Observational bounds on Dark Matter Admixed Neutron Stars from Gravitational Wave Data

TL;DR

This paper introduces a novel method to constrain dark matter properties inside neutron stars using gravitational wave data, providing new bounds on dark matter fraction and particle mass based on real GW observations.

Contribution

It presents the first observational test constraining dark matter within neutron stars using actual gravitational wave signals, analyzing multiple events to derive upper bounds on dark matter parameters.

Findings

GW190814 may be compatible with a dark matter halo in neutron stars.

Strong upper bounds on dark matter fraction are established for GW230529, GW200105, and GW200115.

Constraints on dark matter particle mass are discussed based on the analysis.

Abstract

Recent gravitational-wave (GW) observations offer a unique opportunity to probe the fundamental nature of compact objects. A growing body of research has focused on exploring the role of dark matter (DM) through the concept of DM-admixed neutron stars (NSs), where the presence of DM can significantly alter key physical properties of NSs, such as their mass, radius, and tidal deformability, ultimately affecting the predicted GW waveform emitted during binary coalescences. In this work, we present a novel observational test that, for the first time, places constraints on the influence of DM inside NSs using real GW data. By reanalyzing signals from events such as GW230529, GW200115, and GW200105, we derive new upper bounds on the DM fraction, $F_{\chi}$, and particle mass, $m_{\chi}$, under the assumption that DM is described by a scalar field with a self-interaction potential. We find that the upper bound on $F_{\chi}$ depends on the specific binary system under analysis, indicating that different DM configurations can be consistent with observations in different ways. In particular, the event GW190814 may be compatible with a DM halo configuration. In contrast, the other events analyzed (GW230529, GW200105 and GW200115) are consistent with DM forming a core inside the NS, yielding strong upper bounds on $F_{\chi}$. The corresponding values for the mass scale $m_{\chi}$ are also discussed in the text. This work offers a new approach to probing DM in the context of compact NS objects through GW observations.