Probing fundamental physics with pulsars

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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PULSAR TIMING ARRAYS

International Journal of Modern Physics D ◽

10.1142/s0218271813410083 ◽

2013 ◽

Vol 22 (01) ◽

pp. 1341008 ◽

Cited By ~ 4

Author(s):

BHAL CHANDRA JOSHI

Keyword(s):

Gravitational Wave ◽

Gravitational Waves ◽

Low Frequency ◽

Radio Pulsars ◽

Very Low Frequency ◽

Pulsar Timing ◽

Gravitational Wave Background ◽

Pulsar Timing Array ◽

Current Operating

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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The hunt for new pulsars with the Green Bank Telescope

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312023113 ◽

2012 ◽

Vol 8 (S291) ◽

pp. 41-46

Author(s):

Ryan S. Lynch

Keyword(s):

Globular Clusters ◽

Binary Systems ◽

Radio Pulsars ◽

Large Area ◽

Pulsar Timing ◽

Drift Scan ◽

Radio Transients ◽

Pulsar Searches ◽

Green Bank Telescope ◽

Rotating Radio Transients

AbstractThe Green Bank Telescope (GBT) is the largest fully steerable radio telescope in the world and is one of our greatest tools for discovering and studying radio pulsars. Over the last decade, the GBT has successfully found over 100 new pulsars through large-area surveys. Here I discuss the two most recent—the GBT 350 MHz Drift-scan survey and the Green Bank North Celestial Cap survey. The primary science goal of both surveys is to find interesting individual pulsars, including young pulsars, rotating radio transients, exotic binary systems, and especially bright millisecond pulsars (MSPs) suitable for inclusion in Pulsar Timing Arrays, which are trying to directly detect gravitational waves. These two surveys have combined to discover 85 pulsars to date, among which are 14 MSPs and many unique and fascinating systems. I present highlights from these surveys and discuss future plans. I also discuss recent results from targeted GBT pulsar searches of globular clusters and Fermi sources.

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A pulsar-based time-scale from the International Pulsar Timing Array

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3071 ◽

2019 ◽

Vol 491 (4) ◽

pp. 5951-5965 ◽

Cited By ~ 3

Author(s):

G Hobbs ◽

L Guo ◽

R N Caballero ◽

W Coles ◽

K J Lee ◽

...

Keyword(s):

Time Scales ◽

Time Scale ◽

Limiting Factor ◽

Radio Pulsars ◽

Pulsar Timing ◽

The Us ◽

The Stability ◽

Solar System Dynamics ◽

Noise Models ◽

Pulsar Timing Array

ABSTRACT We have constructed a new time-scale, TT(IPTA16), based on observations of radio pulsars presented in the first data release from the International Pulsar Timing Array (IPTA). We used two analysis techniques with independent estimates of the noise models for the pulsar observations and different algorithms for obtaining the pulsar time-scale. The two analyses agree within the estimated uncertainties and both agree with TT(BIPM17), a post-corrected time-scale produced by the Bureau International des Poids et Mesures (BIPM). We show that both methods could detect significant errors in TT(BIPM17) if they were present. We estimate the stability of the atomic clocks from which TT(BIPM17) is derived using observations of four rubidium fountain clocks at the US Naval Observatory. Comparing the power spectrum of TT(IPTA16) with that of these fountain clocks suggests that pulsar-based time-scales are unlikely to contribute to the stability of the best time-scales over the next decade, but they will remain a valuable independent check on atomic time-scales. We also find that the stability of the pulsar-based time-scale is likely to be limited by our knowledge of solar-system dynamics, and that errors in TT(BIPM17) will not be a limiting factor for the primary goal of the IPTA, which is to search for the signatures of nano-Hertz gravitational waves.

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The Future of Pulsar Research and Facilities

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318000467 ◽

2017 ◽

Vol 13 (S337) ◽

pp. 165-170 ◽

Cited By ~ 1

Author(s):

Matthew Bailes

Keyword(s):

Open Access ◽

Open Source ◽

Large Scale ◽

Radio Pulsars ◽

Fundamental Physics ◽

The Future

AbstractRadio pulsars have been responsible for many astonishing astrophysical and fundamental physics breakthroughs since their discovery 50 years ago. In this review I will discuss many of the highlights, most of which were only possible because of the provision of large-scale observing facilities. The next 50 years of pulsar astronomy can be very bright, but only if our governments properly plan and fund the infrastructure necessary to enable future discoveries. Being a small sub-field of astronomy places an onus on the pulsar community to have an open-source/open access approach to data, software, and major observing facilities to enable new groups to emerge to keep the field vibrant.

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Commensal discovery of four fast radio bursts during Parkes Pulsar Timing Array observations

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1751 ◽

2019 ◽

Vol 488 (1) ◽

pp. 868-875 ◽

Cited By ~ 19

Author(s):

S Osłowski ◽

R M Shannon ◽

V Ravi ◽

J F Kaczmarek ◽

S Zhang ◽

...

Keyword(s):

Radio Telescope ◽

Spectral Properties ◽

Signal To Noise Ratio ◽

Radio Bursts ◽

Signal To Noise ◽

Fundamental Physics ◽

Millisecond Pulsars ◽

Pulsar Timing ◽

Physics Experiments ◽

Pulsar Timing Array

ABSTRACT The Parkes Pulsar Timing Array (PPTA) project monitors two dozen millisecond pulsars (MSPs) in order to undertake a variety of fundamental physics experiments using the Parkes 64-m radio telescope. Since 2017 June, we have been undertaking commensal searches for fast radio bursts (FRBs) during the MSP observations. Here, we report the discovery of four FRBs (171209, 180309, 180311, and 180714). The detected events include an FRB with the highest signal-to-noise ratio ever detected at the Parkes Observatory, which exhibits unusual spectral properties. All four FRBs are highly polarized. We discuss the future of commensal searches for FRBs at Parkes.

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The UTMOST pulsar timing programme – II. Timing noise across the pulsar population

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa615 ◽

2020 ◽

Vol 494 (1) ◽

pp. 228-245 ◽

Cited By ~ 5

Author(s):

M E Lower ◽

M Bailes ◽

R M Shannon ◽

S Johnston ◽

C Flynn ◽

...

Keyword(s):

Large Scale ◽

Rotational Stability ◽

Scaling Relation ◽

Noise Strength ◽

Radio Pulsars ◽

Bayesian Techniques ◽

Pulsar Timing ◽

Rotational Evolution ◽

Timing Noise ◽

Noise Models

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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Searching for gravitational-wave bursts from cosmic string cusps with the Parkes Pulsar Timing Array

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3721 ◽

2020 ◽

Vol 501 (1) ◽

pp. 701-712

Author(s):

N Yonemaru ◽

S Kuroyanagi ◽

G Hobbs ◽

K Takahashi ◽

X-J Zhu ◽

...

Keyword(s):

False Alarm ◽

Gravitational Wave ◽

Cosmic String ◽

Cosmic Strings ◽

False Alarm Probability ◽

String Tension ◽

Detection Algorithm ◽

Pulsar Timing ◽

Upper Limits ◽

Pulsar Timing Array

ABSTRACT Cosmic strings are potential gravitational-wave (GW) sources that can be probed by pulsar timing arrays (PTAs). In this work we develop a detection algorithm for a GW burst from a cusp on a cosmic string, and apply it to Parkes PTA data. We find four events with a false alarm probability less than 1 per cent. However further investigation shows that all of these are likely to be spurious. As there are no convincing detections we place upper limits on the GW amplitude for different event durations. From these bounds we place limits on the cosmic string tension of Gμ ∼ 10−5, and highlight that this bound is independent from those obtained using other techniques. We discuss the physical implications of our results and the prospect of probing cosmic strings in the era of Square Kilometre Array.

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