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InstrumentationMulti-wavelength observations
The Pulsar Timing Array
High precision pulsar timing at Nancay
Ismael Cognard / Jean-Mathias Grießmeier
G.Theureau, A.Lassus (PhD student)LPC2E, UMR6115/CNRS/OSUC, Orleans
I.Cognard / J.-M. Grießmeier - Nancay pulsar timing MODE-SNR-PWN Workshop - Nov 15-17, 2010 1/10
InstrumentationMulti-wavelength observations
The Pulsar Timing Array
Timing of pulsarsThe Nancay coherent pulsar dedispersorObservations programs
Timing of pulsars
Measuring a time of arrival
a large radiotelescopea good clock,and a special instrumentation
to remove the ISM dispersion
Analysis of a collection of measured times of arrival (ToAs)
→ Having a set of parameters (period, position, etc...),→ computing ’calculated times of arrival’,→ fitting the parameters by minimization of the differences (called residuals)
between ’measured ToAs’ and ’calculated ToAs’→ looking at the residuals to find unmodeled effects...
I.Cognard / J.-M. Grießmeier - Nancay pulsar timing MODE-SNR-PWN Workshop - Nov 15-17, 2010 2/10
InstrumentationMulti-wavelength observations
The Pulsar Timing Array
Timing of pulsarsThe Nancay coherent pulsar dedispersorObservations programs
GPUs based coherent dedispersion at Nancay
Diversion of GPUs
Using high performance graphical card (GPU),2 PCs / 4 GPUs easily dedisperse bw 128MHz(512MB/s=4Gb/s) in real time
An ultimate precision
Timing uncertainty can beas good as 30ns for a few pulsars.
A large scale program
Around 50% of the Nancay telescope timeMore than 200 pulsars monitoredMore than 22000 observations since Nov 2004
I.Cognard / J.-M. Grießmeier - Nancay pulsar timing MODE-SNR-PWN Workshop - Nov 15-17, 2010 3/10
InstrumentationMulti-wavelength observations
The Pulsar Timing Array
Timing of pulsarsThe Nancay coherent pulsar dedispersorObservations programs
More bandwidth : from 128MHz to 512MHz...
First tests on pulsar B1937+21 (ROACH/CASPER based instrumentation).
I.Cognard / J.-M. Grießmeier - Nancay pulsar timing MODE-SNR-PWN Workshop - Nov 15-17, 2010 4/10
InstrumentationMulti-wavelength observations
The Pulsar Timing Array
Timing of pulsarsThe Nancay coherent pulsar dedispersorObservations programs
Two main pulsar programs at Nancay
Multi-wavelength observations ∼1000hr/yr
Title : Multi-wavelength study of pulsars from radio to TeV photons :a joint long term program with FERMI
Ephemeris for 118 pulsars are continuously producedto search for high energy pulsations and constrain emission processes
The Pulsar Timing Array (PTA) ∼2000hr/yr
Title : Timing of an array of millisecond pulsars (MSPs)and detection of multi-wavelength gravitational waves
Around 30 highly stables millisecond precisely timed once a weekto search for the signature of gravitational waves (GW) background
A.Lassus PhD work (2010-2013)
I.Cognard / J.-M. Grießmeier - Nancay pulsar timing MODE-SNR-PWN Workshop - Nov 15-17, 2010 5/10
InstrumentationMulti-wavelength observations
The Pulsar Timing ArrayMulti-wavelength observations
FERMI-Nancay main results
Known radio MSPs
A population of millisecond pulsarsseen with FERMIand Nancay ephemerisAbdo et al., Science 5942, 848 (2009)
New radio MSPs
3 new millisecond pulsarsfound at Nancayin Unidentified FERMI sourcesCognard, Guillemot et al., submitted
The first two MSPs J2017+0603 and J2302+4442seen by FERMI (3 energy bands) and Nancay
I.Cognard / J.-M. Grießmeier - Nancay pulsar timing MODE-SNR-PWN Workshop - Nov 15-17, 2010 6/10
InstrumentationMulti-wavelength observations
The Pulsar Timing Array
Detection of a Gravitational Waves BackgroundAn ultra-stable pulsarNancay contribution to PTA
Detection of a Gravitational Waves Background
Many sources...
Supermassive black-holesbinary systems background
Cosmological background fromrelic gravitational wavesor cosmic strings
Correlation...
Searching for a correlated noise,coming from the effect ofthe gravitational waves on Earth,on a set of stable pulsarswell distributed on the sky.→ Pulsar Timing Array
(PTA : EPTA, PPTA, ... )
the ’EPTA’ is a collaborationof the largest european radiotelescopes
Cagliari, I, 64m, A.PossentiEffelsberg, G, 100m, M.KramerJodrell Bank, UK, 76m, B.StappersNancay, F, ∼100m, I.CognardWesterbork, NL, ∼100m, J.Hessels
I.Cognard / J.-M. Grießmeier - Nancay pulsar timing MODE-SNR-PWN Workshop - Nov 15-17, 2010 7/10
InstrumentationMulti-wavelength observations
The Pulsar Timing Array
Detection of a Gravitational Waves BackgroundAn ultra-stable pulsarNancay contribution to PTA
The ultra-stable pulsar PSR J1909-3744 at Nancay
For the pulsar J1909-3744(P=2.95ms, DM=10.39pc.cm−3, Pb=1.53d)
the ToAs residualsare characterized by an rms ∼110ns
I.Cognard / J.-M. Grießmeier - Nancay pulsar timing MODE-SNR-PWN Workshop - Nov 15-17, 2010 8/10
InstrumentationMulti-wavelength observations
The Pulsar Timing Array
Detection of a Gravitational Waves BackgroundAn ultra-stable pulsarNancay contribution to PTA
A major contribution to the Pulsar Timing Array
Many and well done
over 20 stable pulsarsregularly timed at Nancay :
10 are better than 1µs,5 better than 500ns...
for the EPTA
Nancay is a major contributor tothe European Pulsar Timing Array
and... LEAP
Large European Array for Pulsars :ERC funds to builda ’virtual’ 200m radiotelescopeby coherent additionof the voltages recordedat the five telescopes
Pulsar P Pb T Ntoa σ(ms) (days) (years) (µs)
J0030+0451 4.87 − 4.6 402 1.84J0613−0200 3.06 1.2 4.5 280 0.913J0751+1807 3.48 0.26 4.5 158 1.73J0900−3144 11.10 18.7 2.0 199 2.87J1012+5397 5.25 0.6 4.3 107 0.771J1022+1001 16.45 7.8 4.5 136 1.97J1024−0719 5.16 − 3.6 128 1.23J1455−3330 7.99 76.2 4.5 139 2.33J1600−3053 3.60 14.3 2.8 211 0.495J1643−1224 4.62 147 4.5 271 1.7J1713+0747 4.57 67.8 4.5 260 0.350J1730−2304 8.12 − 4.5 85 1.55J1744−1134 4.07 − 4.5 87 0.343J1751−2857 3.91 110.7 3.5 36 0.948J1824−2452 3.05 − 4.5 313 2.63J1857+0943 5.36 12.3 4.5 51 0.860J1909−3744 2.95 1.53 5.2 103 0.111J1910+1256 4.98 58.4 3.5 31 1.04J1939+2134 1.55 − 4.5 277 0.483J2145−0750 16.05 6.84 4.5 159 0.993J2317+1439 3.44 2.46 4.8 163 2.64
I.Cognard / J.-M. Grießmeier - Nancay pulsar timing MODE-SNR-PWN Workshop - Nov 15-17, 2010 9/10
InstrumentationMulti-wavelength observations
The Pulsar Timing Array
Detection of a Gravitational Waves BackgroundAn ultra-stable pulsarNancay contribution to PTA
a Bayesian approach limit on GW background
From EPTA high precision pulsar timing data (4NRT+2EFF+1WSRT)R.van Haasteren (Leiden) determined an upper limit with a Bayesian algorithm
vanHaasteren, in prep, 2010
MSPs ToAs residuals
Joint GWB distributionCharacteristic strain hc (f ) = A(f /yr−1)α
Limit on amplitude A=6×10−15 (2-sigma, α=2/3)
I.Cognard / J.-M. Grießmeier - Nancay pulsar timing MODE-SNR-PWN Workshop - Nov 15-17, 2010 10/10