1. S3 time domain known pulsar search
Rejean Dupuis, Matthew Pitkin and Graham Woan
LSC Meeting LLO
March 21st 2005

2. The story so far …
We have previously been searching for known isolated pulsars with frequencies > 25 Hz (GW freq > 50 Hz)
S2 produced upper limits for gravitational wave amplitude and neutron star ellipticity from 28 pulsars (PRL, accepted)
We know the positions and spin-down parameters of these objects well from radio observations
However there are more pulsars (82) with freqs > 25 Hz, most within binary systems …

3. Pulsars f > 25 Hz
J C J J J J
J D J J
J A J
J E
J A J
J C J
J F J J J J
J G J J J J
J H J J J J
J I J
J A J J
J J J
J B J J
J L J J
J A J
J M
J A
J A J
J D
J N J
J B J
J E
J O J
J C J
J F
J P J
J D J
J G
J Q J
J E J
J H
J R J
J F J J
J S J J
J A
J C
J T J J
J B
J A
J U J J
J C
J B
J V J J
J D J
J W J J
J E J J
J A J J J J
J B J J J
Preliminary results (80)
Awaiting timing data (30)
For S3 the main change has been adding code to take account of Doppler shifts in the binary systems

4. Binary pulsar signal
In a binary system we need to take account of the pulsar motion within that system
This adds extra terms to timing equivalent to those for the solar system
These time delays are parameterised by various measurable properties of the binary system (period P, eccentricity e, angular velocity w, time of periastron T, projected semi-major axis asini etc)
There are also other (model dependent) relativistic parameters
Aberration delay (caused by pulsar rotation)
Roemer deley
(light travel time)

5. Binary pulsar models
70 binary pulsars fall mainly into two model categories
32 ELL1 (low eccentricity)
33 BT (Blandford-Teukolsky)
1 BT2P (two orbiting planets)
4 DD (Damour-Deruelle) including double pulsar binary J A
We have orbital parameters solutions over S3 for the majority of these pulsars from Andrew Lyne and Michael Kramer, Jodrell Bank.

6. Code testing BT
Code has been written to calculate time delay with the three models BT, ELL1 and DD
As we did for the solar system barycentring code, we have checked this against TEMPO
Very good agreement for the parameter values within the validity range of TEMPO’s predictive mode
We have recently had a productive code review, identifying a couple of bugs, now been fixed
-1 ms
1 ms
ELL1
-1 ms
1 ms

7. Analysis Analysis proceeds as for S2:
Heterodyne to remove Dopper/spindown effects (including binary parameters where needed)
Joint Bayesian analysis for unknown pulsar parameters, h0, f0, y and cosi using data (of unknown variance) from three LIGO interferometers

8. Preliminary Results

9. Preliminary Results h0 Pulsars
Several of these could be astrophysically interesting given exotic neutron star equations of state (B. Owen, submitted to PRL)
31 pulsars are in globular clusters so spin-down is masked by Doppler motion within cluster (20 with apparent spin-up) h0
Pulsars
5e-25 < h0 < 1e-24 17
1e-24 < h0 < 5e-24 57
5e-24 < h0 < 1e-23 3
h0 > 1e-23
Ellipticity
Pulsars
1e-6 < e < 5e-6 8
5e-6 < e < 1e-5 16
1e-5 < e < 1e-4 44
e > 1e-4 12
All values assume I = 1038 kgm2 and no error on distance

10. Selected preliminary results
Lowest h0 upper limit:
PSR J (f = Hz, dist = 3.25 kpc)
h0 = 6e-25
Lowest ellipticity upper limit
PSR J (f = Hz, dist = 0.25 kpc)
e = 1.5e-06
Closest to spin-down upper limit
Crab pulsar ~ 5 times greater than spin-down (f = 29.8 Hz, dist = 2.0 kpc)
h0 = 7e-24, e = 3.6e-3
Assumes I = 1038 kgm2

11. Injections Recovered pdfs for PULSAR3 in H1
10 pulsar injections were performed in S3 over large range of signal amplitudes and parameters
Injections have been recovered with the correct parameters (after calibration corrections)
Black lines show injected parameter values

12. Further work
Get timing data for remaining 30 pulsars from Jodrell Bank for S3 analysis
Re-run analysis with code review bug fixes (expect small changes)
Perform binary software injections to fully test binary code (using independent code to produce signals)
Perform binary hardware injections into end of S4
Following the above, we intend to produce a long PRD results paper
Analysis method is mature – results for S4 should follow soon after final S3.