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