RAVEing mad Dissecting our Galaxy

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RAVEing mad!
Dissecting our Galaxy

• A new view of the Universe VIII
• Fred Watson (and the RAVErs)
• April 2005

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More geography of the Milky Way Galaxy
RAVEing mad!
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Galaxies

• NGC 2997 a near-twin of the Milky Way

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Edge-on view of a spiral galaxy Disc Bulge Thick
disc
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The Galaxys halo of dark matter, old stars and
globular clusters
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And lurking at the centre of our Galaxy
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What is RAVE?
RAVEing mad!
(And why are we RAVEing?)
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What is RAVE?
RAdial Velocity Experiment International
collaboration22 scientists in 11 nations PI
Matthias Steinmetz, AIP All-sky survey of stellar
radial velocities ages Ultimate aim 50 million
stars, complete to I15 Enables true galactic
archaeology Spawned from (now-defunct) space
missions UK Schmidt Telescope and a northern
counterpart Completely externally funded (A, ,
, US, ?) Public data-base VO compliant
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Science goals
Comparison with simulations of structure-growthwi
thin a CDM Universe (Steinmetz Navarro,
2002) Substructure in the halo (cold stellar
streams) Chemical signatures (?/Fe, Fe/H) to
identifycommon formation sites among
widely-separated stars Formation of bulges Origin
of the thick disk Dynamical state of the thin
disk and neighbouring spiral arms
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Science goals...
www.aip.de/RAVE/
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The galactic halo is thought to be made up of
swarms of stars.
They come from satellite galaxies gobbled up in
the past by the Milky Way.
We can detect them by plotting their positions in
phase space.
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More galactic archaeology Results from the
Geneva-Copenhagen survey of 14,000 Sun-like stars
in the local neighbourhood. And this is just the
start
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Multi-object spectroscopy with fibre optics
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More RAVEing
Phase I April 2003June 2005, using unallocated
UKST bright-of-moon time during the 6dF Galaxy
Survey, funded by AAO and RAVE. About 100,000
stars with 9ltIlt12. Observe in the far red region
of the spectrum. Currently measuring 700 stars
per clear night. Phase II 200610, all UKST time
once the Galaxy Survey is complete. Goal is to
measure 30,000,000 stars with Ilt15. But need to
measure 22,000 stars per night.
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RAVEing mad!
Instruments for RAVEing
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Phase I instrumentation 6dF robot
Cute, isnt it?
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Yours might be cutebut mines bigger
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6dF on the UK Schmidt Telescope

• 6-deg field-of-view pick-place fibre system
• Off-telescope robot
• Two field plate units
• 1507 science fibres
• Fixed spectrograph
• Turn-round 20 min
• Reconfig. time 60m
• Up to 8 fields/night
• Commissioned 2001
• OzPoz prototype

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6dF field-plate unit
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Back of field-plate unit
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6dF fibre buttons parked on field plate
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Robot at work
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Phase II instrumentation

• 6dF is too slow for 22,000 stars per night...
• Therefore adapt the 400-fibre positioner
  currently being developed by AAO for Subaru

Echidna Ball-Spine Array
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Found in Space
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Prototype spines
Spine B (3 of 3 made)
Spine A (1 of 3 made)
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Echidna for RAVE

• 2250 spines (each with 15 arcmin patrol area)
• Covers full field area of 6 ? 6 deg2
• 1 minute reconfiguration time
• Feeds spectrograph with 3?750 banks of spectra
• AAO estimates positioner will cost 2.4M
• AIP builds the spectrograph _at_ 0.8M ?
• How might it be funded...?

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What about the north?

• UKST can only access the southern 2/3 of the
  sky.
• Therefore RAVE needs a northern-hemisphere
  counterpart.
• Favoured candidate is the 0.8-m Schmidt at Calar
  Alto, Spain.
• It would need its own Ukidna and spectrograph.

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RAVEing mad!
RAVEs Progress
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First data-release July 2005 on Edinburgh
data-server.
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RAVE spectrum?
A vs.
A vs.
A vs. US
A vs.
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RAVEs future
RAVEing mad!
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The Way Forward
On 30.6.2005 the AAT Board ceases to support UKST
operationsUkidna cannot be ready before 2007if
ever Current proposal is to extend Phase I for gt2
years. RAVE uses all UKST time (up to 25 nights
per month). Annual cost to RAVE 250k
visiting observers. Collect gt400,000
spectrabuying time for Phase II... ORprovide a
useful sample with which to end the survey But
the hope and intention is to RAVE on...
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The end
RAVEing mad!