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Journal articles on the topic 'Pulsar timing'

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Author: Grafiati

Published: 4 June 2021

Last updated: 13 February 2022

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1

MANCHESTER, R. N. "PULSAR SEARCHING AND TIMING." International Journal of Modern Physics D 22, no. 01 (January 2013): 1341007. http://dx.doi.org/10.1142/s0218271813410071.

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More than 2000 pulsars are now known. These pulsars may be divided into a number of different classes according to their period, period derivative, binary properties, emission characteristics and so on. Some important classes have relatively few members, e.g. double-neutron-star binary systems, and so continued searches for currently unknown pulsars are important. Such searches are being undertaken at various observatories around the world. Somewhat unexpectedly, the Fermi Gamma-ray Observatory, has proved to be an efficient pulsar detector, especially for millisecond pulsars (MSPs). The great stability of pulsar periods, especially for MSPs, leads to a number of important applications of pulsar timing. The detection and study of relativistic orbit perturbations in double-neutron-star systems has proved to be a powerful tool with measurements of the original binary pulsar, PSR B1913+16, and more recently the double pulsar, PSR J0737-3039A/B, showing that Einstein's general theory of relativity accurately describes these gravitational interactions. Direct detection of gravitational waves using pulsar timing is close to being achieved with the development of pulsar timing arrays (PTAs) in Europe, North America and Australia. Combining data from these PTAs to form the International Pulsar Timing Array (IPTA) will lead to improved significance of such a detection. Ultimately, detailed study of gravitational-wave sources will be possible using future large radio telescopes such as FAST and the SKA.

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2

Rodin, Alexander E. "Pulsar timing array." Proceedings of the International Astronomical Union 5, H15 (November 2009): 229–30. http://dx.doi.org/10.1017/s1743921310008951.

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AbstractSimultaneous timing of several pulsars distributed over the sky, so called Pulsar Timing Array (PTA), is used for a variety of metrological and astronomical applications. Three examples of PTA application are presented: link between celestial reference frames, ensemble pulsar time scale and detection of gravitational waves.

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3

McLaughlin, Maura. "Pulsar Timing Arrays." Proceedings of the International Astronomical Union 11, A29B (August 2015): 321–28. http://dx.doi.org/10.1017/s1743921316005457.

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AbstractI describe the concept of a pulsar timing array and give broad overview of the construction of a pulsar timing array, methods for high-precision timing and noise characterization, and algorithms for gravitational wave detection and source characterization. I then provide an overview of worldwide pulsar timing programs and the scale and sensitivity of the pulsar timing array efforts, with particular attention to the International Pulsar Timing Array (IPTA). I discuss the most recent results from pulsar timing arrays, emphasizing the gravitational wave detection efforts in particular. Finally, I describe the anticipated future growth in participants, telescopes, pulsars, and sensitivity of the IPTA, highlighting the transformational advances that it will enable over the next decade.

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4

Reardon, D. J., R. M. Shannon, A. D. Cameron, B. Goncharov, G. B. Hobbs, H. Middleton, M. Shamohammadi, et al. "The Parkes pulsar timing array second data release: timing analysis." Monthly Notices of the Royal Astronomical Society 507, no. 2 (August 11, 2021): 2137–53. http://dx.doi.org/10.1093/mnras/stab1990.

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ABSTRACT The main goal of pulsar timing array experiments is to detect correlated signals such as nanohertz-frequency gravitational waves. Pulsar timing data collected in dense monitoring campaigns can also be used to study the stars themselves, their binary companions, and the intervening ionized interstellar medium. Timing observations are extraordinarily sensitive to changes in path-length between the pulsar and the Earth, enabling precise measurements of the pulsar positions, distances and velocities, and the shapes of their orbits. Here we present a timing analysis of 25 pulsars observed as part of the Parkes Pulsar Timing Array (PPTA) project over time spans of up to 24 yr. The data are from the second data release of the PPTA, which we have extended by including legacy data. We make the first detection of Shapiro delay in four Southern pulsars (PSRs J1017−7156, J1125−6014, J1545−4550, and J1732−5049), and of parallax in six pulsars. The prominent Shapiro delay of PSR J1125−6014 implies a neutron star mass of Mp = 1.5 ± 0.2 M⊙ (68 per cent credibility interval). Measurements of both Shapiro delay and relativistic periastron advance in PSR J1600−3053 yield a large but uncertain pulsar mass of $M_p = 2.06^{+0.44}_{-0.41}$ M⊙ (68 per cent credibility interval). We measure the distance to PSR J1909−3744 to a precision of 10 lyr, indicating that for gravitational wave periods over a decade, the pulsar provides a coherent baseline for pulsar timing array experiments.

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Yang, Tinggao, and Guangren Ni. "Ensemble Pulsar Time Study by Pulsar Timing Observations." Symposium - International Astronomical Union 218 (2004): 439–40. http://dx.doi.org/10.1017/s0074180900181604.

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Long term timing of multiple millisecond pulsars can contribute to the study of an ensemble pulsar time scale PTens. A wavelet decomposition algorithm (WDA) was applied to define a PTens using the available millisecond pulsar timing datA. The PTens obtained from WDA is more stable than those resulting from other algorithms. The Chinese 50 m radio telescope is specially designed for PTens study and detection of gravitational wave background via millisecond pulsars timing observations. A scheme for multiple millisecond pulsar timing and ensemble pulsar time study is discussed in some detail.

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6

Lower, M. E., M. Bailes, R. M. Shannon, S. Johnston, C. Flynn, S. Osłowski, V. Gupta, et al. "The UTMOST pulsar timing programme – II. Timing noise across the pulsar population." Monthly Notices of the Royal Astronomical Society 494, no. 1 (March 4, 2020): 228–45. http://dx.doi.org/10.1093/mnras/staa615.

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ABSTRACT While pulsars possess exceptional rotational stability, large-scale timing studies have revealed at least two distinct types of irregularities in their rotation: red timing noise and glitches. Using modern Bayesian techniques, we investigated the timing noise properties of 300 bright southern-sky radio pulsars that have been observed over 1.0–4.8 yr by the upgraded Molonglo Observatory Synthesis Telescope (MOST). We reanalysed the spin and spin-down changes associated with nine previously reported pulsar glitches, report the discovery of three new glitches and four unusual glitch-like events in the rotational evolution of PSR J1825−0935. We develop a refined Bayesian framework for determining how red noise strength scales with pulsar spin frequency (ν) and spin-down frequency ($\dot{\nu }$), which we apply to a sample of 280 non-recycled pulsars. With this new method and a simple power-law scaling relation, we show that red noise strength scales across the non-recycled pulsar population as $\nu ^{a} |\dot{\nu }|^{b}$, where $a = -0.84^{+0.47}_{-0.49}$ and $b = 0.97^{+0.16}_{-0.19}$. This method can be easily adapted to utilize more complex, astrophysically motivated red noise models. Lastly, we highlight our timing of the double neutron star PSR J0737−3039, and the rediscovery of a bright radio pulsar originally found during the first Molonglo pulsar surveys with an incorrectly catalogued position.

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7

Perera, B. B. P., M. E. DeCesar, P. B. Demorest, M. Kerr, L. Lentati, D. J. Nice, S. Osłowski, et al. "The International Pulsar Timing Array: second data release." Monthly Notices of the Royal Astronomical Society 490, no. 4 (October 12, 2019): 4666–87. http://dx.doi.org/10.1093/mnras/stz2857.

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ABSTRACT In this paper, we describe the International Pulsar Timing Array second data release, which includes recent pulsar timing data obtained by three regional consortia: the European Pulsar Timing Array, the North American Nanohertz Observatory for Gravitational Waves, and the Parkes Pulsar Timing Array. We analyse and where possible combine high-precision timing data for 65 millisecond pulsars which are regularly observed by these groups. A basic noise analysis, including the processes which are both correlated and uncorrelated in time, provides noise models and timing ephemerides for the pulsars. We find that the timing precisions of pulsars are generally improved compared to the previous data release, mainly due to the addition of new data in the combination. The main purpose of this work is to create the most up-to-date IPTA data release. These data are publicly available for searches for low-frequency gravitational waves and other pulsar science.

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8

Liu, Kuo. "Update on the European Pulsar Timing Array." Proceedings of the International Astronomical Union 8, S291 (August 2012): 180. http://dx.doi.org/10.1017/s1743921312023575.

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AbstractThe European Pulsar Timing Array (EPTA) is one the of three global Pulsar Timing Array communities, aiming to use the clock nature of pulsars to detect gravitational wave. In this talk, I will provide an introduction to the current status of EPTA pulsar observations and present an overview of the recent results. I will also give an update on the progress of the Large European Array for Pulsar (LEAP) project, which attempts to coherently combine the data from the five biggest single site radio telescopes in Europe and make an equivalently 200-metre diameter dish. The LEAP project is an ideal effort in performing high precision pulsar timing and studying characteristics of single pulses from millisecond pulsars.

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9

Hobbs, G. "Pulsar timing array projects." Proceedings of the International Astronomical Union 5, S261 (April 2009): 228–33. http://dx.doi.org/10.1017/s1743921309990445.

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AbstractPulsars are amongst the most stable rotators known in the Universe. Over many years some millisecond pulsars rival the stability of atomic clocks. Comparing observations of many such stable pulsars may allow the first direct detection of gravitational waves, improve the Solar System planetary ephemeris and provide a means to study irregularities in terrestrial time scales. Here we review the goals and status of current and future pulsar timing array projects.

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10

Manchester, R. N., A. G. Lyne, F. Camilo, V. M. Kaspi, I. H. Stairs, F. Crawford, D. J. Morris, J. F. Bell, and N. D’Amico. "Timing the Parkes Multibeam Pulsars." International Astronomical Union Colloquium 177 (2000): 49–54. http://dx.doi.org/10.1017/s0252921100058991.

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AbstractMeasurement of accurate positions, pulse periods and period derivatives is an essential follow-up to any pulsar survey. The procedures being used to obtain timing parameters for the pulsars discovered in the Parkes multibeam pulsar survey are described. Completed solutions have been obtained so far for about 80 pulsars. They show that the survey is preferentially finding pulsars with higher than average surface dipole magnetic fields. Eight pulsars have been shown to be members of binary systems and some of the more interesting results relating to these are presented.

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Manchester, R. N. "The Parkes Pulsar Timing Array Project." Proceedings of the International Astronomical Union 5, H15 (November 2009): 233. http://dx.doi.org/10.1017/s1743921310008987.

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AbstractThe Parkes Pulsar Timing Array project is timing 20 millisecond pulsars with the aims of detecting gravitational waves, establishing a time scale based on pulsar periods and improving solar-system ephemerides.

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12

JOSHI, BHAL CHANDRA. "PULSAR TIMING ARRAYS." International Journal of Modern Physics D 22, no. 01 (January 2013): 1341008. http://dx.doi.org/10.1142/s0218271813410083.

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In the last decade, the use of an ensemble of radio pulsars to constrain the characteristic strain caused by a stochastic gravitational wave background has advanced the cause of detection of very low frequency gravitational waves (GWs) significantly. This electromagnetic means of GW detection, called Pulsar Timing Array (PTA), is reviewed in this paper. The principle of operation of PTA, the current operating PTAs and their status are presented along with a discussion of the main challenges in the detection of GWs using PTA.

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13

Wang, Na, R. N. Manchester, Aili Yusup, Xinji Wu, Jin Zhang, and Maozheng Chen. "Scintillation Observations of Strong Northern Pulsars." International Astronomical Union Colloquium 182 (2001): 57–60. http://dx.doi.org/10.1017/s0252921100000695.

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AbstractScintillation of pulsar radio emission provides information about the interstellar medium along the path to the pulsar and the velocities of pulsars. It also affects the precision of pulse timing observations. Using a pulsar timing system developed at the Urumqi Astronomical Observatory 25 m telescope, we observed diffractive scintillation dynamic spectra for several strong northern pulsars. This paper introduces the observing system and discusses the observational results.

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14

Kaspi, V. M. "High-Precision Timing of Millisecond Pulsars and Precision Astrometry." Symposium - International Astronomical Union 166 (1995): 163–71. http://dx.doi.org/10.1017/s0074180900228027.

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We present the technique of long-term, high-precision timing of millisecond pulsars as applied to precision astrometry. We provide a tutorial on pulsars and pulsar timing, as well as up-to-date results of long-term timing observations of two millisecond pulsars, PSRs B1855+09 and B1937+21. We consider the feasibility of tying the extragalactic and optical reference frames to that defined by solar system objects, and we conclude that precision astrometry from millisecond pulsar timing has a bright future.

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15

Kramer, M., O. Doroshenko, A. Jessner, R. Wielebinski, A. Wolszczan, F. Camilo, J. H. Taylor, and K. M. Xilouris. "Millisecond Pulsar Timing in Effelsberg." International Astronomical Union Colloquium 160 (1996): 95–96. http://dx.doi.org/10.1017/s0252921100041117.

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Millisecond pulsar as clocks are excellent tools for studying a variety of phenomena in physics and astrophysics (e.g. Foster & Backer 1990). We have been observing millisecond pulsars with the 100–m Effelsberg radiotelescope since April 1994. Initially, the goal of this program was to help continuing the timing of Arecibo pulsars during the upgrade–related shutdown period of the 305–m radiotelescope. Gradually, the program has evolved to time and study the emission physics of all short period pulsars detectable from Effelsberg. In particular, polarization measurements are used to make inferences about the emission physics of millisecond pulsars (cf. Xilouris & Kramer, this proceeding). At present, the programme involves approximately monthly observations of a set of 22 sources.

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16

Zhu, Weiwei. "19 Years of high precision timing of the millisecond pulsar J1713+0747." Proceedings of the International Astronomical Union 8, S291 (August 2012): 179. http://dx.doi.org/10.1017/s1743921312023563.

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AbstractWe report the analysis of a 19-year span of timing data on PSR J1713+0747 taken by the Arecibo and Green Bank telescopes. PSR J1713+0747 is one of the best high-timing-precision pulsars monitored by the NANOGrav project for the purpose of detecting gravitational waves. The timing precision of this pulsar can be regarded as the benchmark of NANOGrav timing instruments. We show the precision improvement achieved by multi-generation instruments including the Green Bank Ultimate Pulsar Processing Instrument (GUPPI) and its counterpart in Arecibo. The new timing solution we found improves the measurement of the pulsars mass, its orbital and geometric parameters, sets new limits on alternative gravitational theories, and may provide a high-quality single pulsar gravitational wave upper limit.

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17

Doroshenko, O. V., Yu P. Ilyasov, and V. V. Oreshko. "Pulsar timing at Kalyazin (Russia)." International Astronomical Union Colloquium 177 (2000): 57–60. http://dx.doi.org/10.1017/s0252921100059017.

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AbstractRegular timing observations of millisecond and binary pulsars are made with the 64-m radio telescope at Kalyazin (Russia). Filterbank 160-channel receiver is used for observations at 0.6 GHz in two circular orthogonal polarization. Precise local time service (based upon a rubidium standards and hydrogen maser) is used for measurements of Times-of-Arrival (TOA) from radio pulsars. A local time scale is compared by GPS and TV-systems with the basic AT-scales (UTC(USNO) and UTC(SU)) within an accuracy about 50nsper day. Recently the second 1.4 GHz receiver (250 kHz × 64 channels) was constructed and installed at Kalyazin radio telescope. There is a possibility to combine a part of the 1.4 GHz back-end with the 2.2 GHz front-end to produce timing observations at three frequencies simultaneously. We present a results of precise timing observations conducted by the Kalyazin pulsar system. Most of data were obtained at 0.6 GHz in 1997–1999. The data will be used for valuable applications in fundamental metrology, interstellar medium, general relativity and pulsar physics itself.

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18

Chen, Siyuan, François Vernotte, and Enrico Rubiola. "Applying clock comparison methods to pulsar timing observations." Monthly Notices of the Royal Astronomical Society 503, no. 3 (March 15, 2021): 4496–507. http://dx.doi.org/10.1093/mnras/stab742.

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ABSTRACT Frequency metrology outperforms any other branch of metrology in accuracy (parts in 10−16) and small fluctuations (<10−17). In turn, among celestial bodies, the rotation speed of millisecond pulsars is by far the most stable (<10−18). Therefore, the precise measurement of the time of arrival (TOA) of pulsar signals is expected to disclose information about cosmological phenomena, and to enlarge our astrophysical knowledge. Related to this topic, Pulsar Timing Array projects have been developed and operated for the last decades. The TOAs from a pulsar can be affected by local emission and environmental effects, in the direction of the propagation through the interstellar medium or universally by gravitational waves from super massive black hole binaries. These effects (signals) can manifest as a low-frequency fluctuation over time, phenomenologically similar to a red noise, while the remaining pulsar intrinsic and instrumental background (noise) are white. This article focuses on the frequency metrology of pulsars. From our standpoint, the pulsar is an accurate clock, to be measured simultaneously with several telescopes in order to reject the uncorrelated white noise. We apply the modern statistical methods of time-and-frequency metrology to simulated pulsar data, and we show the detection limit of the correlated red noise signal between telescopes.

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19

Hobbs, George, and Shi Dai. "Gravitational wave research using pulsar timing arrays." National Science Review 4, no. 5 (September 1, 2017): 707–17. http://dx.doi.org/10.1093/nsr/nwx126.

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Abstract A pulsar timing array (PTA) refers to a program of regular, high-precision timing observations of a widely distributed array of millisecond pulsars. Here we review the status of the three primary PTA projects and the joint International Pulsar Timing Array project. We discuss current results related to ultra-low-frequency gravitational wave searches and highlight opportunities for the near future.

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20

Lewandowski, W., M. Konacki, M. Redmerska, G. Feiler, and A. Wolszczan. "Pulsar timing measurements with the 32-m TCfA radiotelescope." International Astronomical Union Colloquium 177 (2000): 63–64. http://dx.doi.org/10.1017/s0252921100059030.

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Accurate, long-term timing measurements of pulsars provide a powerful method to study a variety of astrophysical phenomena. For “normal”, slow pulsars, the dominant factors that limit the timing precision are the intrinsic timing noise and single pulse “jitter” (e.g. Cordes 1993). In fact, because the pulse jitter surpasses radiometer noise for sufficiently strong pulsars and no further improvement of the timing precision can be achieved by increasing the antenna gain, the timing of such sources can be very efficiently conducted with suitably equipped medium-size radiotelescopes.We have been timing slow pulsars with the 32-m TCfA radiotelescope in Toruń, Poland, since July 1996, using a dual-channel, circular polarization L-band receiving system at frequencies around 1.7 GHz, and a 2 × 64 × 3 MHz channel pulsar backend, the Penn State Pulsar Machine - 2 (PSPM-2; for more details, see Konacki et al. 1999). Our gradually expanding source list currently includes 88 pulsars timed once a week with a millisecond precision using the observatory’s UTC-calibrated H-maser clock. Data analysis is routinely performed with the TEMPO software package. With a particularly dense, weekly sampling and a ≤1 ms timing precision, the TCfA program has a sensitivity to detect previously overlooked short period, low orbital inclination binaries, as well as very low-mass, planetary companions. In addition, it will be very useful in identifying and monitoring pulsar timing glitches and other forms of the timing noise.

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21

Ilyasov, Yu P., V. V. Oreshko, V. A. Potapov, and A. E. Rodin. "Timing of Binary Pulsars at Kalyazin, Russia." Symposium - International Astronomical Union 218 (2004): 433–34. http://dx.doi.org/10.1017/s0074180900181574.

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Regular high-precision timing of the binary pulsars J0613−0200, J1012+5307, J1022+1001, J1640+2224, J1643−1224, J1713+0747, J2145−0750 and the pulsar B1937+21 has been conducted at the Kalyazin (Russia) radio telescope RT-64 at 0.6 GHz over more than 6 years. Several of the pulsars monitored have been found to be good probes for gravitational wave background (GWB) tests, while others, having a shorter orbital period, can be used for establishing a dynamical binary pulsar timescale. Upper limits for the GWB energy density were estimated.

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22

Lorimer, Duncan R., and Maura A. McLaughlin. "Probing fundamental physics with pulsars." Proceedings of the International Astronomical Union 5, H15 (November 2009): 131–36. http://dx.doi.org/10.1017/s1743921310008513.

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AbstractPulsars provide a wealth of information about General Relativity, the equation of state of superdense matter, relativistic particle acceleration in high magnetic fields, the Galaxy's interstellar medium and magnetic field, stellar and binary evolution, celestial mechanics, planetary physics and even cosmology. The wide variety of physical applications currently being investigated through studies of radio pulsars rely on: (i) finding interesting objects to study via large-scale and targeted surveys; (ii) high-precision timing measurements which exploit their remarkable clock-like stability. We review current surveys and the principles of pulsar timing and highlight progress made in the rotating radio transients, intermittent pulsars, tests of relativity, understanding pulsar evolution, measuring neutron star masses and the pulsar timing array

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23

Parthasarathy, A., R. M. Shannon, S. Johnston, L. Lentati, M. Bailes, S. Dai, M. Kerr, et al. "Timing of young radio pulsars – I. Timing noise, periodic modulation, and proper motion." Monthly Notices of the Royal Astronomical Society 489, no. 3 (August 30, 2019): 3810–26. http://dx.doi.org/10.1093/mnras/stz2383.

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ABSTRACT The smooth spin-down of young pulsars is perturbed by two non-deterministic phenomenon, glitches, and timing noise. Although the timing noise provides insights into nuclear and plasma physics at extreme densities, it acts as a barrier to high-precision pulsar timing experiments. An improved methodology based on the Bayesian inference is developed to simultaneously model the stochastic and deterministic parameters for a sample of 85 high-$\dot{E}$ radio pulsars observed for ∼10 yr with the 64-m Parkes radio telescope. Timing noise is known to be a red process and we develop a parametrization based on the red-noise amplitude (Ared) and spectral index (β). We measure the median Ared to be $-10.4^{+1.8}_{-1.7}$ yr3/2 and β to be $-5.2^{+3.0}_{-3.8}$ and show that the strength of timing noise scales proportionally to $\nu ^{1}|\dot{\nu }|^{-0.6\pm 0.1}$, where ν is the spin frequency of the pulsar and $\dot{\nu }$ is its spin-down rate. Finally, we measure significant braking indices for 19 pulsars and proper motions for 2 pulsars, and discuss the presence of periodic modulation in the arrival times of 5 pulsars.

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24

Stappers, B. W. "The Future of Pulsar Timing Arrays." Proceedings of the International Astronomical Union 11, A29B (August 2015): 344–50. http://dx.doi.org/10.1017/s1743921316005494.

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AbstractSignificant advances have been made in the sensitivity of pulsar timing arrays for the detection of gravitational waves in the last decade. This presentation looked forward to consider where the development of pulsar timing arrays might go as we head towards the Square Kilometre Array (SKA) and then beyond. I reviewed where progress needs to be made in terms of sensitivity to gravitational waves, including improvements to existing observing approaches and new telescopes such as MeerKAT and FAST and techniques like LEAP. The dramatic increase in the number of millisecond pulsars is presented and how that might affect progress towards a first detection is discussed. Developments in analytic techniques were also discussed, including the removal of interstellar medium effects, red noise and pulse profile variations. A summary of how the SKA can contribute through an increased millisecond pulsar population and pulsar timing sensitivity was presented. With the likelihood that the SKA will implement some form of Key Science Project approach, some ideas of how will this affect how the International Pulsar Timing Array effort and how it might evolve into a KSP were discussed.

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Gancio, G., C. O. Lousto, L. Combi, S. del Palacio, F. G. López Armengol, J. A. Combi, F. García, et al. "Upgraded antennas for pulsar observations in the Argentine Institute of Radio astronomy." Astronomy & Astrophysics 633 (January 2020): A84. http://dx.doi.org/10.1051/0004-6361/201936525.

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Context. The Argentine Institute of Radio astronomy (IAR) is equipped with two single-dish 30 m radio antennas capable of performing daily observations of pulsars and radio transients in the southern hemisphere at 1.4 GHz. Aims. We aim to introduce to the international community the upgrades performed and to show that the IAR observatory has become suitable for investigations in numerous areas of pulsar radio astronomy, such as pulsar timing arrays, targeted searches of continuous gravitational waves sources, monitoring of magnetars and glitching pulsars, and studies of a short time scale interstellar scintillation. Methods. We refurbished the two antennas at IAR to achieve high-quality timing observations. We gathered more than 1000 h of observations with both antennas in order to study the timing precision and sensitivity they can achieve. Results. We introduce the new developments for both radio telescopes at IAR. We present daily observations of the millisecond pulsar J0437−4715 with timing precision better than 1 μs. We also present a follow-up of the reactivation of the magnetar XTE J1810–197 and the measurement and monitoring of the latest (Feb. 1, 2019) glitch of the Vela pulsar (J0835–4510). Conclusions. We show that IAR is capable of performing pulsar monitoring in the 1.4 GHz radio band for long periods of time with a daily cadence. This opens up the possibility of pursuing several goals in pulsar science, including coordinated multi-wavelength observations with other observatories. In particular, daily observations of the millisecond pulsar J0437−4715 would increase the sensitivity of pulsar timing arrays. We also show IAR’s great potential for studying targets of opportunity and transient phenomena, such as magnetars, glitches, and fast-radio-burst sources.

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Liu, X. J., M. J. Keith, C. G. Bassa, and B. W. Stappers. "Correlated timing noise and high-precision pulsar timing: measuring frequency second derivatives as an example." Monthly Notices of the Royal Astronomical Society 488, no. 2 (July 2, 2019): 2190–201. http://dx.doi.org/10.1093/mnras/stz1801.

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Abstract We investigate the impact of noise processes on high-precision pulsar timing. Our analysis focuses on the measurability of the second spin frequency derivative $\ddot{\nu }$. This $\ddot{\nu }$ can be induced by several factors including the radial velocity of a pulsar. We use Bayesian methods to model the pulsar times-of-arrival in the presence of red timing noise and dispersion measure variations, modelling the noise processes as power laws. Using simulated times-of-arrival that both include red noise, dispersion measure variations, and non-zero $\ddot{\nu }$ values, we find that we are able to recover the injected $\ddot{\nu }$, even when the noise model used to inject and recover the input parameters are different. Using simulations, we show that the measurement uncertainty on $\ddot{\nu }$ decreases with the timing baseline T as Tγ, where γ = −7/2 + α/2 for power-law noise models with shallow power-law indices α (0 < α < 4). For steep power-law indices (α > 8), the measurement uncertainty reduces with T−1/2. We applied this method to times-of-arrival from the European Pulsar Timing Array and the Parkes Pulsar Timing Array and determined $\ddot{\nu }$ probability density functions for 49 millisecond pulsars. We find a statistically significant $\ddot{\nu }$ value for PSR B1937+21 and consider possible options for its origin. Significant (95 per cent C.L.) values for $\ddot{\nu }$ are also measured for PSRs J0621+1002 and J1022+1001, thus future studies should consider including it in their ephemerides. For binary pulsars with small orbital eccentricities, such as PSR J1909−3744, extended ELL1 models should be used to overcome computational issues. The impacts of our results on the detection of gravitational waves are also discussed.

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Flanagan, C. S. "A Large Timing Discontinuity in the Vela Pulsar, July 1985." Symposium - International Astronomical Union 125 (1987): 64. http://dx.doi.org/10.1017/s0074180900160504.

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A pulsar-monitoring programme has been running at Hartebeesthoek Radio Astronomy Observatory over the last three years, at 2.32 and (during the last year) at 1.67 GHz. Twenty pulsars are observed once or twice a fortnight, and PSRs 1641-45 and 0833-45 (the Vela pulsar) daily.

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Kocz, J., W. Majid, L. White, L. Snedeker, and M. Franco. "Pulsar Timing at the Deep Space Network." Journal of Astronomical Instrumentation 05, no. 04 (December 2016): 1641013. http://dx.doi.org/10.1142/s2251171716410130.

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The 70-m DSN’s Deep Space Station antenna 14 (DSS-14) at Goldstone has recently been outfitted with instrumentation to enable pulsar searching and timing operation. Systems capable of similar operations are undergoing installation at DSS-63, and are planned for DSS-43. The Goldstone system is the first of these to become operational with a 640[Formula: see text]MHz bandwidth stretching from 1325–1965[Formula: see text]MHz. Initial results from the pulsar timing pipeline show short-term residuals of [Formula: see text][Formula: see text]ns for pulsar B1937+21. Commissioning observations at DSS-14 to obtain a baseline set of time of arrival (TOA) measurements on several millisecond pulsars (MSPs) are currently underway.

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Wang, Na, XinJi Wu, Jin Zhang, R. N. Manchester, Aili Yusup, and K. S. Cheng. "Pulsar Timing at Urumqi Astronomical Observatory." International Astronomical Union Colloquium 177 (2000): 65–66. http://dx.doi.org/10.1017/s0252921100059042.

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AbstractA pulsar timing system has been set up using the 25-m Nanshan telescope of the Urumqi Astronomical Observatory. It uses a dual polarization receiver operating at 18 cm and a filterbank receiver. The data acquisition system is based on a PC using the Windows NT operating system. Timing properties of about 100 pulsars will be monitored with this system.

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Shannon, Ryan. "Constraining the nanohertz gravitational wave background with the Parkes Pulsar Timing Array." Proceedings of the International Astronomical Union 8, S291 (August 2012): 177. http://dx.doi.org/10.1017/s174392131202354x.

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AbstractThe direct detection of gravitational waves will usher in a new era of astrophysics, enabling the study of regions of the universe opaque to electromagnetic radiation or electromagnetically quiet. An ensemble of pulsars (referred to as a pulsar timing array) provides a set of clocks distributed across the Galaxy sensitive to gravitational waves with periods on the order of five years (frequencies of many nanohertz). Plausible source of gravitational waves in this frequency band include massive black hole binaries in the throes of mergers and oscillating cosmic strings. The stochastic gravitational wave background, the sum of gravitational waves emitted throughout the universe, is the most likely signal to be detected by a pulsar timing array.While the detection of gravitational waves will be a milestone in pulsar astronomy, a constraining limit on the strength of the gravitational wave background can be used to constrain cosmological models and early Universe physics. Here we present a new algorithm that can be used to constrain the strength of the GWB with a pulsar timing array. We then apply this technique to Parkes Pulsar Timing Array observations and place a new limit on the strength of the GWB. We conclude by discussing the astrophysical implications of this limit and the prospects for detecting gravitational waves with pulsars.

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Straubmeier, Christian, and Gottfried Kanbach. "OPTIMA An Optical Pulsar Timing Analyser." International Astronomical Union Colloquium 177 (2000): 311–12. http://dx.doi.org/10.1017/s0252921100059844.

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AbstractOPTIMA is a small and mobile highspeed photometer which is primarily intended for the observation of young high energy pulsars at optical wavelengths. The detector system consists of a fiber fed photon counter based on avalanche photodiodes, a GPS timing receiver and an integrating CCD camera to ensure the correct positioning of the targeted object. In January 1999, OPTIMA proved its functionality by measuring the lightcurve of the Crab pulsar.

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Goncharov, Boris, Xing-Jiang Zhu, and Eric Thrane. "Is there a spectral turnover in the spin noise of millisecond pulsars?" Monthly Notices of the Royal Astronomical Society 497, no. 3 (August 10, 2020): 3264–72. http://dx.doi.org/10.1093/mnras/staa2081.

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ABSTRACT Pulsar timing arrays provide a unique means to detect nanohertz gravitational waves through long-term measurements of pulse arrival times from an ensemble of millisecond pulsars. After years of observations, some timing array pulsars have been shown to be dominated by low-frequency red noise, including spin noise that might be associated with pulsar rotational irregularities. The power spectral density of pulsar timing red noise is usually modelled with a power law or a power law with a turnover frequency below which the noise power spectrum plateaus. If there is a turnover in the spin noise of millisecond pulsars, residing within the observation band of current and/or future pulsar timing measurements, it may be easier than projected to resolve the gravitational-wave background from supermassive binary black holes. Additionally, the spectral turnover can provide valuable insights on neutron star physics. In the recent study by Melatos and Link, the authors provided a derivation of the model for power spectral density of spin noise from superfluid turbulence in the core of a neutron star, from first principles. The model features a spectral turnover, which depends on the dynamical response time of the superfluid and the steady-state angular velocity lag between the crust and the core of the star. In this work, we search for a spectral turnover in spin noise using the first data release of the International Pulsar Timing Array. Through Bayesian model selection, we find no evidence of a spectral turnover. Our analysis also shows that data from PSRs J1939+2134, J1024–0719, and J1713+0747 prefers the power-law model to the superfluid turbulence model.

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33

Taylor, J. H. "The Next Five Years of Pulsar Timing." International Astronomical Union Colloquium 160 (1996): 65–71. http://dx.doi.org/10.1017/s0252921100041063.

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AbstractTiming measurements of pulsars have yielded a number of important results over the years, and their value is generally a strong function of measurement accuracy. I briefly summarize the present state of affairs in pulsar timing, and then offer some judgments about what may help to produce the best results in coming years.

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34

Hobbs, G. "Developing a pulsar-based time standard." Proceedings of the International Astronomical Union 10, H16 (August 2012): 207–8. http://dx.doi.org/10.1017/s1743921314005432.

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AbstractWe describe how observations of pulsars from the Parkes Pulsar Timing Array (PPTA) project have been used to develop a pulsar-based timescale. This is the first such timescale that has a precision comparable to uncertainties in international atomic timescales.

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35

Caballero, R. N. "Solar-System Studies with Pulsar Timing Arrays." Proceedings of the International Astronomical Union 13, S337 (September 2017): 154–57. http://dx.doi.org/10.1017/s1743921317009905.

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AbstractHigh-precision pulsar timing is central to a wide range of astrophysics and fundamental physics applications. When timing an ensemble of millisecond pulsars in different sky positions, known as a pulsar timing array (PTA), one can search for ultra-low-frequency gravitational waves (GWs) through the spatial correlations that spacetime deformations by passing GWs are predicted to induce on the pulses’ times-of-arrival (TOAs). A pulsar-timing model, requires the use of a solar-system ephemeris (SSE) to properly predict the position of the solar-system barycentre, the (quasi-)inertial frame where all TOAs are referred. Here, I discuss how while errors in SSEs can introduce correlations in the TOAs that may interfere with GW searches, one can make use of PTAs to study the solar system. I discuss work done within the context of the European Pulsar Timing Array and the International Pulsar Timing Array collaborations. These include new updates on the masses of planets from PTA data, first limits on masses of the most massive asteroids, and comparisons between SSEs from independent groups. Finally, I discuss a new approach in setting limits on the masses of unknown bodies in the solar system and calculate mass sensitivity curves for PTA data.

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36

Heflin, K., and R. Lieu. "Galactic orbital effects on pulsar timing." Monthly Notices of the Royal Astronomical Society 504, no. 1 (March 11, 2021): 166–71. http://dx.doi.org/10.1093/mnras/stab703.

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ABSTRACT In the currently accepted paradigm, dark matter is hypothesized as an explanation of the flat rotation curves of galaxies under the assumption of virialized orbits. The use of millisecond pulsar timing as a probe of Galactic dark matter content is explored as a means of relaxing this assumption. A method of inference of the Galactic potential using the frequency derivative $\dot{\nu }$ is produced, and an estimate for a virialized Galactic rotation curve is given through direct observation of acceleration. The data set used includes 210 pulsars with known $\dot{\nu }$ and astrometric properties, a subset of which also have measured $\ddot{\nu }$. In principle, this enables the exploration of kinematic effects, but in practice, $\ddot{\nu }$ values are found to be too imprecise at present to adequately constrain radial velocities of pulsars. Additionally, surface magnetic field strengths are inferred from $\dot{\nu }$ and the magnetic spin-down contribution to $\ddot{\nu }$ is estimated. For several pulsars, the radial velocity is known, and the kinematic contribution to $\ddot{\nu }$ is estimated accordingly. The binary orbital periods of PSR J1713+0747 and other binary pulsars are also used to constrain Galactic mass density models.

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37

Bell, J. F. "Radio pulsar timing." Advances in Space Research 21, no. 1-2 (January 1998): 137–47. http://dx.doi.org/10.1016/s0273-1177(97)00798-9.

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38

Hobbs, G., A. Lyne, and M. Kramer. "Pulsar Timing Noise." Chinese Journal of Astronomy and Astrophysics 6, S2 (October 2006): 169–75. http://dx.doi.org/10.1088/1009-9271/6/s2/31.

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39

Lynch, Ryan S. "Pulsar Timing Arrays." Journal of Physics: Conference Series 610 (May 11, 2015): 012017. http://dx.doi.org/10.1088/1742-6596/610/1/012017.

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40

Bizouard, M. A., F. Jenet, R. Price, and C. M. Will. "Pulsar timing arrays." Classical and Quantum Gravity 30, no. 22 (October 21, 2013): 220301. http://dx.doi.org/10.1088/0264-9381/30/22/220301.

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41

Lommen, Andrea N., and Paul Demorest. "Pulsar timing techniques." Classical and Quantum Gravity 30, no. 22 (November 4, 2013): 224001. http://dx.doi.org/10.1088/0264-9381/30/22/224001.

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42

Tiburzi, C., G. M. Shaifullah, C. G. Bassa, P. Zucca, J. P. W. Verbiest, N. K. Porayko, E. van der Wateren, et al. "The impact of solar wind variability on pulsar timing." Astronomy & Astrophysics 647 (March 2021): A84. http://dx.doi.org/10.1051/0004-6361/202039846.

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Context. High-precision pulsar timing requires accurate corrections for dispersive delays of radio waves, parametrized by the dispersion measure (DM), particularly if these delays are variable in time. In a previous paper, we studied the solar wind (SW) models used in pulsar timing to mitigate the excess of DM that is annually induced by the SW and found these to be insufficient for high-precision pulsar timing. Here we analyze additional pulsar datasets to further investigate which aspects of the SW models currently used in pulsar timing can be readily improved, and at what levels of timing precision SW mitigation is possible. Aims. Our goals are to verify: (a) whether the data are better described by a spherical model of the SW with a time-variable amplitude, rather than a time-invariant one as suggested in literature, and (b) whether a temporal trend of such a model’s amplitudes can be detected. Methods. We use the pulsar timing technique on low-frequency pulsar observations to estimate the DM and quantify how this value changes as the Earth moves around the Sun. Specifically, we monitor the DM in weekly to monthly observations of 14 pulsars taken with parts of the LOw-Frequency ARray (LOFAR) across time spans of up to 6 years. We develop an informed algorithm to separate the interstellar variations in the DM from those caused by the SW and demonstrate the functionality of this algorithm with extensive simulations. Assuming a spherically symmetric model for the SW density, we derive the amplitude of this model for each year of observations. Results. We show that a spherical model with a time-variable amplitude models the observations better than a spherical model with a constant amplitude, but that both approaches leave significant SW-induced delays uncorrected in a number of pulsars in the sample. The amplitude of the spherical model is found to be variable in time, as opposed to what has been previously suggested.

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43

Spiewak, R., C. Flynn, S. Johnston, E. F. Keane, M. Bailes, E. D. Barr, S. Bhandari, et al. "The SUrvey for pulsars and extragalactic radio bursts V: recent discoveries and full timing solutions." Monthly Notices of the Royal Astronomical Society 496, no. 4 (June 27, 2020): 4836–48. http://dx.doi.org/10.1093/mnras/staa1869.

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ABSTRACT The SUrvey for Pulsars and Extragalactic Radio Bursts ran from 2014 April to 2019 August, covering a large fraction of the Southern hemisphere at mid- to high-galactic latitudes and consisting of 9-min pointings taken with the 20-cm multibeam receiver on the Parkes Radio Telescope. Data up to 2017 September 21 have been searched using standard Fourier techniques, single-pulse searches, and Fast Folding Algorithm searches. We present 19 new discoveries, bringing the total to 27 discoveries in the programme, and we report the results of follow-up timing observations at Parkes for 26 of these pulsars, including the millisecond pulsar PSR J1421−4409; the faint, highly modulated, slow pulsar PSR J1646−1910; and the nulling pulsar PSR J1337−4441. We present new timing solutions for 23 pulsars, and we report flux densities, modulation indices, and polarization properties.

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Cameron, A. D., D. J. Champion, M. Bailes, V. Balakrishnan, E. D. Barr, C. G. Bassa, S. Bates, et al. "The High Time Resolution Universe Pulsar Survey – XVI. Discovery and timing of 40 pulsars from the southern Galactic plane." Monthly Notices of the Royal Astronomical Society 493, no. 1 (January 14, 2020): 1063–87. http://dx.doi.org/10.1093/mnras/staa039.

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ABSTRACT We present the results of processing an additional 44 per cent of the High Time Resolution Universe South Low Latitude (HTRU-S LowLat) pulsar survey, the most sensitive blind pulsar survey of the southern Galactic plane to date. Our partially coherent segmented acceleration search pipeline is designed to enable the discovery of pulsars in short, highly accelerated orbits, while our 72-min integration lengths will allow us to discover pulsars at the lower end of the pulsar luminosity distribution. We report the discovery of 40 pulsars, including three millisecond pulsar-white dwarf binary systems (PSRs J1537−5312, J1547−5709, and J1618−4624), a black-widow binary system (PSR J1745−23) and a candidate black-widow binary system (PSR J1727−2951), a glitching pulsar (PSR J1706−4434), an eclipsing binary pulsar with a 1.5-yr orbital period (PSR J1653−45), and a pair of long spin-period binary pulsars which display either nulling or intermittent behaviour (PSRs J1812−15 and J1831−04). We show that the total population of 100 pulsars discovered in the HTRU-S LowLat survey to date represents both an older and lower luminosity population, and indicates that we have yet to reach the bottom of the luminosity distribution function. We present evaluations of the performance of our search technique and of the overall yield of the survey, considering the 94 per cent of the survey which we have processed to date. We show that our pulsar yield falls below earlier predictions by approximately 25 per cent (especially in the case of millisecond pulsars), and discuss explanations for this discrepancy as well as future adaptations in RFI mitigation and searching techniques which may address these shortfalls.

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Hobbs, G., D. Miller, R. N. Manchester, J. Dempsey, J. M. Chapman, J. Khoo, J. Applegate, et al. "The Parkes Observatory Pulsar Data Archive." Publications of the Astronomical Society of Australia 28, no. 3 (2011): 202–14. http://dx.doi.org/10.1071/as11016.

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AbstractThe Parkes pulsar data archive currently provides access to 144044 data files obtained from observations carried out at the Parkes observatory since the year 1991. Around 105 files are from surveys of the sky, the remainder are observations of 775 individual pulsars and their corresponding calibration signals. Survey observations are included from the Parkes 70 cm and the Swinburne Intermediate Latitude surveys. Individual pulsar observations are included from young pulsar timing projects, the Parkes Pulsar Timing Array and from the PULSE@Parkes outreach program. The data files and access methods are compatible with Virtual Observatory protocols. This paper describes the data currently stored in the archive and presents ways in which these data can be searched and downloaded.

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46

Fairhead, L. "Systematic Astrometric Errors in Pulsar Timing." Symposium - International Astronomical Union 141 (1990): 205–12. http://dx.doi.org/10.1017/s007418090008685x.

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A new analysis of the timing data acquired on the fast pulsar PSR1937+214 is presented. Parameters are evaluated with various models based on two ephemerides, two atomic time scales and two TT—TB time transformations. Comparisons are carried out with results from other programs. We provide evidence that systematic errors induced by the model adopted are 5 to 10 times larger than the formal uncertainties calculated by the fitting procedure. Great care must thus be taken when using results from different millisecond pulsars timing programs for accurate astrometric purposes.

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Nice, David J., Eric M. Splaver, and Ingrid H. Stairs. "Heavy Neutron Stars? A Status Report on Arecibo Timing of Four Pulsar – White Dwarf Systems." Symposium - International Astronomical Union 218 (2004): 49–52. http://dx.doi.org/10.1017/s0074180900180568.

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Relativistic phenomena (orbital precession, Shapiro delay, and/or orbital decay) have been measured in Arecibo timing observations of four pulsar-white dwarf binaries, leading to constraints on the neutron star masses. We have detected the decay of the PSR J0751+1807 orbit due to gravitational radiation emission, the first such measurement in a binary with a low mass ratio (m2/m1 ≪ 1). Timing data constrains the mass of this pulsar to bet between 1.6 and 2.8 M⊙. Masses of the other pulsars are in marginal agreement with the canonical pulsar mass of 1.35 M⊙, but higher values are preferred.

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Wang, Na, Jin Zhang, and Xin-Ji Wu. "Pulsar Observations in China – Status and Results." Symposium - International Astronomical Union 214 (2003): 159–62. http://dx.doi.org/10.1017/s007418090019432x.

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We present the status and results of pulsar observations in China. Pulsar observations at Urumqi Observatory over more than two years have resulted in updated rotation parameters for 74 pulsars. Comparison with earlier observations shows that long-term period and period-derivative fluctuations are probably dominated by unseen glitches. We also monitored the variation of pulsar scintillation dynamic spectra for a few strong pulsars. The data show major variations in the scintillation parameters. A new system at a lower frequency is planned to allow investigation of the frequency dependence of pulsar properties. A 50-m telescope for millisecond pulsar timing is also being planned at the National Astronomical Observatories, Beijing, and should be constructed within three years.

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Namkham, Nakornping, Phrudth Jaroenjittichai, and Simon Johnston. "Diagnostics of timing noise in middle-aged pulsars." Monthly Notices of the Royal Astronomical Society 487, no. 4 (June 19, 2019): 5854–61. http://dx.doi.org/10.1093/mnras/stz1671.

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ABSTRACT Radio pulsars are often used as clocks in a wide variety of experiments. Imperfections in the clock, known as timing noise, have the potential to reduce the significance of, or even thwart e.g. the attempt to find a stochastic gravitational wave (GW) background. We measure the timing noise in a group of 129 mostly middle-aged pulsars (i.e. characteristic ages near 1 Myr) observed with the Parkes radio telescope on a monthly basis since 2014. We examine four different metrics for timing noise, but it remains unclear which, if any, provides the best determination. In spite of this, it is evident that these pulsars have significantly less timing noise than their younger counterparts, but significantly more than the (much older) millisecond pulsars (MSPs). As with previous authors, we find a strong correlation between timing noise and the pulsar spin-down rate, $\dot{\nu}$. However, for a given $\dot{\nu}$ there is a spread of about a factor of 30 in the strength of the timing noise likely indicating that nuclear conditions in the interior of the stars differ between objects. We briefly comment on the implications for GW detection through pulsar timing arrays as the level of timing noise in MSPs may be less than predicted.

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Larchenkova, T. I., and O. V. Doroshenko. "A Possible Manifestation Of Microlensing In Pulsar Timing." Symposium - International Astronomical Union 173 (1996): 239–40. http://dx.doi.org/10.1017/s0074180900231409.

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Gravitational lensing and the time delay of a pulsar signal in the gravitational field of a mass are General Relativistic effects that may be used as a tool to detect the observational parameters of dark matter in our Galaxy. We propose to use observations of the time delay of pulses from pulsars to detect lensing objects located close to the line of the sight, to study the distribution of dark matter in our Galaxy. We discuss the possibility of finding such an event by measuring the delay of pulses from a pulsar, and apply it to data for PSR B0525+21.

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