Supermassive black hole binary environments: Effects on the scaling laws and time to detection for the stochastic background

Vigeland, Sarah J.; Siemens, X.

doi:10.1103/physrevd.94.123003

Cited by 13 publications

(10 citation statements)

References 24 publications

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“…Sensitivity improves as more millisecond pulsars (MSPs) are added to the PTA, and therefore it is essential to have as many well-timed MSPs as possible (Siemens et al 2013;Vigeland & Siemens 2016). For every MSP, we must construct an accurate timing model that accounts for all known effects on the pulsar times of arrival (TOAs) over decade timescales (Jenet et al 2005;Cordes & Shannon 2010).…”

Section: Introductionmentioning

confidence: 99%

The NANOGrav Nine-year Data Set: Measurement and Analysis of Variations in Dispersion Measures

Jones

McLaughlin

Lam

et al. 2017

ApJ

101

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We analyze dispersion measure (DM) variations of 37 millisecond pulsars in the nine-year North American Nanohertz Observatory for Gravitational Waves (NANOGrav) data release and constrain the sources of these variations. DM variations can result from a changing distance between Earth and the pulsar, inhomogeneities in the interstellar medium, and solar effects. Variations are significant for nearly all pulsars, with characteristic timescales comparable to or even shorter than the average spacing between observations. Five pulsars have periodic annual variations, 14 pulsars have monotonically increasing or decreasing trends, and 14 pulsars show both effects. Of the four pulsars with linear trends that have line-of-sight velocity measurements, three are consistent with a changing distance and require an overdensity of free electrons local to the pulsar. Several pulsars show correlations between DM excesses and lines of sight that pass close to the Sun. Mapping of the DM variations as a function of the pulsar trajectory can identify localized interstellar medium features and, in one case, an upper limit to the size of the dispersing region of 4 au. Four pulsars show roughly Kolmogorov structure functions (SFs), and another four show SFs less steep than Kolmogorov. One pulsar has too large an uncertainty to allow comparisons. We discuss explanations for apparent departures from a Kolmogorov-like spectrum, and we show that the presence of other trends and localized features or gradients in the interstellar medium is the most likely cause.

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Section: Introductionmentioning

confidence: 99%

The NANOGrav Nine-year Data Set: Measurement and Analysis of Variations in Dispersion Measures

Jones

McLaughlin

Lam

et al. 2017

ApJ

101

View full text Add to dashboard Cite

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“…NANOGrav currently employs a mixed observational strategy such that it targets several of its best timed pulsars more frequently than the others expressedly for this purpose (Arzoumanian et al 2018a). The second approach is to increase the number of pulsars, which is of primary interest for detecting and characterizing the stochastic background of gravitational waves and its anisotropies (Mingarelli et al 2013;Siemens et al 2013;Chamberlin et al 2015;Vigeland & Siemens 2016). The third attempts to optimize the allocation of resources by choosing time and frequency coverage tailored to individual pulsars' characteristics (Lee et al 2012;Lam et al 2018a;Lam 2018).…”

Section: Precision Timing Ptas and Wideband Receiversmentioning

confidence: 99%

Frequency-dependent Template Profiles for High-precision Pulsar Timing

Pennucci

2019

ApJ

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Pulsar timing experiments require high fidelity template profiles in order to minimize the biases in pulse time-of-arrival (TOA) measurements and their uncertainties. Efforts to acquire more precise TOAs given fixed effective area of telescopes, finite receiver noise, and limited integration time have led pulsar astronomers to the solution of implementing ultra-wideband receivers. This solution, however, has run up against the problem that pulse profile shapes evolve with frequency, which raises the question of how to properly measure and analyze TOAs obtained using template-matching methods. This paper proposes a new method for one facet of this problem, that of template profile generation, and demonstrates it on the well-timed millisecond pulsar J1713+0747. Specifically, we decompose pulse profile evolution into a linear combination of basis eigenvectors, the coefficients of which change slowly with frequency such that their evolution is modeled simply by a sum of low degree piecewise polynomial spline functions. These noise-free, high fidelity, frequency-dependent templates can be used to make measurements of so-called "wideband TOAs" simultaneously with an estimate of the instantaneous dispersion measure. The use of wideband TOAs is becoming important for pulsar timing array experiments, as the volume of datasets comprised of conventional, subbanded TOAs are quickly becoming unwieldly for the Bayesian analyses needed to uncover latent gravitational wave signals. Although motivated by high precision timing experiments, our technique is applicable in more general pulsar observations.

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“…Unlike the first detections of GWs from compact binary coalescences (Abbott et al 2016(Abbott et al , 2017, a detection of the GWB will not appear as a single event, but rather a steady growth in significance over the course of a number of data releases. The evolution of detection statistics has been studied in the literature extensively Vigeland & Siemens 2016), including theoretical studies of the scaling of the frequentist optimal statistic and numerical simulations using realistic data to predict when PTAs will reach specified sensitivities. Work of this kind is important for understanding the context of current data releases and the near-future ability to characterize nanohertz GW astrophysics.…”

Section: Evolution Of Gwb Statisticsmentioning

confidence: 99%

The NANOGrav 11-Year Data Set: Evolution of Gravitational Wave Background Statistics

Hazboun,

Simon,

Taylor

et al. 2019

Preprint

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An ensemble of inspiraling supermassive black hole binaries should produce a stochastic background of very low frequency gravitational waves. This stochastic background is predicted to be a power law, with a spectral index of -2/3, and it should be detectable by a network of precisely timed millisecond pulsars, widely distributed on the sky. This paper reports a new "time slicing" analysis of the 11-year data release from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) using 34 millisecond pulsars. Methods to flag potential "false positive" signatures are developed, including techniques to identify responsible pulsars. Mitigation strategies are then presented. We demonstrate how an incorrect noise model can lead to spurious signals, and show how independently modeling noise across 30 Fourier components, spanning NANOGrav's frequency range, effectively diagnoses and absorbs the excess power in gravitational-wave searches. This results in a nominal, and expected, progression of our gravitational-wave statistics. Additionally we show that the first interstellar medium event in PSR J1713+0747 pollutes the common red noise process with low-spectral index noise, and use a tailored noise model to remove these effects.

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Supermassive black hole binary environments: Effects on the scaling laws and time to detection for the stochastic background

Cited by 13 publications

References 24 publications

The NANOGrav Nine-year Data Set: Measurement and Analysis of Variations in Dispersion Measures

The NANOGrav Nine-year Data Set: Measurement and Analysis of Variations in Dispersion Measures

Frequency-dependent Template Profiles for High-precision Pulsar Timing

The NANOGrav 11-Year Data Set: Evolution of Gravitational Wave Background Statistics

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