The Nanograv Nine-Year Data Set: Observations, Arrival Time Measurements, and Analysis of 37 Millisecond Pulsars

Arzoumanian, Zaven; Brazier, A.; Burke-Spolaor, S.; Chamberlin, S. J.; Chatterjee, Shami; Christy, B.; Cordes, J. M.; Cornish, N.; Crowter, Kathryn; Demorest, Paul; Dolch, Timothy; Ellis, Justin; Ferdman, R. D.; Fonseca, Emmanuel; Garver-Daniels, Nathan; Gonzalez, Marjorie; Jenet, Fredrick; Jones, Glenn; Jones, Megan L.; Kaspi, V. M.; Koop, Michael J.; Lam, Michael T.; Lazio, T. Joseph W.; Levin, Lina; Lommen, A. N.; Lorimer, D. R.; Luo, Jing; Lynch, R.; Madison, D. R.; McLaughlin, M. A.; McWilliams, S. T.; Nice, D. J.; Palliyaguru, Nipuni; Pennucci, Timothy T.; Ransom, S. M.; Siemens, X.; Stairs, I. H.; Stinebring, Daniel R.; Stovall, K.; Swiggum, Joseph K.; Vallisneri, Michele; Haasteren, Rutger van; Wang, Yan; Zhu, Weiwei

doi:10.1088/0004-637x/813/1/65

Cited by 220 publications

(166 citation statements)

References 48 publications

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“…Each of the above are meant to describe separate astrophysical phenomena but note that there will be large covariances between the terms; future work is needed in determining best practices for modeling longer-term chromatic variations in TOA timeseries. In addition to these Model A components, we added either a power-law Gaussian process ∝ν −4 component that accounts for possible scattering or refractive variations (Foster & Cordes 1990) over the entire timeseries (Model B) or a ∝ν −4 exponential decay term with the same start time and decay constant as the ν −2 delay term for the second event (Model C); our earlier data around the time of the first event are not sensitive to multiple chromatic components because of the small bandwidths observed for the individual bands as previously described (see also Arzoumanian et al 2015). The components for all three models are described in Table 1.…”

Section: Multicomponent Chromatic Fittingmentioning

confidence: 64%

“…We observed pulse profiles with AO at 1400 and 2300MHz using the Arecibo Signal Processor backend (ASP; up to 64 MHz bandwidth) and then the larger-bandwidth Puerto Rico Ultimate Pulsar Processing Instrument backend (PUPPI; up to 800 MHz bandwidth) since 2012 (Arzoumanian et al 2015). At GBT, we used the nearly identical Green Bank Astronomical Signal Processor (GASP) backend and then the Green Bank Ultimate Pulsar Processing Instrument (GUPPI) backend after 2010 to observe at 820 and 1400MHz.…”

Section: Observationsmentioning

confidence: 99%

“…The DM model assumes a step-wise value of DM (DMX), i.e., constant over rolling periods of up to six days as in NG11. We used an F-test described by Arzoumanian et al (2015) to determine if new parameters should be added but none were found to be significant. Figure 2 shows the Dt 2,1400 ∝ν −2 timeseries modeled by our step-wise DM model and the trajectory of the pulsar across the sky, with decreasing values shown by darker colors, similar to the depiction in Jones et al (2017).…”

Section: Traditional Timing Model Fitting With Per-epoch Dm Variationmentioning

confidence: 99%

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A Second Chromatic Timing Event of Interstellar Origin toward PSR J1713+0747

Lam

Ellis

Grillo

et al. 2018

ApJ

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The frequency dependence of radio pulse arrival times provides a probe of structures in the intervening media. Demorest et al. was the first to show a short-term (∼100-200 days) reduction in the electron content along the line of sight to PSRJ1713+0747 in data from 2008 (approximately MJD 54750) based on an apparent dip in the dispersion measure of the pulsar. We report on a similar event in 2016 (approximately MJD 57510), with average residual pulse-arrival times ≈−3.0, −1.3, and −0.7 μs at 820, 1400, and 2300MHz, respectively. Timing analyses indicate possible departures from the standard ν −2 dispersive-delay dependence. We discuss and rule out a wide variety of potential interpretations. We find the likeliest scenario to be lensing of the radio emission by some structure in the interstellar medium, which causes multiple frequency-dependent pulse arrival-time delays.

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Section: Multicomponent Chromatic Fittingmentioning

confidence: 64%

Section: Observationsmentioning

confidence: 99%

Section: Traditional Timing Model Fitting With Per-epoch Dm Variationmentioning

confidence: 99%

See 1 more Smart Citation

A Second Chromatic Timing Event of Interstellar Origin toward PSR J1713+0747

Lam

Ellis

Grillo

et al. 2018

ApJ

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“…PSR J1713+0747 shows the best timing precision in current timing-array efforts Arzoumanian et al 2015). It also shows only modest levels of scattering with ∆ν d ≈ 30 MHz at a frequency of 1.4 GHz (Keith et al 2013).…”

Section: Turbulent Mediamentioning

confidence: 98%

Modelling and mitigating refractive propagation effects in precision pulsar timing observations

Shannon

Cordes

2016

Mon. Not. R. Astron. Soc.

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To obtain the most accurate pulse arrival times from radio pulsars, it is necessary to correct or mitigate the effects of the propagation of radio waves through the warm and ionised interstellar medium. We examine both the strength of propagation effects associated with large-scale electron-density variations and the methodology used to estimate infinite-frequency arrival times. Using simulations of two-dimensional phasevarying screens, we assess the strength and non-stationarity of timing perturbations associated with large-scale density variations. We identify additional contributions to arrival times that are stochastic in both radio frequency and time and therefore not amenable to correction solely using times of arrival. We attribute this to the frequency dependence of the trajectories of the propagating radio waves. We find that this limits the efficacy of low-frequency (metre-wavelength) observations. Incorporating low-frequency pulsar observations into precision timing campaigns is increasingly problematic for pulsars with larger dispersion measures.

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“…In Fig. 3 (middle-right panel) we show the epoch-averaged residuals when modelling the profile evolution using the 'FD' parameterisation (Arzoumanian et al 2015). The FD parameters model profile evolution as a shift in the arrival time given by:…”

Section: Simulationsmentioning

confidence: 99%

Wide-band profile domain pulsar timing analysis

Lentati

Kerr

Dai

et al. 2016

Mon. Not. R. Astron. Soc.

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We extend profile domain pulsar timing to incorporate wide-band effects such as frequencydependent profile evolution and broadband shape variation in the pulse profile. We also incorporate models for temporal variations in both pulse width and in the separation in phase of the main pulse and interpulse. We perform the analysis with both nested sampling and Hamiltonian Monte Carlo methods. In the latter case we introduce a new parameterisation of the posterior that is extremely efficient in the low signal-to-noise regime and can be readily applied to a wide range of scientific problems. We apply this methodology to a series of simulations, and to between seven and nine yr of observations for PSRs J1713+0747, J1744−1134, and J1909−3744 with frequency coverage that spans 700-3600 MHz. We use a smooth model for profile evolution across the full frequency range, and compare smooth and piecewise models for the temporal variations in DM. We find the profile domain framework consistently results in improved timing precision compared to the standard analysis paradigm by as much as 40% for timing parameters. Incorporating smoothness in the DM variations into the model further improves timing precision by as much as 30%. For PSR J1713+0747 we also detect pulse shape variation uncorrelated between epochs, which we attribute to variation intrinsic to the pulsar at a level consistent with previously published analyses. Not accounting for this shape variation biases the measured arrival times at the level of ∼30 ns, the same order of magnitude as the expected shift due to gravitational-waves in the pulsar timing band.

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The Nanograv Nine-Year Data Set: Observations, Arrival Time Measurements, and Analysis of 37 Millisecond Pulsars

Cited by 220 publications

References 48 publications

A Second Chromatic Timing Event of Interstellar Origin toward PSR J1713+0747

A Second Chromatic Timing Event of Interstellar Origin toward PSR J1713+0747

Modelling and mitigating refractive propagation effects in precision pulsar timing observations

Wide-band profile domain pulsar timing analysis

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