Testing strengths, limitations and biases of current Pulsar Timing Arrays detection analyses on realistic data

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Main Authors: Valtolina, Serena, Shaifullah, Golam, Samajdar, Anuradha, Sesana, Alberto
Format: Preprint
Published: 2023
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author Valtolina, Serena
Shaifullah, Golam
Samajdar, Anuradha
Sesana, Alberto
author_facet Valtolina, Serena
Shaifullah, Golam
Samajdar, Anuradha
Sesana, Alberto
contents State-of-the-art searches for gravitational waves (GWs) in pulsar timing array (PTA) datasets model the signal as an isotropic, Gaussian and stationary process described by a power-law. In practice, none of these properties are expected to hold for an incoherent superposition of GWs generated by a cosmic ensemble of supermassive black hole binaries (SMBHBs), which is expected to be the primary signal in the PTA band. We perform a systematic investigation of the performance of current search algorithms, using a simple power law model to characterize GW signals in realistic datasets. We use, as the baseline dataset, synthetic realisations of timing residuals mimicking the European PTA (EPTA) second data release (DR2). Thus, we include in the dataset uneven time stamps, achromatic and chromatic red noise and multi-frequency observations. We then inject timing residuals from an ideal isotropic, Gaussian, single power-law stochastic process and from a realistic population of SMBHBs, performing a methodical investigation of the recovered signal. We find that current search models are efficient at recovering the GW signal, but several biases can be identified due to the signal-template mismatch, which we identify via probability-probability (P-P) plots and quantify using Kolmogorov-Smirnov (KS) statistics. We discuss our findings in light of the signal observed in the EPTA DR2 and corroborate its consistency with an SMBHB origin.
format Preprint
id arxiv_https___arxiv_org_abs_2309_13117
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Testing strengths, limitations and biases of current Pulsar Timing Arrays detection analyses on realistic data
Valtolina, Serena
Shaifullah, Golam
Samajdar, Anuradha
Sesana, Alberto
High Energy Astrophysical Phenomena
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
General Relativity and Quantum Cosmology
State-of-the-art searches for gravitational waves (GWs) in pulsar timing array (PTA) datasets model the signal as an isotropic, Gaussian and stationary process described by a power-law. In practice, none of these properties are expected to hold for an incoherent superposition of GWs generated by a cosmic ensemble of supermassive black hole binaries (SMBHBs), which is expected to be the primary signal in the PTA band. We perform a systematic investigation of the performance of current search algorithms, using a simple power law model to characterize GW signals in realistic datasets. We use, as the baseline dataset, synthetic realisations of timing residuals mimicking the European PTA (EPTA) second data release (DR2). Thus, we include in the dataset uneven time stamps, achromatic and chromatic red noise and multi-frequency observations. We then inject timing residuals from an ideal isotropic, Gaussian, single power-law stochastic process and from a realistic population of SMBHBs, performing a methodical investigation of the recovered signal. We find that current search models are efficient at recovering the GW signal, but several biases can be identified due to the signal-template mismatch, which we identify via probability-probability (P-P) plots and quantify using Kolmogorov-Smirnov (KS) statistics. We discuss our findings in light of the signal observed in the EPTA DR2 and corroborate its consistency with an SMBHB origin.
title Testing strengths, limitations and biases of current Pulsar Timing Arrays detection analyses on realistic data
topic High Energy Astrophysical Phenomena
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2309.13117