English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We investigate the impact of noise processes on high-precision pulsar timing.Our analysis focuses on the measurability of the second spin frequencyderivative $\ddot{\nu}$. This $\ddot{\nu}$ can be induced by several factorsincluding the radial velocity of a pulsar. We use Bayesian methods to model thepulsar times-of-arrival in the presence of red timing noise and dispersionmeasure variations, modelling the noise processes as power laws. Usingsimulated times-of-arrival that both include red noise, dispersion measurevariations and non-zero $\ddot{\nu}$ values, we find that we are able torecover the injected $\ddot{\nu}$, even when the noise model used to inject andrecover the input parameters are different. Using simulations, we show that themeasurement uncertainty on $\ddot{\nu}$ decreases with the timing baseline $T$as $T^\gamma$, where $\gamma=-7/2+\alpha/2$ for power law noise models withshallow power law indices $\alpha$ ($0<\alpha<4$). For steep power law indices($\alpha>8$), the measurement uncertainty reduces with $T^{-1/2}$. We appliedthis method to times-of-arrival from the European Pulsar Timing Array and theParkes Pulsar Timing Array and determined $\ddot{\nu}$ probability densityfunctions for 49 millisecond pulsars. We find a statistically significant$\ddot{\nu}$ value for PSR\,B1937+21 and consider possible options for itsorigin. Significant (95 per cent C.L.) values for $\ddot{\nu}$ are alsomeasured for PSRs\,J0621+1002 and J1022+1001, thus future studies shouldconsider including it in their ephemerides. For binary pulsars with smallorbital eccentricities, like PSR\,J1909$-$3744, extended ELL1 models should beused to overcome computational issues. The impacts of our results on thedetection of gravitational waves are also discussed.

Correlated timing noise and high precision pulsar timing: Measuring frequency second derivatives as an example