Angular Resolution of a Bayesian Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA

Fuente: arXiv
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Main Authors: Bloom, Malachy, Criswell, Alexander, Mandic, Vuk
Format: Preprint
Published: 2024
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author Bloom, Malachy
Criswell, Alexander
Mandic, Vuk
author_facet Bloom, Malachy
Criswell, Alexander
Mandic, Vuk
contents The Laser Interferometer Space Antenna (LISA), a spaceborne gravitational wave (GW) detector set to launch in 2035, will observe several stochastic GW backgrounds in the mHz frequency band. At least one of these signals -- arising from the tens of millions of unresolved white dwarf binaries in the Milky Way -- is expected to be highly anisotropic on the sky. We evaluate the angular resolution of LISA and its ability to characterize anisotropic stochastic GW backgrounds (ASGWBs) using the Bayesian Spherical Harmonic formalism in the Bayesian LISA Inference Package (BLIP). We use \blip to simulate and analyze ASGWB signals in LISA across a large grid in total observing time, ASGWB amplitude, and angular size. We consider the ability of the \blip anisotropic search algorithm to both characterize single point sources and to separate two point sources on the sky, using a full-width half-max (FWHM) metric to measure the quality and spread of the recovered spatial distributions. We find that the number of spherical harmonic coefficients used in the anisotropic search model is the primary factor that limits the search's angular resolution. Notably, this trend continues until computational limitations become relevant around $\ell_{\mathrm{max}}=16$; this exceeds the maximum angular resolution achieved by other map-making techniques for LISA ASGWBs.
format Preprint
id arxiv_https___arxiv_org_abs_2412_16372
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Angular Resolution of a Bayesian Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA
Bloom, Malachy
Criswell, Alexander
Mandic, Vuk
General Relativity and Quantum Cosmology
Instrumentation and Methods for Astrophysics
The Laser Interferometer Space Antenna (LISA), a spaceborne gravitational wave (GW) detector set to launch in 2035, will observe several stochastic GW backgrounds in the mHz frequency band. At least one of these signals -- arising from the tens of millions of unresolved white dwarf binaries in the Milky Way -- is expected to be highly anisotropic on the sky. We evaluate the angular resolution of LISA and its ability to characterize anisotropic stochastic GW backgrounds (ASGWBs) using the Bayesian Spherical Harmonic formalism in the Bayesian LISA Inference Package (BLIP). We use \blip to simulate and analyze ASGWB signals in LISA across a large grid in total observing time, ASGWB amplitude, and angular size. We consider the ability of the \blip anisotropic search algorithm to both characterize single point sources and to separate two point sources on the sky, using a full-width half-max (FWHM) metric to measure the quality and spread of the recovered spatial distributions. We find that the number of spherical harmonic coefficients used in the anisotropic search model is the primary factor that limits the search's angular resolution. Notably, this trend continues until computational limitations become relevant around $\ell_{\mathrm{max}}=16$; this exceeds the maximum angular resolution achieved by other map-making techniques for LISA ASGWBs.
title Angular Resolution of a Bayesian Search for Anisotropic Stochastic Gravitational Wave Backgrounds with LISA
topic General Relativity and Quantum Cosmology
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2412.16372