New Directions in Observational New Directions in Observational Cosmology: A New View of our Cosmology: A New View of our

UniverseUniverse

Tony TysonUC Davis

Berkeley May 4, 2007

Technology drives the New SkyTechnology drives the New Sky

Microelectronics Software Large Optics Fabrication

Wide+Deep+Fast: EtendueWide+Deep+Fast: Etendue

Primary mirror diameter

Field of view(full moon is 0.5 degrees)

KeckTelescope

0.2 degrees10 m

3.5 degrees

LSST

Relative Survey PowerRelative Survey Power

0

40

80

120

160

200

240

280

320

Ete

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ue

(m

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LSST PS4 PS1 Subaru CFHT SDSS MMT DESx0.3

4m VST VISTAIR

SNAPx2

15 sec exposures

2000 exposures per field

Large Synoptic Survey Large Synoptic Survey TelescopeTelescope

The LSST optical design: three large The LSST optical design: three large mirrorsmirrors

The telescope design is completeThe telescope design is complete

Altitude over azimuth configuration

Camera andSecondary assembly

Carrousel dome

Finite elementanalysis

The LSST siteThe LSST site

1.5m photometriccalibration telescope

3.2 gigapixel camera3.2 gigapixel camera

Five Filters in stored locationL1 Lens

L2 Lens

ShutterL1/L2 Housing

Camera Housing

L3 Lens

Raft Tower

Filter in light path

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

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

1E+06

1E+07

1E+08

1E+09

1E+10

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

Year

Nu

mb

er

of

pix

els

Pan-STARRS

GAIA (space)SLAC VXD3CFHT & SAO Megacam

LSSTSNAP (space)

ESO omegacam

SDSS

UH4K

NOAO4K

lots of 8K mosaics!

Large CCD mosaicsLarge CCD mosaics

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)

basic building block: the raft basic building block: the raft towertower

The LSST thick CCD SensorThe LSST thick CCD Sensor

16 segments/CCD200 CCDs total3200 Total Outputs

LSST ProjectLSST Project

Cerro Pachón2006 Site Selection

Construction Proposals

(NSF and DOE)

2007-2009 Complete Engineering

2010-2015 Construction

2015 Commissioning

Milestones and Schedule

Partnership of government Partnership of government (NSF and DOE) and private (NSF and DOE) and private support.support.

The Data ChallengeThe Data Challenge

~2 Terabytes per ~2 Terabytes per hour that must hour that must be mined in real be mined in real time.time.

More than 10 More than 10 billion objects billion objects will be monitored will be monitored for important for important variations in real variations in real time.time.

Knowledge Knowledge extraction in real extraction in real time. time.

The LSST Corporation has 21 members The LSST Corporation has 21 members

Brookhaven National Laboratory California Institute of TechnologyColumbia UniversityGoogle, Inc. Harvard-Smithsonian Center for Astrophysics  Johns Hopkins University  Kavli Institute for Particle Astrophysics and Cosmology - Stanford University Las Cumbres Observatory Global Telescope Network, Inc. Lawrence Livermore National Laboratory  National Optical Astronomy Observatory Princeton University Research Corporation Stanford Linear Accelerator Center  The Pennsylvania State University Purdue UniversityThe University of ArizonaUniversity of California at Davis University of California at Irvine University of Illinois at Urbana-Champaign  University of Pennsylvania University of Washington

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

Figure : Visits numbers per field for the 10 year simulated survey

Photometric RedshiftsPhotometric Redshifts

• 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 lenses1 million lenses new phenomenanew phenomena

LSST survey of 20,000 sq LSST survey of 20,000 sq degdeg

LSST Science Charts New LSST Science Charts New TerritoryTerritory

Probing Dark MatterAnd Dark Energy Mapping the Milky Way

Finding Near Earth Asteroids

3-D Mass Tomography3-D Mass Tomography

2x2 degree mass map from Deep Lens Survey

Resolving galaxiesResolving galaxies

A given galaxy at high redshift should appear smaller. But two effects oppose this: cosmological angle-redshift relation, and greater star formation in the past (higher surface brightness).

Here are plots of galaxy surface brightness vs radius (arcsec) in redshift bins from z = 0.5 – 3.0 for 23-25 apparent mag. At a surface brightness of 28 i mag/sq.arcsec (horizontal dashed line) most galaxies at z<3 are resolved in 0.6 arcsec FWHM seeing (vertical dashed line).

HST/ACS GOODS, Ferguson 2007

Comparing HST with SubaruComparing HST with Subaru

ACS: 34 min (1 orbit)PSF: 0.1 arcsec (FWHM)

2 arcmin

Comparing HST with SubaruComparing HST with Subaru

Suprime-Cam: 20 minPSF: 0.52 arcsec (FWHM)

DSS: digitized photographic DSS: digitized photographic platesplates

On

e q

ua

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r th

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iam

eter

of

the

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Sloan Digital Sky SurveySloan Digital Sky Survey

Deep Lens SurveyDeep Lens Survey

Massively Parallel Massively Parallel AstrophysicsAstrophysics

• Dark matter/dark energy via weak lensingDark matter/dark energy via weak lensing• Dark energy via baryon acoustic oscillations Dark energy via baryon acoustic oscillations • Dark energy via supernovaeDark energy via supernovae• Galactic Structure encompassing local groupGalactic Structure encompassing local group• Dense astrometry over 20000 sq.deg: rare moving objectsDense astrometry over 20000 sq.deg: rare moving objects• Gamma Ray Bursts and transients to high redshiftGamma Ray Bursts and transients to high redshift• Gravitational micro-lensingGravitational micro-lensing• Strong galaxy & cluster lensing: physics of dark matterStrong galaxy & cluster lensing: physics of dark matter• Multi-image lensed SN time delays: separate test of Multi-image lensed SN time delays: separate test of

cosmologycosmology• Variable stars/galaxies: black hole accretionVariable stars/galaxies: black hole accretion• QSO time delays vs z: independent test of dark energyQSO time delays vs z: independent test of dark energy• Optical bursters to 25 mag: the unknownOptical bursters to 25 mag: the unknown• 5-band 27 mag photometric survey: unprecedented 5-band 27 mag photometric survey: unprecedented

volumevolume• Solar System Probes: Earth-crossing asteroids, Comets, Solar System Probes: Earth-crossing asteroids, Comets,

TNOsTNOs

Key LSST Mission: Dark Key LSST Mission: Dark EnergyEnergy

Precision measurements of all four dark energy signatures in a single data set. Separately measure geometry and growth of dark matter structure vs cosmic time.

Weak gravitational lensing correlations + CMB

(multiple lensing probes!) Baryon acoustic oscillations (BAO) + CMB Counts of dark matter clusters + CMB Supernovae to redshift 1

(complementary to JDEM)

Critical IssuesCritical Issues

WL shear reconstruction errors Show control to better than required precision Show control to better than required precision

using existing new facilitiesusing existing new facilities Photometric redshift errors

Develop robust photo-z calibration planDevelop robust photo-z calibration plan Undertake world campaign for spectroscopyUndertake world campaign for spectroscopy ()

Photometry errors Develop and test precision flux calibration Develop and test precision flux calibration

techniquetechnique

Distinguishing DE theoriesDistinguishing DE theories

Zhan/0605696

Dark Energy Precision vs timeDark Energy Precision vs time

CombinedCombinedSeparate DE ProbesSeparate DE Probes

Mass in CL0024LSST will constrain the nature of dark matterLSST will constrain the nature of dark matter

Mass in CL0024LSST will measure total neutrino massLSST will measure total neutrino mass

LSST WL+BAO+P(k) + Planck

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)

http://www.lsst.org

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

DLS

DS

= 4GM/bc2

b

DLS

DS4GM/bc2

sheared image

shear

Gravity & Cosmology change the growth rate of mass structureCosmology changes

geometric distance factors

Cosmic shear vs redshiftCosmic shear vs redshift

Shear TomographyShear Tomography

Shear spatial power spectra at redshifts to z Shear spatial power spectra at redshifts to z 2. 2.

z

z

0.01

0.001

Ne

ede

d sh

ear sen

sitivity

Linear regime Non-linear regime

ΛCDM

Cosmology Fit Region

Residual shear correlationResidual shear correlation

Cosmic shear signalTest of shear systematics: Use faint stars as proxies for galaxies, and calculate the shear-shear correlation after correcting for PSF ellipticity via a different set of stars.

Compare with expected cosmic shear signal.

Conclusion: 200 exposures per sky patch will yield negligible PSF induced shear systematics. Wittman (2005)

Stars

• Characteristic Characteristic oscillations in oscillations in the CMB the CMB powerpower

WMAP reveals a picture of the fireball at the moment of decoupling: redshift z = 1080

Tem

pera

ture

Pow

er

Angular scale

Cosmic Microwave Cosmic Microwave BackgoundBackgound

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)