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Main Authors: Johnson, Aaron D., Roulet, Javier, Chatziioannou, Katerina, Vallisneri, Michele, Trejo, Chris G., Gersbach, Kyle A.
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2502.14818
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author Johnson, Aaron D.
Roulet, Javier
Chatziioannou, Katerina
Vallisneri, Michele
Trejo, Chris G.
Gersbach, Kyle A.
author_facet Johnson, Aaron D.
Roulet, Javier
Chatziioannou, Katerina
Vallisneri, Michele
Trejo, Chris G.
Gersbach, Kyle A.
contents The Laser Interferometer Space Antenna (LISA) will detect mHz gravitational waves from many astrophysical sources, including millions of compact binaries in the Galaxy, thousands of which may be individually resolvable. The large number of signals overlapping in the LISA dataset requires a \emph{global fit} in which an unknown number of sources are modeled simultaneously. This introduces a \emph{label-switching ambiguity} for sources in the same class, making it challenging to distill a traditional astronomical catalog from global-fit posteriors. We present a method to construct a catalog by post-processing the global-fit posterior, relabeling samples to minimize the statistical divergence between the global fit and a factorized catalog representation. The resulting catalog consists of the source posterior distributions and their probabilities of having an astrophysical origin. We demonstrate our algorithm on two toy models and on a small simulated LISA dataset of Galactic binaries. Our method is implemented in the open-source Python package \textsc{petra\_catalogs}, and it can be applied in postprocessing to the output of any global-fit sampler.
format Preprint
id arxiv_https___arxiv_org_abs_2502_14818
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle PETRA: From the LISA global fit to a catalog of Galactic binaries
Johnson, Aaron D.
Roulet, Javier
Chatziioannou, Katerina
Vallisneri, Michele
Trejo, Chris G.
Gersbach, Kyle A.
General Relativity and Quantum Cosmology
The Laser Interferometer Space Antenna (LISA) will detect mHz gravitational waves from many astrophysical sources, including millions of compact binaries in the Galaxy, thousands of which may be individually resolvable. The large number of signals overlapping in the LISA dataset requires a \emph{global fit} in which an unknown number of sources are modeled simultaneously. This introduces a \emph{label-switching ambiguity} for sources in the same class, making it challenging to distill a traditional astronomical catalog from global-fit posteriors. We present a method to construct a catalog by post-processing the global-fit posterior, relabeling samples to minimize the statistical divergence between the global fit and a factorized catalog representation. The resulting catalog consists of the source posterior distributions and their probabilities of having an astrophysical origin. We demonstrate our algorithm on two toy models and on a small simulated LISA dataset of Galactic binaries. Our method is implemented in the open-source Python package \textsc{petra\_catalogs}, and it can be applied in postprocessing to the output of any global-fit sampler.
title PETRA: From the LISA global fit to a catalog of Galactic binaries
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2502.14818