the large synoptic survey telescope

The Large Synoptic Survey TelescopeThe Large Synoptic Survey Telescope

Presentation to AAACOctober 13, 2006

Anthony TysonDirector, LSST

Physics Department, Univ. of California, Davis

AAAC PresentationOctober 13, 2006

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Large Synoptic Survey TelescopeLarge Synoptic Survey Telescope

History:

The need for a facility to survey the sky Wide, Fast and Deep, has been recognized for many years.

1996-2000 “Dark Matter Telescope”Emphasized mapping dark matter

2000- “LSST”Emphasized a broad range of science from the same multi-wavelength survey data


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Wide+Deep+Fast: Wide+Deep+Fast: EtendueEtendue

Primary mirror diameter

Field of view

KeckTelescope

0.2 degrees10 m

3.5 degrees

LSST


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• 4 billion galaxies with redshifts4 billion galaxies with redshifts• Time domain: Time domain: 100,000 asteroids100,000 asteroids 1 million supernovae1 million supernovae 1 million gravitational lenses1 million gravitational lenses gamma ray burstersgamma ray bursters new phenomenanew phenomena

LSST survey of 20,000 sq degLSST survey of 20,000 sq deg


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Relative Etendue (= ARelative Etendue (= A))

0

40

80

120

160

200

240

280

320

Ete

nd

ue

(m

2 de

g2 )

LSST PS4 PS1 Subaru CFHT SDSS MMT DES 4m VST VISTAIR

All facilities assumed operating100% in one survey

15 sec exposures

2000 exposures per field


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0

40

80

120

160

200

Re

lati

ve

Fig

ure

of

Me

rit

LSST SNAP Pan-STARRs

Subaru CFHT SDSS MMT

Time (x10)

Stellar

Stellar ( J band )

Galactic (x2)

Opening Time DomainOpening Time Domain


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LSST SurveyLSST Survey

• 6-band Survey: ugrizy 320–1050 nm Frequent revisits: grizy

• Sky area covered: >20,000 deg2 0.2 arcsec / pixel

• Each 10 sq.deg FOV revisited ~2000 times

• Limiting magnitude: 27.7 AB magnitude @5 25 AB mag /visit = 2x15 seconds• Photometry precision: 0.01 mag requirement, 0.001 mag goal


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Massively Parallel AstrophysicsMassively Parallel Astrophysics

– Dark matter/dark energy via weak lensing – Dark matter/dark energy via baryon acoustic oscillations– Dark energy via supernovae– Dark energy via counts of clusters of galaxies– Galactic Structure encompassing local group– Dense astrometry over 20000 sq.deg: rare moving objects– Gamma Ray Bursts and transients to high redshift– Gravitational micro-lensing– Strong galaxy & cluster lensing: physics of dark matter– Multi-image lensed SN time delays: separate test of cosmology– Variable stars/galaxies: black hole accretion– QSO time delays vs z: independent test of dark energy– Optical bursters to 25 mag: the unknown– 5-band 27 mag photometric survey: unprecedented volume– Solar System Probes: Earth-crossing asteroids, Comets, trans-

Neptunian objects


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LSST Ranked High PriorityLSST Ranked High Priority

• NRC Astronomy Decadal Survey

• NRC New Frontiers in the Solar System

• NRC Quarks-to-Cosmos

• SAGENAP

• Quantum Universe

• Physics of the Universe

• Dark Energy Task Force + P5


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LSST Funding TimelineLSST Funding Timeline

• FY-2004 R&D proposal to NSF AST

• FY-2005 $14.2M LSST R&D grant

• FY-2006 DOE CD-0 Ground-based dark energy

• FY-2007 LSST NSF MREFC Proposal submitted

• FY-2009 NSB moves LSST to readiness phase

• FY-2009 DOE MIE funding begins for camera

• FY-2010 NSF MREFC award to begin construction

• FY-2014 First light and commissioning


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LSST Probes Dark Energy and Dark MatterLSST Probes Dark Energy and Dark Matter

Weak lensing (multiple probes) Baryon acoustic oscillations Counts of massive structures vs redshift Supernova cosmology (complementary to JDEM) Mass power spectrum on very large scales tests CDM paradigm Shortest scales of dark matter clumping tests models of dark

matter particle physics

The LSST survey will address all with a single dataset!


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Weak Gravitational Lensing HeritageWeak Gravitational Lensing Heritage

2-degree by 2-degree mass map of one of five Deep Lens Survey fields. All four clusters examined in this field have been verified with spectroscopy and X-ray observations (2005)

1983-2000 Weak gravitational lens experiments using Blanco telescope

2000 First detection of cosmic shear

2000-2005 Deep Lens Survey

1996- Emerging need for an all-sky deep multi-wavelength facility with controllable systematic errors

Today, several distinct groupsworldwide are pursuing weak lens cosmology on a varietyof telescopes.


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z=0.6

z=3.0

20000 sq.deg WL survey shear 20000 sq.deg WL survey shear power spectrapower spectra

z=1100 z=3.2

z=0.2

z=0.6

LSST shear systematics floor

0.001 shear

Blanco shear systematics floor

z=3.2

z=0.2

Require: shear error < 0.0002Require: shear error < 0.0002

0.01 shear

0.001 shear


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Addressing DETF Critical IssuesAddressing DETF Critical Issues

WL shear reconstruction errors Show control to better than required precision

using existing new facilities Photometric redshift errors Develop robust photo-z calibration plan Undertake world campaign for spectroscopy

Photometry errors Develop and test precision flux calibration

technique


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Subaru 10 sec ExposuresSubaru 10 sec Exposures

Raw de-trailed PSF corrected

<shear> <shear> = 0.07= 0.07

<shear> <shear> = 0.000013= 0.00001313

arc

min

(l

= 1

000)

<shear> <shear> = 0.04= 0.04

Single exposure in 0.65 arcsec seeing

<shear> <shear> < 0.0001< 0.0001


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Residual Subaru Shear CorrelationResidual Subaru Shear Correlation

Cosmic shear signalTest of shear systematics: Use faint stars as proxies for galaxies, and calculate the shear-shear correlation.

Compare with expected cosmic shear signal.

Conclusion: 500 exposures per sky patch will yield negligible PSF induced shear systematics. Wittman (2005)


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Photometric RedshiftsPhotometric Redshifts

Calibration: angular correlation between photo-z and spectroscopic samples enables high precision photo-z: http://www.lsst.org/Science/Phot-z-plan.pdf

Precision calibration plan: underway. Likely will exceed requirements.Precision calibration plan: underway. Likely will exceed requirements.


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12-band Super Photo-z Training Set12-band Super Photo-z Training Set

Using angular correlations this training set enables LSST photo-z error calibration to better than required precision

Systematic error:0.003(1+z) calibratableNeed 20,000 spectroscopic redshifts


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RS~140 Mpc

Standard Ruler

Two Dimensions on the Sky Angular Diameter Distances

Three Dimensions in Space-Time Hubble Parameter

Baryon Acoustic OscillationsBaryon Acoustic Oscillations

CMB (z = 1080) BAO (z < 3)


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LSST Precision on Dark Energy LSST Precision on Dark Energy

WL+BAO and Cluster counts give separate estimates. Both require WL+BAO and Cluster counts give separate estimates. Both require wide sky area deep survey.wide sky area deep survey.

Zhan 2006


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Dark Energy Precision vs timeDark Energy Precision vs time

CombinedCombinedSeparate DE ProbesSeparate DE Probes


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LSST Project OrganizationLSST Project Organization

• The LSST is a public/private project with public support through NSF-AST and DOE-OHEP.

• Private support is devoted primarily to project infrastructure and fabrication of the primary/tertiary and secondary mirrors, which are long-lead items.

• NSF support is proposed to fund the telescope. DOE support is proposed to fund the camera.

• Both agencies would contribute to data management and operations.

Camera

Steven Kahn, Sci.

Kirk Gilmore, Mgr.

Telescope/Site

Charles Claver, Sci.

Victor Krabbendam, Mgr.

System Engineering

William Althouse

Science Working Groups

Data Management

Timothy Axelrod, Sci.

Jeffrey Kantor, Mgr.

Science Advisory

Committee (SAC )

Michael Strauss

System Scientist &

Chair of Science Council

Zeljko IvezicEd & Pub Outreach

Suzanne Jacoby

DirectorAnthony Tyson

Steve Kahn, Deputy

Project ManagerDonald Sweeney

Victor Krabbendam, Deputy

Board of Directors

Simulation & Data

Philip Pinto

PresidentJohn Schaefer

System Calibration

David Burke

LSST Organization Chart


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The LSST CorporationThe LSST Corporation

• The project is overseen by the LSSTC, a 501(c)3 non-profit Arizona corporation based in Tucson.

• LSSTC is the recipient of private funding, and is the Principal Investigator organization for the NSF D&D funding.

LSSTC member institutionsLSSTC member institutions

Brookhaven National Laboratory

Harvard-Smithsonian Center for Astrophysics

Johns Hopkins University

Las Cumbres Observatory

Lawrence Livermore National Laboratory

National Optical Astronomy Observatory

Pennsylvania State University

Research Corporation

Stanford Linear Accelerator Center

Stanford University

University of Arizona

University of California, Davis

University of California, Irvine

University of Illinois

University of Pennsylvania

University of Washington

16 current member institutions.Google Corp. has applied.More pending.

+ Several foreign groups.

Foreign prospective membersForeign prospective members

• German university group (led by Matthias Steinmetz)

• French group (IN2P3 Collaboration)

• UK university group (led by Andrew Lawrence)

• European Southern Observatory (Catherine Cesarsky, Dir)


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LSST integrates Astronomy & Physics LSST integrates Astronomy & Physics communitiescommunities

astronomy particle

physicsLSST

Project

NSF DOE

LSST Science CollaborationsLSST Science Collaborations

1. Supernovae: M. Wood-Vasey (CfA) 2. Weak lensing: D. Wittman (UCD) and B. Jain (Penn)3. Stellar Populations: Abi Saha (NOAO) 4. Active Galactic Nuclei: Niel Brandt (Penn State) 5. Solar System: Steve Chesley (JPL) 6. Galaxies: Harry Ferguson (STScI) 7. Transients/variable stars: Shri Kulkarni (Caltech) 8. Large-scale Structure/BAO: Andrew Hamilton (Colorado) 9. Milky Way Structure: Connie Rockosi (UCSC)10. Strong gravitational lensing: Phil Marshall (UCSB)

171 signed on already, from member institutions and project team.


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54

64cm focal plane

3 refractive lenses

Primary

Tertiary

Secondary

LSST optical design has a 3.5LSST optical design has a 3.5oo FOV, 8.4m FOV, 8.4mprimary, <0.2 arcsec PSF from primary, <0.2 arcsec PSF from ll=320-1050nm=320-1050nm


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Mirror DesignsMirror Designs

8.4 Meters

Primary Surface

Tertiary Surface

0.9 M

• Unique Monolithic Mirror: Primary and Tertiary Surfaces Polished Into Single Substrate

• Cast Borosilicate Design

Mirror Cell (Yellow)

Secondary Mirror

Baffle (Black)

• Thin Meniscus Low Expansion Glass Design for Secondary Mirror

• 102 Support Actuators

Secondary Mirror

Primary/Tertiary Mirror


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The telescope baseline design is completeThe telescope baseline design is complete

Altitude over azimuth configuration

Camera andSecondary assembly

Carrousel dome

Finite elementanalysis

30 meters

The LSST carrousel dome is 30m in diameterThe LSST carrousel dome is 30m in diameter


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The LSST will be on El Penon peak inThe LSST will be on El Penon peak inNorthern Chile in an NSF compoundNorthern Chile in an NSF compound

1.5m photometriccalibration telescope


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The LSST camera will have 3 gigapixelsThe LSST camera will have 3 gigapixelsin a 64cm diameter image planein a 64cm diameter image plane

Five Filters in stored locationL1 Lens

L2 Lens

ShutterL1/L2 Housing

Camera Housing

L3 Lens

Raft Tower

Filter in light path


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Shutter

Filter Changer

Filter Carousel

Manual Changer access port

Back Flange

Filter Changer rail

Camera body with five filters and shutterCamera body with five filters and shutter


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Wavefront Sensor Layout

Guide Sensors (8 locations)

Wavefront Sensors (4 locations)

3.5 degree Field of View (634 mm diameter)

Curvature Sensor Side View Configuration

Focal plane2d

40 mm

Sci CCD

The LSST Focal PlaneThe LSST Focal Plane


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RAFT TOWER

Electronics

Raft Assembly

Flex Cable &

Electronics Cage

Thermal Straps

3 x 3 CCD Sensor Array

SENSOR

4Kx4K Si CCD Sensor

CCD Carrier

Thermal Strap(s)

The basic building block for the The basic building block for the camera is the raft towercamera is the raft tower


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The LSST CCD SensorThe LSST CCD Sensor

16 segments/CCD200 CCDs total3200 Total Outputs


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Applications Science Image processing, database queries, …

Middleware Interface wrapper Device drivers, system management,…

Infrastructure Hardware Computers, disks, data links, ,,,

LSST Data Management Model

LSST generates 6GB of raw data every 15 seconds that must be calibrated, processed, cataloged,

indexed, and queried, etc. often in real time

The LSST Data Management The LSST Data Management


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Data Management is a major part of the Data Management is a major part of the LSST missionLSST mission

The LSSTC partnership has DOE national labs (LLNL, SLAC, BNL), NSF centers (NCSA/UI-

UC), US industry (Google, Inc.) and academic centers (Caltech, Stanford,

Harvard) to create and operate a World-Class data management center


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LSST imaging & operations simulationsLSST imaging & operations simulations

Sheared HDF raytraced + perturbation + atmosphere + wind + optics + pixel

LSST Operations, including real weather data: coverage + depth

Performance verification using Subaru 15 sec imagingPerformance verification using Subaru 15 sec imaging


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Project Management StatusProject Management Status

• Reference Design complete• Full WBS with dictionary and task breakdown• Task-based estimate complete • Integrated cost/schedule complete• NSF MREFC proposal for submission ~Dec’06• NSF Concept Design Review planned in FY07• DOE CD-1 review planned in FY08


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ConstructionCommissioning

Operations

Timeline and budget for the LSSTTimeline and budget for the LSST

FY-06 2007 2008 2009 2010 2011 2012 2013 2014 2015

Design and Development

Submit NSF MREFC Proposal

NSF and CD-2a funding begins

First light 51 months

CD-0

(and early procurement)

Fiscal Years

CD-1

Requests (Then Year USD):

NSF $15M $263M $15M/yrDOE $20M $109M $15M/yrPrivate/other $10M $ 66M $15M/yr

Escalated task-based estimate with 30% contingency


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Why Now?Why Now?

– Broad science community interestBroad science community interest– Synergy with 2013- multi-wavelength facilitiesSynergy with 2013- multi-wavelength facilities– Multiple endorsementsMultiple endorsements– Systematic risks addressedSystematic risks addressed– Technically readyTechnically ready


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Q&A slides


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DE Science Drives Short ExposuresDE Science Drives Short Exposures

• Weak lensing requires exquisite control of shape systematics.

• One needs hundreds of exposures per filter per sky patch for chopping.

• Short exposures allow us to optimally weight.• Many exposures with sky rotated on detector permit

another chop.• These require high etendue and short exposures.


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Near Earth ObjectsNear Earth Objects

• Inventory of solar system is incomplete

• LSST would get orbits of nearly all NEOs larger than 140m (per congressional mandate)

• Demanding project: requires mapping the sky down to 24th magnitude every few days, individual exposures not to exceed 15 sec

• Uses same sky tiling cadence optimal for dark energy


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Difference imagingDifference imaging

Deep Lens Survey


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Full sampling improves linkingFull sampling improves linking

per visit

LSST baseline cadenceusing r band data only


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Formation of our Galaxy and GroupFormation of our Galaxy and Group

SDSS

LSST


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Optical flashesOptical flashes

Deep Lens Survey

difference

CerroPachonLa

Serena

LSST will use existing NSF-funded fiber optic networksLSST will use existing NSF-funded fiber optic networks

Typical data raterequired ~2GB/sec

the large synoptic survey telescope

Documents

dark energy fy

supernovae dark energy

dark matterweak

band survey

mag photometric survey

deep lens survey fields

camera fy

construction fy