w. m. keck observatory’s next generation adaptive optics (ngao) facility peter wizinowich, sean...
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W. M. Keck Observatory’sW. M. Keck Observatory’sNext Generation Adaptive OpticsNext Generation Adaptive Optics
(NGAO) Facility(NGAO) FacilityPeter Wizinowich, Sean Adkins, Rich Dekany, Peter Wizinowich, Sean Adkins, Rich Dekany,
Don Gavel, Claire MaxDon Gavel, Claire Maxfor NGAO Team:for NGAO Team: R. Bartos, J. Chin, A. Conrad, A. Delacroix, R. Kupke, R. Bartos, J. Chin, A. Conrad, A. Delacroix, R. Kupke, C. Lockwood, J. Lyke, E. McGrath, D. Medeiros, D. Morrison, C. Neyman, C. Lockwood, J. Lyke, E. McGrath, D. Medeiros, D. Morrison, C. Neyman,
S. Panteleev, C. Pollard, M. Reinig, T. Stalcup, S. Thomas, M. Troy, S. Panteleev, C. Pollard, M. Reinig, T. Stalcup, S. Thomas, M. Troy, K. Tsubota, V. Velur, K. Wallace, E. WetherellK. Tsubota, V. Velur, K. Wallace, E. Wetherell
SPIE, San DiegoSPIE, San DiegoJune 28, 2010June 28, 2010
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Context for NGAO – growing demand for LGS-AO on large telescopes
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Credit: M. Liu
Refereed Keck AO Science Papers by Year
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5
10
15
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25
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35
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45
50
1999 2001 2003 2005 2007 2009
Year
Nu
mb
er o
f P
aper
s
~270 Keck AO science papers
~50% of Keck II science nights
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NGAO - Next Generation AO
Key New Science Capabilities
Near Diffraction-Limited in Near-IR (K-Strehl ~80%)
AO correction at Red Wavelengths (0.7-1.0 m)
Increased Sky Coverage
Improved Angular Resolution, Sensitivity and Contrast
Improved Photometric and Astrometric Accuracy
Imaging and Integral Field Spectroscopy
Key Science Goals
Understanding the Formation and Evolution of Today’s Galaxies since z=3
Measuring Dark Matter in our Galaxy and Beyond
Testing the Theory of General Relativity in the Galactic Center
Understanding the Formation of Planetary Systems around Nearby Stars
Exploring the Origins of Our Solar System
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Flowed-Down Key Architectural FeaturesG
alax
y A
ssem
bly
BH
mas
ses
in
near
by
AG
Ns
GR
at
the
Gal
actic
Cen
ter
Pla
nets
aro
und
low
-mas
s st
ars
Min
or P
lane
ts
Lase
r to
mog
raph
y
AO
-cor
rect
ed
NIR
TT
Coo
led
AO
Hig
h-o
rder
DM
DA
VIN
CI
Near diffraction-limited in near-IR
AO correction at red wavelengths
Increased sky coverage
Improved sensitivity
Improved contrastImproved photometric
accuracyImproved astrometric
accuracy
ImagingIntegral field spectroscopy
Key Science Drivers Key Architectural Features
Key New Science Capabilities
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NGAO System Architecture
Key Features:1. Fixed narrow field laser tomography2. AO corrected NIR TT sensors3. Cooled AO enclosure4. Cascaded relay5. Combined imager/IFU instrument
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NGAO: AO Layout
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NGAO: AO Bench
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LGS Wavefront Sensor Assembly
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Low Order Wavefront Sensor Assembly
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DAVINCI – Imager & IFS
Entrance window
Coronagraph mask wheel
Imager detector
headImager/IFS
selector mirror
Pupil imager wheel
Filter and pupil mask wheels
IFS detector head
Grating selector wheel
• On axis imager 28.7" x 28.7" FOV– 7 mas pixel scale
• On axis selectable IFS– 50 mas pixel scale FOV 5.6" x 3"
– 35 mas, FOV 3.92" x 2.1"
– 10 mas, FOV 1.12" x 0.6"
Adkins et al.7735-287
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AO Enclosure
DAVINCI Instrument
Overhead HEPAs
LGSWFS
Gowning Room Area
AO Bench
Secondary Instrument
Interferometer DSM
Thermal Management
DM Electronics
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LGS Facility
TOPTICA/MPBC7736-252
RC Optical
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Control Loops – LGS AO Example
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Control Loops – LGS AO Example
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Control Loops – LGS AO Example
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Control Loops – LGS AO Example
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Control Loops – LGS AO Example
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Control Loops – LGS AO Example
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The RTC System Architecture is Mapped to the Critical Signal Paths
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At the heart of the science wavefront control is the Tomography Engine
TomographyTomography
Tip/TiltTip/Tilt
TT Star Sharpenning
TT Star Sharpenning
Reinig & Gavel7736-130
2020
Science Case Performance Summary
10 mas
35 mas
50 mas
70 mas
1Galaxy Assembly K 158 4.9 180 77% 4% 36% 56% 75%
2 Nearby AGN Z 158 4.8 176 21% 8% 29% 30% 31%
3aGalactic Center Imaging K 208 2.2 212 69% 4% 31% 48% 65%
3bGalactic Center Spectra H 191 2.4 195 57% 5% 38% 52% 59%
4 Exo-planets H 155 2.9 162 68% 6% 46% 62% 71%5 Minor Planets Z 157 4.7 175 21% 8% 29% 30% 31%6 Io Z 116 2.1 119 48% 14% 51% 53% 53%
Ensquared Energy in Spaxel
Case # Science Case
Science Band
RMS High-order
Wavefront Error (nm)
RMS Tip-Tilt Error
(mas)
Effective RMS
Wavefront Error (nm)
Strehl Ratio
Galaxy assembly: 30º zenith angle, 60º galactic latitude, 30 min integ.
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NGAO Performance vs. Sky Coverage NGAO Performance vs. Sky Coverage (Galaxy Assembly Science Case)(Galaxy Assembly Science Case)
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Strehl
EE 35 mas
EE 50 mas
EE 70 mas
Resid. TT error
• Nominal Ensquared Energy (EE) requirement = 30% sky coverage
• But very little degradation in EE even for 70% sky coverage
• Nominal Ensquared Energy (EE) requirement = 30% sky coverage
• But very little degradation in EE even for 70% sky coverage
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NGAO is robust against conditions and design
assumptions
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0%10%20%30%40%50%60%70%80%90%
100%
0.00 0.05 0.10 0.15 0.20 0.25
Fram
e ra
te [H
z]
K-ba
nd S
treh
l rati
o or
Ens
quar
ed E
nerg
y
r0 [m]
Strehl EE 35 mas EE 50 mas EE 70 mas HO WFS Frame Rate
0
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400
600
800
1000
1200
1400
0%10%20%30%40%50%60%70%80%90%
100%
0 20 40 60 80 100
Fram
e ra
te [H
z]
K-ba
nd S
treh
l rati
o or
Ens
quar
ed E
nerg
y
Total Fixed Laser Asterism Power [W]
Strehl EE 35 mas EE 50 mas EE 70 mas HO WFS Frame Rate
0
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400
600
800
1000
1200
1400
0%10%20%30%40%50%60%70%80%90%
100%
0 10 20 30 40 50 60 70
Fram
e ra
te [H
z]
K-ba
nd S
treh
l rati
o or
Ens
quar
ed E
nerg
y
Zenith Angle [deg]
Strehl EE 35 mas EE 50 mas EE 70 mas HO WFS Frame Rate
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0
5
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5% 10%
15%
20%
25%
30%
35%
40%
45%
50%
55%
60%
65%
70%
75%
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85%
90%
95%
100%
Freq
uenc
y
K-band Strehl Ratio
AO performance comparison
Liu's K2 LGS AO Data K2 LGS AO Model NGAO Model
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NGAO changes the AO observing experience
Monte Carlo performance estimate simulating 44 nights observing (Galaxy Assembly science case), drawing random values for r0, wind speed, sodium
abundance, and zenith angle
Includes comparison with M. Liu’s measured K2 LGS data (<SR> = 17%), the model prediction for K2 LGS (<SR> = 20%), and NGAO predict (<SR> = 70%)
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Early Science Benefits from NGAO - 1
• NGAO laser launch telescope– NSF-MRI (Aug/09) funding to procure & implement a K2 center
launch telescope
• NGAO laser– Preliminary designs completed (Dec/09) from 2 vendors.
Collaboration with ESO, AURA, GMT & TMT. TOPTICA/MPBC selected to begin final design.
– MRI proposal submitted to procure & implement 1st NGAO laser on K2. Collaboration with TMT & ESO
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Relative Positional Error
0.00
0.50
1.00
1.50
2.00
2.50
0.05 0.1 0.15 0.2 0.25 0.3 0.35
Strehl Ratio (K-band)
Re
lati
ve
Po
sit
ion
al E
rro
r (m
as
)
Current K2 LGS AO
+ Center Projection
+ New Laser
Relative Magnitude Error
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.05 0.1 0.15 0.2 0.25 0.3 0.35
Strehl Ratio (K-band)
Re
lati
ve
Err
or
(de
lta
ma
g) Current K2 LGS AO
+ Center Projection
+ New Laser
Keck II Center Launch + New LaserPredicted Performance for T Dwarf Binary Case
Factor of 2x improvement 6x in dynamical mass determination
R = 16.2 NGS 31” off-axis50 zenith angle
1% photometry
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Early Science Benefits from NGAO - 2
• PSF reconstruction– Collaboration with Gemini & U. Groningen to demonstrate on-axis
NGS AO PSF reconstruction on Gemini & Keck Jolissaint et al., 7736-50
– Plan to implement off-axis LGS AO PSF reconstruction with Keck– MASS/DIMM implemented (Sept/09) as a Mauna Kea facility
• Focal anisoplanatism reduction– Risk reduction to demonstrate 20% reduction using Cn2 data
• Tip-tilt vibration reduction– Risk reduction plan to prototype parametric oscillator on K2 AO
• NIR tip-tilt sensing (no object selection or AO correction)– ATI (Jun/10) funding to implement a near-IR tip-tilt sensor
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NIR Tip-Tilt SensorPredicted Performance for High Redshift Galaxies Case
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Keck AO First TAC-allocated Science Milestones
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1
Jan
-99
Jan
-00
Jan
-01
Jan
-02
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Jan
-04
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-05
Jan
-06
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Jan
-08
Jan
-09
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-11
Jan
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Jan
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Jan
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Jan
-15
Date
K2
NG
S
K2
LGS
K2
NIR
SP
AO
K2
NIR
C2
K1&
2 N
GS
Int
erfe
rom
eter
K2
OS
IRIS
K1&
2 W
FC
Upg
rade
K1
LGS
+ O
SIR
IS +
In
terf
erom
eter
K2
NG
AO
+ C
amer
a
K2
Cen
ter
Laun
ch
K2
NG
AO
Las
er 1
NIR
Tip
-Tilt
Sen
sor
Major Keck AO Science Capability Milestones
Future
Chin 7736-66; LMCT -69
In ClosingIn Closing
• Keck AO has been delivering great science
• NGAO will ensure cutting edge high angular resolution science for the US community
NGAO PD funding from NSF/AURA TSIP
Keck AO NGAO