Measuring Interstellar Delays of PSR J0613-0200 over 7 years, using the Large European Array for Pulsars

Main, R. A.; Sanidas, S. A.; Antoniadis, J.; Bassa, C.; Chen, S.; Cognard, I.; Gaikwad, M.; Hu, H.; Janssen, G. H.; Karuppusamy, R.; Kramer, M.; Lee, K. J.; Liu, K.; Mall, G.; McKee, J. W.; Mickaliger, M. B.; Perrodin, D.; Stappers, B. W.; Tiburzi, C.; Wucknitz, O.; Wang, L.; Zhu, W. W.

doi:10.48550/arxiv.2009.10707

Cited by 3 publications

(3 citation statements)

References 35 publications

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“…if scattering and flux density variations caused by variable DM in scattering screens can be predicted. This will be especially the case in systems with solved scattering screen geometry, either through VLBI or multi-station time delays (Brisken et al 2010;Fadeev et al 2018;Simard et al 2019), or through annual variations of scintillation timescales and bandwidths (Rickett et al 2014;Reardon et al 2019) or scintillation arc curvatures (Reardon et al 2020;Main et al 2020).…”

Section: Conclusion and Further Workmentioning

confidence: 99%

Discovery and modelling of broad-scale plasma lensing in black-widow pulsar J2051$-$0827

Lin,

Main,

Verbiest

et al. 2021

Preprint

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We report on an unusually bright observation of PSR J2051−0827 recorded during a regular monitoring campaign of blackwidow pulsar systems with the Effelsberg 100-m telescope. Through fortunate coincidence, a particularly bright scintillation maximum is simultaneous with the eclipse by the companion, enabling precise measurements of variations in the flux density, dispersion measure (DM), and scattering strength throughout the eclipse. The flux density is highly variable throughout the eclipse, with a peak 1.7 times the average away from the eclipse, and yet does not significantly decrease on average. We recover the flux density variations from the measured DM variations using geometric optics, with a relative velocity as the only free parameter. We measure an effective velocity of 470 ± 10 km/s, consistent with the relative orbital motion of the companion, suggesting that the outflow velocity of the lensing material is low, or is directly along the line-of-sight. The 2% uncertainty on the effective velocity is a formal error; systematics related to our current model are likely to dominate, and we detail several extensions to the model to be considered in a full treatment of lensing. This is a demonstration of the causal link between DM and lensing; the flux density variations can be predicted directly through the derivatives of DM. Going forward, this approach can be applied to investigate the dynamics of other eclipsing systems, and to investigate the physical nature of scintillation and lensing in the ionized interstellar medium.

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Section: Conclusion and Further Workmentioning

confidence: 99%

Discovery and modelling of broad-scale plasma lensing in black-widow pulsar J2051$-$0827

Lin,

Main,

Verbiest

et al. 2021

Preprint

Self Cite

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show abstract

“…In particular, for experiments designed to detect nanohertz GWs, advanced noise modeling techniques such as those discussed in Arzoumanian et al (2020b) will benefit greatly from disentangling the covariances between DM and scattering where precision down to ∼ 100s of nanoseconds is required (e.g., Lam et al 2018;Lam 2018;Lam et al 2019). Techniques such as cyclic spectroscopy (Dolch et al 2020;Turner et al 2020), or alternative methods of quantifying time-variable scattering such as those described in Main et al (2020) will be necessary to break this covariance.…”

Section: Implications For Precision Pulsar Timingmentioning

confidence: 99%

A Study in Frequency-Dependent Effects on Precision Pulsar Timing Parameters with the Pulsar Signal Simulator

Shapiro-Albert,

Hazboun,

McLaughlin

et al. 2020

Preprint

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In this paper we introduce a new PYTHON package, the PULSAR SIGNAL SIMULATOR, or PSRSIGSIM, which is designed to simulate a pulsar signal from emission at the pulsar, through the interstellar medium, to observation by a radio telescope, and digitization in a standard data format. We use the PSRSIGSIM to simulate observations of three millisecond pulsars, PSRs J1744-1134, B1855+09, and B1953+29, to explore the covariances between frequency-dependent parameters, such as variations in the dispersion measure (DM), pulse profile evolution with frequency, and pulse scatter broadening. We show that the PSRSIGSIM can produce realistic simulated data and can accurately recover the parameters injected into the data. We also find that while there are covariances when fitting DM variations and frequency-dependent parameters, they have little effect on timing precision. Our simulations also show that time-variable scattering delays decrease the accuracy and increase the variability of the recovered DM and frequency-dependent parameters. Despite this, our simulations also show that the time-variable scattering delays have little impact on the root mean square of the timing residuals. This suggests that the variability seen in recovered DM, when time-variable scattering delays are present, is due to a covariance between the two parameters, with the DM modeling out the additional scattering delays.

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“…However this arc curvature model for PSR J0737−3039A was inferior to an earlier model of scintillation timescale variations observed in the dynamic spectrum (Ransom et al 2004), because the arcs were not sharp. Main et al (2020) has also observed annual arc curvature variations in the millisecond pulsar, PSR J0613−0200. PSR J0437−4715 was the first pulsar to have its full three-dimensional orbital motion determined (van Straten et al 2001), and it also has the most precisely measured distance of any pulsar, D = 156.79 ± 0.25 pc (Reardon et al 2016).…”

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confidence: 91%

Precision orbital dynamics from interstellar scintillation arcs for PSR J0437-4715

Reardon,

Coles,

Bailes

et al. 2020

Preprint

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Intensity scintillations of radio pulsars are known to originate from interference between waves scattered by the electron density irregularities of interstellar plasma, often leading to parabolic arcs in the two-dimensional power spectrum of the recorded dynamic spectrum. The degree of arc curvature depends on the distance to the scattering plasma and its transverse velocity with respect to the lineof-sight. We report the observation of annual and orbital variations in the curvature of scintillation arcs over a period of 16 years for the bright millisecond pulsar, PSR J0437−4715. These variations are the signature of the relative transverse motions of the Earth, pulsar, and scattering medium, which we model to obtain precise measurements of parameters of the pulsar's binary orbit and the scattering medium itself. We observe two clear scintillation arcs in most of our >5000 observations and we show that they originate from scattering by thin screens located at distances D 1 = 89.8 ± 0.4 pc and D 2 = 124 ± 3 pc from Earth. The best-fit scattering model we derive for the brightest arc yields the pulsar's orbital inclination angle i = 137.1 ± 0.3 • , and longitude of ascending node, Ω = 206.3 ± 0.4 • . Using scintillation arcs for precise astrometry and orbital dynamics can be superior to modelling variations in the diffractive scintillation timescale, because the arc curvature is independent of variations in the level of turbulence of interstellar plasma. This technique can be used in combination with pulsar timing to determine the full three-dimensional orbital geometries of binary pulsars, and provides parameters essential for testing theories of gravity and constraining neutron star masses.

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Measuring Interstellar Delays of PSR J0613-0200 over 7 years, using the Large European Array for Pulsars

Cited by 3 publications

References 35 publications

Discovery and modelling of broad-scale plasma lensing in black-widow pulsar J2051$-$0827

Discovery and modelling of broad-scale plasma lensing in black-widow pulsar J2051$-$0827

A Study in Frequency-Dependent Effects on Precision Pulsar Timing Parameters with the Pulsar Signal Simulator

Precision orbital dynamics from interstellar scintillation arcs for PSR J0437-4715

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