scholarly journals Testing the Universality of Free Fall with the Triple System J0337+1715

2017 ◽  
Vol 13 (S337) ◽  
pp. 138-141 ◽  
Author(s):  
A. M. Archibald ◽  
N. V. Gusinskaia ◽  
J. W. T. Hessels ◽  
D. R. Lorimer ◽  
R. S. Lynch ◽  
...  
Keyword(s):  
White Dwarf ◽  
Triple System ◽  
Free Fall ◽  
Analysis Procedure ◽  
Time Of Arrival ◽  
Pulse Time ◽  
Millisecond Pulsar ◽  
Timing Model ◽  
Universality Of Free Fall ◽  
Pulsar Timing

AbstractThe millisecond pulsar PSR J0337+1715 is in a mildly relativistic hierarchical triple system with two white dwarfs. This offers the possibility of testing the universality of free fall: does the neutron star fall with the same acceleration as the inner white dwarf in the gravity of the outer white dwarf? We have carried out an intensive pulsar timing campaign, yielding some 27000 pulse time-of-arrival (TOA) measurements with a median uncertainty of 1.2 μs. Here we describe our analysis procedure and timing model.

scholarly journals Radio timing in a millisecond pulsar – extreme/intermediate mass ratio binary system

2020 ◽  
Vol 644 ◽  
pp. A167
Author(s):  
T. Kimpson ◽  
K. Wu ◽  
S. Zane
Keyword(s):  
Globular Clusters ◽  
Relativistic Effects ◽  
Propagation Delay ◽  
Higher Order ◽  
Galactic Centre ◽  
Millisecond Pulsar ◽  
Fundamental Physics ◽  
Timing Model ◽  
Pulsar Timing ◽  
Timing Models

Radio timing observations of a millisecond pulsar in orbit around the Galactic centre black hole (BH) or a BH at the centre of globular clusters could answer foundational questions in astrophysics and fundamental physics. Pulsar radio astronomy typically employs the post-Keplerian approximation to determine the system parameters. However, in the strong gravitational field around the central BH, higher order relativistic effects may become important. We compare the pulsar timing delays given by the post-Keplerian approximation with those given by a relativistic timing model. We find significant discrepancies between the solutions derived for the Einstein delay and the propagation delay (i.e. Roemer and Sharpiro delay) compared to the fully relativistic solutions. Correcting for these higher order relativistic effects is essential in order to construct accurate radio timing models for pulsar systems at the Galactic centre and the centre of globular clusters and informing issues related to their detection.

scholarly journals Universality of free fall from the orbital motion of a pulsar in a stellar triple system

Nature ◽  
2018 ◽  
Vol 559 (7712) ◽  
pp. 73-76 ◽  
Author(s):  
Anne M. Archibald ◽  
Nina V. Gusinskaia ◽  
Jason W. T. Hessels ◽  
Adam T. Deller ◽  
David L. Kaplan ◽  
...  
Keyword(s):  
Triple System ◽  
Orbital Motion ◽  
Free Fall ◽  
Universality Of Free Fall

scholarly journals Ensemble Pulsar Time Study by Pulsar Timing Observations

2004 ◽  
Vol 218 ◽  
pp. 439-440
Author(s):  
Tinggao Yang ◽  
Guangren Ni
Keyword(s):  
Time Scale ◽  
Wavelet Decomposition ◽  
Time Study ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Pulsar Time ◽  
Pulsar Timing ◽  
Timing Data ◽  
Gravitational Wave Background

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.

Error analysis of initial phase estimation for X-ray pulsar navigation system

2021 ◽  
pp. 2150287
Author(s):  
Wei Li ◽  
Ning-Juan Ruan ◽  
Xun Liu ◽  
Feng Yan
Keyword(s):  
Navigation System ◽  
Initial Phase ◽  
Estimation Error ◽  
Nonlinear Least Squares ◽  
Great Promise ◽  
Phase Estimation ◽  
Time Of Arrival ◽  
Pulse Time ◽  
X Ray ◽  
Pulsar Navigation

In this paper, a nonlinear least squares estimator based on the extending cost function is derived, and its performance is analyzed in a Monte-Carlo simulation. Numerical results show that estimation error of the pulse time of arrival satisfies the normal distribution, the relation between the variance and the number of X-ray photon obtained by our simulation is compared with the analytical model. In addition, the effect of time bin size on the statically behavior of estimation error is also studied. This work holds great promise for designing the parameters of X-ray camera adopted in the pulsar navigation system.

scholarly journals The ultracool helium-atmosphere white dwarf companion of PSR J0740+6620?

2019 ◽  
Vol 485 (3) ◽  
pp. 3715-3720 ◽  
Author(s):  
D M Beronya ◽  
A V Karpova ◽  
A Yu Kirichenko ◽  
S V Zharikov ◽  
D A Zyuzin ◽  
...  
Keyword(s):  
White Dwarf ◽  
Millisecond Pulsar ◽  
Helium Atmosphere

ABSTRACT We report detection of the likely companion of the binary millisecond pulsar (MSP) J0740+6620 with the Gran Telescopio Canarias in the r′ and i′ bands. The position of the detected starlike source coincides with the pulsar coordinates within the 1σ uncertainty of ≈0.2 arcsec. Its magnitudes are r′ = 26.51 ± 0.17 and i′ = 25.49 ± 0.15. Comparing the data with the white dwarf (WD) cooling tracks suggests that it can be an ultracool helium-atmosphere WD with the temperature ≲3500 K and cooling age ≳5 Gyr. The age is consistent with the pulsar characteristic age corrected for kinematic effects. This is the reddest source among known WD companions of MSPs. Detection of the source in other bands would be useful to clarify its properties and nature.

scholarly journals The Temperature and Cooling Age of t h e White-Dwarf Companion to the Millisecond Pulsar PSR B1855+09

2000 ◽  
Vol 177 ◽  
pp. 633-634
Author(s):  
Jon Bell ◽  
Marten van Kerkwijk ◽  
Vicky Kaspi ◽  
Shri Kulkarni
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Measured Temperature ◽  
Millisecond Pulsar ◽  
Nuclear Burning ◽  
Low Mass ◽  
Cooling Model ◽  
Age Discrepancy

AbstractWe report on Keck and HST observations of the binary millisecond pulsar PSR B1855+09. We detect its white-dwarf companion and measuremF555W= 25.90 ± 0.12 andmF814W= 24.19 ± 0.11 (Vega system). From the reddening-corrected color we infer a temperatureTeff= 4800 ± 800 K. The companion mass is known accurately from measurements of the Shapiro delay of the pulsar signal,. Given a cooling model, one can use the measured temperature to determine the cooling age. The main uncertainty in the cooling models for such low-mass white dwarfs is the amount of residual nuclear burning, which depends on the thickness of the hydrogen layer surrounding the helium core. For PSR B1855+09, such models lead to a cooling age of ∼10Gyr, which is twice the spin-down age of the pulsar. It may be that the pulsar does not brake (n=3.0) like a dipole rotatingin vacuo. For other pulsar companions, however, ages well over lOGyr are inferred, indicating that the problem may lie with the cooling models. There is no age discrepancy for models in which the white dwarfs are formed with thinner hydrogen layers (< 3 × 10−4M⊙). See van Kerkwijk et al. ApJ (submitted) for more details.

scholarly journals High-Precision Timing of Millisecond Pulsars and Precision Astrometry

1995 ◽  
Vol 166 ◽  
pp. 163-171 ◽  
Author(s):  
V. M. Kaspi
Keyword(s):  
Solar System ◽  
High Precision ◽  
Reference Frames ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Pulsar Timing ◽  
Solar System Objects ◽  
Optical Reference ◽  
Precision Astrometry

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.

scholarly journals Millisecond Pulsar Timing in Effelsberg

1996 ◽  
Vol 160 ◽  
pp. 95-96 ◽  
Author(s):  
M. Kramer ◽  
O. Doroshenko ◽  
A. Jessner ◽  
R. Wielebinski ◽  
A. Wolszczan ◽  
...  
Keyword(s):  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Polarization Measurements ◽  
Pulsar Timing ◽  
Short Period

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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