Transcript Document

Next Generation Deep 2m Survey:
Reconnoitering the Dark Ages
Jeremy Mould, Swinburne University
Recent Progress in theoretical and observational cosmology
IHEP Beijing, Nov 7, 2011
A vital goal of astronomy today is to
understand the evolution of galaxies
The earliest galaxies emit in the infrared
where for maximum sensitivity telescopes
should be based in Antarctica
The End of the Dark Ages: First
Light and Reionization
Until around 400 million years after the Big Bang,
the Universe was a very dark place. There were
no stars, and there were no galaxies.
Scientists would like to unravel the story of exactly
what happened after the Big Bang.
The PILOT survey telescope and the James
Webb Space Telescope will pierce this veil of
mystery and reveal the story of the formation of
the first stars and galaxies in the Universe.
Spectra and images of the first galaxies
JWST
PILOT Survey Telescope
The PILOT telescope is to be
erected on a tower on the Antarctic
plateau, as that is how and where
the best images are obtained.
http://www.aao.gov.au/pilot/
Project Leader: John Storey
Project Manager: Roger Haynes
Telescope Scientist: Will Saunders
UKIDSS
• 7500 square degrees of the Northern sky,
extending over both high and low Galactic
latitudes, in JHK to K=18.3.
• three magnitudes deeper than 2MASS.
• UKIDSS = near-infrared SDSS
• Also a panoramic atlas of the Galactic plane.
• UKIDSS = five surveys
• two deep extra-Galactic elements, one covering
35 square degrees to K=21, and the other
reaching K=23 over 0.77 square degrees.
The Current State of the Art
VIKING - VISTA Kilo-Degree Infrared Galaxy
Survey. PI Will Sutherland
The VIKING survey will image the same 1500 square degrees of the
sky in Z, Y, J, H, and Ks to a limiting magnitude 1.4 mag deeper
than the UKIDSS Large Area Survey.
• very accurate photometric redshifts, especially at z > 1, important
step in weak lensing analysis and observation of Baryon Acoustic
Oscillations.
• Other science drivers include the hunt for high redshift quasars,
galaxy clusters, and the study of
•
galaxy stellar masses.
PILOT 2m survey
• Offner relay reflective cold stop design
(diffraction limited) by Jon Lawrence
• On chip guiding
• up to 8K x 8K arrays => 16'x 16' @ 0.125"/pixel
• Assumed K background 1mJy/‫ "ﬦ‬i.e. 14.54 mag.
• 0.2 arcsec aperture background is K = 14.54 2.5log(p0.01) = 20.8 mag
• NICMOS sensitivity is H = 25, gives S/N = 0.5 in
900s with background adjusted for aperture.
• To reach S/N = 2 =>16 times longer, that is 4hr.
Image Quality Tip-Tilt removed PSF
from SPIE 4836
Diffraction limited
D
Best 25% South Pole
The other two curves are
MK and average SP
arcsec
PILOT survey
NIRSpec 70 nJy
23 nJy is K = 26.2 mag
2p sr
The Camera for the
PILOT Telescope
Plan A
Clone the GSAOI
focal plane
Type
Array sizes
2048 x 2048 pixels each (2040 x 2040
active)
Detector area
4080 x 4080 pixels (~ 85" x 85")
Physical Pixel size
18 μm
Pixel scale
5 electrons read noise
Spectral Response
Gains
6/11/11
Rockwell HAWAII-2RG HgCdTe
0.02" (TBC)
0.9 μm to 2.6 μm (data / plot)
~ 2.8 e-/ADU (TBC)
Dark current
~ 0.01 e-/s/pix (~12 e- in the maximum
integration time of 20 minutes)
Saturation
~ 48,000 ADU (TBC)
On-Detector Guide
Windows (ODGW)
One programmable ODGW per
detector
Cost of Infrared Camera
• $750,000 per 20482
• $125,000 per ASIC (one for each chip)
• 40962 totals $3.5M (8.5 arcmin field)
• 2 x 40962 totals $7M (8.5 x 17 arcmin)
• Plus cost of dewar and filters
• Plus cost of labour
Plan B
SOFRADIR SATURN SW HgCdTe SWIR
ARRAY FEATURES
Format: 1000x256
Pixel pitch: 30 µmx30 µm
Material spectral response: 0.8µm – 2.5 µm
FPA Operating Temperature: up to 200 K
ROIC FEATURES
Modes: snap shot operation, integrate while read mode, programmable
integration time, anti blooming system
Input stage: Capacitance TransImpedance Amplifier (CTIA)
Charge handling capacity: 0.4 106 / 10.6 106 (for 100% well fill)
Electrical dynamic range: > 2 V (75 dB)
Readout noise: < 150 e- (for 0.4 Me- gain) &< 450 e- (for 1.6 Me- gain)
Signal outputs: 4 or 8 (user selectable)
6/11/11
Science Goals see Michael Burton’s talk
• Although there are many science goals for a
survey deeper than any previous one,
• e.g. the lowest mass stars
• Star formation regions in our galaxy
• See also ARENA and Dome F proposals
• one of the most exciting is finding galaxies at
redshift > 10 from the H dropout method.
• These have no flux at 1.6m
• But are detected at 2.2m
• Redshift = 1.6/0.09 – 1 = 16.8
• Spectra of these objects would be obtained with JWST
The Antarctic advantage
• Almost diffraction limited images
• Wide field
• Low 2m background
• This combination is only available from
• the Antarctic plateau
• high altitude balloons
• space
More details
http://www.kdust.org/KDUST/KDUST.html
and arXiv:1108.1992
The competition is space: WFIRST
Exoplanets and
dark energy
WFIRST (or Euclid) vs PILOT
Advantages of WFIRST
Disadvantages of WFIRST
•Top ranked in ASTRO 2010
•Smaller aperture, 1.5 metre
•Broader band possible, e.g.
1.6-3.6m
•Lower resolution
•No clouds
•3 year mission lifetime
•2020 launch
•Order of magnitude higher cost
•200 nJy limit vs 70 nJy with
PILOT
Euclid see Jason Rhodes talk
Euclid: Mapping the geometry of the dark Universe
Theme: How did the Universe originate and what is it made of?
Primary Goal: To understand the nature of dark energy and dark matter by accurate
measurement of the accelerated expansion of the Universe through different independent
methods.
Targets: Galaxies and clusters of galaxies out to z~2, in a wide extragalactic survey covering 15
000 deg², plus a deep survey covering an area of 40 deg²
Wavelength: Visible and near-infrared
Telescope: 1.2 m Korsch
Orbit: Second Sun-Earth Lagrange point, L2
Lifetime: 6 years
Type: M-class mission
Euclid's cosmological probes
Euclid will map the large-scale structure of the Universe over the entire extragalactic sky - or half of
the full sky excluding the regions dominated by the stars in our Milky Way. It will measure galaxies
out to redshifts of ~2, which corresponds to a look-back time of about 10 billion years, thus
covering the period over which dark energy accelerated the expansion of the Universe.
Euclid is optimised for two primary cosmological probes:
Weak gravitational Lensing (WL): Weak lensing is a method to map the dark matter and measure
dark energy by measuring the distortions of galaxy images by mass inhomogeneities along the
line-of-sight.
Baryonic Acoustic Oscillations (BAO): BAOs are wiggle patterns, imprinted in the clustering of
galaxies, which provide a standard ruler to measure dark energy and the expansion in the
Universe.
Weak gravitational lensing requires extremely high image quality because possible image
distortions by the optical system must be suppressed or calibrated-out to be able to measure the
true distortions by gravity.
PILOT Survey logistics
• Implement 20’ field: 26 years/sr
• assuming 180 x 24 clear hours per year
• but that’s probably faster than WFIRST
• ARENA’s PLT design offers 40’, 6 years/sr
• If K background is 0.1mJy/sq” then 0.26 years/sr
• other wavelengths also become doable in a 5 year ‘mission’
• ~100 Pb of data to cover 2p sr
• not a problem according to Moore’s Law
• data could be served from CAASTRO website
• Will not be obsolete until KDUST 8 is operational
• That will reach ABK = 29 mag
Stellar pops in the EOR
2 micron background
Denizens of the epoch of reionization
•
1m band dropouts at z = 1.1/0.09 -1 = 11
•
J band dropouts at z = 1.4/0.09 -1 = 14
•
Galaxies with 108 year old stellar pops at z = 6
•
Pair production SNe (massive stars) at MK = -23
•
Activity from progenitors of supermassive black
holes
•
Dark Stars, see Ilie et al astro-ph 1110.6202
•
Young globular clusters with 106 year free fall
times and M/L approaching 10-4
•
Rare bright objects require wide field survey,
The next steps
• Is this project compatible with KDUST 2.5 ?
• Finalize camera configuration
• Find LIEF partners
• Swinburne University, J. Mould
• UNSW, M. Burton
• Macquarie University, J. Lawrence
• Melbourne University, S. Wyithe
• ANU, P. McGregor
• CAASTRO and AAO ?
• Texas A & M University
ARC LIEF facts of life
• $9M is a very big proposal for ARC
• Funding spread over 2013,4,5
• But the chips need purchasing in 2013
• Most proposals are unfunded
• This proposal needs to be very strong
• Universities must contribute 25% cash
• CAASTRO may be able to contribute a postdoc
Construction and operations
schedule (tentative)
• January 2013 LIEF funding
• Preliminary Design Review
• 2013 Texas A & M purchases Teledyne arrays
• ANU purchases dewar and filters
• 2014 Integrate and test focal plane at ANU
• January 2015 Integrate telescope and camera in
Fremantle
• 2015-2019 operations (within the international
antarctic science region) at Kunlun Station
• 2020 return of focal plane to USA
Collaboration
A collaboration in which KDUST 2.5 is built in
China, fitted with an Australian camera and
operated for 5 years at Kunlun Station would be
extremely rewarding
All scientific goals discussed so far at this
meeting, cosmology, dark ages, planet finding
are accessible.