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Transcript of GMT and SKA - Giant Magellan · PDF fileGMT and the SKA P. McCarthy GMT ... 1AU at 100pc - 100...
Astronomical Society of Australia Meeting - Perth July 08 1
Scientific Synergy Between
GMT and the SKA
P. McCarthy
GMT
Astronomical Society of Australia Meeting - Perth July 08 2
• Common Science Drivers
• Exoplanets
• Galaxy Evolution
• Dark Energy
• First Light & the Epoch of Reionization
Topics
Astronomical Society of Australia Meeting - Perth July 08 3
Three Approaches:
Discovery Space
Contemporary Science Drivers
Synergy with Current and Future Facilities
Scientific Strengths of the GMT Design:
High angular resolution - 10mas at 1μm
1AU at 100pc - 100 pc at z = 1
Large collecting area - 380 m2 - 10 x Magellan 6.5m
Wide Field - practical paths to seeing-limited survey instruments
Gregorian Adaptive Secondary - GLAO, Great mid-IR performance
GMT Science Drivers
Astronomical Society of Australia Meeting - Perth July 08 4
GMT SCIENCE: CONTEXT & SYNERGY
JWSTALMA
LSST
SKA
Broad Synergy Across Wavelength, Spatial and Time Domains
Magellan
Physical DiagnosticsDeep/Wide Surveys
High-resolution imagingHigh SNR & Res. Spectroscopy
Astronomical Society of Australia Meeting - Perth July 08 5
SKA Key Science Projects
• The Cradle of Life Exoplanets• Strong-Field Test of GR Black Holes/Pulsars• Cosmic Magnetism Galactic/IGM fields• Galaxy Evolution & Cosmology
HI in GalaxiesEvolution of Dark Energy
• Probing the Dark Ages Reionization
Astronomical Society of Australia Meeting - Perth July 08 6
GMT Science Goals
• Planets and Their Formation
• Stellar Populations and Chemical Evolution
• Assembly of Galaxies
• Black Holes in the Universe
• The Accelerating Universe
• First Light and Reionization of the Universe
http://www.gmto.org/sciencecase
Astronomical Society of Australia Meeting - Perth July 08 7
GMT Science Goals
• Planets and Their Formation
• Stellar Populations and Chemical Evolution
• Assembly of Galaxies
• Black Holes in the Universe
• The Accelerating Universe
• First Light and Reionization of the Universe
http://www.gmto.org/sciencecase
Astronomical Society of Australia Meeting - Perth July 08 8
Imaging Exoplanets
Exoplanets are faint!…
Jupiter reflects 10-9 Lsun
Earth reflects 10-10 Lsun
…and close in
Jupiter 0.5´´ @ 10pc
Earth 0.1´´ @10pc
Suppression of diffraction is essential
Coronagraphy, phase modulation, nulling, μ-lensing, transits, PRV
Image by David Aguilar, CfA
Astronomical Society of Australia Meeting - Perth July 08 9
GMT PSF with phase apodization
1.65 μm, 5% bandwidth
10-6 suppression at 4 λ/D, 56 mas
10-5 companion
Young planets are best detected in the 5μm and 10μm bands. There are dozens of young star clusters visible from Chile and hundreds of candidate planetary systems.
Typical mass sensitivities:
Age < 100Myr M < 1Mjup
0.5 Gyr ~2-5 Mj
1.0 Gyr ~5-10 Mj
Astronomical Society of Australia Meeting - Perth July 08 10
Internal Structure of Distant Galaxies
Z = 0.1 HST Hα + Continuum Z = 1.4 GMT @1.6μm 1-Hour
|------ 1 arcsecond ------|
GMT- 15mas @1.6μm
150mas with GLAO -8′ fov
SKA - 17mas @5Ghz
140mas @591 MHz
Astronomical Society of Australia Meeting - Perth July 08 11
GMT Survey InstrumentsIMACS f/2
GMACS
NIRMOS
18′
… maybe not “wide field” by Australian standards, but large
by ELT standards
GMACS = 10 x Deimos on Keck
Astronomical Society of Australia Meeting - Perth July 08 12
Stellar Populations in Massive Galaxies
Kreik et al.
Current State of the Art
Gemini GNIRS
Astronomical Society of Australia Meeting - Perth July 08 13
The sky may not be the limit!
Sky subtracted
OH removed inPost processing
OH suppressionBefore dispersion
Photon counting
Detector + OH Suppression
Z = 1.5
Old Galaxy
Astronomical Society of Australia Meeting - Perth July 08 14
Dark Energy Studies with GMT
• BAO at z = 5 if w ≠-1 ….. then what?
…….Lyα based BAO study at z = 5 with GMT cost is high (~100 - 200 nights) but possible
• SNe spectroscopy at z > 1
• Identification of LISA sourcesCosmological Distances to ≤ 1%
… may need some help with pre-imaging
SNe Ia at
z = 1
Astronomical Society of Australia Meeting - Perth July 08 15
Probing the EOR with GMT & SKA
N. Gnedin
HIIHI
Key Questions:
- What is “the” redshift of reionization?
- What is the source(s) of ionization?
- How does the topology evolve with redshift?
Astronomical Society of Australia Meeting - Perth July 08 16
Lyα as a probe of the EOR
- Gunn-Peterson effect
- “Dark” GRBs ?
- Lyα florescence from boundary regions
- Evolution of the Lyα luminosity density
- Spatial correlation between SKA HI maps and LAEs
- Pencil beam surveys targeted from SKA
How can ELTs explore the end of the Dark Ages?
Astronomical Society of Australia Meeting - Perth July 08 17
Gunn-Peterson Effect & Reionization Topology
White et al. 2003
High
τGP
High
τGP
11-hour exposures with Keck 10m
Larger aperture needed to sample more sight-lines
Astronomical Society of Australia Meeting - Perth July 08 18
Reionization History - Double Reionization?
X. Fan
Z=9.4 QSO
Magellan 8hrs
GMT 8hrs
Astronomical Society of Australia Meeting - Perth July 08 19
Lyα Florescence at z ~ 3
Adelberger et al. 2005
There is a strong case for florescence at z ~ 3
Lyα abs
Lyα emission
QSO Cont.
At z = 3 all of the HI is in damped Lyα systems
Astronomical Society of Australia Meeting - Perth July 08 20
Lyα Florescence at the EOR?
HI
FUV
Lyα
Lyα at z ~ 9Florescence signal from the metagalactic flux is faint!
Lyα florescence from bright QSO is potentially detectable, if there are bright sources at the reionization epoch.
Sensitive to
local Jν, xHI
Astronomical Society of Australia Meeting - Perth July 08 21
Visible Halos at z ~ 9
Fully Ionized
50% Neutral 75% Neutral
25% Neutral
250Mpc = 15 degrees!
Lyα LF & distribution provides a probe of the neutral faction at high z
Scales are very large - impractical at z > 7?
Damping wings are primary escape path
for Lyα photons
Astronomical Society of Australia Meeting - Perth July 08 22
Evolving UV Luminosity DensityEvolving UV Luminosity Density
Bouwens et al.A steep drop off for z > 6.5 could signal the end of the
EOR
Astronomical Society of Australia Meeting - Perth July 08 23
Lyα Luminosity Function at z ~ 6
Ly α luminosity function from Malhotra & Rhoads
Wide-field NB imagingStrong Lensing
Astronomical Society of Australia Meeting - Perth July 08 24
Lyα Luminosity Function at z ~ 6
35 hour integrations with GMOS on Gemini S. Faintest objects have F = 5E-18.
Stanway et al. 2006.
Astronomical Society of Australia Meeting - Perth July 08 25
Use Case: Lyα Luminosity Function at z ~ 6
500 km/s FWHM
Wλ = 100Å
30hr integration with GMACS using 0.5” slits in 0.5” seeing
30% throughput
Gemini sky spectrum
Nod & Shuffle sky rejection
R = 5000 rebinned to
R = 1200, Gaussian smoothing
Astronomical Society of Australia Meeting - Perth July 08 26
Mock Lyα Luminosity Function at z ~ 6 with GMT
How do we extend this to z > 8?
Move to the near-IR, but fields of view are
smaller, so must target fields using HI
maps
Astronomical Society of Australia Meeting - Perth July 08 27
IGM Structure at z ~ 9
130 Mpc
~20
“Pencil beam”surveys can easily miss the important structures
SKA can provide the map needed to make an informed survey for Lyα at the end of the EOR.
Astronomical Society of Australia Meeting - Perth July 08 28
Lyα Spectroscopy in the Near-IR
Lyα at z = 8.7
in the J-band
NIRMOS Properties with current Near-IR detectors
200 km/sec line widths
25 hour exposures
7′ x 7′ field of view
Pho
tons
/sec
/cm
2
4Msun/yr
MW Star formation
rate!
MW Star formation
rate?
Astronomical Society of Australia Meeting - Perth July 08 29
Lyα Spectroscopy in the Near-IR
NIRMOS Properties with OH Suppression and low-noise
Near-IR detectors
200 km/sec line widths
25 hour exposures
7′ x 7′ field of view
With OH suppression
Astronomical Society of Australia Meeting - Perth July 08 30
Lyα Spectroscopy in the Near-IR
NIRMOS Properties with OH Suppression and low-noise
Near-IR detectors
200 km/sec line widths
25 hour exposures
7′ x 7′ field of view
With OH suppression
Astronomical Society of Australia Meeting - Perth July 08 31
Structure at z ~ 10
Numerical simulation of gas cooling at z = 10
Dave’, Katz & Weinberg
Astronomical Society of Australia Meeting - Perth July 08 32
Ly alpha image with
GMT GLAO
R=3000 filter
20% escape fraction for
Lyα
8 hour exposure
Laser Tomography
AO
Lyα HeII 1640
Internal Structure in Galaxies at z ~ 10
Very top-heavy IMF!
Astronomical Society of Australia Meeting - Perth July 08 33
Things to take away…..
1. Like SKA, the scientific motivation for GMT is compelling
2. The two projects are more powerful together than either is alone
3. Australia can make major contributions to the scientific and technical development
instruments, adaptive optics, photonics….