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Upper limit map of a Gravitational Wave Background

Explore the upper limit map of a gravitational wave background for stochastic analysis. Details on the detection strategy, point spread function, optimal filter, and frequency-dependent strain. Includes software injection point sources analysis. Stefan Ballmer, Caltech.

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Upper limit map of a Gravitational Wave Background

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  1. Upper limit map of aGravitational Wave Background For the stochastic analysis group Stefan Ballmer California Institute of Technology Stefan Ballmer, Caltech

  2. Outline • Reminder: The S4 Radiometer analysis • Additional checks since August LSC meeting(Asked for by review committee) Stefan Ballmer, Caltech

  3. Detection Strategy, point source Point Spread Function • Cross-correlation estimator • Theoretical variance • Optimal Filter Strain Power: Choose N such that: Stefan Ballmer, Caltech

  4. S4 Upper Limit map , H(f)=const Stefan Ballmer, Caltech

  5. S4 Upper Limit map , H(f)~f-3 Stefan Ballmer, Caltech

  6. Frequency dependentStrain Upper Limit Sco-X1 Artist’s impression: NASA Strain (RMS) Stefan Ballmer, Caltech

  7. Software InjectionPoint Sources at 1e-47 (SNR~10) BTW: Isotropic search returns only a 1.2 sigma result for this! Stefan Ballmer, Caltech

  8. Software InjectionPoint Sources # ra dec Inj. Point_Estimate ratio Sigma SNR ----------------------------------------------------------------------------- 1 6 45 2e-48 1.474e-48 0.7368 9.456e-49 1.559 2 9 -60 2e-48 2.831e-48 1.415 1.102e-48 2.569 3 12 60 2e-48 1.839e-48 0.9193 9.913e-49 1.855 4 15 -75 2e-48 3.009e-48 1.505 1.171e-48 2.569 5 18 0 2e-48 3.068e-48 1.534 1.267e-48 2.422 1 6 45 1e-47 9.602e-48 0.9602 9.5e-49 10.11 2 9 -60 1e-47 1.032e-47 1.032 1.105e-48 9.34 3 12 60 1e-47 1.014e-47 1.014 1.005e-48 10.09 4 15 -75 1e-47 1.102e-47 1.102 1.175e-48 9.38 5 18 0 1e-47 1.065e-47 1.065 1.276e-48 8.349 Stefan Ballmer, Caltech

  9. Effect of timing transient Stefan Ballmer, Caltech

  10. Effect of timing transient Stefan Ballmer, Caltech

  11. Effect of timing transientDifference But is there a residual effect? Stefan Ballmer, Caltech

  12. Effect of timing transientDifference between H1 and L1 TT There is a small systematic associated with this… Stefan Ballmer, Caltech

  13. Conservative estimateof systematic error • Use maximumdifference betweenL1 and H1, x 1/sqrt(2)as maximum errorestimate • Use no-subtraction minus H1-subtraction difference as position dependence map • Add systematic to statistical error in quadrature Stefan Ballmer, Caltech

  14. Change in upper limit mapBefore Stefan Ballmer, Caltech

  15. Change in upper limit mapAfter Stefan Ballmer, Caltech

  16. Summary • Most questions/remarks from review committee addressed • Will be presented at Texas Symposium, Melbourne • Some minor corrections needed for Paper, will becirculated to LSC shortly. Stefan Ballmer, Caltech

  17. The End Stefan Ballmer, Caltech

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