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Ian Jones (University of Southampton)25/04/2016, 09:10Isolated neutron stars can emit gravitational waves via a variety of mechanisms. These emission channels are highly sensitive to the nature of matter in the star, and can potentially reveal information on the high density equation of state not accessible via other means. In this talk I will review these mechanisms, and discuss how they relate to the microphysics of the stellar matter. I will...Go to contribution page
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Kostas Glampedakis25/04/2016, 10:00This talk will provide an update on gravitational wave emission from isolated neutron stars and on the dynamics of the associated unstable oscillation modes.Go to contribution page
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Matthias Hempel (Basel University)25/04/2016, 11:20Recently it was shown that a phase transition to deconfined quark matter can lead to the formation of a novel kind of third family of compact stars, that is present only in the hot, early stages of their evolution. Such a feature can be related to unusual thermal properties of the equation of state in the phase coexistence region, which manifest themselves as a negative slope of the phase...Go to contribution page
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Dr Tolga Güver (Istanbul University)25/04/2016, 12:10In this talk I will present the current state of mass and radius measurements of neutron stars in low mass X-ray binaries obtained during thermonuclear X-ray bursts or in quiescence. Taking into account a number of systematic uncertainties that may be present in the measurements as well as the results of recent theoretical calculations we obtain strong and quantitative constraints on...Go to contribution page
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Mr Onur Akbal25/04/2016, 14:00We estimate the critical strain angle throughout the neutron star crust. We propose that the critical strain angle is proportional to the ratio of the total Coulomb potential energy to the kinetic energy of the relativistic electrons, $\theta_{cr} \sim E_{C}/E_{K}$, in one Wigner-Sietz cell. Since the character of the Coulomb interaction varies throughout the inner crust according to the...Go to contribution page
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Mr Constança Provdência25/04/2016, 14:20The effect of strong magnetic fields, of the order of 10^{16}-10^{17}G, on the extension of the crust of magnetized neutron stars is discussed. The dynamical instability region of neutron-proton-electron matter at subsaturation densities and the mode with the largest growth rate are determined within a relativistic mean field model. It is shown that a strong magnetic field has a large effect...Go to contribution page
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Dr Mohsen Bigdeli25/04/2016, 14:40It is well known that the magnetars and the pulsars are neutron stars have strong surface magnetic field about 1015 [2] and 1013 [3] Gauss, respectively. The structural properties of these objects, such as its maximum mass and the location of core-crusts interface, is a subject that theoretical astrophysicists have desired to study. In order to determine the core-crust transition parameters,...Go to contribution page
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Adriana Raduta (IFIN-HH)25/04/2016, 15:00The importance of microphysical inputs from laboratory nuclear experiments and theoretical nuclear structure calculations in the understanding of core collapse dynamics and the subsequent supernova explosion, is largely recognized in the recent literature. In this work, we analyze the impact of the masses of very neutron rich nuclei on the matter composition during collapse, and the...Go to contribution page
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Mr Antonio Graziano Pili25/04/2016, 15:20Physical and observational properties of neutron stars (NSs) are deeply influenced by the morphology of their magnetic field. Therefore an accurate description of both the interior and exterior stellar magnetic field is necessary to improve our understanding of NS phenomenology. I will present a comprehensive numerical study of GR equilibria of magnetised NSs, taking into account different...Go to contribution page
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Manoneeta Chakraborty (Tata Institute of Fundamental Research)25/04/2016, 16:00Magnetars are highly magnetized neutron star and energetic X-ray/ soft gamma ray bursts are often observed from these sources. The most energetic of these bursts,- the giant flares have been observed only from a few sources and exhibit distinct observational characteristics. The 2011 outburst of the relatively low magnetic field magnetar was quite extraordinary because of the unusual timing...Go to contribution page
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Dr Vladimir Karas (Astronomical Institute, Czech Academy of Sciences)25/04/2016, 16:20standard talk
We examine the role of a dipole-type magnetic field of a compact (neutron) star for its interaction with the ambient interstellar medium, and the resulting drag as the star orbits near a supermassive black hole. The enhancement of the orbital decay is found to be very small in the Galactic centre (the mini-spiral region of Sgr A*), where the environment density is very low, but it becomes...
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Friedrich Thielemann, Andreas Lohs (University of Basel)26/04/2016, 09:10
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Laura Tolos (University of Groningen)26/04/2016, 10:00
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Dr Niccolo Bucciantini26/04/2016, 11:20
The properties of late time activity in Long and Short GRBs, point strongly toward a long lived energy injection mechanism. The millisecond magnetar model provides naturally with such input in the form of a relativistic magnetically driven wind. The standard pictures however predicts a steady smooth injection, that looks at odds with the presence of late time bursts observed in the light-curve...
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Prof. Pierre Pizzochero26/04/2016, 12:10The superfluid state of neutrons strongly affects the rotational properties of neutron stars, since their angular momentum is quantized in vortex lines whose interaction with the nuclear lattice in the crust can explain the rotational glitches observed in numerous pulsars. The study of those interactions at the microscopic level and their implementation in macroscopic and realistic models for...Go to contribution page
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Mr Marco Antonelli26/04/2016, 14:00In my presentation I'll describe an analytical two-components model for pulsar rotational dynamics: the aim is to reduce the computationally difficult 3D hydrodynamics to a 1D (radial) problem. The model takes into account consistently for the non-uniform structure of the star and superfluid entrainment. I'll show how this simple model can be used to put a constraint to the mass of the pulsars...Go to contribution page
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Prof. Şolen Balman26/04/2016, 14:20
I review accretion in Cataclysmic Variable systems with emphasis on flicker
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noise and its variations that have been a diagnostic tool in understanding the structure in accretion disks.
I study the nature of time variability of brightness of non-magnetic
cataclysmic variables. Dwarf novae demonstrate band limited noise in the UV and X-ray energy bands, which can be adequately explained
in the... -
Dr Taner Akgün26/04/2016, 14:40Evolution of magnetic fields in neutron stars depends strongly on the specific boundary conditions imposed at the stellar surface and the properties of the surrounding magnetosphere. In this talk, I will present various current-free (vacuum) and force-free models of neutron star magnetospheres, describe the resulting boundary conditions, and discuss their implications for the evolution of the...Go to contribution page
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Luca Del Zanna26/04/2016, 15:00Axisymmetric GRMHD equilibria in 3+1: general formalism, numerical methods, and application to magnetized NS modeling We review the force-free and GRMHD equations for stationary and axisymmetric equilibria in general relativity within the 3+1 formalism. Numerical methods and detailed GRMHD modeling for the description of the structure and magnetosphere of magnetized neutron stars are shown and...Go to contribution page
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Mr Gregory Ashton26/04/2016, 15:20I present results studying the periodic variations in PSR B1828-11 and demonstrate that the evidence is in favour of a precession interpretation over the recent claims that this pulsar is undergoing magnetospheric switching. Furthermore, I will establish that the periodicity is changing and discuss the consequence that this has for both models.Go to contribution page
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Dr Justin Elfritz26/04/2016, 15:40We have recently developed a 3D numerical model to evolve the Hall-Ohmic magnetic field in neutron stars (NSs). Our model is an important extension to the state-of-the-art 2D magneto-thermal model of Pons+ (2007, 2009), Vigano+ (2012, 2013). We have now validated and benchmarked our new 3D model, and we are beginning to investigate how Hall-driven evolution in 3D compares to the known...Go to contribution page
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Dr Sergey Tsygankov26/04/2016, 16:20Propeller effect in X-ray pulsars Propeller effect, i.e. centrifugal inhibition of accretion, is an immediate evidence of the presence of a strong dipole magnetic field in accreting neutron stars. Observation of this effect requires high sensitivity of X-ray telescopes and become possible only recently. From the theoretical point of view many aspects of this effect (spectrum formation, matter...Go to contribution page
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Dr Alexander Mushtukov26/04/2016, 16:40We study properties of luminous X-ray pulsars using a simplified model of the accretion column based on diffusion approach. The maximal possible luminosity is calculated as a function of the neutron star (NS) magnetic field strength and spin period. It is shown that the luminosity can reach values of the order of 10^{40} erg/s for the magnetar-like magnetic field (B > 10^{14}G) and long spin...Go to contribution page
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Luciano Rezzolla (Institute for Theoretical Physics, Frankfurt, Germany)27/04/2016, 09:10
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Prof. Chris Pethick (University of Illinois at Urbana-Champaign)27/04/2016, 10:00I shall discuss a number of subjects including the equation of state of uniform nucleonic matter, collective oscillations in the inner crust of neutron stars, the neutron superfluid density in the inner crust, elastic properties of the crust, induced interactions between nucleons and the transition to quark matter.Go to contribution page
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Dr Daniela Doneva27/04/2016, 11:20The talk is devoted on neutron stars in alternative theories of gravity: their structure, deviations from pure general relativity and astrophysical implications. Both static and rapidly rotating solutions are considered. A wide range of universal relations for neutron star and their generalization to alternative theories of gravity are also discussed. Among them are gravitational wave...Go to contribution page
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Prof. Stoytcho Yazadjiev27/04/2016, 12:10
In the scalar-tensor theories with a massive scalar field the coupling constants, and the coupling functions in general, which are observationally allowed, can differ significantly from those in the massless case. This fact naturally implies that the scalar-tensor neutron stars with a massive scalar field can have rather different structure and properties in comparison with their counterparts...
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Dr Antonia Rowlinson28/04/2016, 09:10It has now been shown that many short GRBs also have plateau phases which are comparable to those observed in long GRBs. However, this challenges the typical short GRB progenitor model (the merger of two neutron stars or a neutron star and a black hole) as all significant accretion onto the black hole is expected to occur during the prompt emission phase. The recent discovery of massive...Go to contribution page
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Paul Lasky28/04/2016, 10:00Isolated neutron stars are potentially excellent emitters of gravitational waves throughout many stages of their lives. I will review recent advances in our understanding of gravitational wave emission mechanisms from both young and old neutron stars. I will also discuss ongoing efforts to detect these gravitational waves with Advanced LIGO.Go to contribution page
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Dr Isaak Vidana28/04/2016, 11:20
In this work I review the role of hyperons on the properties of neutron and proto-neutron stars. In particular, I revise the so-called ``hyperon puzzle", go over some of the solutions proposed to tackle it, and discuss the implications that the recent measurements of unusually high neutron star masses have on our present knowledge of hypernuclear physics. I reexamine also the role of hyperons...
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Gergely Gabor Barnaföldi- Szilvia Karsai-Peter Posfay (Wigner RCP Hungarian Academy of Sciences (HU))28/04/2016, 12:10Recently we have explored the properties of an interacting fermionic compact star in a 1+4 dimensional Kaluza--Klein-like spacetime, where an extra microscopical spacelike dimension was introduced (See Sz. Karsai's talk). Here, we present wether we would able to measure the effect of these extra dimensions by gravitational wave detectors.Go to contribution page
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Mr Kevin Ebinger28/04/2016, 14:20Core-Collapse Supernovae (CCSNe) occur at the end of the evolution of massive stars. The detailed explosion mechanism of these violent events and their outcomes are still not fully understood. On the one hand multi-dimensional simulations of CCSNe are needed to investigate the underlying explosion mechanism. On the other hand they are currently too expensive to allow broad systematic studies,...Go to contribution page
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Mr Luke Bovard28/04/2016, 14:40The question of the origin of heavy elements has undergone a change in the last few years. Recent numerical simulations have demonstrated that binary neutron star mergers are the most likely progenitors of heavy elements in our galaxy instead of core-collapse supernova. This is due to a more neutron-rich environment that allows a more robust rapid neutron capture (r-process) nucleosynthesis....Go to contribution page
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Mr Oliver Heinimann28/04/2016, 15:00The subject of this presentation is the quark-hadron phase transition in neutron stars (NS) and core collapse supernovae (CCSN). We employ a hybrid equation of state consisting of the the state-of-the-art EOS HS(DD2) for the hadronic part and the constant speed of sound EOS for the quark phase. We show how this EOS is related to a standard bag model. We systematically vary the phase transition...Go to contribution page
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Aleksi Vuorinen28/04/2016, 15:20I will report results from recent efforts in perturbative QCD to build a framework for dealing with the bulk thermodynamic properties of dense quark matter at small but nonzero temperatures. The new results extend the applicability of the current state-of-the-art Equation of State of zero-temperature quark matter, smoothly connecting it to that of hot quark-gluon plasma. Applications of the...Go to contribution page
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Dr Andreas Lohs28/04/2016, 15:40Neutrino-nucleon interactions at high density and temperature play a major role in the outcome of various processes during core-collapse supernovae (CCSNe) explosions. Their impact ranges from shock revival via neutrino heating to determining nucleosynthesis of heavy elements in the neutrino driven wind or via neutrino nucleosynthesis. Precise modelling of these scenarios requires accurate...Go to contribution page
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Ms Cosima BREU28/04/2016, 16:20A number of recent works have highlighted that it is possible to express the properties of general-relativistic stellar equilibrium configurations in terms of functions that do not depend on the specific equation of state employed to describe matter at nuclear densities. These functions are normally referred to as "universal relations" and have been found to apply, within limits, both to...Go to contribution page
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Mr Federico Guercilena28/04/2016, 16:40Artificial entropy viscosity in numerical relativistic hydrodynamics Large scale numerical simulations are one of the most useful tools to shed light on the physics of neutron stars, but due to their high computational cost and great accuracy requirements the research for better numerical methods is constantly ongoing. We present a new fast and accurate numerical scheme called artificial...Go to contribution page
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Dr Bettina Posselt29/04/2016, 09:10
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Silvia Zane (university college London)29/04/2016, 10:00Multi-wavelength observations over the last decades proved the existence of observationally very diverse manifestations of isolated NSs (INSs) and led to the separation of INSs into distinct classes. Most of the ~2,300 known INSs are radio pulsars with periods P < 8 s and magnetic field B ~ 10 12 G, but there are objects with much greater potential for understanding the INSs diversity. This...Go to contribution page
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Prof. M. Ali Alpar (Istanbul University)29/04/2016, 11:30Plenary talk
Theoretical basis and observational evidence for nonlinear dynamics will be discussed.
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Dr Morgane Fortin29/04/2016, 11:50I will review several ongoing projects which aim at examining how astrophysical observations of neutron stars (mass, radius, spin frequency, thermal emission and evolution,...) may constrain the properties and composition of neutron star matter.Go to contribution page
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Maria Chernyakova (DCU)29/04/2016, 12:40
Gamma-ray loud binaries are are a recently identified class of X-ray binaries in which interaction of an outflow from the compact object with the wind and radiation emitted by a companion star leads to the production of very-high energy gamma-ray emission. Only five systems have been firmly detected so far as persistent or regularly variable TeV gamma-ray emitters. The nature of the TeV...
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Prof. Nils Paar29/04/2016, 14:00
Recent developments of the relativistic nuclear energy density functional (RNEDF) provide a self-consistent framework for the description of a variety of nuclear properties of astrophysical relevance, including the nuclear matter equation of state, and various neutron star properties. The RNEDF is supplemented with the covariance analysis in order to assess statistical uncertainties of...
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Denitsa Staicova29/04/2016, 14:20The minimal dilatonic gravity (MDG) is a theory, which is locally equivalent to the f(R) theories of gravity and gives an alternative description of the effects of dark matter and dark energy. In this talk we report the progress on modelling relativistic static spherically symmetric stars in MDG under different equations of state (EOS) of neutron matter and we discuss the dependence of the...Go to contribution page
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Mr Sercan Çıkıntoğlu29/04/2016, 14:40
We study the structure of relativistic stars in R+alpha*R^2 theory using the method of matched asymptotic expansion to handle the higher order derivatives in field equations arising from the higher order curvature term. We find solutions, parametrized by $\alpha$, for uniform density stars matching to the Schwarzschild solution outside the star. We obtain the mass-radius relations and study...
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Prof. Ludwik Turko29/04/2016, 15:00
After a short review on the role of excluded volume corrections for the equation of state (EoS) of hadronic matter as probed in heavy-ion collision experiments [1], we present recent applications of excluded volume modifications in the EoS of neutron stars including a Bayesian analysis of mass-radius constraints and hybrid star phenomenology [2] and neutron star cooling [3]. We argue that the...
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Mr Erbil Gügercinoğlu29/04/2016, 15:20Rotational dynamics of a neutron star is governed by the distribution and motion of vortex lines within the neutron superfluid. Interaction of the vortex lines with the ambient matter plays a significant role in the glitches, thermal evolution and magnetic field evolution of pulsars. Thus, correctly treating the vortex motion in the inner crust and the outer core of neutron stars is a key...Go to contribution page
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Marcio de Avellar (Universidade de São Paulo)29/04/2016, 15:40A step towards to understanding how radiative processes give rise to the rich set of variability features, namely the quasi-periodic oscillations, actually seen in the X-ray light curves of low-mass X-ray binaries is given by the study of the energy and frequency dependence of the phase lags of the QPOs in the light curves. Here we studied the phase lags of all QPOs in the range of 1 Hz to...Go to contribution page
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