Noise analysis in the European Pulsar Timing Array data release 2 and its implications on the gravitational-wave background search
Abstract
The European Pulsar Timing Array (EPTA) collaboration has recently released an extended data set for six pulsars (DR2) and reported evidence for a common red noise signal. Here we present a noise analysis for each of the six pulsars. We consider several types of noise: (i) radio frequency independent, "achromatic", and time-correlated red noise; (ii) variations of dispersion measure and scattering; (iii) system and band noise; and (iv) deterministic signals (other than gravitational waves) that could be present in the PTA data. We perform Bayesian model selection to find the optimal combination of noise components for each pulsar. Using these custom models we revisit the presence of the common uncorrelated red noise signal previously reported in the EPTA DR2 and show that the data still supports it with a high statistical significance. Next, we confirm that there is no preference for or against the Hellings-Downs spatial correlations expected for the stochastic gravitational-wave background. The main conclusion of the EPTA DR2 paper remains unchanged despite a very significant change in the noise model of each pulsar. However, modelling the noise is essential for the robust detection of gravitational waves and its impact could be significant when analysing the next EPTA data release, which will include a larger number of pulsars and more precise measurements.
Keywords
Cite
@article{arxiv.2111.05186,
title = {Noise analysis in the European Pulsar Timing Array data release 2 and its implications on the gravitational-wave background search},
author = {A. Chalumeau and S. Babak and A. Petiteau and S. Chen and A. Samajdar and R. N. Caballero and G. Theureau and L. Guillemot and G. Desvignes and A. Parthasarathy and K. Liu and G. Shaifullah and H. Hu and E. van der Wateren and J. Antoniadis and A. -S. Bak Nielsen and C. G. Bassa and A. Berthereau and M. Burgay and D. J. Champion and I. Cognard and M. Falxa and R. D. Ferdman and P. C. C. Freire and J. R. Gair and E. Graikou and Y. J. Guo and J. Jang and G. H. Janssen and R. Karuppusamy and M. J. Keith and M. Kramer and K. J. Lee and X. J. Liu and A. G. Lyne and R. A. Main and J. W. McKee and M. B. Mickaliger and B. B. P. Perera and D. Perrodin and N. K. Porayko and A. Possenti and S. A. Sanidas and A. Sesana and L. Speri and B. W. Stappers and C. Tiburzi and A. Vecchio and J. P. W. Verbiest and J. Wang and L. Wang and H. Xu},
journal= {arXiv preprint arXiv:2111.05186},
year = {2021}
}
Comments
21 pages, 11 figures, 7 tables, 1 appendix figure and 1 appendix table, accepted for publication to MNRAS