Tony Tyson (UC Davis), "The LSST Project and Dark Energy"
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Tony Tyson (UC Davis), "The LSST Project and Dark Energy"

LSST and Dark Energy: astro-ph/0609516

Technology drives the New Sky‣ Microelectronics‣ Software‣ Large Optics Fabrication

Sky Surveying‣ Wavelength‣ Angular resolution‣ Area surveyed‣ Depth‣ Time resolution

The LSST: Deep Wide Fast3.4m SecondaryMeniscus Mirror3.5° Photometric Camera8.4m Primary-TertiaryMonolithic Mirror

LSST optical design

Large Mirror Fabrication

Camera and Focal Plane ArrayFilters andShutter~ 2mWavefront Sensors andFast Guide Sensors0.65m DiameterFocal Plane Array3.2 Giga pixelsRefractive Optics“Raft” of nine4kx4k CCDs.

Wide+Deep+Fast: EtenduePrimary mirrordiameterField of view(full moon is 0.5 degrees)10 m0.2 degreesKeckTelescope3.5 degreesLSST

Relative Survey Power320280240Etendue (m 2 deg 2 )20016012080400LSST PS4 PS1 Subaru CFHT SDSS MMT DESx0.34m VST VISTAIRSNAPx2

LSST image quality80% and 50% polychromatic diffraction energyarc-sec diameter0.320. 50.0 100.0 150.0 200.0 250.0 300.0Detector radial position ( mm )g: 50% r:50% i:50% z:50% y:50%g:80% r:80% i:80% z:80% y:80%

LSST endorsed byfour NAS studies:• Astronomy and Astrophysics in the New Millennium• New Frontiers in the Solar System• From Quarks to the Cosmos• Physics of the Universe

LSST ProjectPartnership of government(NSF and DOE) and privateinterest and support.Milestones and ScheduleCerro Pachón2006 Site SelectionConstruction Proposals(NSF and DOE)2007-2008 Complete Engineering2009-2012 Construction2013 Commissioning

LSST SimulatorsPhotons from source galaxies raytraced+ lensing + atmosphere + wind + optics+ pixel + noiseLSST Operations, including realweather data: coverage & depth+ LSST-like observing on Subaru telescope

LSST Survey‣ 6-band Survey: ugrizy 320–1050 nm‣ Sky area covered: >20,000 deg 20.2 arcsec / pixel‣ Each 10 sq.deg field revisited ~2000 times‣ Limiting magnitude: 26.5 AB magnitude @10σ25 AB mag /visit = 2x15 seconds‣ Photometry precision: 0.01 mag requirement,0.001 mag goal

Photometric RedshiftsMust calibrate!Michael Schneider et al (astroph/0606098).Jeff Newman (this session).

3-D D Mass Tomography2x2 degree mass map from Deep Lens Survey

Cosmic shear vs redshift

Shear TomographyShear power spectra at redshifts to z ≅ 2.ΛCDMz=3.2z= shear sensitivityCosmology Fit RegionLinear regimeNon-linear regime

Baryon Acoustic OscillationsR S ~140 MpcCMB (z = 1080) BAO (z < 3)Standard RulerTwo Dimensions on the SkyAngular Diameter DistancesThree Dimensions in Space-TimeHubble Parameter

Precision on Dark Energy ParametersZhan 2006Measurements have differentsystematic limitsWith systematicsCurvature freeCombination of Weak Lensing and BAO is significantly better thaneither alone. Both require wide sky area deep survey.

Precision on Dark Energy ParametersMeasurements have differentsystematic limitsAdding constraints from supernovae helps

LSST probes of dark energy• WL shear-shear tomography• WL bi-spectrum tomography• Distribution of 250,000 shear peaks• Baryon acoustic oscillations• 1 million SNe Ia, z

Distinguishing theoriesZhan/0605696

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