SkyMapper and the Stromlo Southern Sky Survey

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SkyMapper andthe Stromlo Southern Sky Survey

• Stefan Keller, Brian Schmidt, Paul Francis and
  Mike Bessell

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What is SkyMapper?

• 1.35m with a 5.7 sq. degree fov
• To reside at Siding Spring Observatory
• First light in Dec 2006
• To conduct a multi colour/epoch Stromlo Southern
  Sky Survey
• Replacement for the 50 Great Melbourne Telescope

Rest in Peace
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Why a SkyMapper?

• There is no deep digital optical map of the
  southern sky
• no instrument is planned that can map the entire
  southern sky in multiple colours and epochs
• SkyMapper will provide an automated large-scale
  imaging capability that is matched to Australian
• Science strengths
• Instrumentation (AAOmega, Gemini etc.), and
• Conditions poor seeing a benefit ? cover the
  sky faster!

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The Stromlo Southern Sky Survey S4

• Major component of SkyMapper telescope will be
  providing a survey of the southern sky
• Multi-colour, multi-epoch of southerly 2?
  steradian
• Star and Galaxy photometry (3 global accuracy)
• Astrometry (better than 50 mas )
• Cadence hours, days, months and years.
• Five years to complete
• Data supplied to the community without
  proprietary period as part of Virtual Observatory
  work
• Complementary to SDSS but w. improvements!

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Survey Science

• The survey science goals are broad but some of
  the areas where I think SkyMapper stands to have
  largest impact are
• What is the distribution of large Solar-System
  objects beyond Neptune?
• What is the history of the youngest stars in the
  Solar neighbourhood?
• How far does the dark matter halo of our galaxy
  extend and what is its shape?
• Gravity and metallicity for on order of 100
  million stars ? the assembly and chemical
  enrichment history of the bulge, thin/thick disk
  and halo?
• Extremely metal poor stars.
• Undiscovered members of the local group
• accurate photometric calibration of galaxy
  redshift surveys 2dF/6dF.
• bright zgt6 QSOs ? probes of the ionization
  history of the Universe.

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SkyMapper Filter Set
Ex-atmosphere
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Expected S4 limits
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z coverage

• Spectroscopic redshifts
• rlt18 for SDSS
• BJlt19.5 (? rlt18.5) for 2dFGRS
• Photometric redshifts
• SDSS to r20.5
• From SDSS EDR Csabai 2003

SDSS (EDR)
2dFGRS
S4 to provide Spirals to z0.3-0.4 E0 to z0.7
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SkyMapper and SUMSS/SKAMP

• By cross-comparison of radio and optical sources
  we can ask
• Which members of known classes of optical objects
  are detected as radio sources?
• and with redshifts we can ask
• How does the radio luminosity function evolve
  with redshift?
• Quantify 3D clustering of radio sources

SUMSSDSS From Sadler Hunstead 1999

• around 1.5 SUMSS detections are galaxies in
  the 2dFGRS (Blt19.5)
• 30 are bright enough to appear in the DSS
  (Blt22) Sadler Hunstead 2001
• The Stromlo Southern Sky Survey will go around a
  magnitude fainter than the DSS
• ? photometric z 0.06 for 30 of SUMSS

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S4 Data Products

• Deliverables to the Outside User
• Data (epoch, RA, DEC, mags, galaxy shape info,)
  to be available through a web-served interface
  which provides catalogs over a user defined area
• Images to be available through a web-served
  interface which provides images over a user
  defined area (maximum size will be limited)

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S4 Data Products

• How Much Data???
• 6 epochs x 6 colours x 4000 268,000,000 pixel
  images 150 Terabytes
• 25 Terabytes of calibration images
• 1 Billion Objects observed 36 times with
• Database is 2 Terabytes (1 billion rows x 500
  columns)

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A Concluding Timeline

• Funding Decision, Jun 2004
• Optical elements ordered
• Conceptual Design Review, Oct 2004
• CCDs ordered, Feb 2004
• Critical Design Review, August 2005
• Pipeline development,
• mirror Blank Failures, Sep-Oct 2005
• Site Works begin Dec 2005
• First Light, Dec 2006
• Regular Operations, Apr 2007

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A Concluding Timeline

• Funding Decision, Jun 2004
• Optical elements ordered
• Conceptual Design Review, Oct 2004
• CCDs ordered, Feb 2004
• Critical Design Review, August 2005
• Data reduction pipeline development,
• mirror Blank Failures, Sep-Oct 2005
• Site Works begin Dec 2005
• First Light, Dec 2006
• Regular Operations, Apr 2007

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