Cluster Cosmology at LPPC

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Cluster Cosmology at LPPC. Illuminating Dark Energy with BCS and PISCO F. William High 2 nd Year Grad Student Harvard Univ Dept of Physics Monday, 21 August 2006. Cluster Cosmology. Redshift z: 1 + z = λ (observed) / λ (emitted). Today. - PowerPoint PPT Presentation

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  • Cluster Cosmology at LPPCIlluminating Dark Energy with BCS and PISCO

    F. William High2nd Year Grad StudentHarvard Univ Dept of Physics

    Monday, 21 August 2006

    F. William High

    Cluster CosmologyDark Energy dominatest ~ 9 Gyrt ~ 3 Gyrt = 0Galaxies start clusteringBig BangGalaxies start formingt ~ 1 Gyrt ~ 14 GyrTodayRedshift z: 1 + z = (observed) / (emitted) z = 0z ~ z ~ 2z ~ 6z = Dark Energy takes effectt ~ 7 Gyrz ~ 1

    F. William High

    Cluster Cosmology: Illuminating Dark EnergyAccelerating expansion: Einsteins cosmo-logical constantw: eqn of state (w = -1)Cluster abundance versus redshiftDepends heavily on and wOverall normalization depends on 81/10 of the skyredshiftNumber of clusters

    F. William High

    Discovering ClustersSZ effectAPEX, ACT, SPT, Redshift independent signal in mmmm-waveX-ray

    F. William High

    BCS (500 clusters), then PISCO (3000 clusters), then DES (the rest)THE REST

    F. William High

    Two ChallengesMass of clusters?

    Solution: BCSDistance to clusters?

    Solution: PISCO

    Observable:Probability:Matter evolution:

    F. William High

    BCSBlanco Cosmology SurveyPre-SPTTo z ~ 1Training set for SPT and PISCOWeak gravitational lensing to calibrate SZ cluster mass estimatorPI: Joe Mohr (U Illinois)

    F. William High

    PISCOParallel Imager for Southern Cosmological ObservationsDedicated camera to measure redshift of high-z clustersField of view matched to size of high redshift clusters: 5 = 1 Mpc at z = , clusters are 1-10 Mpc acrossHighest possible efficiency broadband photometer: 4 simultaneous bandsTo be mounted on 6.5m Magellan, Chile

    F. William High

    PISCO: Photo-zPrinciple: measure differential broadband flux (color) of objects with broad features in spectrumPhoto-z gives redshifts (to 10%) from the colors of luminous red galaxies (LRG)Cluster member galaxies have scatter in redshift at 3% level

    PISCO measures photo-zs of all galaxies in a cluster at once, in a single exposureLRG spectrum

    F. William High

    PISCO: DesignIdeal broadband photometer!Dichroic beamsplitters define bandpasses

    F. William High

    PISCO: Design

    F. William High

    PISCO: StatusConcept completedDetectors in hand, ready to testSimulate expected bandpassesSimulate photo-z signals

    F. William High

    PISCO: To Do ListModelingOptimize survey strategySimulate photo-zHardwareFinish design, order opticsBegin fabricationCharacterize/optimize electronics and detectorsIntegrate, test systemSoftwarePull existing software (object detection, photometry, photo-z, ) into one pipelineTest with real dataIntegrate with instrument

    F. William High

    PISCO: CollaborationChristopher StubbsTony Stark (SAO)John Geary (CfA)James Battat (LPPC)Ned Henry (LPPC)SPT: John Carlstrom (Chicago), Joe Mohr (Illinois),

    F. William High

    Constant Cosmological Constant?Ultimate goal with BCS and PISCO: measure whether dark energy is a constant vacuum energyDark (vacuum) energy equation of state parameter w = p/Matter evolves as:Hubble parameter:Dark energyDark energy eqn of state parameter

    F. William High

    CC@LPPC Summary

    Use weak gravitational lensing to calibrate other cluster mass-observablesImprove cluster mass estimation for all future surveysStatus: first year data reduced, ready to do start WL study in September

    Characterize DE with clusters quickly, cheaply, efficientlyCan get zs of all SPT clusters in 10 nights at Magellan!Status: CCDs in hand, CCD control online, design soon finalized, Carnegie enthusiastic, BCSPISCO