GMT’s Near IR Multiple Object Spectrograph - NIRMOS Daniel Fabricant Center for Astrophysics

NIRMOS Scientific Drivers Discovery and characterization of the first galaxies Assembly and evolution of galaxies at z=2 to 3 Chemical evolution of galaxies

GMT and NIRMOS probe galaxy evolution from first light Tentative IR detection of Ly α emission looking back 13 Gyr (Stark et al. 2007) ~10 hrs with Keck. “At the faint limits now being probed, we have found the reliable identification and verification of distant Ly α emitters to be a very challenging endeavor, even with the most powerful facilities available to us.”

Galaxies in formation 11 Gyr ago

Galaxies are different at z=2 Kriek et al. 2009

Compact red sequence galaxy 11 Gyr ago Van Dokkum, Kriek & Franx 2009 This galaxy has a stellar mass of 3 x Mסּ despite its tiny size!

Evolution of massive galaxies van Dokkum et al R e = 3 kpc 10 Gyr ago R e = 8 kpc 6 Gyr ago Galaxies selected from mass-number density relation at constant number density

29 hr spectrum of H=20 Galaxy with Gemini 8 m GMT will attain S/N of 10 for H=22.5 in 10,000 sec in natural seeing Van Dokkum, Kriek & Franx 2009 Kriek et al. 2009

JWST and GMT: natural partners James Webb Space Telescope 2014 Giant Magellan Telescope 2018

JWST NIRCam imaging 2 arcminutes 10 square arcminutes in two bands 0.07″ images at 2.2 µm Superb photometry and galaxy stucture

JWST’s NIRSpec At R=100 with very low background, JWST is a superb tool for rapid redshift measurements and selection of galaxy samples At the resolution needed for dynamical mass measurements, a GMT instrument can provide greater sensitivity and larger fields of view than NIRSpec Multiple object spectrograph at R=100 and R=1000 with 9 square arcminute FOV IFU and long slit at R= ″ nominal slit width

GMT IR spectroscopy of distant galaxies Go faint: Observe galaxies 11 Gyr ago with ~3 x M סּ H Vega =22.5 or H AB =24 Infrared: Distant quiescent galaxies are bright at λ > 1.4 µm Wide-field: ~3 galaxies arcmin -2 at z > 2 Spectral resolution: λ/Δλ~3000 for 100 km s -1 resolution and to reduce OH contamination Angular resolution: 3 kpc ~0.36 arcsec (LCO median at H), GLAO assist helpful

GMT’s NIRMOS NIRMOS Field of View 35 square arcminutes ~105 z>2 galaxies! 0.9 to 2.5 μm imaging spectrograph Natural seeing or GLAO R~3000 with 0.5″ slit and full J, H, or K coverage – higher resolution possible Superb image quality: worst 80% EE better than 0.15″ Volume Phase Holographic gratings reduce scattering (and OH background) by order of magnitude NN NIRSpec GMT/NIRMOS at R=3000 is twice as sensitive as JWST/NIRSpec at R=1000, with 4x the field of view

Ground Layer Adaptive Optics GLAO will improve spatial resolution by ~2 1.5 kpc resolution at z=2.5, same as JWST NIRSpec Ground layer wavefront errors are weakly dependent on field angle

NIRMOS optical layout Fused Quartz CaF 2 (four segments) CaF 2 aspheric S-TIM28 Fused Quartz 275 mm collimated beam diameter CaF 2 lens blanks < 390 mm diameter available from current production Volume Phase Holographic gratings for dispersers 4 meters

Critical technologies for NIRMOS TechnologyStatus Large calcium fluoride lens blanks Canon/Optron quote in hand Large S-TIM28 lens blanks Ohara quote in hand Detector array Teledyne will produce, estimate in hand Large cryogenic VPH gratings -Kaiser Optical could produce, K band performance the major open item Ground layer adaptive optics $Dependent on adaptive secondary mirror – soft fallback to seeing limited operation

NIRMOS at GMT’s Gregorian Focus

NIRMOS mechanical layout Optics and mechanics cooled to 120 K Collimator optics Camera Optics Filter and grating wheels Slit mask cassette Imaging Spectroscopy 5m

NIRMOS focal plane area Manifest fibers Tip/tilt guiders Slit mask cassette Cryocoolers

Conclusions We believe that NIRMOS has great scientific potential, is technically feasible and affordable We invite our GMT partners to explore NIRMOS science with us We look forward to exploiting the potential of IR fiber technology with the MANIFEST team We are interested in collaborations in IR technology with GMT partners

The End

High Altitude Turbulence Restricts the Diffraction-limited Field of View *

NIRMOS in the JWST era NIRMOS at R=3000 is 2x as sensitive than NIRSpec at R=1000, with 4x the field of view NIRMOS at R=3000 is ~10x more sensitive than NIRSpec at R=3000 and retains MOS In natural seeing, NIRMOS attains S/N of 10 in 10,000 s at H=22.5 (0.5 x 0.5 arcsec)

NIRMOS at GMT’s Gregorian focus

NIRMOS mechanical layout Optics and mechanics cooled to < 100 K