Limits on the Stochastic Gravitational Wave Background From the North American Nanohertz Observatory for Gravitational Waves

Demorest, Paul; Ferdman, R. D.; Gonzalez, M. E.; Nice, D. J.; Ransom, S. M.; Stairs, I. H.; Arzoumanian, Zaven; Brazier, A.; Burke-Spolaor, S.; Chamberlin, S. J.; Cordes, J. M.; Ellis, Justin; Finn, L. S.; Freire, P. C. C.; Giampanis, S.; Jenet, Fredrick; Kaspi, V. M.; Lazio, Joseph; Lommen, A. N.; McLaughlin, M. A.; Palliyaguru, N.; Perrodin, D.; Shannon, R. M.; Siemens, X.; Stinebring, D. R.; Swiggum, Joseph K.; Zhu, Weiwei

doi:10.1088/0004-637x/762/2/94

Cited by 334 publications

(453 citation statements)

References 46 publications

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“…Pulsars were included in the data set based on the anticipated stability of their timing, their TOA precision, and their detection over a wide frequency range. Of the 37 MSPs included in the data release, 17 were reported on in Demorest et al (2013). Observations took place roughly once a month between 2004 and 2013 with observing time spans of individual pulsars ranging from 0.6 to 9.0 years.…”

Section: Datamentioning

confidence: 99%

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

Jones

McLaughlin

Lam

et al. 2017

ApJ

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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: Datamentioning

confidence: 99%

“…Observing at least two frequencies is necessary to solve for the DM for a measured time delay. This time delay can be significant when compared to the pulsar period, and therefore the DM must be fit when creating a timing model and corrected for at each epoch (e.g., Demorest et al 2013;Arzoumanian et al 2015).…”

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

Self Cite

101

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“…We want the relative change of K in Equation (7) to be less 10% during the time span ∆t (so that the change of the variance of the GW-induced timing residuals < 1%). From Equations (12) and (13) we know that…”

Section: Target Sourcesmentioning

confidence: 99%

“…Among the various proposed methods, the pulsar timing array (PTA) method shows promise in identifying GWimprinted structure in the timing residuals of a number of pulsars [10,11]. Although no detection has been made, more and more stringent upper limits of both individual GWs and GW background have been set using this method [12][13][14][15]. The traditional pulsar timing method has an upper limit on the frequency of detectable GWs, which is known as the Nyquist frequency ( f Ny ).…”

mentioning

confidence: 99%

“…We test the feasibility of our method on simulated timing data in Section 3. A subset of pulsars is selected from the Parkes Pulsar Timing Array data release 1 (PPTA DR1) [17] and the North American Nanohertz Observatory for Gravitational Waves (NANOGrav dfg+12) publicly available datasets [12]. The selected PTA is used to search for SNFGWs using the proposed method in Section 4.…”

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confidence: 99%

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Detecting super-Nyquist-frequency gravitational waves using a pulsar timing array

Zhang

2016

Sci. China Phys. Mech. Astron.

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The maximum frequency of gravitational waves (GWs) detectable with traditional pulsar timing methods is set by the Nyquist frequency ( f Ny ) of the observation. Beyond this frequency, GWs leave no temporal-correlated signals; instead, they appear as white noise in the timing residuals. The variance of the GW-induced white noise is a function of the position of the pulsars relative to the GW source. By observing this unique functional form in the timing data, we propose that we can detect GWs of frequency > f Ny (super-Nyquist frequency GWs; SNFGWs). We demonstrate the feasibility of the proposed method with simulated timing data. Using a selected dataset from the Parkes Pulsar Timing Array data release 1 and the North American Nanohertz Observatory for Gravitational Waves publicly available datasets, we try to detect the signals from single SNFGW sources. The result is consistent with no GW detection with 65.5% probability. An all-sky map of the sensitivity of the selected pulsar timing array to single SNFGW sources is generated, and the position of the GW source where the selected pulsar timing array is most sensitive to is λ s = −0.82, β s = −1.03 (rad); the corresponding minimum GW strain is h = 6.31 × 10 −11 at f = 1 × 10 −5 Hz. gravitational wave, pulsar, black hole PACS number(s): 25.60. Je, 21.10.Jx, 25.40.Lw, 26.20.+f

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Pulsar Timing Arrays and the Challenge of Massive Black Hole Binary Astrophysics

Sesana

2014

Gravitational Wave Astrophysics

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Pulsar timing arrays (PTAs) are designed to detect gravitational waves (GWs) at nHz frequencies. The expected dominant signal is given by the superposition of all waves emitted by the cosmological population of supermassive black hole (SMBH) binaries. Such superposition creates an incoherent stochastic background, on top of which particularly bright or nearby sources might be individually resolved. In this contribution I describe the properties of the expected GW signal, highlighting its dependence on the overall binary population, the relation between SMBHs and their hosts, and their coupling with the stellar and gaseous environment. I describe the status of current PTA efforts, and prospect of future detection and SMBH binary astrophysics.

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Limits on the Stochastic Gravitational Wave Background From the North American Nanohertz Observatory for Gravitational Waves

Cited by 334 publications

References 46 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

Detecting super-Nyquist-frequency gravitational waves using a pulsar timing array

Pulsar Timing Arrays and the Challenge of Massive Black Hole Binary Astrophysics

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