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1 Known Isolated Pulsars Preliminary S2 Results Réjean Dupuis, Matt Pitkin, Graham Woan LIGO-G030584-00-Z.

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Presentation on theme: "1 Known Isolated Pulsars Preliminary S2 Results Réjean Dupuis, Matt Pitkin, Graham Woan LIGO-G030584-00-Z."— Presentation transcript:

1 1 Known Isolated Pulsars Preliminary S2 Results Réjean Dupuis, Matt Pitkin, Graham Woan LIGO-G030584-00-Z

2 2 Outline 1.Quick review of TDS 2.E2E Validation of TDS – S2 injections 3.Preliminary S2 results 4.Promises and future plans

3 3 Quick review of TDS 1.For known pulsars phase evolution is removed by heterodyning to dc. 2.A Bayesian approach is used to determine the joint posterior distribution of the probability of the unknown parameters = {h 0, i,    posterior priorlikelihood model B k ’s are processed data noise estimate

4 4 E2E validation – S2 injections All the parameters of the injected signals were successfully extracted from the noise. http://www.astro.gla.ac.uk/users/rejean/lsc/S2injections Multi-detector analysis successfully increased confidence. Signal P1 individual IFOs all IFOs p(h 0,cos  | B k ) e.g.

5 5 S2 known pulsar analysis Analyzed the 38 known isolated pulsars with 2f rot > 50 Hz. Using same procedure as S1 directly gives reasonable results for about 28 pulsars. For 10 of the pulsars we had to remove lines in order to correctly estimate the noise. Now have noise modelled within factor of 2 for all pulsars (in at least 1-2 IFOs). Crab pulsar heterodyned to take timing noise into account.

6 6 Spectra of tricky pulsars H1 We use a 4 Hz band around the signal frequency to estimate the noise in our B k ’s. Lines in this band generally made us overestimate the noise. Noise estimates were improved by removing lines.

7 7 Estimating noise Changes from S1: –IIR cutoff frequencies –Removed lines in band ~360 Hz ~60 Hz

8 8 Preliminary multi-detector upper limits Performed joint coherent analysis for all 38 pulsars using data from all IFOs. The variance is off by less than a factor of 2 for most pulsars. Upper limits should not change much when we improve the noise estimation. 95% upper limits 10 -24

9 9 Upper limits on ellipticity Equatorial ellipticity: equatorial ellipticity S2 upper limits Spindown-based upper limits 10 -5

10 10 Future plans for TDS 1.Wrap up S2 analysis for isolated pulsars by the end of January, 2004. 2.Implement similar search for known binary pulsars with f GW > 50 Hz. 3.Implement directed searches using MCMC approach (e.g., SN87A, Cas A). GWDAW – Presentation on hardware signal injections?


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