Correlations for an anisotropic polarized stochastic gravitational wave background in pulsar timing arrays

Abstract

The recent compelling observation of the nanohertz stochastic gravitational wave background has brought to light a new galactic arena to test gravity. In this paper, we derive a formula for the most general expression of the stochastic gravitational wave background correlation that could be tested with pulsar timing and future square kilometer arrays. Our expressions extends the harmonic space analysis, also often referred to as the power spectrum approach, to predict the correlation signatures of an anisotropic polarized stochastic gravitational wave background with subluminal tensor, vector, and scalar gravitational degrees of freedom. We present the first few nontrivial anisotropy and polarization signatures in the correlation and discuss their dependence on the gravitational wave speed and pulsar distances. Our results set up tests that could potentially be used to rigorously examine the isotropy of the stochastic gravitational wave background and strengthen the existing constraints on possible non-Einsteinian polarizations in the nanohertz gravitational wave regime.

29 pages + refs, 6 figures, to appear in JCAP, our codes https://github.com/reggiebernardo/PTAfast

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Cited by in corpus (9)

• Realisation of the ultra-slow roll phase in Galileon inflation and PBH overproduction
• Obviating PBH overproduction for SIGWs generated by Pulsar Timing Arrays in loop corrected EFT of bounce
• Pulsar Timing Array Harmonic Analysis and Source Angular Correlations
• Charting the Nanohertz Gravitational Wave Sky with Pulsar Timing Arrays
• Untangling PBH overproduction in $w$-SIGWs generated by Pulsar Timing Arrays for MST-EFT of single field inflation
• Measuring anisotropies in the PTA band with cross-correlations
• Mitigating cosmic variance in the Hellings-Downs curve: a Cosmic Microwave Background analogy
• Connecting Inflation to the NANOGrav 15-year Data Set via Massive Gravity
• Spatial Correlation between Pulsars from Interfering Gravitational-Wave Sources in Massive Gravity