Dr
Hans-Josef Schulze
(INFN Sezione di Catania)
24/03/2014, 09:10
The main features of the EOS of neutron star matter are reviewed,
comprising nucleonic, hyperonic, and quark matter contributions.
The focus in on the Brueckner-Hartree-Fock theoretical method,
but also other approaches will be regarded.
Prof.
Pawel Danielewicz
(East Lansing, MSU (USA))
24/03/2014, 09:50
Constraints on the nuclear equation of state, following from heavy ion collisions and from structure, are reviewed. The collisions produce matter transiently reaching densities few times the normal. Isolating observables testing such densities is challenging, though, and interpretation of those observables suffers from theoretical uncertainities. Structure observables can be generally...
Dr
Juergen Schaffner-Bielich
(Institut fuer Theoretische Physik, Goethe Universitaet, Frankfurt)
24/03/2014, 10:30
In the dense interior of compact stars the composition might change
considerably. Due to weak equilibrium in neutron star matter particles
carrying strangeness can appear changing the overall global properties as well
as the transport properties of compact stars. The new pulsar mass limit of two
solar masses gives new information on the presence of strange matter in the
core of compact...
Prof.
Mark Alford
(Washington University in St. Louis, USA)
24/03/2014, 11:40
At high pressure, nuclear matter will undergo a transition to
quark matter, so sufficiently heavy neutron stars may really be
``hybrid stars'' with quark matter cores. We discuss possible
signatures of the presence of a quark matter core, such as
characteristics of the mass-radius relation, and the allowed
range of values of the spin frequency, which is sensitive to
quark matter in the...
Prof.
Peter Senger
(GSI Helmholtzzentrum für Schwerionenforschung)
24/03/2014, 12:20
Nucleus-nucleus collisions provide a unique opportunity to create and to investigate dense nuclear matter in the laboratory. These experiments address fundamental aspects of strong-interaction physics: the nuclear equation-of-state at high baryon densities, the in-medium modifications of hadrons, and the phase transition from hadronic to partonic degrees of freedom. These phenomena play an...
Dr
Paulo Freire
(MPI Bonn)
24/03/2014, 14:30
Millisecond pulsars (MSPs) are believed to be old neutron stars, formed via type~Ib/c core-collapse supernovae, which have subsequently been spun up to high rotation rates via accretion from a companion star in a highly circularised low-mass X-ray binary. The recent discoveries of Galactic field binary MSPs in eccentric orbits, and mass functions compatible with that expected for helium white...
Prof.
C. Providência
(University of Coimbra)
24/03/2014, 14:30
The effect of the symmetry energy on several properties of neutron stars is discussed. First, we analyze the effect of the symmetry energy on the pasta phase. It is shown that the size of the pasta clusters, number of nucleons and the cluster proton fraction depend on the density dependence of the symmetry energy: a small L gives rise to larger clusters. The influence of the equation of state...
Prof.
Francesca Gulminelli
(LPC and Univ.of Caen)
24/03/2014, 14:50
Dense matter as it can be found in core-collapse supernovae and neutron stars is expected to exhibit different phase transitions which impact the matter composition and equation of state, with important consequences on the dynamics of core-collapse supernova explosion and on the structure of neutron stars. In this talk we will address the specific phenomenology of two of such transitions,...
Dr
Jerome Margueron
(IPN Lyon, France)
24/03/2014, 15:10
Exotic and drip-line nuclei as well as nuclei immersed in a low-density gas of neutrons in the inner crust of neutron stars are systematically investigated with respect to their neutron pairing properties. This is done using Skyrme density-functional and different pairing forces such as a density-dependent contact interaction and a separable form of a finite-range Gogny interaction....
Dr
Thomas Tauris
(MPIfR Bonn)
24/03/2014, 15:10
Recent discoveries of weak and fast optical transients raise the question of their origin. We investigate the minimum ejecta mass associated with core-collapse supernovae (SNe) of Type Ic. We show that mass transfer from a helium star to a compact companion can produce an ultra-stripped core which undergoes iron core collapse and leads to an extremely fast and faint SN Ic. In this Letter, a...
Dr
Adriana Raduta
(IFIN-HH)
24/03/2014, 15:30
Though generally agreed that the symmetry energy plays a dramatic role in determining the structure of neutron stars and the evolution of core-collapsing supernovae, little is known in what concerns its value away from normal nuclear matter density and, even more important, the correct definition of this quantity in the case of unhomogeneous matter. Indeed, nuclear matter traditionally...
Dr
Jason Dexter
(UC Berkeley)
24/03/2014, 15:30
Wide-field optical surveys have discovered a population of super-luminous supernova explosions in the past several years, including some where it is difficult to explain the light curve shape using energy deposition from radioactive decay. Many of these events can be explained by a model in which a rapidly rotating magnetar forms in the explosion and deposits its spindown energy into the...
Dr
Debora Menezes
(Universidade Federal de Santa Catarina)
24/03/2014, 15:45
Based on the SU(3) symmetry group, we fix the hyperon-meson coupling constants and constrain them to experimental nuclear matter results and astrophysical observations. We then study the effects of meson-hyperon coupling constants on the onset of hyperons in dense nuclear matter. While the discovery of massive pulsars PSR J1614-2230 and PSR J0348+0432 points towards a very stiff equation of...
Dr
Albino Perego
(TU Darmstadt, Institut für Kernphysik Theoriezentrum)
24/03/2014, 15:50
Binary neutron star mergers are among the most extreme events
happening in the Universe. These very powerful events are expected to
release large amounts of energy in form of neutrinos, gravitational
waves and electromagnetic radiation, together with the ejection of a
small fraction of their original mass. In particular, they are
expected to be sites for r-process nucleosynthesis, as well...
Kristian Petrik
(Institute of Physics, Slovak Academy of Sciences)
24/03/2014, 16:00
Recent progress in astronomical observations, namely accurate estimation of the mass of the pulsars J1614-2230 and J0348+0432, which yields values around 2 M_sol, demands that any reliable nuclear equation of state (EoS) should be able to reproduce these results. Common feature of models that include hyperon degrees of freedom, kaon condensates or other forms of exotic hadronic matter, is...
Stefan Gmuca
(Institute of Physics, Slovak Academy of Sciences)
24/03/2014, 16:15
The exchange part of energy density of the linear Dirac-Hartree-Fock (DHF) model in dense matter is evaluated in a parameter-free closed form and expressed as density functional. After the rearranging terms the relativistic mean-field approach with density-dependent couplings may be recovered with density dependence coming from the Fock interaction. The formalism developed, is then extended to...
Prof.
Dirk Rischke
(Institut für Theoretische Physik Johann Wolfgang Goethe-Universität)
24/03/2014, 17:00
Calculations within QCD-inspired models as well within QCD in the large-N_c
limit show that dense quark matter features inhomogeneous phases. The order
parameter for
chiral symmetry breaking varies periodically, in the form of a chiral density
wave ("chiral spiral")
or in the functional form of a Jacobi elliptic function. In this talk, I will
demonstrate that this
phenomenon also occurs...
Prof.
Peter Gonthier
(Hope College)
24/03/2014, 17:00
We present preliminary results of a population statistics study of normal pulsars (NP) from the Galactic disk using Markov Chain Monte Carlo techniques. The model parameters are varied to maximize the log of the likelihood obtained from the comparisons of two and one dimensional distributions of radio and gamma-ray pulsar characteristics. The computer code simulates neutron stars at birth...
Miguel Gullón
(University of Alicante)
24/03/2014, 17:15
The neutron star zoo has witnessed a continuous increase in the number of species during the last decades, as more sensitive
instruments were developed, in particular in the high energy band (Fermi-LAT, XMM-Newton, Chandra...).
Despite the observational diversity, a consistent theory must be able to explain the different manifestations in terms of different initial conditions...
Prof.
Stefan Schramm
(Frankfurt Institute for Advanced Studies Johann Wolfgang Goethe Universität)
24/03/2014, 17:20
With the measurements of two-solar-mass neutron stars the question of how to reconcile the existence of large masses with the possibility of more exotic compact objects like hyper stars and hybrid stars has gained major importance. In order to address this point theoretical approaches to model stars containing quarks as well as nucleons and hyperons are discussed, also considering the general...
Prof.
Veronica Dexheimer
(Kent State University)
24/03/2014, 17:40
I model hybrid compact stars making use of a self-consistent equations of state. In this approach, the degrees of freedom change from hadrons to quarks in a self-consistent way. This means that the particles appear, in principle, in arbitrary proportions with the interactions leading to the correct behavior for low, respectively high, densities and temperatures. Chiral symmetry restoration and...
Dr
Dario Zappalà
(INFN Cezione di Catania)
24/03/2014, 18:00
The Field Correlator Method provides an approximation of the full
Quantum Chromodynamics Equation of State (EoS) for quark matter,
which is parametrized in terms of the gluon condensate and the
large distance quark-antiquark potential. This EoS can be confronted
with the hadronic EoS to analyze the phase transition from nuclear to
quark matter, thus providing a simple framework to...
Dr
Ricardo Heras
(University College London)
24/03/2014, 18:00
Millisecond pulsars, radio pulsars, and magnetars are distinct classes of neutron stars that currently exhibit different periods, magnetic fields and space velocities. In my talk, I speculate with the idea that these current properties of neutron stars could have had similar values during the birth of these stars. I develop a relatively simple model based on the assumption that neutron stars...
Dr
Miroslav Shaltev
(Albert Einstein Institute, Hannover)
24/03/2014, 18:15
Isolated neutron stars are possible sources of continuous gravitational
waves. If the source parameters are known, a putative signal can be
searched at negligible computing cost. For unknown source parameters,
the weakness of the expected signal combined with the large parameter
space
to search yields an unfeasible computing cost for fully coherent
search techniques.
Therefore...
Prof.
Nobutoshi Yasutake
(Chiba Institute of Technology)
24/03/2014, 18:20
We study the quark-hadron phase transition with the finite size effects for neutron star matter. Generally, non-uniform structures appear in the phase transition of multi-component system. Namely, we call them as the pasta structures. In this study, the properties of the mixed phase are clarified by considering the finite size effects. We find that, if the surface tension is strong, the EOS...
Prof.
Nicolas Chamel
(Universitè Libre de Bruxelles, Belgium)
25/03/2014, 09:00
At the endpoint of stellar evolution, pulsars are spinning extremely rapidly with periods
ranging from milliseconds to seconds and delays of a few milliseconds per year at most, thus
providing the most accurate clocks in the universe. Nevertheless, some pulsars exhibit sudden
decreases of their spin period. Because it was the first observed pulsar to exhibit such “glitches”, Vela has become...
Prof.
Dmitry Yakovlev
(IOFFE Institute)
25/03/2014, 09:40
Cooling neutron stars may serve as natural laboratories of superdense matter in their interiors. We discuss current theories of neutron star cooling. We outline the main regulators of the cooling such as the equation of state, neutrino emission mechanisms, heat capacity and superfluidity in superdense stellar cores as well as the properties of heat-blanketing envelopes of neutron stars. Next...
Dr
Andrew Melatos
(University of Melbourne, Australia)
25/03/2014, 10:20
I will review some key aspects of the physics of neutron star superfluidity
and superconductivity, which play an important role in the phenomena of
pulsar timing noise and rotational glitches. New results will be presented
from quantum mechanical Gross-Pitaevskii simulations of vortex avalanches
in a pinned, decelerating superfluid, which show the correlated nature of
vortex motion during...
Prof.
Edo Berger
(Harvard, USA)
25/03/2014, 11:30
While short-duration gamma-ray bursts (GRBs) have long been suspected to result from the mergers of compact object binary mergers, it is only over the past few years that observational data have been available. In this talk I will present the results of several detailed studies of short GRBs and their environments which demonstrate a connection to neutron star binary mergers, and which can be...
Scott Ransom
(National Radio Astronomy Observatory)
25/03/2014, 12:10
The central densities of neutron stars are the highest known in the Universe, so measurements probing the interiors of radio pulsars, or even just their masses and radii, can give us unique insights into the physics of matter at extreme densities. The discovery of several interesting new pulsars as well as improved instrumentation has finally allowed us to start measuring the masses of the...
Dr
Sergei Popov
(SAI Moscow)
25/03/2014, 14:30
Up to now it is unclear how magnetars obtain their large magnetic
fields. In the standard model it is proposed that fields are enhanced
via a dynamo mechanism. This scenario requires that the neutron star
has very rapid initial rotation. Such assumption, on one hand,
requires rapid rotation of the progenitor, and so a specific
evolution; on another hand, this assumption leads us to...
Dr
Andrzej Szary
(Kepler Institute of Astronomy, Univ. Zielona Gora, Poland)
25/03/2014, 14:50
Coherent pulsar radio emission requires an existence of inner acceleration region above the polar cap. The most advanced implementation of the inner gap idea is the Partially Screened Gap (PSG) model, based on recent calculations of the surface binding energy and Hall drift induced surface magnetic field in neutron stars.
The PSG model has a great predictive power and can be tested...
Dr
Laura Tolos
(ICE (CSIC-IEEC))
25/03/2014, 14:50
We study the shear and bulk viscosity coefficients as well as the thermal conductivity as arising from the collisions among phonons in superfluid neutron stars. We use effective field theory techniques to extract the allowed phonon collisional processes, written as a function of the equation of state of the system.
We analyze the shear viscosity taking into account the contribution of...
Toshio Nakano
(University of tokyo)
25/03/2014, 15:10
Magnetars, i.e., neutron stars (NSs) with extremely strong magnetic fields, are thought to be produced by Type II supernovae (SNe), like other NSs. Indeed, several of them are located inside supernova remnants (SNRs). However, we do not know how the magnetar-producing SNe differ from those creating the other NSs.
Observations of the SNRs associated with magnetars are expected to provide...
Dr
Rafael C. R. de Lima
(Universidade do Estado de Santa Catarina)
25/03/2014, 15:30
The effect of strong magnetic fields on the properties of the pasta structure is calculated within a Thomas-Fermi
approach using relativistic mean-field models to modulate stellar matter. It is shown how quantities such as the
size of the clusters and Wigner-Seitz cells, the surface tension, and the transition between configurations are
affected. It is expected that these effects may give...
Dr
Alfio Bonanno
(INAF-Catania)
25/03/2014, 15:30
The thermomagnetic evolution of the young neutron star in Cassiopea A is studied by considering fast neutrino emission processes. In particular, we consider neutron star models obtained from the equation of state computed in the framework of the Brueckner-Bethe-Goldstone many-body theory and variational methods, and models obtained with the Akmal-Pandharipande-Ravenhall equation of state. It...
Dr
Rudiney Casali
(Institut de Physique Nucléaire de Lyon)
25/03/2014, 15:45
We apply magnetic fields of the order of 10^17 G and 10^18 G to nuclear matter, and study its influence on the symmetry energy and its slope. We also study the effects caused by the inclusion of anomalous magnetic moments to these quantities. Then, we investigate the effects caused by strong magnetic fields on the properties of compact objects, composed by hadronic matter in β-equilibrium,...
Armen Sedrakian
(Frankfurt University)
25/03/2014, 15:50
I will discuss the recent work on the effects of superfluidity of baryonic and
quark matter on the cooling of compact stars. In particular I will focus on the
effects of (1) pair-breaking processes on the cooling; (2) color superconductivity;
and (3) the problem of the fitting of Cas A data with different
models.
Prof.
George Melikidze
(J. Kepler Institute of Astronomy, University of Zielona Gora, Poland)
25/03/2014, 16:00
We present circumstances that should be fulfilled in the magnetosphere of the neutron stars to “switch” the mechanism for radio emission on. We claim that the curvature of magnetic field lines at the stellar surface is the most influential factor affecting the radio emission process. The most plausible mechanism for the radio emission which most probably is the coherent curvature radiation...
Dr
Tsuneo Noda
(Kurume Institute of Technology)
25/03/2014, 16:10
The observations of the central source of Cassiopeia A (Cas A) indicates that the compact star has large mass and high effective temperature, and suggests that its location on the cooling diagram is in the standard cooling region. There are some other compact stars which have low effective temperature, and they require an exotic phase which appears at high density, for large neutrino...
Dr
Jaroslaw Dyks
(Nicolaus Copernicus Astronomical Center)
25/03/2014, 16:15
There is a growing evidence that radio beams of some pulsars are azimuthally-structured.
When viewed down the dipole axis, the beam resembles spokes in a wheel,
with narrow emission stripes spreading away from the dipole axis.
I will present objects for which the spoke-like model describes their profiles
more successfully than the traditional conal geometry. Further from the dipole...
Andreas Schmitt
(Vienna University of Technology)
25/03/2014, 17:00
Compact stars are likely to contain superfluid matter, either in the form of nuclear or quark matter, or both. The hydrodynamics of superfluids is usually described in terms of a two-fluid model. I will discuss how such a two-fluid model can be derived from field theory and apply the results to compute the properties of first and second sound for arbitrary temperatures and (uniform) superfluid...
David Blaschke
(University of Wroclaw)
25/03/2014, 17:00
We introduce two sets of models with symmetry energy functionals which at
high baryon densities differ in stiffness. The symmetric part of the energy
per baryon is the same for all models and is based on the APR EoS. We test
the behavior of the symmetry energy by using a constraint on the total
baryon mass for a gravitational mass of a 1.25 M$_{\odot}$ neutron star.
This constraint is the...
Mr
Gabriele Taranto
(INFN)
25/03/2014, 17:30
We calculate the effective masses of neutrons and protons in dense nuclear matter within the microscopic Brueckner-Hartree-Fock many-body theory and study the impact on the neutrino emissivity processes of neu- tron stars. We compare results based on different nucleon-nucleon potentials and nuclear three-body forces. Useful parametrizations of the numerical results are given. We find...
Dr
Arnau Rios Huguet
(University of Surrey)
25/03/2014, 17:40
The equation of state of neutron matter is a basic ingredient in the theoretical understanding of neutron stars. From a nuclear theory perspective, the problem has two major sources of uncertainty: the nuclear hamiltonian and the treatment of quantum many-body correlations. I will review a series of recent theoretical advances within the many-body Green's functions approach that help tackle...
Mr
Roshan Sellahewa
(University of Surrey)
25/03/2014, 17:45
The equation of state and internal composition of neutron stars is not very well constrained yet. In this work, I have used theoretical nuclear physics techniques to predict the bulk properties of neutron stars starting from the Gogny interaction. The results of 10 different parametrizations of this nuclear interaction have been compared to constraints obtained from nuclear physics...
Dr
Luca Franci
(Università di Parma)
25/03/2014, 18:00
We present numerical results on the dynamical bar-mode (m=2)
instability in differentially rotating relativistic star models with a
polytropic EoS, obtained by means of full 3D ideal
magneto-hydrodynamics simulations in full General Relativity. We
focus our attention on two different ingredients that may affect the
onset and the dynamics of the instability, i.e., the magnetization...
Dr
Adam Szmagliński
(Institute of Physics, Cracow University of Technology)
25/03/2014, 18:00
We study properties of the proton component of neutron star matter for a number of realistic nuclear models. Vanishing of the nuclear symmetry energy implies proton-neutron separation in dense nuclear matter. Protons which form admixture tend to be localized in potential wells. Here we extend the description of proton localization to finite temperatures. It appears that the protons are still...
Dr
Kenji Fukukawa
(INFN Sezione di Catania)
25/03/2014, 18:15
Baryon-baryon (BB) interactions are most fundamental in nuclear structure and matter properties. The purpose of this talk is to discuss properties of the realistic quark-model (QM) BB interaction and the prospects in the application to the nuclear matter physics. QM BB interactions are constructed in the framework of resonating-group method for two three-quark clusters[1]. QM BB interactions...
Dr
Nanda Rea
(nstitute of Space Sciences (CSIC-IEEC), Barcelona, ES)
26/03/2014, 09:00
I will review the latest observational results on strongly magnetized neutron stars, underlying the evolutionary connection of these objects with the rest of the isolated pulsar population. In this respect, I will show how the recent discovery of three low magnetic field magnetars was crucial in understanding the evolutionary link between different isolated neutron star classes.
Prof.
Jose Pons
(University of Alicante, Spain)
26/03/2014, 09:40
Observations of magnetars and some of the high magnetic field pulsars have shown that their thermal luminosity is systematically higher than that of classical radio-pulsars, thus confirming the idea that magnetic fields are involved in their X-ray emission. In this talk I review the most recent results of 2D simulations of the fully coupled evolution of temperature and magnetic field in...
Dr
Andrei Beloborodov
(Columbia University)
26/03/2014, 10:20
Mechanisms of energy dissipation in magnetars will be discussed,
including dissipation inside and outside the neutron star.
Different modes of dissipation are responsible for various components
of magnetar activity: persistent emission and bursts, thermal and
nonthermal X-ray emission, and low-frequency emission.
Dr
Elena Pian
(INAF, Italy)
26/03/2014, 11:30
A few long Gamma-Ray Bursts and X-ray Flashes at redshift lower than ~0.3 are firmly associated with well studied core-collapse stripped-envelope Supernovae with broad spectral lines and high kinetic energies. A number of higher redshift GRBs are also accompanied by Supernovae that have properties consistent with those of energetic core-collapse SNe. This suggests that the majority of long...
Dr
Niccolò Bucciantini
(INAF Osservatorio di Arcetri)
26/03/2014, 12:10
The character of the prompt emission, of the afterglow, the presence of an associated supernova (SN), and the environment, all characterize and constrain the possible central engine of Long and Short Gamma Ray Bursts (GRBs). However, despite the observed variety, there is little diversity among models for the central engine and essentially all can be simply classified as a rotating compact...
Prof.
Kohsuke Sumiyoshi
(Numazu College of Technology, Japan)
26/03/2014, 14:30
Properties of hot and dense matter play a key role in the explosion dynamics of core-collapse supernovae. The equation of state (EOS) affects the energetics of core-bounce and the following revival of shock wave for explosions. The EOS determines the final fate of compact objects together with emergent signals of neutrinos. Therefore, systematic sets of data for supernova EOS are essential...
Hajime SOTANI
(Kyoto University)
26/03/2014, 15:15
Neutron stars can be suitable laboratory to see the physics under the ultra-high density region. The direct observations of neutron stars help us to understand the nuclear matter properties and equation of state. On the other hand, the terrestrial nuclear experiments directly reveal such properties especially around the saturation density, which are strongly coupled with not only the crust...
Hamidreza Moshfegh
(University of Tehran)
26/03/2014, 15:35
Using the lowest order constrained variational method (LOCV) we calculate the equation of state of pure neutron matter (PNM) as well as the charge neutral (n,p,e,μ) matter in beta equilibrium with AV18 two-body nucleon-nucleon interaction supplemented by a microscopic three-body force. The neutron star gravitational mass limit obtained with this interaction is 2.62 M⊙ for PNM and 2.41 M⊙ in...
Dr
Giulia Pagliaroli
(INFN - LNGS)
26/03/2014, 15:55
Strange stars with a crystalline color superconducting crust can sustain
large shear stresses, supporting torsional oscillations of large
amplitude. Moreover if a bare quark matter surface is present electrons
spill in the star exterior forming an electromagnetically bounded
atmosphere hundreds of Fermi thick. We investigate the electromagnetic
signature connected with a torsional...
Dr
Paul Lasky
(School of Physics, melbourne University)
26/03/2014, 15:55
The favoured progenitor model for short gamma-ray bursts (SGRBs) is the merger of two neutron stars that triggers an explosion with a burst of collimated gamma-rays. Following the initial prompt emission, some SGRBs exhibit a plateau phase in their X-ray light curves that indicates additional energy injection from a central engine, believed to be a rapidly rotating, highly magnetised neutron...
Dr
M. De Pasquale
(Mullard Space Science Laboratory - University College London)
26/03/2014, 16:15
We present observations of GRB 130831A obtained by Swift, Chandra, and multiple ground-based observatories. This burst shows a remarkable drop in the X-ray light curve at about 10^5 s after the trigger, with a decay slope of \alpha_X \simeq 5. Such behaviour cannot be explained in the standard Forward Shock (FS) model, whereas it can be explained if the high energy emission is powered by a...
Toshiki Maruyama
(Japan Atomic Energy Agency)
26/03/2014, 16:15
We investigate inhomogeneous structures and properties of low-density nuclear matter by a relativistic mean-field approach with a fully three-dimensional geometry [1]. By avoiding usage of Wigner-Seitz approximation, we can discuss a priori the structure of matter.
We show that nuclear droplets form a body-centered-cubic (bcc) lattice at lower densities. With increasing density, it changes to...
Prof.
Xavier Vinas
(Universitat de Barcelona)
26/03/2014, 17:00
Within a microscopic approximation the structure of Neutron Stars is usually studied by modelling the homogeneous nuclear matter of the core by a suitable Equation of State, based on a many-body theory, and the crust by a functional based on a more phenomenological approach. We present here the first calculation of Neutron Star overall structure by adopting for the core an Equation of State...
Mr
Paul Scholz
(McGill University)
26/03/2014, 17:00
The magnetar Swift J1822.3-1606 was discovered when it entered an outburst phase in 2011 July. Previous X-ray studies of its post-outburst rotational evolution yielded inconsistent measurements of the spin-inferred magnetic field. However, it was clear that Swift J1822.3-1606 has the second lowest spin-inferred magnetic field of all known magnetars. Here we present the timing behavior and flux...
87.
Repeated, Delayed Torque Instabilities Following Flux Enhancement in the Magnetar 1E 1048.1 5937
Robert Archibald
26/03/2014, 17:20
1E 1048.1-5937 is one of the most active magnetars, having exhibited three long-term flux flares, as well as several SGR-like bursts, pulse profile changes, and timing anomalies in 16 years of previous monitoring. This pulsar has also displayed behavior not seen in any other magnetar: on the order of 100 days after the start of two of these flux flares, the spin-down rate underwent a period of...
Dr
Anthea Fantina
(Institut d'Astronomie et d'Astrophysique, Université Libre de Bruxelles)
26/03/2014, 17:20
A set of unified equations of state (EoSs) for neutron-star matter, based on generalised Skyrme energy-density functionals, will be presented. The underlying functionals will be discussed in connection with present data coming from nuclear physics experiments.
The structure of neutron stars constructed with these EoSs will be discussed, in connection with both astrophysical observations (such...
Helena Pais
(University of Coimbra)
26/03/2014, 17:40
The core-collapse supernova phenomenon, one of the most explosive events in the Universe, presents a challenge to theoretical astrophysics. Of the large variety of forms of matter present in core-collapse supernova, we focus on the transitional region between homogeneous (uniform) and inhomogeneous (pasta) phases. We perform a three-dimensional, finite temperature Skyrme-Hartree-Fock + BCS...
Dr
Michael Gabler
(MPA Garching)
26/03/2014, 17:40
Our numerical simulations show that axisymmetric, torsional,
magnetoelastic oscillations of magnetars with a superfluid core
can explain the whole range of observed quasiperiodic
oscillations (QPOs) in the giant flares of soft gamma-ray repeaters. There exist constant phase QPOs at $f\lesssim150$\,Hz and resonantly excited high-frequency QPOs ($f>500$\,Hz), in good agreement...
Dr
Andrea Passamonti
(INAF-Observatory of Rome)
26/03/2014, 18:00
The analysis of Quasi Periodic Oscillations (QPOs) in Magnetars provided the first application of Asteroseismology in neutron stars. These oscillations are likely identified with magneto-elastic waves which originate in the giant flares. Cooling calculations show that magnetars become superfluid/superconducting systems in few hundred years from their birth. In this talk I will present the...
Mr
François Aymard
(LPC Caen, France)
26/03/2014, 18:00
It is nowadays well established that the properties of the nuclear effective interaction through the equation of state have a very important influence in different astrophysical phenomena, from the dynamics of the Core Collapse Supernovae, to the cooling of Proto-Neutron Stars and the structure of Neutron Stars. The self-consistent mean-field theory is an appealing framework to establish a...
Prof.
Friedrich Roepke
(MPA Garching)
27/03/2014, 09:00
Compact objects can change their state and configuration in combustion processes. In the case of white dwarfs, thermonuclear burning leads to an explosion as Type Ia supernova -- a phenomenon well studied in observations and theoretical models. Combustion processes, however, may also be adequate to describe phase transitions in neutron stars, in particular the "burning" of hadronic matter into...
Dr
Christian Ott
(Caltech, USA)
27/03/2014, 09:40
The next galactic core-collapse supernova will be observed in the
electromagnetic spectrum, in neutrinos, and, for the first time, in
gravitational waves. I review gravitational wave emission from stellar
collapse and the subsequent core-collapse supernova evolution and
discuss how gravitational waves can be used to probe aspects of the
explosion mechanism and physical parameters of the...
Prof.
Alice K. Harding
(NASA Goddard Space Flight Center)
27/03/2014, 10:20
Of the several thousand pulsars that have been discovered by radio telescopes over the past forty year, only a handful were known to emit gamma-ray pulsations before the launch in June, 2008 of the Fermi Gamma-Ray Space Telescope. After five years of operation, 130 gamma-ray pulsars have been detected and several new populations have been discovered. Millisecond pulsars have been confirmed...
Prof.
Gogi Melikidze
(University of Zielona Gora), Prof.
Janusz Gil
(University of Zielona Gora), Prof.
Ulrich Geppert
(DLR and University of Zielona Gora)
27/03/2014, 14:30
Models of pulsar radio emission that are based on an inner accelerating region require the existence of very
strong and small scale surface magnetic field structures at or near the canonical polar cap.
The aim of this paper is to identify a mechanism that creates such
field structures and maintains them over a pulsar's lifetime. The
likely physical process that can create the required...
Dr
Ramandeep Gill
(CITA (University of Toronto))
27/03/2014, 14:50
The cooling theory of neutron stars is corroborated by its comparison with observations of thermally emitting isolated neutron stars and accreting neutron stars in binary systems. An important ingredient for such an analysis is the age of the object, which, typically, is obtained from the spin-down history. This age is highly uncertain if the object's magnetic field varies appreciably over...
Dr
Nathalie Degenaar
(University of Michigan)
27/03/2014, 15:10
In transient X-ray binaries, the crust of a neutron star becomes temporarily heated during accretion outbursts, while it subsequently cools in quiescence when accretion has ceased. This crustal cooling can be observed by studying the thermal X-ray emission from quiescent neutron stars with sensitive X-ray satellites. Comparing these observations with theoretical simulations provides a unique...
Dr
Roberto Mignani
(INAF/IASF)
27/03/2014, 15:10
In this talk, we present the outcome of X-ray and optical/IR observations of gamma-ray pulsars detected by Fermi, as a part of a program aimed at completing the multi-wavelength coverage of these sources. We found X-ray counterparts for five Fermi pulsars, and we observed in X-ray some unidentified Fermi sources believed to be isolatd neutron stars.
Dr
Deborah Aguilera
(Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Bremen, Germany)
27/03/2014, 15:30
The theoretical modeling of the thermal relaxation of the
neutron star crust in low mass X-ray binaries may be used to establish
constraints on the crust and envelope composition and transport
properties, depending on the astrophysical scenarios assumed. I will show
numerical simulations of the neutron star crust thermal evolution and
compare them with inferred surface temperatures for...
David Keitel
(Albert Einstein Institute)
27/03/2014, 15:30
The distributed computing project Einstein@Home searches for unknown pulsars in large data sets. So far, more than 350,000 volunteers from the world-wide public have signed up their computers to run scientific analyses with their spare cycles, reaching a teraflop peak performance. Einstein@Home was originally created to search for continuous gravitational waves (GWs), but is now also analysing...
Carlotta Pittori
(ASDC and INAF-OAR)
27/03/2014, 16:15
AGILE is an Italian Space Agency (ASI) space mission, built and operated in cooperation with INAF, INFN and CIFS, dedicated to the observation of the gamma-ray Universe in the 30 MeV - 50 GeV energy range, with simultaneous X-ray imaging capability.
The AGILE satellite, launched on April 23rd, 2007, is substantially contributing to improve our knowledge on gamma-ray sources.
I will...
Prof.
Pawel Haensel
(Nicholaus Copernicus Astronomical Centre, Warsaw, Poland)
27/03/2014, 16:15
We study the impact of the presence of a hyperon core on the R-M relation for neutron stars (NS). Using observational constraint Mmax>2Msun, and available EOSs, we show difference between R-M relation in the mass range 1.2 - 1.6 Msun between NS with nucleon cores and those based on EOS that allow for sizable hyperon cores in high mass NS. We find correlation between pressure at...
Dr
Holger Stiele
(Shanghai Astronomical Observatory)
27/03/2014, 16:45
4U 1636-536 is a well-studied LMXB, consisting of a neutron star in a 3.8 hr orbit with a companion star of about 0.4 solar mass. The X-ray source shows the full range of rapid time variability, among them, burst oscillations and mHz QPOs are associated with thermonuclear burning on the neutron star. We performed a variability study of archival broadband X-ray observations of 4U 1636-536 and...
Manoneeta Chakraborty
(Tata Institute of Fundamental Research)
27/03/2014, 17:00
Intense X-ray bursts (type-I bursts), originating from unstable thermonuclear conflagration, are observed from the surfaces of many accreting neutron star Low Mass X-ray Binary (LMXB) systems and are useful tools to constrain the equation of state and probe strong gravity regime. A series of such X-ray bursts were observed during the 2010 outburst of the transient pulsar IGR J17480-2446. These...
Dr
Hans Thomas Janka
(MPI Garching)
28/03/2014, 09:00
Review talk on numerical modelling of neutron star coalesence and their remnants.
Prof.
Benjamin Owen
(Penn State, USA)
28/03/2014, 09:40
Mechanisms of continuous gravitational-wave emission from neutron stars include long-lived r-mode oscillations and rotations of static deformations (“mountains”). Emission depends on the equation of state and transport coefficients of matter above nuclear density. Therefore gravitational-wave searches may be guided by, and reveal information on, the equation of state and other properties of...
Prof.
Luciano Rezzolla
(AEI)
28/03/2014, 10:50
I will review the recent progress made in modelling binaries of compact
objects and the role played by magnetic fields in their
evolution. Special attention will be paid to binary neutron stars and to
highlighting how the progress of ab-initio fully relativitistic
calculations can be used to several aspects of the phenomenology of short
gamma-ray burst.
Dr
Tanja Hinderer
(Caltech, USA)
28/03/2014, 11:30
Binary neutron stars and neutron star-black hole systems are some of the most promising sources for gravitational-wave observations with Advanced terrestrial interferometer detectors. For such systems, the matter contributes to the spacetime dynamics, leaving an imprint on the gravitational radiation from the system. I will discuss how we can understand and model this imprint, so that we can...
Dr
Andreas Bauswein
(Department of Physics, Aristotle University of Thessaloniki)
28/03/2014, 14:00
By a representative set of hydrodynamical simulations we investigate the influence of the high-density equation of state on observable features of neutron-star mergers. The dependence of the gravitational-wave emission on the equation of state of neutron-star matter is addressed. On the basis of our survey we point out a novel possibility to determine neutron-star radii from gravitational-wave...
Dr
Cristiano Palomba
(INFN Roma)
28/03/2014, 14:20
A spinning neutron star, if asymmetric respect to the rotation axis, is expected to emit a continuous gravitational wave signal.
In this talk I present a summary of the results obtained in the analysis of LIGO and Virgo data searching for continuous gravitational wave signals emitted by known pulsars. I focus attention on the astrophysical interpretation of the most interesting upper limits...
Dr
Shuta Tanaka
(Institute for Cosmic Ray Research, The University of Tokyo)
28/03/2014, 14:30
Pulsar winds have problems in energy conversion and pair-cascade processes which determine the magnetization, the pair multiplicity and the bulk Lorentz factor of the wind.
We study induced Compton scattering by a relativistically moving cold plasma to constrain wind properties by imposing that radio pulses from the pulsar itself are not scattered by the wind as was first studied by Wilson &...
Dr
Plamen Fiziev
(Foundation of Theoretical and Computational Physics and Astrophysics (TCPA) Sofia University)
28/03/2014, 14:40
We present the basic equations and relations for the relativistic static
spherically symmetric stars (SSSS) in the model of minimal dilatonic
gravity (MDG) 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. The results for a simplest form of relativistic equation
of state (EOS) of neutron...
Prof.
Luigi Stella
(INAF - OAR)
28/03/2014, 15:00
High-time-resolution and spectroscopic X-ray observations of compact objects provide access to strong-field gravity, the equation of state of ultra-dense matter and black hole masses and spins. A 10 m^2-class instrument in combination with good energy resolution is required to exploit diagnostics and answer two of the fundamental questions of the European Space Agency (ESA) Cosmic Vision...
Dr
Lubos Neslusan
(Astronomical Institute, Slovak Academy of Sciences)
28/03/2014, 15:15
Neutron stars (NSs) are the compact objects with the metrics detectably deviated from the flat spacetime. In the interior of every NS the metrics can be calculated from the model of its internal structure. In the surrounding empty space the metrics is described by the outer Schwarzschild solution (OSS) of Einstein field equations if a non-rotating NS is considered. In the linkup of both NS and...
Prof.
Leonardo Gualtieri
(Rome University "La Sapienza", Italy)
28/03/2014, 15:20
The gravitational signal emitted in the late inspiral of a binary system, composed by a neutron star and another compact object, encodes the deformability properties of the neutron star, which depend on the behaviour of matter in the stellar interior. We discuss how the detection of this signal from ground based interferometers of second and third generation, can be used to extract information...
Mr
Rodrigo Souza
(IAG - USP Sao Paulo)
28/03/2014, 15:30
Recently, it has been suggested that a critical electrical field arises during the gravitational collapse of massive stars leading to a vacuum polarization. This, in turn, leads to the necessity of a reexamination of the gravito-electrodynamical properties of compact stars of the class of neutron stars. Rotondo, Rueda, Ruffini and Xue claim to have proved the impossibility of local charge...
Ms
Sofie Fehlmann
(University of Basel)
28/03/2014, 16:30
Neutron stars in low mass X-ray binary systems with an accretion flow of matter from the companion star have been observed to exhibit regular bursts. These so-called type I X-ray bursts are thermonuclear explosions occurring in the surface layers of neutron stars. After thousands of type I X-ray bursts, enough ashes have been accumulated and a rare superburst event may take place. Such an...
Mr
Khaled Elshamouty
(University of Alberta)
28/03/2014, 16:45
Spectral analyses of quiescent neutron stars in X-ray binaries have been used to constrain the mass and radius of the neutron stars. A question not yet explored is the effect of undetected hot spots on the spectrum, and thus on the inferred mass and radius of a quiescent neutron star. We simulate light curves for hydrogen atmosphere neutron stars with hot spots, performing Monte Carlo...
Ms
Aida Kirichenko
(Ioffe Physical Technical Institute)
28/03/2014, 17:00
Recent discoveries of the Fermi mission have increased the number of known gamma-ray pulsars by a factor of twenty. Multiwavelength investigations of these objects are crucial for unveiling the pulsar emission nature. Because gamma-ray pulsars are typically nearby and energetic, they, in particular, appear to be promising targets for studies in X-ray and optical domains. We present new...
M. Bronzato de Avellar
(IAG in San Paulo, Brasil)
28/03/2014, 17:15
We present an analysis of the energy and frequency dependence of the Fourier time lags of the hectoHertz quasi-periodic oscillations (QPOs) and of the QPOs at the frequency at which the power density spectrum shows a break in the neutron-star low-mass X-ray binary 4U 1636−53, using a large data set obtained with the Rossi X-ray Timing Explorer.
We found that: (i) For the break frequency...
Prof.
Igor Iosilevskiy
(Joint Institute for High Temperature (Russian Academy of Science), Moscow Institute of Physics and Technology (State University))
Features of Gas-Liquid (GL) and Quark-Hadron (QH) phase transitions (PT) in dense nuclear matter are under discussion in comparison with their terrestrial counterparts, so- called ionization- and dissociation-driven PTs in warm dense hydrogen, nitrogen, xenon etc. Both, GLPT and QHPT, when being represented in widely accepted T-μ plane are often considered as equivalent PTs, i.e. amenable to...
Dr
M. A. Perez-Garcia
(University of Salamanca and IUFFyM)
Using techniques of finite-temperature microscopic computational many-body modelling, we evaluate the microscopic structure of the neutron star crust at low nuclear densities for different isospin composition conditions focusing on temperature effects.
We will discuss about how the latter alter the inhomogenous pasta phases through the arising droplet configurations and, consequently, about...
Dr
Ali Taani
(Al-Balqa' Applied University- Aqaba University College)
The Recycling process is usually considered as a standard model to produce Millisecond Pulsars (MSPs).I will discuss another possible
channel involving the Accretion Induced Collapse (AIC) of a white dwarf (WD) in binaries. As accreting binaries lead to orbit
circularization due to tidal coupling during the accretion phase, Low-Mass X-Ray Binaries (LMXBs) and Cataclysmic...
Dr
Felipe Olivares E.
(Universidad Andrés Bello)
After the discovery of SN 1998bw associated with GRB 980425, the first connection between Gamma-Ray Bursts (GRBs) and Supernovae (SNe) occurred almost 15 years ago, no more than two dozens SN-like rebrightenings and seven solid spectroscopically-confirmed associations have been observed to date. In this talk we present data from the Gamma-Ray Burst Optical and Near-infrared Detector (GROND)...
Dr
Sergey Moiseenko
(Space Research Institute)
We present results of formation of protoneutron star as a result of magnetorotational supernova explosion. At the formation stage the magnetic field on the surface of the NS is chaotic and strong ~ 10(14)G. We found oscillations of the NS in simualtions. Details of magnetorotational supernova exlosion mechanism are discussed.
Dr
Craig Heinke
(University of Alberta)
I'll give a review talk, specifically covering studies of quiescent neutron stars in globular clusters. Depending on what other speakers cover, I may also cover X-ray burst spectral constraints (e.g. Ozel, Steiner, etc.), and constraints on compactness from pulse shape modeling (e.g. works by Bogdanov, Morsink, etc).
Dr
Miroslav Shaltev
(Albert Einstein Institute, Hannover)
The search for continuous gravitational waves in a wide parameter space is most efficiently done with semi-coherent
methods, e.g. StackSlide, due to the prohibitive computing cost of the
fully-coherent search strategies. Recently we have developed an
analytical method for finding optimal StackSlide parameters at
fixed computing cost under ideal conditions, i.e. gap-less data and
constant...
