Neural Simulation-Based Inference of the Neutron Star Equation of State directly from Telescope Spectra

Fuente: arXiv
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Auteurs principaux: Brandes, Len, Modi, Chirag, Ghosh, Aishik, Farrell, Delaney, Lindblom, Lee, Heinrich, Lukas, Steiner, Andrew W., Weber, Fridolin, Whiteson, Daniel
Format: Preprint
Publié: 2024
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author Brandes, Len
Modi, Chirag
Ghosh, Aishik
Farrell, Delaney
Lindblom, Lee
Heinrich, Lukas
Steiner, Andrew W.
Weber, Fridolin
Whiteson, Daniel
author_facet Brandes, Len
Modi, Chirag
Ghosh, Aishik
Farrell, Delaney
Lindblom, Lee
Heinrich, Lukas
Steiner, Andrew W.
Weber, Fridolin
Whiteson, Daniel
contents Neutron stars provide a unique opportunity to study strongly interacting matter under extreme density conditions. The intricacies of matter inside neutron stars and their equation of state are not directly visible, but determine bulk properties, such as mass and radius, which affect the star's thermal X-ray emissions. However, the telescope spectra of these emissions are also affected by the stellar distance, hydrogen column, and effective surface temperature, which are not always well-constrained. Uncertainties on these nuisance parameters must be accounted for when making a robust estimation of the equation of state. In this study, we develop a novel methodology that, for the first time, can infer the full posterior distribution of both the equation of state and nuisance parameters directly from telescope observations. This method relies on the use of neural likelihood estimation, in which normalizing flows use samples of simulated telescope data to learn the likelihood of the neutron star spectra as a function of these parameters, coupled with Hamiltonian Monte Carlo methods to efficiently sample from the corresponding posterior distribution. Our approach surpasses the accuracy of previous methods, improves the interpretability of the results by providing access to the full posterior distribution, and naturally scales to a growing number of neutron star observations expected in the coming years.
format Preprint
id arxiv_https___arxiv_org_abs_2403_00287
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Neural Simulation-Based Inference of the Neutron Star Equation of State directly from Telescope Spectra
Brandes, Len
Modi, Chirag
Ghosh, Aishik
Farrell, Delaney
Lindblom, Lee
Heinrich, Lukas
Steiner, Andrew W.
Weber, Fridolin
Whiteson, Daniel
High Energy Astrophysical Phenomena
Instrumentation and Methods for Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
Nuclear Theory
Neutron stars provide a unique opportunity to study strongly interacting matter under extreme density conditions. The intricacies of matter inside neutron stars and their equation of state are not directly visible, but determine bulk properties, such as mass and radius, which affect the star's thermal X-ray emissions. However, the telescope spectra of these emissions are also affected by the stellar distance, hydrogen column, and effective surface temperature, which are not always well-constrained. Uncertainties on these nuisance parameters must be accounted for when making a robust estimation of the equation of state. In this study, we develop a novel methodology that, for the first time, can infer the full posterior distribution of both the equation of state and nuisance parameters directly from telescope observations. This method relies on the use of neural likelihood estimation, in which normalizing flows use samples of simulated telescope data to learn the likelihood of the neutron star spectra as a function of these parameters, coupled with Hamiltonian Monte Carlo methods to efficiently sample from the corresponding posterior distribution. Our approach surpasses the accuracy of previous methods, improves the interpretability of the results by providing access to the full posterior distribution, and naturally scales to a growing number of neutron star observations expected in the coming years.
title Neural Simulation-Based Inference of the Neutron Star Equation of State directly from Telescope Spectra
topic High Energy Astrophysical Phenomena
Instrumentation and Methods for Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
Nuclear Theory
url https://arxiv.org/abs/2403.00287