The Next Big Thing in Astronomy

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The Next Big Thing in Astronomy

• Dr John Davies
• UK Astronomy Technology Centre.

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In the unlikely event of an emergency.
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Why Size Really is Important.

• Sensitivity depends on collecting area and
  spatial resolution.
• Bigger telescope more light, and the area of a
  telescope goes as the square of diameter. So an 8
  metre telescope has 4, not 2, times the
  collecting power of a 4 metre.
• Resolving power of a telescope goes as 1.22 x
  lambda/diameter. So the bigger the telescope the
  more fine detail it can see (in principle anyway!)

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What is needed to build a bigger telescope?

• New questions that only a more powerful (usually
  bigger) telescope can answer.
• New technology that makes a bigger (or different)
  telescope feasible.
• New money to make it affordable or new politics
  to make it desirable.

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Optical telescopes (1609- 2005)
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Radio telescopes (1930-2005)
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X-ray telescopes (1970-2005)
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What are the big questions?

• Earthlike planets and the search for life
• The origin of the Universe, the first stars and
  galaxies.

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X-ray telescopes

• Must operate in Space
• Use Grazing Incidence Optics

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Next generation X-ray telescopes

• Problem Chandra XMM Newton already fill the
  biggest existing and foreseen launch vehicles
  (Space Shuttle and Ariane 5)
• Solution Use lightweight optics and decouple
  telescope from detectors for long focal length.
• Proposal The ESA XEUS Mission. 100 times more
  sensitive than XMM and with a 15 year lifetime.

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XEUS. Original Plan
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XEUS Plan B

• Space Station option unaffordable for many
  reasons.
• Development of new, micropore mirror technology
  makes a new mission concept possible.

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Micropore Mirrors
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XEUS Spacecraft
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XEUS Mission
Launch date 2015 Cost 750 Million Euro
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Sub-Millimetre Astronomy

• Detects cool material and emission from molecules
• Needs dry, hence high, sites.

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Sub-mm Astronomy today.

• Limited angular resolution from single
  dishes, and only just getting sub-millimetre
  cameras

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Interferometry Aperture Synthesis
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ALMA

• Build a large array of sub-millimetre telescopes
  to both increase collecting area and provide
  much improved angular resolution.
• International Project (Europe, USA and Japan)

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ALMA Concept
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Alma Site from Space
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Alma Site
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ALMA Science Goals

• Emission from the first galaxies
• Star formation in dark clouds
• Disks around nearby stars in which planets are
  forming
• Chemistry of comets

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Test Antennas
Operational Date 2011. Cost 500 million Euro
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Radio Astronomy, towards the SKA

• Cosmic Microwave Background
• Quasars
• Cosmological evolution
• Gravitational lenses
• Superluminal motions
• Dark matter
• Masers
• Pulsars
• Gravitational radiation
• First extra-solar planetary system

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and in 21cm-line of hydrogen
The universe in starlight
Very different views -- but the hydrogen
signal is weak ! (Transition probability
for spin-flip about once per million years)

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The revolution in radio telescopes

• Based on phased arrays of
  receivers

Focal plane arrays (radio cameras)
Aperture arrays (solid state fish-eye lens cf.
shaped metal telescope)
MANY STEERABLE FIELDS-OF-VIEW !
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Small dish Smart feed

• Smart feed based on SKADS digital phased array
  2-PAD
• SKADS partners include
• Karoo Array Telescope
• (South Africa)
• xNTD array
• (Australia)

Two prototypes doing SKA-style science by 2009
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SKA poster (multi-beams)
Many beams offer great flexibility
Many targets/users
Interference rejection
SKADS prototype EMBRACE to be built in
Netherlands
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SKA in Motion
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Timescales for the SKA

• Technology development phase to 2009
• - international selection of collector
  concept(s) and proceed to final design
• - selection of site short list 2006
  (Australia, South Africa, China, Argentina)
• Construction phases (2010 - 2020)
• - start with 10 pathfinder (central array)
• Estimated final cost 1 B is the aim
• 35 Europe
• 35 USA
• 30 Australia, Canada, China, India, Japan,
  South Africa,

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What about Life?

• Planets are hard to see due to the brightness of
  their parent star.
• Observing in the infrared makes the planet easier
  to see study as the contrast is a million times
  better.

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Life Jim, but just as we know it
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Nulling Interferometer
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Darwin Telescope
Passive Cooled Automatic Station Keeping L2
orbit
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Darwin Free Flying Space Interferometer
Launch date 2015 and counting. Cost About 750
million Euro
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Next Generation Optical Telescope

• Historically costs rise as a large power of the
  diameter of the telescope.
• Large Mirrors are hard to make.
• Segmented telescopes are the only future

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Keck 10m Telescope
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USA The TMT.
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EURO 50
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OWL
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ELT Challenges

• Adaptive Optics
• Structure
• Manufacturing segments
• Instrument size and detectors.

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ELT Science Goals

• Images planets with spacecraft like quality
• Study individual stars in distant galaxies
• Spectroscopic follow up of very eary galaxies
  discovered by JWST
• Image planets around other stars

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The next big thing in Astronomy?