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CW Seminar: Application of a hierarchical MCMC follow-up to Advanced LIGO continuous gravitational-wave candidates

June 21, 2021 @ 3:30 pm - 4:30 pm

The 21th of June will be a  seminar at the CW group of the Max-Planck-Institut für Gravitationsphysik by Rodrigo.

Title: Application of a hierarchical MCMC follow-up to Advanced LIGO continuous gravitational-wave candidatesAuthor: Rodrigo Tenorio

Searches for continuous gravitational waves from unknown sources generally produce a significant number of outliers. Existing follow-up methods to confirm or exclude these as viable candidates are usually limited to a particular search pipeline and require extensive calibration. We present the first application of a general-purpose hierarchical Markov chain Monte Carlo (MCMC) follow-up on continuous gravitational-wave candidates from real-data searches. The follow-up uses an MCMC sampler to draw parameter-space points following the F-statistic. As outliers are narrowed down, coherence time increases, imposing more restrictive phase evolution templates. This method is simpler to set up than current grid-based approaches. We introduce a Bayes factor to compare results from different stages: The probability under the signal hypothesis is derived from first principles, while for the probability under the noise hypothesis we use extreme value theory to derive a background model. The effectiveness of our proposal is evaluated on fake Gaussian data and applied to a set of 30 outliers produced by different continuous wave searches on O2 Advanced LIGO data. The results of our analysis suggest a non-astrophysical origin of all but three outliers, which we manually ascribe to instrumental artifacts and a strong hardware injection present in the data.

Online Link: https://mpi-aei.zoom.us/my/m.a.papa


June 21, 2021
3:30 pm - 4:30 pm
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