Transcript Document

Strategic Planning for Adaptive
Optics at Keck
Claire Max and Mike Liu
on behalf of Keck AO Working Group
Antonin Bouchez (Caltech), Rich Dekany (Caltech),
David Koo (UCSC), Bruce Macintosh (LLNL), Franck
Marchis (UCB), Keith Matthews (Caltech)
Outline
• Role of AO Working Group
• Near-term Keck AO
• Strategic planning:
– Previous strategic plans
– What should next-generation AO system look like:
– High Strehl over narrow field?
– Moderate Strehl over wider field?
– Other?
We need your feedback!
We need your help to compare science cases for future AO options!
AO Working Group
• Second-generation AO Working Group
• Co-chairs: Mike Liu (UH) and Claire Max (UCSC)
• Members: Antonin Bouchez (Caltech), Rich Dekany (Caltech),
David Koo (UCSC), Bruce Macintosh (LLNL), Franck Marchis (UCB),
Keith Matthews (Caltech)
• Charter: "To assist in prioritization and advocate the optimization
of the scientific output of the Keck adaptive optics facilities, in
conjunction with the adaptive optics science instruments."
Near-term Keck AO
• Current Status:
– Keck II laser guide star now doing shared-risk science
– Working VERY well (5 science papers from past semester, many
more coming)
• Near-term upgrades:
– Wavefront controller upgrade (KI and KII)
– Procurement of laser for KI under way
• 77 Keck AO papers to date (!) including 5 laser guide
star papers in the past 6 months
Keck AO Refereed Science Papers
77 (including 5 Interferometer).
12
10
8
6
4
2
Galactic
0
2000
Planetary
2001
2002
2003
ExtraGal
2004
2005N
2005L
5 LGS
54%
30%
16%

Previous strategic plan
 Complete
 In progress




X

X Went to Gemini
• 77 Keck AO papers to
date (!) including 5 laser
guide star papers in the
past 6 months
We need your advice
KPAO Strehl in visible and near-infrared
1.00
0.90
Ha
J
K
H
110 nm
120 nm
130 nm
0.80
0.70
Strehl
0.60
X
0.50
X Keck
NGS
today
X
0.40
0.30
X
0.20
0.10
0.00
300
800
1300
Wavelength (nm)
1800
2300
Wider field MCAO (graph from Gemini S)
• Strehl and PSF approx. uniform over ~ 1.5 arc min diameter field
MCAO
Conventional AO
Should we continue to pursue KPAO, or
should we head to wider field AO?
• Comparison of KPAO with Gemini MCAO
KPAO Strehl
MCAO Strehl
K band
J band
90%
60%
65%
20%
KPAO advantage
8000A
Ha
40%
2%
22%
very low
MCAO advantage
Planetary Science: KPAO is the most promising
technology
Jovian moons, asteroids, trans-neptunian objects are small
enough to fit into KPAO’s field of view
KPAO in visible has high potential for asteroids, TNO’s
Volcanism: variable phenomenon
• Io
• Triton
• Enceladus
-> find smaller fragments
around asteroids and TNO’s
(multiple systems)
-> Bulk-Density and formation
scenario
South pole clouds
Surface at 2 m
87 Sylvia and its two moonlets
Quic kT ime™ and a
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Cryo-volcanoes?
Keck
Keck
KPAO in visible has high potential for asteroids, TNO’s
• Better angular resolution, sensitivity(?), spectral capabilities
• PSF quality and stability + sensitivity must be quantified
•
Better angular resolution
•
Better sensitivity?
-> find smaller fragments
around asteroids and TNO’s
(multiple systems)
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-> Bulk-Density and formation
scenario
87 Sylvia and its two moonlets
(Marchis et al. 2005)
KPAO can fulfill needs of most Galactic
Astronomy programs
What is the diversity of planetary systems?
Imaging of dusty circumstellar disks
•
Disk sub-structure tells about the planet
formation process.
•
Low-mass planets too faint to directly
image can be studied by the dynamical
signatures they produce in the dust.
•
Multi-wavelength optical + IR colors tell
us about grain growth.
•
KPAO AO @ I-band: resolution ~0.01”
(0.1-0.5 AU scales).
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KPAO: Imaging of planets around lowmass stars and brown dwarfs
• KPAO can detect 1 MJ companion to 40
MJ/10 Gyr brown dwarf
• Can detect 1 MJ companion to T Tauri star
@ 50 AU
• These targets are inaccessible to bright-star
ExAO systems
System
Detectable contrast @
0.5”
Mag. Limit
Current AO
104-105
R<18 mag
Extreme AO
107-108
I<9 mag
KPAO
105-106
H<18 mag?
KPAO: better orbits for stars around
Galactic Ctr  General Relativity
Extragalactic astronomy requires large samples:
some preference for wide field of view AO
• Color-magnitude diagrams of stars out to Virgo
– Best with KPAO (higher Strehl for confusion limited imaging)
• Wide field AO preferred for
– Evolution of bulges, disks, bars, AGNs, starbursts at high z
– Multi-IFU spectroscopy and high resolution imaging are
possible (in principle) with both MCAO and MOAO
• We will understand galaxy evolution by using large
samples of galaxies at high z
• Tradeoff between sensitivity (Strehl) and sample size
NGS AO
LGS AO
(1)
(2)
GOODS-N
1%
Metallicity
Gradients
GOODS-N
MCAO AO
(3)
15
%
GOODS-N
35
%
MOAO AO
Velocity
Kinematics z=1 Galaxy
(5) HII region
Star
Formation
Rates
Bulge
(6)
Super
Nova?
0.5”
-
Note: Sauron Data from local galaxies, de Zeeuw et al. 2002
Spiral Arm
(4)
Synergy between KPAO and wide
field AO options
KPAO
narrow FOV
High Strehl
KPAO will measure
turbulence using multiple
laser guide stars and
tomography
Wide field AO will use these
meas’ts to correct atmosphere
Multi-Conjugate AO
2’ FOV
Moderate Strehl
Multi-Object AO
Many small fields of view
within larger field of regard,
moderate Strehl
Key Issue: Need to compare the science
cases for KPAO, wide field AO
• AOWG has put together a
few example science cases
• Gemini MCAO Science Case
is much more extensive
• We need your help in
fleshing out a science-case
comparison between KPAO
and wide-field AO
External environment considerations
• HST is possibly/probably going to die in 3-5 years
– After that, Keck AO would be the best/only high resolution system
available.
• In the optical, Keck could deliver 4x the resolution as HST
– For high-resolution science in local universe (e.g.resolved stellar
population studies of nearby galaxies), 64x the effective volume would
be available, so a much larger sample of objects can be studied.
• Laser technology is making significant strides
– Lasers for Gemini MCAO are being built today
– Lasers for optical AO are no longer a pipe dream
• TMT is a long way in the future
– There is ample time for at least one next-generation Keck AO system
(and likely more).
• For planetary science, next-generation Keck AO will happen a lot
sooner than any new space missions (except Moon-Mars!)
We need your input!
• What capabilities would you need from a next-generation Keck AO
system for your own science?
– NOW is the time to begin planning this
– Are you most excited about a high Strehl, modest FOV AO system
with optical (red) wavelength capability?
– Would a larger field of view with lower Strehl but only IR wavelength
coverage be of most interest to you?
• HST users: what does HST provide for you that Keck AO doesn’t
(aside from funding)?
• Please help us work on comparing science cases!
– Form a mini-working group
– CfAO and Keck could co-sponsor a workshop
– Science closely tied with AO and instrument capabilities