More Eccentric, Not Always Less Detectable: High Mass Holds Its Ground, Low Mass Loses Reach

Abstract

Gravitational waves from eccentric compact binary coalescences trace dynamical binary formation, but matched-filtering searches responsible for most detections rely on quasicircular templates. Quantifying any sensitivity loss is crucial for assessing population completeness and the need for dedicated eccentric template banks. We present the first systematic GstLAL search study spanning eccentricities up to $e_{\rm 15Hz}=0.99$ and broad ranges of chirp mass, mass ratio, inclination, and aligned spin. Using TEOBResumS-Dalí waveforms, we inject eccentric signals and measure recovered signal-to-noise ratio, signal-consistency statistics, false-alarm rate, and sensitive volume and distance. For high-mass binaries ($\mathcal{M}_c\gtrsim30\,M_\odot$), sensitive distance is nearly independent of eccentricity, demonstrating that greater eccentricity does not necessarily reduce search sensitivity. In contrast, for low-mass binaries, sensitive distance falls by up to $\sim50\%$ near $e_{\rm 15Hz}\approx0.75$. Although the absolute loss in reach is modest given their low quasicircular sensitivity, this relative reduction exceeds the increase in sensitive distance between the second and third observing runs of the LIGO--Virgo--KAGRA collaboration and is consistent with previous low-mass studies. We also find that waveform matches at fixed source parameters substantially overpredict search sensitivity loss, meaning that the pipeline's signal-consistency test and maximization over its template bank mitigate much of the predicted sensitivity loss. This highlights the need for end-to-end injection campaigns to establish the detectability of eccentric binaries.