SearcharxivSearch

arXiv · 2504.00198

Sky localization and polarization mode reconstruction of gravitational waves from GW170104 and GW150914

Abstract

The detections\citep{KAGRA:2023pio,LIGOScientific:2019lzm} and analysis of gravitational waves(GWs) have introduced us in a new era of our understanding of the cosmos, providing new insights into astrophysical systems involving massive objects as black holes and neutron stars. Normally the precise sky localization of a GW source needs data from three or more observatories\citep{LIGOScientific:2016lio,Abbott:2017oio}. However, the results presented in this article demonstrate that it is in fact possible to obtain the position of a GW source in a small region of the celestial sphere using data from just two GW observatories, in this case LIGO Hanford and LIGO Livingston. Furthermore, we are also able to reconstruct the gravitational-wave polarization\citep{Poisson2014} modes(PMs) for the GW170104\citep{Abbott:2017vtc} and GW150914\citep{TheLIGOScientific:2016qqj} events, with data from only these two detectors. The procedure only uses the spin 2 properties of the GW, so that it does not rely on specific assumptions on the nature of the source. Our findings are possible through careful data filtering methods\citep{Moreschi:2019vxw}, the use of refined signal processing algorithms\citep{Moreschi:2024njx}, and the application of dedicated denoising\citep{Mallat2009} techniques. This progress in the GW studies represents the first instance of a direct measurement of PMs using such a limited observational data. We provide detailed validation through the reconstruction of PMs for different polarization angles, and calculations of residuals for the GW170104 event. We also test the procedure with synthetic data with ten different source locations and polarization angles.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Osvaldo M. Moreschi. 2025-03-31. Sky localization and polarization mode reconstruction of gravitational waves from GW170104 and GW150914. https://doi.org/10.1007/s10509-025-04465-0

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Electrovacuum Black Hole Uniqueness

We prove the black hole uniqueness conjecture in the axially symmetric, stationary, electrovacuum setting, subject to the refined asymptotic analysis of the associated singular harmonic maps, which includes an analyticity hypothesis at the axes. More precisely, it is shown that any asymptotically flat solution of the Einstein--Maxwell equations in this class, with more than one black hole horizon component is either: Majumdar--Papapetrou, up to a duality rotation, in which case all logarithmic angle defects vanish, or every finite axis rod logarithmic angle defect is strictly negative and hence every interaction force is strictly attractive. The proof extends the singular harmonic map method used for vacuum Kerr uniqueness in [18].

gr-qc

Constraining Modified Mass-to-Horizon Cosmology Through Primordial Inflationary Observables

We investigate slow-roll inflation in a modified cosmological framework inspired by a generalized mass-to-horizon relation (MHR), $M=\gamma {c^2 L^n}/{G}$, where $n$ is a real parameter and $\gamma$ a dimensional constant. Using Padmanabhan's emergence paradigm, we derive the modified Friedmann equations for a flat FRW universe and analyze the dynamics of a canonical scalar field (inflaton) under the slow-roll approximation. We study the resulting inflationary phenomenology for power-law and Starobinsky potentials. For power-law potentials, the MHR modification fails to reconcile these models with current CMB constraints on $r$ and $n_s$. In contrast, Starobinsky inflation exhibits significant sensitivity to deviations from $n=1$. A perturbative analysis ($n=1+\Delta$) yields corrections to inflationary observables. We observe that the scalar power-spectrum normalization, under a fixed-Starobinsky prescription, imposes the stringent constraint $0.960 \lesssim n \lesssim 1.040$ for $N=60$ efolds. This is considerably tighter than spectral-index bounds. Our results establish inflation, particularly Starobinsky-like models, as a sensitive probe of generalized horizon thermodynamics and departures from standard MHR scaling.

gr-qc

Improving the Sensitivity of Gravitational Wave Detection with Weighted Conformal Prediction

In the last decade, kilometre-scale interferometric gravitational-wave detectors have observed hundreds of compact binary mergers, the majority of which are binary black holes. However, the data are noise-dominated, and multiple independent search algorithms (pipelines) are used to enhance sensitivity and improve robustness. Rather than the standard approach of selecting the most significant pipeline output, we combine the outputs from all pipelines using a conformal prediction-based framework to provide statistically rigorous confidence estimates for candidate events. While combining pipelines improves sensitivity and ranking robustness, it requires a principled statistical framework that remains valid as data properties evolve across observing runs. A key challenge is distribution shifts between simulated datasets used for training and calibration and the real, unlabelled, observations used for testing, which can invalidate coverage guarantees and bias confidence estimates. In this work, we address this challenge by incorporating likelihood-ratio reweighting into our conformal prediction framework to account for covariate shift. Using mock datasets containing simulated signals, we demonstrate that weighted conformal prediction restores well-calibrated coverage under covariate shift and increases the confidence of events near the detection threshold, recovering true signals that would otherwise be missed.

gr-qc