Gravitational wave echoes from strange quark stars in the equation of state with density-dependent quark masses

• Published in: Nuclear science and techniques Vol. 34; no. 11; pp. 112 - 119
• Main Authors: Xu, Jian-Feng, Cui, Lei, Lu, Zhen-Yan, Xia, Cheng-Jun, Peng, Guang-Xiong
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01.11.2023; Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China; School of arts and sciences,Suqian University,Suqian 223800,China%Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials,School of Physics and Electronics,Hunan University of Science and Technology,Xiangtan 411201,China%Center for Gravitation and Cosmology,College of Physical Science and Technology,Yangzhou University,Yangzhou 225009,China%School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Beijing 100049,China
• Subjects: Beam Physics; Nuclear Energy; Particle Acceleration and Detection; Particle and Nuclear Physics; Physics; Physics and Astronomy; Strange quark matter; Gravitational wave echoes; Color-flavour-locked phase; Strange quark star
• ISSN: 1001-8042; 2210-3147
• DOI: 10.1007/s41365-023-01336-7

According to the recent studies, the gravitational wave (GW) echoes are expected to be generated by quark stars composed of ultrastiff quark matter. The ultrastiff equations of state (EOS) for quark matter were usually obtained either by a simple bag model with artificially assigned sound velocity or by employing interacting strange quark matter (SQM) depicted by simple reparameterization and rescaling. In this study, we investigate GW echoes with EOSs for SQM in the framework of the equivparticle model with density-dependent quark masses and pairing effects. We conclude that strange quark stars (SQSs) can be sufficiently compact to possess a photon sphere capable of generating GW echoes with frequencies in the range of approximately 20 kHz. However, SQSs cannot account for the observed 72 Hz signal in GW170817 event. Furthermore, we determined that quark-pairing effects play a crucial role in enabling SQSs to satisfy the necessary conditions for producing these types of echoes.