Extragalactic Science with GMTNIRS - Texas A&M...

Extragalactic Science with Extragalactic Science with GMTNIRSGMTNIRS

Giant Magellan Telescope Giant Magellan Telescope NearNear--Infrared SpectrographInfrared Spectrograph

SunghoSungho LeeLeeKorea Astronomy and Space Science Institute (Korea Astronomy and Space Science Institute (KASIKASI))

Daniel T. Jaffe Daniel T. Jaffe (UT), (UT), MooMoo--Young Chun Young Chun (KASI), (KASI), SoojongSoojong Pak Pak (KHU),(KHU), Marc Marc RafalRafal (UT),(UT),Stuart Barnes Stuart Barnes (Univ. of Canterbury/UT),(Univ. of Canterbury/UT), InIn--SooSoo Yuk Yuk (KASI),(KASI), Chan Park Chan Park (KASI),(KASI),

Mike Worthington Mike Worthington (CEM),(CEM), Tim Beets Tim Beets (CEM),(CEM), Joseph Joseph BenoBeno (CEM),(CEM), Joseph Joseph StrubharStrubhar(UT),(UT), WeisongWeisong Wang Wang (UT),(UT), Casey Casey DeenDeen (UT),(UT), Michael GullyMichael Gully--Santiago Santiago (UT),(UT),KangKang--Min Kim Min Kim (KASI),(KASI), HeeyoungHeeyoung Oh Oh (KASI/KHU),(KASI/KHU), TaeTae--SooSoo PyoPyo (Subaru)(Subaru)

GMTNIRS GMT workshop

GMTNIRSGMTNIRSHigh resolution infrared spectrograph with very broad instantaneous wavelength coverage

~16 cm R3 silicon ~16 cm R3 silicon immersion grating immersion grating (x 2)(x 2)

~7.5 cm R3 silicon ~7.5 cm R3 silicon immersion grating immersion grating (x 3)(x 3)

GratingGratingSlit Slit dimensiondimension

Wavelength Wavelength coveragecoverage

RR((λ/∆λ)λ/∆λ)

100,000LongLong--Wavelength Wavelength ((LMLM) Module ) Module

0.085 x 1.2 arcsec

All of J (>1.15 µm), H, K, L, M bandsin one exposure

50,000ShortShort--Wavelength Wavelength

((JHKJHK) Module ) Module


GMTNIRS AdvantagesGMTNIRS AdvantagesNearNear--IR spectroscopy (1IR spectroscopy (1--5 5 µµm)m): :

Plentiful lines from stars, planets, disks, ISMPlentiful lines from stars, planets, disks, ISM……Less extinctionLess extinctionBrighter lateBrighter late--type starstype stars

High spectral resolution (R > 50,000):High spectral resolution (R > 50,000):Resolved line profiles enable studies of chemical abundances, Resolved line profiles enable studies of chemical abundances, radial velocities, magnetic fields, isotopic ratios radial velocities, magnetic fields, isotopic ratios ……

Broad instantaneous wavelength coverage:Broad instantaneous wavelength coverage:Two orders of magnitude wider than CRIRES (VLT; Two orders of magnitude wider than CRIRES (VLT; λλ/70/70) or ) or PHOENIX (Gemini ; PHOENIX (Gemini ; λλ/200/200))

High sensitivity:High sensitivity:Gain faster than DGain faster than D22 by higher throughput of gratings and by higher throughput of gratings and detectorsdetectorsGMTNIRS can produce R > 50,000 spectra for any source in the GMTNIRS can produce R > 50,000 spectra for any source in the 2MASS catalog with a decent S/N2MASS catalog with a decent S/N


Immersion GratingsImmersion GratingsAdvanced capability of GMTNIRS in a compact design comes from silicon immersion gratings.The high refractive index (n=3.4) of silicon keep the high spectral resolution with a much smaller beam size.Silicon lithography can make a very coarse grating which enables continuous spectral coverage.

max

(sin sin )2 sin

2 tan

G

G

G

m nn LR

ndd

λ σ α βδ

λββ

λ λ

= +

=

=


UT Silicon GratingsUT Silicon GratingsSOFIA-FORCAST mid-IRgrisms (complete 2008)

JWST-NIRCam 3-5 µmgrisms (complete 2009)

NASA-IRTF ISHELL Immersion grating (proto-type 2008)


Optical LayoutOptical Layout


Optics: ForeOptics: Fore--opticsoptics


Optics: JHK ModuleOptics: JHK Module

f/7f/7Camera

H2RG (2k x 2k)H2RG (2k x 2k)Detector

Direct Feed to the Immersion GratingDirect Feed to the Immersion Grating

VPH gratingVPH gratingCross-disperser

25 mm25 mmBeam diameter

50,000R=λ/∆λ

1.1 - 2.5 µm Wavelength


Optics: LM ModuleOptics: LM Module

f/5.6f/5.6Camera

H4RG (4k x 4k)H4RG (4k x 4k)Detector

White Pupil DesignWhite Pupil Design

FrontFront--surface gratingsurface gratingCross-disperser

52 mm52 mmBeam diameter

100,000R=λ/∆λ

2.9 - 5.3 µmWavelength


Spectral Format (LSpectral Format (L--band)band)

The LThe L--band is the broadest spectral band among JHKLM.band is the broadest spectral band among JHKLM.Continuous coverage of the whole LContinuous coverage of the whole L--band on a H4RG detectorband on a H4RG detector


Mechanics Mechanics –– Optical BenchOptical BenchOptics: 50 KDetector: 37 K


Mechanics Mechanics -- CryostatCryostat

2m

3m


DetectorsDetectorsJHK moduleJHK module

(3 (3 FPAsFPAs))

4096 x 40964096 x 40962048 x 20482048 x 2048Format (pixels)Format (pixels)

5.3 5.3 µµmm2.5 2.5 µµmmCutoff wavelengthCutoff wavelength

SIDECAR ASICSIDECAR ASICControllerController

< 0.01 < 0.01 ee--/s/pixel/s/pixelDark currentDark current

< 12 e< 12 e--Read noise (CDS)Read noise (CDS)

15 15 µµmm18 18 µµmmPixel sizePixel size

HAWAIIHAWAII--4RG4RGHAWAIIHAWAII--2RG2RGROICROIC

LM moduleLM module(2 (2 FPAsFPAs))

References: www.teledyne-si.com, Beletic et al. (2008)


ProtoProto--type: IGRINS type: IGRINS IImmersionmmersion GRGRatingating ININfraredfraredSSpectrographpectrograph

H & K (1.49H & K (1.49--2.46 2.46 µµmm) ) R=40,000 R=40,000 Operation starts in 2013Operation starts in 2013McDonald 2.7McDonald 2.7--m telescopem telescope

SharingSharing design elements with design elements with GMTNIRSGMTNIRS

Immersion grating Immersion grating VPH gratings VPH gratings H2RG & SIDECAR ASICH2RG & SIDECAR ASIC80% software commonality80% software commonalitySimilar optics mount & Similar optics mount & detector mountdetector mount


IGRINS IGRINS -- Immersion GratingImmersion GratingSilicon R3 grating (10 cm) Silicon R3 grating (10 cm) (same as for GMTNIRS JHK)(same as for GMTNIRS JHK)

Spectral ghost < 2 x 10Spectral ghost < 2 x 10--33

(~5 nm periodic error; Dec 2009)(~5 nm periodic error; Dec 2009)(GMTNIRS requires < 4 nm.)(GMTNIRS requires < 4 nm.)

Spectral grass ~10Spectral grass ~10--55

(scattering at groove surfaces)(scattering at groove surfaces)


IGRINS IGRINS -- CameraCamera


GMTNIRS Sensitivity (Vega1)GMTNIRS Sensitivity (Vega1)

• Integration time = 1 hr (6 x 600 sec)

• 2MASS completeness limits (80%) (Vega mag):J = 16.0, H = 15.1, K = 14.3

1

10

100

1,000

8 10 12 14 16 18 20

J

H

K

L

M

Vega Magnitude

S/N


GMTNIRS Sensitivity (Vega2)GMTNIRS Sensitivity (Vega2)

• Integration time = 10 hrs, Binning to R=20,000

• Limiting mag with S/N = 30 (Vega mag):J = 19.4, H = 19.5, K = 19.0

1

10

100

1,000

12 14 16 18 20 22 24

J

H

K

L

M

Vega Magnitude

S/N


GMTNIRS Sensitivity (AB1)GMTNIRS Sensitivity (AB1)


• Limiting mag with S/N = 30 (AB mag):J = 20.3, H = 20.9, K = 20.9

1

10

100

1,000

12 14 16 18 20 22 24

J

H

K

L

M

AB Magnitude

S/N


GMTNIRS Sensitivity (AB2)GMTNIRS Sensitivity (AB2)


• Limiting mag with S/N = 30 (AB mag):J = 18.9, H = 19.5, K = 19.5

1

10

100

1,000

12 14 16 18 20 22 24

J

H

K

L

M

AB Magnitude

S/N


Science Cases Science Cases –– In the GalaxyIn the Galaxy

ProtostarsProtostarsProtoplanetaryProtoplanetary disksdisksChemical evolutionChemical evolutionAtmospheres of Atmospheres of exoplanetsexoplanetsSolar system objectsSolar system objectsAbundance of ISMAbundance of ISM……

NICMOS Observations of HD 189733B, Swain et al. (2008), Nature


Extragalactic Science Extragalactic Science –– Chemical Chemical evolution in the Local Groupevolution in the Local Group

Combination of huge collecting area (GMT) and wide spectral coverage at high resolution (GMTNIRS)

New ways to solve key questions in chemical evolution of stars

Structure of photospheresNucleosynthesis and Mixing Mass loss rates

Chemical history of galaxies and clusters

The Galaxy: disk, bulge, haloOther systems: LMC, SMC, dwarf galaxies, globular clusters

(Melendez et al. 2008)▲ Bulge● Thick disk○ Thin disk☆ Halo

Sensitivity for red supergiantsM_V = -6 M_K = -8.1GMTNIRS K-limit = 17.5

(S/N = 100 for abundance study)DM = 25.6 1.3 Mpc

(almost cover the Local Group)


Extragalactic Science Extragalactic Science –– Velocity Velocity Dispersion of Dwarf Galaxies and Dispersion of Dwarf Galaxies and

Globular Clusters in Nearby Globular Clusters in Nearby GalaxiesGalaxies

To measure mass-velocity dispersion relationObserving narrow line spectra of late type stars

Sensitivity for globular clusters in near-by galaxiesM33: M_V = -7 M_K = -9M31: M_V = -8 M_K = -10GMTNIRS K-limit = 20.0

(assuming S/N = 10 for velocity measurement)DM = 29 ~ 30 6.3 Mpc ~ 10 MpcInclude M83 Group, Sculptor Group, M94 Group, NGC1023 Group…


Extragalactic Science Extragalactic Science –– moremore

Evolution of the IGM (Hsiao-Wen Chen)Low mass stars in superstar clustersBlack hole in the GC; kinematics and relativity……


SummarySummaryGMTNIRS will solve various astrophysical questions and provide aperformance revolution, particularly in wavelength coverage.

GMTNIRS can produce R>50,000 spectra for any source in the 2MASS catalog with a decent S/N

GMTNIRS can reach the following depth at S/N = 30 (AB mag) with the 10 hrs integration at R=20,000:J = 20.3, H = 20.9, K = 20.9

GMTNIRS can observe most super-giants in the Local Group for abundance study

GMTNIRS can measure velocity dispersions of globular clusters innearby galaxy groups

Extragalactic Science with GMTNIRS - Texas A&M...

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