Abstract Details

Name: BHASKAR BISWAS
Affiliation: The Inter-University Centre for Astronomy and Astrophysics
Conference ID: ASI2021_208
Title : GW190814: On the properties of the secondary component of the binary
Authors and Co-Authors : 1. Bhaskar Biswas(Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007, India) 2. Rana Nandi(Polba Mahavidyalaya, Hooghly, West Bengal 712148, India) 3. Prasanta Char (Space sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, Bât. B5a, 4000 Liège, Belgium) 4. Sukanta Bose(Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007, India) 5. Nikolaos Stergioulas (Aristotle University of Thessaloniki, Department of Physics, University Campus Laboratory of Astronomy, 54124 Thessaloniki, Greece)
Abstract Type : Oral
Abstract Category : General Relativity and Cosmology
Abstract : We show that the odds of the mass-gap (secondary) object in GW190814 being a neutron star (NS) improve if one allows for a stiff high-density equation of state (EoS) or a large spin, when employing a nuclear parameterization of the EoS. Since its mass is $\in (2.50,2.67) M_{\odot}$, establishing its true nature will make it either the heaviest neutron star or the lightest black hole (BH), and can have far-reaching implications on neutron star EoS and compact object formation channels. When limiting oneself to the NS hypothesis, we deduce the secondary's properties by using a Bayesian framework with a nuclear-physics informed model of NS equation of state and combining a variety of astrophysical observations. For the slow-rotation scenario, GW190814 implies a very stiff EoS and a stringent constraint on the equation of state specially in the high-density region. On the other hand, assuming a conservative maximum mass for nonrotating neutron stars requires rapid rotation and we constrain its rotational frequency to be $f=1143^{+194}_{-155}$ Hz, within a $90\%$ confidence interval. In this scenario, the secondary object in GW190814 would qualify as the fastest rotating neutron star ever observed. However, for this scenario to be viable, rotational instabilities would have to be suppressed both during formation and the subsequent evolution until merger, otherwise the secondary of GW190814 is more likely to be a black hole.