Which is which? Identification of the two compact objects in gravitational-wave binaries

Fuente: arXiv
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Autori principali: Gerosa, Davide, De Renzis, Viola, Tettoni, Federica, Mould, Matthew, Vecchio, Alberto, Pacilio, Costantino
Natura: Preprint
Pubblicazione: 2024
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author Gerosa, Davide
De Renzis, Viola
Tettoni, Federica
Mould, Matthew
Vecchio, Alberto
Pacilio, Costantino
author_facet Gerosa, Davide
De Renzis, Viola
Tettoni, Federica
Mould, Matthew
Vecchio, Alberto
Pacilio, Costantino
contents Compact objects observed in gravitational-wave astronomy so far always come in pairs and never individually. Identifying the two components of a binary system is a delicate operation that is often taken for granted. The labeling procedure (i.e., which is object "1" and which is object "2") effectively acts as systematics, or, equivalently an unspecified prior, in gravitational-wave data inference. The common approach is to label the objects solely by their masses, on a sample-by-sample basis. We show that object identification can instead be tackled using the posterior distribution as a whole. We frame the problem in terms of constrained clustering -- a flavor of semi-supervised machine learning -- and find that unfolding the labeling systematics can significantly impact, and arguably improve, our interpretation of the data. In particular, the precision of black-hole spin measurements improves by up to 50%, multimodalities and tails tend to disappear, posteriors become closer to Gaussian distributions, and the identification of the nature of the object (i.e. black hole vs. neutron star) is facilitated. We estimate that about 10% of the LIGO/Virgo posterior samples are affected by this relabeling, i.e. they might have been attributed to the other compact object in the observed binaries.
format Preprint
id arxiv_https___arxiv_org_abs_2409_07519
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Which is which? Identification of the two compact objects in gravitational-wave binaries
Gerosa, Davide
De Renzis, Viola
Tettoni, Federica
Mould, Matthew
Vecchio, Alberto
Pacilio, Costantino
General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
Compact objects observed in gravitational-wave astronomy so far always come in pairs and never individually. Identifying the two components of a binary system is a delicate operation that is often taken for granted. The labeling procedure (i.e., which is object "1" and which is object "2") effectively acts as systematics, or, equivalently an unspecified prior, in gravitational-wave data inference. The common approach is to label the objects solely by their masses, on a sample-by-sample basis. We show that object identification can instead be tackled using the posterior distribution as a whole. We frame the problem in terms of constrained clustering -- a flavor of semi-supervised machine learning -- and find that unfolding the labeling systematics can significantly impact, and arguably improve, our interpretation of the data. In particular, the precision of black-hole spin measurements improves by up to 50%, multimodalities and tails tend to disappear, posteriors become closer to Gaussian distributions, and the identification of the nature of the object (i.e. black hole vs. neutron star) is facilitated. We estimate that about 10% of the LIGO/Virgo posterior samples are affected by this relabeling, i.e. they might have been attributed to the other compact object in the observed binaries.
title Which is which? Identification of the two compact objects in gravitational-wave binaries
topic General Relativity and Quantum Cosmology
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2409.07519