Probing the nuclear equation of state from the existence of a $\sim 2.6M_{\odot }$ neutron star: the GW190814 puzzle

Abstract

On August 14, 2019, the LIGO/Virgo collaboration observed a compact object with mass $\sim 2.59_{-0.09}^{+0.08}{M}_{\odot }$, as a component of a system where the main companion was a black hole with mass $\sim 23M_{\odot }$. A scientific debate initiated concerning the identification of the low mass component, as it falls into the neutron star - black hole mass gap. The understanding of the nature of GW190814 event will offer rich information concerning open issues, the speed of sound and the possible phase transition into other degrees of freedom. In the present work, we made an effort to probe the nuclear equation of state along with the GW190814 event. Firstly, we examine possible constraints on the nuclear equation of state inferred from the consideration that the low mass companion is a slow or rapidly rotating neutron star. In this case, the role of the upper bounds on the speed of sound is revealed, in connection with the dense nuclear matter properties. Secondly, we systematically study the tidal deformability of a possible high mass candidate existing as an individual star or as a component one in a binary neutron star system. As the tidal deformability and radius are quantities very sensitive on the neutron star equation of state, they are excellent counters on dense matter properties. We conjecture that similar isolated neutron stars or systems may exist in the Universe and their possible future observation will shed light on the maximum neutron star mass problem.

v1: 18 pages, 8 figures, 2 tables. v2: 23 pages, 9 figures, 3 tables; accepted for publication in Symmetry

References in corpus (13)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• A Massive Pulsar in a Compact Relativistic Binary
• GW190814: Gravitational Waves from the Coalescence of a 23 M${}_{\odot }$ Black Hole with a 2.6 M${}_{\odot }$ Compact Object
• Tidal Love numbers of neutron stars
• Constraining neutron star tidal Love numbers with gravitational wave detectors
• Reconstructing the neutron-star equation of state with gravitational-wave detectors from a realistic population of inspiralling binary neutron stars
• A lower bound on the maximum mass if the secondary in GW190814 was once a rapidly spinning neutron star
• Constraining the High-Density Behavior of Nuclear Symmetry Energy with the Tidal Polarizability of Neutron Stars
• Exploring the Lower Mass Gap and Unequal Mass Regime in Compact Binary Evolution
• Confronting GW190814 with hyperonization in dense matter and hypernuclear compact stars
• A Population-Informed Mass Estimate for Pulsar J0740+6620
• Formation of mass gap objects in highly asymmetric mergers
• Speed of sound constraints on maximally rotating neutron stars

Cited by in corpus (4)

• Gravitational wave echoes from interacting quark stars
• Quasi-universality of the magnetic deformation of neutron stars in general relativity and beyond
• $2.6M_{\odot }$ Compact Object and Neutron Stars within Eddington-Inspired Born-Infeld Theory of Gravity
• Neutron Stars and Gravitational Waves: the Key Role of Nuclear Equation of State