GFH-v2 Pipeline for Searches of Long-Transient Gravitational Waves from Newborn Magnetars

TL;DR

This paper introduces GFH-v2, an improved algorithm for detecting long transient gravitational waves from newborn magnetars, enhancing sensitivity and computational efficiency for future astrophysical searches.

Contribution

The paper develops and describes GFH-v2, an advanced version of the Frequency Hough Transform algorithm, optimized for long transient gravitational wave searches from newborn magnetars.

Findings

Enhanced sensitivity compared to previous methods

Improved computational performance

Validated with simulated signals in O4a data

Abstract

This paper presents an enhanced methodology for searching long transient gravitational waves associated with a newborn magnetar, with particular focus on the regime in which the early spin-down is dominated by gravitational-wave emission. The analysis is performed using a strongly improved version of the generalized Frequency Hough Transform algorithm, called GFH-v2. We describe the main developments introduced relative to the original implementation and outline the optimized parameter-space selection used in the search. We then compute the theoretical sensitivity of the method and compare it with an empirical sensitivity estimate obtained by injecting simulated signals into LIGO-Virgo-KAGRA O4a data. The updated framework achieves improved sensitivity and computational performance. These results provide a robust basis for future directed searches for long-transient gravitational-wave signals from core-collapse supernovae and other transient events in current and upcoming observing runs.