https://doi.org/10.1140/epjc/s10052-025-15231-5
Regular Article - Theoretical Physics
GW230529: unveiling the hidden realm of the anisotropic neutron stars in the lower mass gap with gravitational wave echoes
Department of Physics, Jadavpur University, 700032, Kolkata, West Bengal, India
a
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Received:
8
November
2025
Accepted:
13
December
2025
Published online:
26
December
2025
Abstract
Recent discovery of a compact binary coalescence through GW230529 by LIGO has indicated the merger event of a compact object of mass between 
with a neutron star of mass between 
. The mass of the unknown compact object makes it within the heaviest neutron star never tracked out or the lightest black hole ever detected. Here, we have shown that such a mass gap neutron star with this observed mass () can be explained consistently by f(R) gravity. We have also adopted the presence of pressure anisotropy inside the neutron star which supports a massive neutron star with mass more than 
, compatible with LIGO data (GW190814). Further, the modified Tollman–Oppenheimer–Volkoff equations have acknowledged such a compact stellar structure that can produce gravitational wave echoes (frequencies remain in the range of 
kHz).
© The Author(s) 2025
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Funded by SCOAP3.
