. Wa, XPY acknowledges support by NNSF of China (U1231120) and FRFCU (XDJK2015B012)

A. A. Abdo, LARGE AREA TELESCOPE, The Astrophysical Journal, vol.699, issue.2, p.1171, 2009.
DOI : 10.1088/0004-637X/699/2/1171

URL : https://hal.archives-ouvertes.fr/in2p3-00497544

A. A. Abdo, LARGE AREA TELESCOPE: A CASE FOR CO-LOCATED RADIO AND ??-RAY EMISSION REGIONS, The Astrophysical Journal, vol.712, issue.2, p.957, 2010.
DOI : 10.1088/0004-637X/712/2/957

A. M. Archibald, V. I. Kondratiev, J. W. Hessels, and D. R. Stinebring, MILLISECOND PULSAR SCINTILLATION STUDIES WITH LOFAR: INITIAL RESULTS, The Astrophysical Journal, vol.790, issue.2, p.22, 2014.
DOI : 10.1088/2041-8205/790/2/L22

URL : http://arxiv.org/abs/1407.0171

J. W. Armstrong, B. J. Rickett, and S. R. Spangler, Electron density power spectrum in the local interstellar medium, The Astrophysical Journal, vol.443, p.209, 1995.
DOI : 10.1086/175515

DOI : 10.1088/0004-637X/794/2/141

D. C. Backer, S. R. Kulkarni, C. Heiles, M. M. Davis, and W. M. Goss, A millisecond pulsar, Nature, vol.300, issue.5893, p.615, 1982.
DOI : 10.1038/300615a0

E. D. Barr, The Northern High Time Resolution Universe pulsar survey - I. Setup and initial discoveries, Monthly Notices of the Royal Astronomical Society, vol.435, issue.3, p.2234, 2013.
DOI : 10.1093/mnras/stt1440

C. G. Bassa, LEAP: the Large European Array for Pulsars, Monthly Notices of the Royal Astronomical Society, vol.456, issue.2, p.2196, 2016.
DOI : 10.1093/mnras/stv2755

URL : https://hal.archives-ouvertes.fr/insu-01369844

N. D. Bhat, THE LOW-FREQUENCY CHARACTERISTICS OF PSR J0437???4715 OBSERVED WITH THE MURCHISON WIDE-FIELD ARRAY, The Astrophysical Journal, vol.791, issue.2, pp.32-101, 2012.
DOI : 10.1088/2041-8205/791/2/L32

V. Boriakoff, R. Buccheri, and F. Fauci, Discovery of a 6.1-ms binary pulsar PSR1953 + 29, Nature, vol.15, issue.5925, p.417, 1983.
DOI : 10.1038/304417a0

L. A. Boyle and A. Buonanno, Relating gravitational wave constraints from primordial nucleosynthesis, pulsar timing, laser interferometers, and the CMB: Implications for the early universe, Physical Review D, vol.78, issue.4, p.43531, 2008.
DOI : 10.1103/PhysRevD.78.043531

P. E. Boynton, E. J. Groth, D. P. Hutchinson, G. P. Nanos, R. B. Partridge et al., Optical Timing of the Crab Pulsar, NP 0532, The Astrophysical Journal, vol.175, p.217, 1972.
DOI : 10.1086/151550

F. Camilo, D. J. Nice, J. A. Shrauner, and J. H. Taylor, Princeton-Arecibo Declination-Strip Survey for Millisecond Pulsars. I., The Astrophysical Journal, vol.469, p.819, 1996.
DOI : 10.1086/177829

W. A. Coles, PULSAR OBSERVATIONS OF EXTREME SCATTERING EVENTS, The Astrophysical Journal, vol.808, issue.2, p.113, 2015.
DOI : 10.1088/0004-637X/808/2/113

J. M. Cordes, Arecibo Pulsar Survey Using ALFA. I. Survey Strategy and First Discoveries, The Astrophysical Journal, vol.637, issue.1, p.446, 2006.
DOI : 10.1086/498335

J. M. Cordes, R. M. Shannon, and D. R. Stinebring, FREQUENCY-DEPENDENT DISPERSION MEASURES AND IMPLICATIONS FOR PULSAR TIMING, The Astrophysical Journal, vol.817, issue.1, p.16, 2016.
DOI : 10.3847/0004-637X/817/1/16

T. Damour and A. Vilenkin, Gravitational Wave Bursts from Cosmic Strings, Physical Review Letters, vol.85, issue.18, p.3761, 2000.
DOI : 10.1103/PhysRevLett.85.3761

DOI : 10.1088/0004-637X/762/2/94

T. Dolch, A 24 HR GLOBAL CAMPAIGN TO ASSESS PRECISION TIMING OF THE MILLISECOND PULSAR J1713+0747, The Astrophysical Journal, vol.794, issue.1, p.21, 2014.
DOI : 10.1088/0004-637X/794/1/21

URL : https://hal.archives-ouvertes.fr/insu-01270525

J. Dowell, DETECTION AND FLUX DENSITY MEASUREMENTS OF THE MILLISECOND PULSAR J2145???0750 BELOW 100 MHz, The Astrophysical Journal, vol.775, issue.1, p.28, 2013.
DOI : 10.1088/2041-8205/775/1/L28

Y. Du, J. Yang, R. M. Campbell, G. Janssen, B. Stappers et al., VERY LONG BASELINE INTERFEROMETRY MEASURED PROPER MOTION AND PARALLAX OF THE ??-RAY MILLISECOND PULSAR PSR J0218+4232, The Astrophysical Journal, vol.782, issue.2, pp.38-801, 2001.
DOI : 10.1088/2041-8205/782/2/L38

M. Enoki and M. Nagashima, The Effect of Orbital Eccentricity on Gravitational Wave Background Radiation from Supermassive Black Hole Binaries, Progress of Theoretical Physics, vol.117, issue.2, p.241, 2007.
DOI : 10.1143/PTP.117.241

A. J. Faulkner, The Parkes Multibeam Pulsar Survey - V. Finding binary and millisecond pulsars, Monthly Notices of the Royal Astronomical Society, vol.355, issue.1, p.147, 2004.
DOI : 10.1111/j.1365-2966.2004.08310.x

M. Favata and R. D. Ferdman, NONLINEAR GRAVITATIONAL-WAVE MEMORY FROM BINARY BLACK HOLE MERGERS, The Astrophysical Journal, vol.696, issue.2, pp.159-711, 2009.
DOI : 10.1088/0004-637X/696/2/L159

W. M. Folkner, J. G. Williams, and D. H. Boggs, The Interplanetary Network (IPN) Progress Report, The Planetary and Lunar Ephemeris DE 421, p.42, 2009.

R. S. Foster and J. M. Cordes, Interstellar propagation effects and the precision of pulsar timing, The Astrophysical Journal, vol.364, p.123, 1990.
DOI : 10.1086/169393

DOI : 10.1088/0004-637X/743/2/102

L. P. Grishchuk, Relic gravitational waves and cosmology, Physics-Uspekhi, vol.48, issue.12, p.1235, 2005.
DOI : 10.1070/PU2005v048n12ABEH005795

T. E. Hassall, Wide-band simultaneous observations of pulsars: disentangling dispersion measure and profile variations, Astronomy & Astrophysics, vol.543, issue.674, pp.66-103, 1983.
DOI : 10.1051/0004-6361/201218970

URL : https://hal.archives-ouvertes.fr/insu-01253922

G. Hobbs, The International Pulsar Timing Array project: using pulsars as a gravitational wave detector, Classical and Quantum Gravity, vol.27, issue.8, p.84013, 2010.
DOI : 10.1088/0264-9381/27/8/084013

B. A. Jacoby, B. A. Jacoby, M. Bailes, M. H. Van-kerkwijk, S. Ord et al., PSR J1909-3744: A Binary Millisecond Pulsar with a Very Small Duty Cycle, The Astrophysical Journal, vol.599, issue.2, p.99, 2003.
DOI : 10.1086/381260

B. A. Jacoby, M. Bailes, S. M. Ord, H. S. Knight, and A. W. Hotan, Discovery of Five Recycled Pulsars in a High Galactic Latitude Survey, The Astrophysical Journal, vol.656, issue.1, p.408, 2007.
DOI : 10.1086/509312

G. H. Janssen, B. W. Stappers, C. G. Bassa, I. Cognard, M. Kramer et al., Long-term timing of four millisecond pulsars, Astronomy and Astrophysics, vol.514, p.74, 2010.
DOI : 10.1051/0004-6361/200911728

V. M. Kaspi, J. H. Taylor, and M. Ryba, High-precision timing of millisecond pulsars. 3: Long-term monitoring of PSRs B1855+09 and B1937+21, The Astrophysical Journal, vol.428, p.713, 1994.
DOI : 10.1086/174280

M. J. Keith, The High Time Resolution Universe Pulsar Survey - I. System configuration and initial discoveries, Monthly Notices of the Royal Astronomical Society, vol.409, issue.2, p.619, 2010.
DOI : 10.1111/j.1365-2966.2010.17325.x

M. J. Keith, Measurement and correction of variations in interstellar dispersion in high-precision pulsar timing, Monthly Notices of the Royal Astronomical Society, vol.429, issue.3, p.2161, 2013.
DOI : 10.1093/mnras/sts486

M. Kramer, K. M. Xilouris, D. R. Lorimer, O. Doroshenko, A. Jessner et al., The Characteristics of Millisecond Pulsar Emission. I. Spectra, Pulse Shapes, and the Beaming Fraction, The Astrophysical Journal, vol.501, issue.1, p.270, 1998.
DOI : 10.1086/305790

A. N. Lommen, A. Zepka, D. C. Backer, M. Mclaughlin, J. M. Cordes et al., New Pulsars from an Arecibo Drift Scan Search, The Astrophysical Journal, vol.545, issue.2, p.1007, 2000.
DOI : 10.1086/317841

A. N. Lommen, R. A. Kipphorn, D. J. Nice, E. M. Splaver, I. H. Stairs et al., The Parallax and Proper Motion of PSR J0030+0451, The Astrophysical Journal, vol.642, issue.2, p.1012, 2006.
DOI : 10.1086/501067

D. R. Lorimer, M. Kramer, and D. R. Lorimer, Four new millisecond pulsars in the galactic disk, The Astrophysical Journal, vol.439, p.933, 1995.
DOI : 10.1086/175230

D. R. Lorimer, The Parkes Multibeam Pulsar Survey - VI. Discovery and timing of 142 pulsars and a Galactic population analysis, Monthly Notices of the Royal Astronomical Society, vol.372, issue.2, p.777, 2006.
DOI : 10.1111/j.1365-2966.2006.10887.x

S. C. Lundgren, A. F. Zepka, and J. M. Cordes, A Millisecond Pulsar in a 6 Hour Orbit: PSR J0751+1807, The Astrophysical Journal, vol.453, p.419, 1995.
DOI : 10.1086/176402

A. G. Lyne, A. Brinklow, J. Middleditch, S. R. Kulkarni, D. C. Backer et al., The discovery of a millisecond pulsar in the globular cluster M28, Nature, vol.328, issue.6129, p.399, 1987.
DOI : 10.1038/328399a0

O. Löhmer, W. Lewandowski, A. Wolszczan, and R. Wielebinski, Shapiro Delay in the PSR J1640+2224 Binary System, The Astrophysical Journal, vol.621, issue.1, p.388, 2005.
DOI : 10.1086/427404

V. Maitia, J. Lestrade, and I. Cognard, A 3 Year Long Extreme Scattering Event in the Direction of the Millisecond Pulsar J1643???1224, The Astrophysical Journal, vol.582, issue.2, p.972, 2003.
DOI : 10.1086/344816

R. N. Iptamanchester, The International Pulsar Timing Array, Classical and Quantum Gravity, vol.30, issue.22, p.224010, 2013.
DOI : 10.1088/0264-9381/30/22/224010

R. Nan, THE FIVE-HUNDRED-METER APERTURE SPHERICAL RADIO TELESCOPE (FAST) PROJECT, International Journal of Modern Physics D, vol.20, issue.06, p.989, 2011.
DOI : 10.1142/S0218271811019335

D. J. Nice, E. M. Splaver, I. H. Stairs, O. Löhmer, A. Jessner et al., Pulsar Measured by Relativistic Orbital Decay, The Astrophysical Journal, vol.634, issue.2, p.1242, 2005.
DOI : 10.1086/497109

S. M. Ord, S. Johnston, and J. Sarkissian, The Magnetic Field of the Solar Corona from Pulsar Observations, Solar Physics, vol.209, issue.1, p.109, 2007.
DOI : 10.1007/s11207-007-9030-6

T. T. Pennucci, P. B. Demorest, and S. M. Ransom, ELEMENTARY WIDEBAND TIMING OF RADIO PULSARS, The Astrophysical Journal, vol.790, issue.2, p.93, 2014.
DOI : 10.1088/0004-637X/790/2/93

N. K. Porayko and K. A. Postnov, Constraints on ultralight scalar dark matter from pulsar timing, Physical Review D, vol.90, issue.6, p.62008, 2014.
DOI : 10.1103/PhysRevD.90.062008

M. Rajagopal and R. W. Romani, Ultra--Low-Frequency Gravitational Radiation from Massive Black Hole Binaries, The Astrophysical Journal, vol.446, p.543, 1995.
DOI : 10.1086/175813

P. S. Ray, S. E. Thorsett, F. A. Jenet, M. H. Van-kerkwijk, S. R. Kulkarni et al., A Survey for Millisecond Pulsars, The Astrophysical Journal, vol.470, p.1103, 1996.
DOI : 10.1086/177934

R. W. Romani, Timing Neutron Stars Timing a Millisecond Pulsar Array, p.113, 1989.

S. A. Sanidas, R. A. Battye, and B. W. Stappers, Constraints on cosmic string tension imposed by the limit on the stochastic gravitational wave background from the European Pulsar Timing Array, Physical Review D, vol.85, issue.12, p.122003, 2012.
DOI : 10.1103/PhysRevD.85.122003

P. Schwaller, Gravitational Waves from a Dark Phase Transition, Physical Review Letters, vol.115, issue.18, p.181101, 2015.
DOI : 10.1103/PhysRevLett.115.181101

D. J. Segelstein, L. A. Rawley, D. R. Stinebring, A. S. Fruchter, and J. H. Taylor, New millisecond pulsar in a binary system, Nature, vol.306, issue.6081, p.714, 1986.
DOI : 10.1038/322714a0

R. M. Shannon, Limitations in timing precision due to single-pulse shape variability in millisecond pulsars, Monthly Notices of the Royal Astronomical Society, vol.443, issue.2, p.1463, 2014.
DOI : 10.1093/mnras/stu1213

R. M. Shannon, Gravitational waves from binary supermassive black holes missing in pulsar observations, Science, vol.349, issue.6255, p.1522, 2015.
DOI : 10.1126/science.aab1910

X. Siemens, J. Ellis, F. Jenet, and J. D. Romano, The stochastic background: scaling laws and time to detection for pulsar timing arrays, Classical and Quantum Gravity, vol.30, issue.22, p.224015, 2013.
DOI : 10.1088/0264-9381/30/22/224015

C. Sotomayor-beltran, Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes, Astronomy & Astrophysics, vol.552, pp.58-581, 2004.
DOI : 10.1051/0004-6361/201220728

URL : https://hal.archives-ouvertes.fr/insu-01291256

E. M. Splaver, D. J. Nice, I. H. Stairs, A. N. Lommen, and D. C. Backer, Masses, Parallax, and Relativistic Timing of the PSR J1713+0747 Binary System, The Astrophysical Journal, vol.620, issue.1, p.405, 2005.
DOI : 10.1086/426804

I. H. Stairs, Discovery of Three Wide???Orbit Binary Pulsars: Implications for Binary Evolution and Equivalence Principles, The Astrophysical Journal, vol.632, issue.2, p.1060, 2005.
DOI : 10.1086/432526

B. W. Stappers, J. W. Hessels, A. Alexov, K. Anderson, and T. Coenen, Observing pulsars and fast transients with LOFAR, Astronomy & Astrophysics, vol.530, p.80, 2011.
DOI : 10.1051/0004-6361/201116681

URL : https://hal.archives-ouvertes.fr/insu-01310941

D. Stinebring, Effects of the interstellar medium on detection of low-frequency gravitational waves, Classical and Quantum Gravity, vol.30, issue.22, p.224006, 2013.
DOI : 10.1088/0264-9381/30/22/224006

J. H. Taylor, Pulsar Timing and Relativistic Gravity, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, vol.341, issue.1660, p.117, 1992.
DOI : 10.1098/rsta.1992.0088

S. R. Taylor, Limits on Anisotropy in the Nanohertz Stochastic Gravitational Wave Background, Physical Review Letters, vol.115, issue.4, p.41101, 2015.
DOI : 10.1103/PhysRevLett.115.041101

URL : https://hal.archives-ouvertes.fr/insu-01265421

M. Toscano, M. Bailes, R. Manchester, and J. Sandhu, Spectra of Southern Pulsars, The Astrophysical Journal, vol.506, issue.2, p.863, 1998.
DOI : 10.1086/306282

W. Van-straten, Radio Astronomical Polarimetry and High???Precision Pulsar Timing, The Astrophysical Journal, vol.642, issue.2, p.1004, 2006.
DOI : 10.1086/501001

W. Van-straten, HIGH-FIDELITY RADIO ASTRONOMICAL POLARIMETRY USING A MILLISECOND PULSAR AS A POLARIZED REFERENCE SOURCE, The Astrophysical Journal Supplement Series, vol.204, issue.1, p.13, 2013.
DOI : 10.1088/0067-0049/204/1/13

J. P. Verbiest, Precision Timing of PSR J0437???4715: An Accurate Pulsar Distance, a High Pulsar Mass, and a Limit on the Variation of Newton???s Gravitational Constant, The Astrophysical Journal, vol.679, issue.1, p.675, 2008.
DOI : 10.1086/529576

J. P. Verbiest, M. Bailes, N. D. Bhat, S. Burke-spolaor, and D. J. Champion, Status update of the Parkes pulsar timing array, Classical and Quantum Gravity, vol.27, issue.8, p.84015, 2010.
DOI : 10.1088/0264-9381/27/8/084015

J. P. Verbiest, J. M. Weisberg, A. A. Chael, K. J. Lee, and D. R. Lorimer, ON PULSAR DISTANCE MEASUREMENTS AND THEIR UNCERTAINTIES, The Astrophysical Journal, vol.755, issue.1, p.39, 2012.
DOI : 10.1088/0004-637X/755/1/39

M. A. Walker, P. B. Demorest, and W. Van-straten, CYCLIC SPECTROSCOPY OF THE MILLISECOND PULSAR, B1937+21, The Astrophysical Journal, vol.779, issue.2, p.99, 2013.
DOI : 10.1088/0004-637X/779/2/99

J. B. Wang, Searching for gravitational wave memory bursts with the Parkes Pulsar Timing Array, Monthly Notices of the Royal Astronomical Society, vol.446, issue.2, p.1657, 2015.
DOI : 10.1093/mnras/stu2137

A. Wolszczan, Timing Observations of Four Millisecond Pulsars with the Arecibo and Effelsberg Radio Telescopes, The Astrophysical Journal, vol.528, issue.2, p.907, 2000.
DOI : 10.1086/308206

X. You, Dispersion measure variations and their effect on precision pulsar timing, Monthly Notices of the Royal Astronomical Society, vol.378, issue.2, p.493, 2007.
DOI : 10.1111/j.1365-2966.2007.11617.x

X. P. You, G. B. Hobbs, W. A. Coles, R. N. Manchester, and J. L. Han, An Improved Solar Wind Electron Density Model for Pulsar Timing, The Astrophysical Journal, vol.671, issue.1, p.907, 2007.
DOI : 10.1086/522227

Y. Yue, D. Li, and R. Nan, Neutron Stars and Pulsars: Challenges and Opportunities after 80 years, Proc. IAU Symp. 291, p.577, 2013.

W. Zhao, Y. Zhang, X. You, and Z. Zhu, Constraints of relic gravitational waves by pulsar timing arrays: Forecasts for the FAST and SKA projects, Physical Review D, vol.87, issue.12, p.124012, 2013.
DOI : 10.1103/PhysRevD.87.124012

X. Zhu, An all-sky search for continuous gravitational waves in the Parkes Pulsar Timing Array data set, Monthly Notices of the Royal Astronomical Society, vol.444, issue.4, p.3709, 2014.
DOI : 10.1093/mnras/stu1717

W. W. Zhu, TESTING THEORIES OF GRAVITATION USING 21-YEAR TIMING OF PULSAR BINARY J1713+0747, The Astrophysical Journal, vol.809, issue.1, p.41, 2015.
DOI : 10.1088/0004-637X/809/1/41

C. Insu and F. , 19 Laboratoire de Physique et Chimie de l'Environnement et de l'Espace LPC2E CNRS-Université d'Orléans, F-45071 Orléans, France 20 Station de radioastronomie de Nançay, 25 School of Mathematics, King's Buildings, pp.899-911, 18330.

. Ae and . Vancouver, Australia 31 Kavli institute for astronomy and astrophysics, Science Park 904, NL-1098 XH Amsterdam 33 National Radio Astronomy Observatory, 520 Edgemont Rd 22903, USA 34 TAPIR, California Institute of Technology Batiment Condorcet , 10 rue Alice Domont et Léonie Duquet, F-75205 Paris Cedex 13, France 39 Centre for Astrophysics and Supercomputing 42 Physics and Astronomy Department, pp.350-367, 41051.