scholarly journals Pulsar timing at Kalyazin (Russia)

2000 ◽  
Vol 177 ◽  
pp. 57-60
Author(s):  
O.V. Doroshenko ◽  
Yu.P. Ilyasov ◽  
V.V. Oreshko
Keyword(s):  
General Relativity ◽  
Local Time ◽  
Radio Telescope ◽  
Orthogonal Polarization ◽  
Hydrogen Maser ◽  
Radio Pulsars ◽  
Time Service ◽  
Binary Pulsars ◽  
Front End ◽  
Pulsar Timing

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.

scholarly journals Timing of young radio pulsars – II. Braking indices and their interpretation

2020 ◽  
Vol 494 (2) ◽  
pp. 2012-2026 ◽  
Author(s):  
A Parthasarathy ◽  
S Johnston ◽  
R M Shannon ◽  
L Lentati ◽  
M Bailes ◽  
...  
Keyword(s):  
Time Scales ◽  
Radio Telescope ◽  
Archival Data ◽  
Radio Pulsars ◽  
Pulsar Timing ◽  
Timing Noise

ABSTRACT In Paper I of this series, we detected a significant value of the braking index (n) for 19 young, high-$\dot{E}$ radio pulsars using ∼10 yr of timing observations from the 64-m Parkes radio telescope. Here, we investigate this result in more detail using a Bayesian pulsar timing framework to model timing noise and to perform selection to distinguish between models containing exponential glitch recovery and braking index signatures. We show that consistent values of n are maintained with the addition of substantial archival data, even in the presence of glitches. We provide strong arguments that our measurements are unlikely due to exponential recovery signals from unseen glitches even though glitches play a key role in the evolution of a pulsar’s spin frequency. We conclude that, at least over decadal time-scales, the value of n can be significantly larger than the canonical 3 and discuss the implications for the evolution of pulsars.

Fundamentals of a Radio Telescope

2020 ◽  
pp. 33-55
Author(s):  
Kim Ho Yeap ◽  
Kazuhiro Hirasawa
Keyword(s):  
Radio Telescope ◽  
Local Oscillator ◽  
Orthogonal Polarization ◽  
Processing Unit ◽  
Radio Waves ◽  
Front End ◽  
Astronomical Instruments ◽  
Corrugated Horn ◽  
Working Principle ◽  
Feed Horns

In radio astronomy, radio telescopes are used to collect radio waves emanated from cosmic sources. By analyzing these signals, the properties of the sources could be unraveled. A telescope typically consists of the following astronomical instruments: a primary and a secondary reflector, receiver optics which usually includes a lens or a pair of mirrors and a pair of feed horns (one for each orthogonal polarization [or simply a corrugated horn with an orthomode transducer OMT]), waveguides, a mixer circuit, a local oscillator, amplifiers, a detector circuit, and a data processing unit. This chapter provides a concise but complete overview of the working principle of the astronomical instruments involved in the construction of a radio telescope. The underlying physics of the components in a radio telescope, ranging from the antenna to the front-end and back-end systems, are illustrated.

scholarly journals Diagnostics of timing noise in middle-aged pulsars

2019 ◽  
Vol 487 (4) ◽  
pp. 5854-5861 ◽  
Author(s):  
Nakornping Namkham ◽  
Phrudth Jaroenjittichai ◽  
Simon Johnston
Keyword(s):  
Gravitational Wave ◽  
Radio Telescope ◽  
Strong Correlation ◽  
Radio Pulsars ◽  
Middle Aged ◽  
Monthly Basis ◽  
Millisecond Pulsars ◽  
Pulsar Timing ◽  
Timing Noise

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.

scholarly journals Precision Pulsar Timing with NASA's Deep Space Network

2015 ◽  
Vol 11 (A29B) ◽  
pp. 367-369
Author(s):  
Lawrence Teitelbaum ◽  
Walid Majid ◽  
Manuel M. Franco ◽  
Daniel J. Hoppe ◽  
Shinji Horiuchi ◽  
...  
Keyword(s):  
Low Frequency ◽  
Radio Waves ◽  
Deep Space ◽  
Radio Pulsars ◽  
Deep Space Network ◽  
Space Network ◽  
The Earth ◽  
Pulsar Timing ◽  
Initial Results ◽  
Stable Rotation

AbstractMillisecond pulsars (MSPs) are a class of radio pulsars with extremely stable rotation. Their excellent timing stability can be used to study a wide variety of astrophysical phenomena. In particular, a large sample of these pulsars can be used to detect low-frequency gravitational waves. We have developed a precision pulsar timing backend for the NASA Deep Space Network (DSN), which will allow the use of short gaps in tracking schedules to time pulses from an ensemble of MSPs. The DSN operates clusters of large dish antennas (up to 70-m in diameter), located roughly equidistant around the Earth, for communication and tracking of deep-space spacecraft. The backend system will be capable of removing entirely the dispersive effects of propagation of radio waves through the interstellar medium in real-time. We will describe our development work, initial results, and prospects for future observations over the next few years.

scholarly journals Pulsar science with the CHIME telescope

2017 ◽  
Vol 13 (S337) ◽  
pp. 179-182 ◽  
Author(s):  
Cherry Ng
Keyword(s):  
Northern Hemisphere ◽  
Radio Telescope ◽  
Field Of View ◽  
Radio Bursts ◽  
Radio Telescopes ◽  
Acoustic Oscillations ◽  
Daily Monitoring ◽  
Intensity Mapping ◽  
Pulsar Timing ◽  
Pulsar Timing Array

AbstractThe CHIME telescope (the Canadian Hydrogen Intensity Mapping Experiment) recently built in Penticton, Canada, is currently being commissioned. Originally designed as a cosmology experiment, it was soon recognized that CHIME has the potential to simultaneously serve as an incredibly useful radio telescope for pulsar science. CHIME operates across a wide bandwidth of 400–800 MHz and will have a collecting area and sensitivity comparable to that of the 100-m class radio telescopes. CHIME has a huge field of view of ~250 square degrees. It will be capable of observing 10 pulsars simultaneously, 24-hours per day, every day, while still accomplishing its missions to study Baryon Acoustic Oscillations and Fast Radio Bursts. It will carry out daily monitoring of roughly half of all pulsars in the northern hemisphere, including all NANOGrav pulsars employed in the Pulsar Timing Array project. It will cycle through all pulsars in the northern hemisphere with a range of cadence of no more than 10 days.

scholarly journals On the 2PN Periastron Precession of the Double Pulsar PSR J0737–3039A/B

Universe ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 443
Author(s):  
Lorenzo Iorio
Keyword(s):  
General Relativity ◽  
Present Author ◽  
Moment Of Inertia ◽  
The Other ◽  
Orbital Elements ◽  
Binary Pulsars ◽  
Orbital Phase ◽  
Order Of Magnitude ◽  
General Relativistic ◽  
The Moment

One of the post-Keplerian (PK) parameters determined in timing analyses of several binary pulsars is the fractional periastron advance per orbit kPK. Along with other PK parameters, it is used in testing general relativity once it is translated into the periastron precession ω˙PK. It was recently remarked that the periastron ω of PSR J0737–3039A/B may be used to measure/constrain the moment of inertia of A through the extraction of the general relativistic Lense–Thirring precession ω˙LT,A≃−0.00060∘yr−1 from the experimentally determined periastron rate ω˙obs provided that the other post-Newtonian (PN) contributions to ω˙exp can be accurately modeled. Among them, the 2PN seems to be of the same order of magnitude of ω˙LT,A. An analytical expression of the total 2PN periastron precession ω˙2PN in terms of the osculating Keplerian orbital elements, valid not only for binary pulsars, is provided, thereby elucidating the subtleties implied in correctly calculating it from k1PN+k2PN and correcting some past errors by the present author. The formula for ω˙2PN is demonstrated to be equivalent to that obtainable from k1PN+k2PN by Damour and Schäfer expressed in the Damour–Deruelle (DD) parameterization. ω˙2PN actually depends on the initial orbital phase, hidden in the DD picture, so that −0.00080∘yr−1≤ω˙2PN≤−0.00045∘yr−1. A recently released prediction of ω˙2PN for PSR J0737–3039A/B is discussed.

scholarly journals Constraining the dense matter equation-of-state with radio pulsars

2020 ◽  
Vol 497 (3) ◽  
pp. 3118-3130 ◽  
Author(s):  
Huanchen Hu ◽  
Michael Kramer ◽  
Norbert Wex ◽  
David J Champion ◽  
Marcel S Kehl
Keyword(s):  
Equations Of State ◽  
Dense Matter ◽  
Leading Order ◽  
Radio Pulsars ◽  
Mass Measurements ◽  
Pulsar Timing ◽  
Orbital Periods ◽  
To Come ◽  
The Moment ◽  
First Time

ABSTRACT Radio pulsars provide some of the most important constraints for our understanding of matter at supranuclear densities. So far, these constraints are mostly given by precision mass measurements of neutron stars (NS). By combining single measurements of the two most massive pulsars, J0348+0432 and J0740+6620, the resulting lower limit of 1.98 M⊙ (99 per cent confidence) of the maximum NS mass, excludes a large number of equations of state (EOSs). Further EOS constraints, complementary to other methods, are likely to come from the measurement of the moment of inertia (MOI) of binary pulsars in relativistic orbits. The Double Pulsar, PSR J0737−3039A/B, is the most promising system for the first measurement of the MOI via pulsar timing. Reviewing this method, based in particular on the first MeerKAT observations of the Double Pulsar, we provide well-founded projections into the future by simulating timing observations with MeerKAT and the SKA. For the first time, we account for the spin-down mass-loss in the analysis. Our results suggest that an MOI measurement with 11 per cent accuracy (68 per cent confidence) is possible by 2030. If by 2030 the EOS is sufficiently well known, however, we find that the Double Pulsar will allow for a 7 per cent test of Lense–Thirring precession, or alternatively provide a ∼3σ-measurement of the next-to-leading order gravitational wave damping in GR. Finally, we demonstrate that potential new discoveries of double NS systems with orbital periods shorter than that of the Double Pulsar promise significant improvements in these measurements and the constraints on NS matter.

scholarly journals Deconfinement signals from pulsar timing

2000 ◽  
Vol 177 ◽  
pp. 603-604 ◽  
Author(s):  
Hovik Grigorian ◽  
Gevorg Poghosyan ◽  
Edvard Chubarian ◽  
David Blaschke
Keyword(s):  
General Relativity ◽  
Quark Matter ◽  
Compact Star ◽  
Baryon Number ◽  
Rotational Frequency ◽  
Compact Stars ◽  
Pulsar Timing

AbstractThe occurence of a quark matter core in rotating compact stars has been investigated within general relativity as a function of both the rotational frequency and the total baryon number. We demonstrate that the deviation of the braking index fromn= 3 signals not only the occurence but also the size of a quark matter core in a pulsar. We suggest that in systems with mass accretion onto a rapidly rotating compact star a spin-down to spin-up transition might signal a deconfinement transition in its interior.

scholarly journals Radio emission from a pulsar’s magnetic pole revealed by general relativity

Science ◽  
2019 ◽  
Vol 365 (6457) ◽  
pp. 1013-1017 ◽  
Author(s):  
Gregory Desvignes ◽  
Michael Kramer ◽  
Kejia Lee ◽  
Joeri van Leeuwen ◽  
Ingrid Stairs ◽  
...  
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Radio Emission ◽  
Neutron Stars ◽  
Geometrical Model ◽  
Spin Axis ◽  
Magnetic Pole ◽  
Polarization Model ◽  
Binary Pulsars ◽  
Relativistic Treatment

Binary pulsars are affected by general relativity (GR), causing the spin axis of each pulsar to precess. We present polarimetric radio observations of the pulsar PSR J1906+0746 that demonstrate the validity of the geometrical model of pulsar polarization. We reconstruct the (sky-projected) polarization emission map over the pulsar’s magnetic pole and predict the disappearance of the detectable emission by 2028. Two tests of GR are performed using this system, including the spin precession for strongly self-gravitating bodies. We constrain the relativistic treatment of the pulsar polarization model and measure the pulsar beaming fraction, with implications for the population of neutron stars and the expected rate of neutron star mergers.

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