J. Suresh | Searcharxiv

arXiv2026

Narrow spectral artifact investigation and mitigation in LIGO data from the fourth LIGO-Virgo-KAGRA observing run

We present efforts to identify, characterize, and mitigate narrow spectral artifacts in LIGO detector data during the fourth LIGO-Virgo-KAGRA observing run. Narrow spectral artifacts in gravitational-wave detectors are non-astrophysical noise sources that can degrade searches for narrowband persistent gravitational waves. Identifying and, where possible, mitigating these noise sources is one of the core efforts of the LIGO Detector Characterization group. Key software tools have been updated and new tools deployed for the fourth LIGO-Virgo-KAGRA observing run to facilitate investigations and data monitoring. We discuss these tool upgrades, and present several identified narrowband artifacts that have been successfully investigated and mitigated in LIGO data. Regardless of whether artifacts are mitigated or not, narrowband persistent gravitational-wave searches require information on which frequency bands contain non-astrophysical artifacts. Minimizing the number of bands containing non-astrophysical artifacts is essential to maximize the potential for discovery of a new class of gravitational-wave signals.

astro-ph.IM↗

arXiv2025

\textit{Euclid}: From Galaxies to Gravitational Waves -- Forecasting Stochastic Gravitational Wave Background Anisotropies and Their Cross-Correlation

We estimate the amplitude and spatial anisotropy in the stochastic gravitational wave background (SGWB) energy density due to compact binary coalescence (CBC) events: binary black holes (BBH), binary neutron stars (BNS), and black hole-neutron star (BHNS) mergers. Our starting point is the Flagship Simulation Galaxy Catalogue developed by the Euclid Consortium. For each galaxy in the Catalogue, we use the simulated mass and starformation to constrain the galaxy's star-formation history, and predict its contribution to the gravitational-wave energy density through CBC mergers. Combining such contributions from all galaxies in the Catalogue results in a prediction for the frequency spectrum and spatial anisotropy of the CBC SGWB. We also compare this prediction to semi-analytical models of SGWB generated by compact binaries. We identify a set of effective parameters that capture the key features of these models, and we apply a Bayesian framework to infer these parameters assuming an ideal scenario of cosmic variance-limited search. This represents the first step toward developing a comprehensive framework that will eventually enable the correlation of SGWB anisotropy and \textit{Euclid} galaxy data, potentially allowing us to extract valuable astrophysical information from this new observable.

gr-qc↗