MMT Magellan Infrared Spectrograph ( MMIRS )

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MMT Magellan Infrared Spectrograph (
MMIRS )
P.I. Brian McLeod Warren R. Brown SAO/CfA
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Science Drivers Star formation at high redshift
(Erb 2006)
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Science Drivers Brown dwarfs
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Multi-Slit Spectrograph
(Image from Flamingos)
Detector
Slit Mask
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Basic Operational Modes

• Imaging
• 6.9 x 6.9 arcminute FOV
• 0.202 arcsecond pixels
• Y, J, H, Ks wavelength coverage
• Spectroscopy
• Multi-slit (4'x7') or longslit (7')
• J, H, K _at_ R3500
• HK _at_ R1300

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MMIRS EXTERIOR
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MMIRS INTERIOR
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(No Transcript)
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MMIRS OPTICS
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MMIRS Field of View
Imaging field
Guide camera patrol area
7x7 arcmin
D 14 arcmin A 50 arcmin2 ea
Slit masks
Guider FOV 80
4x7 arcmin, central 2'x7' with full wavelength
coverage
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Detector Information

• HAWAII-2 2k x 2k HgCdTe detector
• Full well 230,000 e-
• Readnoise 16 e- (per pair of reads)
• Dark current 0.05 e-/s/pix at 83 K (temp
  dependent)
• Readout 32 channels at 180 kHz 0.7 sec
• CMOS device
• Bad pixels Dark current Flat field

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Observed Image Quality
1.1 pixel FWHM
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Imaging Information

• Filters Y, J, H, Ks
• Sky background narrow OH emission and broad H2O
  absorption.
• Images unguided
• 5 sec overhead between exposures, including
  telescope dither.

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Imaging Sensitivity
Magnitude of point source (Vega mag) with S/N10
Time (sec) Y J H Ks
60 19.6 19.9 19.7 18.7
300 20.4 20.8 20.6 19.6
3600 21.8 22.2 21.9 21.0
Time for sky to reach half the linear regime 120 sec 180 sec 30 sec ? sec
Total system throughput 0.20 0.25 0.50 0.40
Exposure Time Calculator http//www.cfa.harvard.e
du/mmti/mmirs.html
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Total System Throughput
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Spectroscopic Information

• Dispersed Spectra 1400 pixels long
• Field for complete spectra 2 x 6.9 arcmin
• Full field for spectroscopy 4 x 6.9 arcmin
• 9 slit masks, 7 long slits 420 x 0.2, 0.4, 0.6,
  0.8, 1.0, 1.2, 2.4
• Up to 40 slitlets, of minimum length 10

Grism ? um Grooves lines/mm Resolution 0.4 slit Efficiency
HK 1.45-2.45 80 1300 55-80
R3K 0.9-2.5 62 3500 30-55
JH 0.95-1.82 94 1300 55-80
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Spectroscopic Sensitivity
Lab test real spectra.
Expected S/N per resolution element at R3000
Slit mask
Spectra
Exptime (hr) Mag J Jdark H Hdark K
1 15 118 125 118 165 109
1 17 50 46 36 61 22
2 17 30 66 51 86 31
4 17 71 93 72 122 44
1 19 7 13 7 18 4
2 19 10 19 9 25 5
4 19 15 27 13 35 7
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Schedule

• March/April 2009
• 1 week engineering run
• May/June 2009
• 2 week science commissioning
• Magellan 2010 (MMIRS and Megacam)

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THE WEB SITE http//www.cfa.harvard.edu/mmti/mmir
s.html THE TEAM Principal Investigator B.
McLeod Instrument Scientists G. Furesz, P.
Martini Optical design consultant H.
Epps Co-Investigators D. Fabricant, J. Geary, S.
Kenyon, W. Brown
P. McCarthy, E. Persson, S. Eikenberry Project
Manager T. Norton Project Engineer G.
Nystrom Engineering Staff K. McCracken, J.
Holwell, M. Burke, S. Amato, J. Zajac, H.
Bergner, S. Park, E. Hertz Software D. Curley,
M. Conroy, J. Roll, W. Wyatt Technicians W.
Brymer, F. Collette Machinists K. Bennett, L.
Knowles, and the Harvard Model Shop Commissioning
Team A. Seth, W. Brown, D. Fabricant, B. McLeod