10) Q(11) Q(9 ) Q(10) Q(11) Q(12) Q(13) Q(14) Q(15) Q(16) Q(19) Q(20) Q(23) Q(22) R(0) Q(23) Q(25) Q(27) R(1) Spatial Direction Spectral Direction -Gas cell with low-pressure, room temperature C 2 H 2. The features are mostly from Q- branch at 13.7 microns. -R = 60,000 (FWHM of 12.5 pixels). Expect to reach R=100,000 when EXES is properly focused. -The wavelength coverage is 0.6% at this wavelength: 15% more than TEXES no gaps between echelon orders.

7/2/2015Richter - UC Davis19 Summary -EXES on SOFIA will provide truly unique data because of resolution and atmospheric transmission -EXES is nearly ready for first ground-based run working Si:As array still some work to be done, but on track for first flight in 2013

John Lacy, EXES, and Global Warming -John Lacy (UT Austin) former EXES PI ocal/11/30/1130lacy.html 7/2/2015Richter - UC Davis20