Prasanta Char
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View article: Probing Neutron Star Interiors and the Properties of Cold Ultra-dense Matter with the SKA
Probing Neutron Star Interiors and the Properties of Cold Ultra-dense Matter with the SKA Open
Matter inside neutron stars is compressed to densities several times greater than nuclear saturation density, while maintaining low temperatures and large asymmetries between neutrons and protons. Neutron stars, therefore, provide a unique…
View article: Populations Of Binary Compact Objects: The Present (GWTC-4) And The Future (Einstein Telescope)
Populations Of Binary Compact Objects: The Present (GWTC-4) And The Future (Einstein Telescope) Open
Plenary talk presented at the XXI International Workshop on Neutrino Telescopes - Padova 29 September - 3 October 2025 (https://agenda.infn.it/event/44606/)
View article: Properties of Neutron Stars with Hyperons within a Relativistic Metamodel
Properties of Neutron Stars with Hyperons within a Relativistic Metamodel Open
In this work, we study the effects of $Λ$-hyperons on neutron star properties employing a metamodel framework for the equation of state (EoS). Different choices for defining the hyperonic couplings with different levels of parametric freed…
View article: Systematics from NICER Pulse Profiles Drive Uncertainty in Multi-Messenger Inference of the Neutron Star Equation of State
Systematics from NICER Pulse Profiles Drive Uncertainty in Multi-Messenger Inference of the Neutron Star Equation of State Open
We present new constraints on the neutron star equation of state (EOS) and mass distribution using a unified Bayesian inference framework that incorporates latest NICER measurements, including PSR J0614$-$3329, alongside gravitational wave…
View article: Stellar properties indicating the presence of hyperons in neutron stars
Stellar properties indicating the presence of hyperons in neutron stars Open
We describe distinctive stellar features indicating the presence of hyperons in neutron stars. A strongly negative curvature of the mass-radius relation R(M) is characteristic of hyperons, which can be determined from measurements of neutr…
View article: Exploring the limits of nucleonic metamodelling using different relativistic density functionals
Exploring the limits of nucleonic metamodelling using different relativistic density functionals Open
In this work, we explore two classes of density dependent relativistic mean-field models, their predictions of proton fractions at high densities and neutron star structure. We have used a metamodelling approach to these relativistic densi…
View article: Gauge-invariant perturbations of relativistic nonperfect fluids in spherical spacetime
Gauge-invariant perturbations of relativistic nonperfect fluids in spherical spacetime Open
Astrophysical compact objects are usually studied using a perfect fluid model. However, in astrophysical processes out-of-equilibrium, dissipative effects become important to describe the dynamics of the system. In this work, we obtain gau…
View article: Gauge-invariant perturbations of relativistic non-perfect fluids in spherical spacetime
Gauge-invariant perturbations of relativistic non-perfect fluids in spherical spacetime Open
Astrophysical compact objects are usually studied using a perfect fluid model. However, in astrophysical processes out-of-equilibrium, dissipative effects become important to describe the dynamics of the system. In this work, we obtain gau…
View article: Structural response of neutron stars to rapid rotation and its impact on the braking index
Structural response of neutron stars to rapid rotation and its impact on the braking index Open
Pulsars are rotating neutron stars that are observed to be slowing down, implying a loss of their rotational energy. There can be several different physical mechanisms involved in their spin-down process. The properties of fast-rotating pu…
View article: The compact object of HESS J1731-347 and its implication on neutron star matter
The compact object of HESS J1731-347 and its implication on neutron star matter Open
In this work, we investigate the impact of the possibility of a small, subsolar mass compact star, such as the recently reported central compact object of HESS J1731-347, on the equation of state (EOS) of neutron stars. We have used a hybr…
View article: Tests of General Relativity with GW230529: a neutron star merging with a lower mass-gap compact object
Tests of General Relativity with GW230529: a neutron star merging with a lower mass-gap compact object Open
On 29 May 2023, the LIGO Livingston observatory detected the gravitational-wave signal GW230529_181500 from the merger of a neutron star with a lower mass-gap compact object. Its long inspiral signal provides a unique opportunity to test G…
View article: Stability and instability of strange dwarfs
Stability and instability of strange dwarfs Open
Aims. More than 20 years ago, the existence of stable white dwarfs with a core of strange quark matter was proposed. More recently, via the study of radial modes, it has been concluded instead that such objects are unstable. We aim to clar…
View article: Radial Oscillations of Neutron Stars with Antikaon Condensate
Radial Oscillations of Neutron Stars with Antikaon Condensate Open
In this article, we study the neutron stars with antikaon condensates and their radial oscillations. We incorporate the antikaons $(K^-,\bar{K}^0)$ within a relativistic mean field theory with density dependent couplings. A transition to t…
View article: Generalised description of Neutron Star matter with nucleonic Relativistic Density Functional
Generalised description of Neutron Star matter with nucleonic Relativistic Density Functional Open
In this work, we propose a meta-modelling technique to nuclear matter on the basis of a relativistic density functional with density-dependent couplings. Identical density dependence for the couplings both in the isoscalar and isovector se…
View article: Massive compact stars in the two-families scenario
Massive compact stars in the two-families scenario Open
We review the two-families scenario of compact stars. Under the hypothesis that strange quark matter is the ground state of dense matter one can infer the existence of two separated branches of stars: hadronic stars and quark stars. While …
View article: Stability and instability of strange dwarfs
Stability and instability of strange dwarfs Open
More than 20 years ago, Glendenning, Kettner and Weber proposed the existence of stable white dwarfs with a core of strange quark matter. More recently, by studying radial modes, Alford, Harris and Sachdeva concluded instead that those obj…
View article: Speed of sound in dense matter and two families of compact stars
Speed of sound in dense matter and two families of compact stars Open
The existence of massive compact stars ( M ≳ 2.1 M ⊙ ) implies that the speed of sound exceeds the conformal limit ( c s 2 = 1/3 × the squared speed of light in vacuum) if those stars have an inner and outer crust of ordinary nuclear matte…
View article: Towards mitigation of apparent tension between nuclear physics and astrophysical observations by improved modeling of neutron star matter
Towards mitigation of apparent tension between nuclear physics and astrophysical observations by improved modeling of neutron star matter Open
Observations of neutron stars (NSs) by the LIGO-Virgo and NICER collaborations have provided reasonably precise measurements of their various macroscopic properties. In this paper, we employ a Bayesian framework to combine them and place i…
View article: GW190814: on the properties of the secondary component of the binary
GW190814: on the properties of the secondary component of the binary Open
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. Since its mass is $\in (2.50,2.67) \, \mathrm{M}_{\odot …
View article: Structure of Quark Star: A Comparative Analysis of Bayesian Inference and Neural Network Based Modeling
Structure of Quark Star: A Comparative Analysis of Bayesian Inference and Neural Network Based Modeling Open
In this work, we compare two powerful parameter estimation methods, namely Bayesian inference and neural network based learning, to study the quark matter equation of state with constant speed of sound parameterization and the structure of…
View article: Role of antikaon condensation on the universality relations of hot and rapidly rotating neutron stars
Role of antikaon condensation on the universality relations of hot and rapidly rotating neutron stars Open
We study cold as well as hot neutron star (NS) at finite entropy using density dependent relativistic mean field model in the presence of nucleons and antikaon condensates. The parameters like gravitational mass( M ), radius( R ), moment o…
View article: A Bayesian Analysis on Neutron Stars within Relativistic Mean Field Models
A Bayesian Analysis on Neutron Stars within Relativistic Mean Field Models Open
We present a Bayesian analysis on the equation of state of neutron stars based on a class of relativistic mean field models. The priors on the equation of state are related to the properties of nuclear matter at saturation and the posterio…
View article: Effect of superfluid matter of a neutron star on the tidal deformability
Effect of superfluid matter of a neutron star on the tidal deformability Open
We study the effect of superfluidity on the tidal response of a neutron star\nin a general relativistic framework. In this work, we take a dual-layer\napproach where the superfluid matter is confined in the core of the star. Then,\nthe sup…
View article: Observed glitches in 8 young pulsars
Observed glitches in 8 young pulsars Open
The abrupt change in the pulse period of a pulsar is called a pulsar glitch. In this paper, we present eleven pulsar glitches detected using the Ooty Radio Telescope (ORT) and the upgraded Giant Metrewave Radio Telescope (uGMRT) in high ca…
View article: Role of crustal physics in the tidal deformation of a neutron star
Role of crustal physics in the tidal deformation of a neutron star Open
In the late inspiral phase, gravitational waves from binary neutron star mergers carry the imprint of the equation of state due to the tidally deformed structure of the components. If the stars contain solid crusts, then their shear modulu…
View article: Properties of massive rotating protoneutron stars with hyperons: structure and universality
Properties of massive rotating protoneutron stars with hyperons: structure and universality Open
In this work, we study the properties and structure of a massive and rapidly rotating protoneutron star (PNS) with hyperon content. We follow several stages of quasi-stationary evolution in an approximate way at four discrete steps. We use…
View article: Constraining Strangeness in Dense Matter with GW170817
Constraining Strangeness in Dense Matter with GW170817 Open
Particles with strangeness content are predicted to populate dense matter, modifying the equation of state of matter inside neutron stars as well as their structure and evolution. In this work, we show how the modeling of strangeness conte…
View article: Constraining the relativistic mean-field model equations of state with gravitational wave observations
Constraining the relativistic mean-field model equations of state with gravitational wave observations Open
The first detection of gravitational waves from the binary neutron star merger event GW170817 has started to provide important new constraints on the nuclear equation of state at high density. The tidal deformability bound of GW170817 comb…
View article: How to test the two-families scenario
How to test the two-families scenario Open
We shortly summarize the two-families scenario in which both hadronic stars\nand strange quark stars can exist and we describe the main predictions one can\nobtain from it. We then concentrate on the observables that most likely will be\nm…
View article: Glitch Behavior of Pulsars and Contribution from Neutron Star Crust
Glitch Behavior of Pulsars and Contribution from Neutron Star Crust Open
Pulsars are highly magnetized rotating neutron stars (NSs) with a very stable rotation speed. Irrespective of their stable rotation rate, many pulsars have been observed to feature a sudden jump in the spin frequency, known as a pulsar gli…