Education and Cultural Astronomy (STARS)

• Steven Gullberg (University of Oklahoma)

The importance of including a thorough search for the potential use of astronomy in the examination of any culture is discussed. Educational strategies are included that can enable scholars to add related research knowledge that will enable them to augment their studies in this pursuit. What can be learned from astronomy in culture is examined and the importance of including such research as a part of certain studies is emphasized. A primary goal is to help scholars to learn more about the research of astronomy in culture with the goal of increasing the numbers of those engaged with this in strong research and publication. Educational strategies and emerging programs will be discussed. Such educational initiatives will greatly strengthen this research in the future and will facilitate significant advancements in what we know about the astronomy of ancient and indigenous cultures world-wide.

Exact magnetic contribution to a one-loop charged scalar field potential (STARS)

• Gabriella Piccinelli Bocchi (Centro Tecnológico, FES Aragón, UNAM)

In the context of a warm inflation scenario, we explore the effect of a primordial magnetic field on a charged scalar field potential.

Black holes fueling and coalescence in galaxy mergers (STARS)

• Andrés Escala (Universidad de Chile)

Using a combination of Smooth Particle hydrodynamics and Adaptive Mesh Refinement simulations of galaxy mergers, with sub-parsecs scale resolution, we have study both the mass transport process onto the massive black holes throughout a galactic merger and especially, the posible black holes coalescence at galactic center. The final coalescence of these black holes lead to gravitational radiation emission that would be detectable up to high redshift by future gravitational wave experiment such as eLISA, which is expected to be launched in 2034.

A breakthrough for the study of resolved stellar populations with ELTMOS/MOSAIC (STARS)

• Roth Martin (Leibniz-Institut für Astrophysik Potsdam (AIP))

The study of resolved stellar populations in nearby galaxies outside of the Local Group has come within reach with the new generation of extremely large telescopes, featuring primary mirror diameters on the order of 30 meters. ELT, the European Extremely Large Telescope, is currently being built at the Armazones site in the Atacama desert of Chile. From the instrumentation suite for the ELT, the multi-object spectrograph ELT-MOS stands out with the capability of combining the large light collecting power with adaptive optics over the entire field-of-view of the ELT, thus becoming the perfect instrument to study the spectra of resolved stars in galaxies beyond the Milky Way and the Local Group. With an emphasis of the stellar science case, the instrument at the stage of the completed Phase-A study will be presented and discussed, in particular with a focus on the synergy potential with the MICADO imager at the ELT, and the MUSE IFU at the VLT.

Observation of r-process abundance patterns in stars (STARS)

• Norbert Christlieb (Universität Heidelberg)

Stars conserve in their atmospheres, to a large extent, the chemical composition of the gas cloud from which they formed. The chemical compositions of old, metal-poor stars in the halo of our galaxy can hence be used for reconstructing the chemical enrichment history of the Milky Way, and studying the nucleosynthesis processes that contributed to the enrichment. For example, a unique abundance signature of the rapid neutron-capture process (r-process) has been observed in metal-poor stars strongly enriched in r-process elements, providing constraints on r-process models and the physical conditions of the site of this process. In my talk I will review the recent progress that has been made in identifying large samples of metal-poor stars by means of wide-angle sky surveys, determinations of their chemical compositions with optical high-resolution spectra and state-of-the art stellar model atmospheres, and future prospects in the era of 4-10m telescopes equipped with highly multiplexed spectrographs, as well as the next generation of large ground-based telescopes currently under construction.

Can the symmetry breaking in the SM be determined by the “second minimum” of the Higgs potential? (STARS)

• Alejandro Cabo (Department of Theoretical Physics )

The possibility that the spontaneous symmetry breaking in the Standard Model (SM) may be generated by the Top-Higgs Yukawa interaction (which determines the so called “second minimum” in the SM) is investigated. A former analysis about a QCD action only including the Yukawa interaction of a single quark with a scalar field is here extended. We repeat the calculation done in that study of the two loop effective action for the scalar field of the mentioned model. A correction of the former evaluation allowed to select a strong coupling \alpha(m,LQCD) = 0.2254 GeV at an intermediate scale \mu = 11.63 GeV, in order to fix the minimum of the potential at a scalar mean field determining 175 GeV for the quark mass. Next, a scalar field mass m = 44 GeV is evaluated, which is also of the order of the experimental Higgs mass. The work is also considering the effects of employing a running with momenta strong coupling. For this purpose, the finite part of the two loop potential contribution determined by the strong coupling, was represented as a momentum integral. Next, substituting in this integral the experimental values of the running coupling, the minimum of the potential curve as a function of the mean field was again fixed to the top quark mass by reducing the scale to the value \mu = 4.95 GeV. The consideration of the running coupling also deepened the potential value at the minimum and slightly increased the mass of the scalar field up to 53.58 GeV. These results rested in assuming that the low momentum dependence of the coupling is “saturated” to a constant value being close to its experimental value at the lowest momentum measured.

Magnetic field-dependence of the neutral pion mass in the linear sigma model coupled to quarks: The weak field case (STARS)

• Daryel Manreza Paret (Facultad de Física, Universidad de La Habana)

We compute the neutral pion mass dependence on a magnetic field in the weak field approximation at one-loop order. The calculation is carried out within the linear sigma model coupled to quarks and using Schwinger's proper-time representation for the charged particle propagators. We find that the neutral pion mass decreases with the field strength provided the boson self-coupling magnetic field corrections are also included. The calculation should be regarded as the setting of the trend for the neutral pion mass as the magnetic field is turned on.

Exact configurations for interacting spin-2 fields in three dimensions (STARS)

• Elizabeth Rodríguez Querts (ICIMAF)

We studied some exact configurations for the three-dimensional massive multi-gravity theory called "Viel-dreibein gravity". We find AdS wave solutions (which reflect the main dynamic properties of the model) and analyze their asymptotic behavior. In addition, we explore the existence of black holes in the context of this theory.

Cosmogenic photon and neutrino fluxes in the Auger era (STARS)

• Rogerio de Almeida (Universidade Federal Fluminense)

The interaction of ultra-high-energy cosmic rays (UHECRs) with pervasive photon fields generates associated cosmogenic fluxes of neutrinos and photons due to photohadronic and photonuclear processes taking place in the intergalactic medium. We perform a fit of the UHECR spectrum and composition measured by the Pierre Auger Observatory for four source emissivity scenarios: power-law redshift dependence with one free parameter, active galactic nuclei, gamma-ray bursts, and star formation history. We show that negative source emissivity evolution is favoured if we treat the source evolution as a free parameter. In all cases, the best fit is obtained for relatively hard spectral indices and low maximal rigidities, for compositions at injection dominated by intermediate nuclei (nitrogen and silicon groups). In light of these results, we calculate the associated fluxes of neutrinos and photons. Finally, we discuss the prospects for the future generation of high-energy neutrino and gamma-ray observatories to constrain the sources of UHECRs.

Effective potential of a higher derivative scalar field theory at finite temperature (STARS)

• Angel Sánchez (Facultad de Ciencias, UNAM)

In this contribution, I present the study of the effect of higher derivative terms in the effective potential of a scalar field theory. Preliminary results indicate that quantum correction coming from the higher derivative terms make the curvature of the effective potential, near the origin, becomes flatter. I will discuss how this result could be interesting within a warm inflation scenario.

Charges and torsion (STARS)

• Ernesto Frodden

We review the surface charge method in the Einstein-Cartan formalism and study in particular the role of torsion in the computation of charges. An example in 2+1 gravity is worked out explicitly and some advances in the Einstein-Cartan-Dirac theory are presented.

Scale Invariance in Cosmology and Particle Physics using metric independent measures of integrations in the action (STARS)

• Eduardo Guendelman (Ben Gurion University)

Abstract The use of a metric independent measure of integration in the action opens new possibilities for constructing globally scale invariant theories, since the new measure can be assigned a different scaling transformation than the usual metric dependent measure sqrt(-g). There are various ways to construct a density that can serve as a metric independent measure of integration, from the derivatives of 4 scalar fields or the derivative of a three index tensor field contracted with the alternating symbol. The integration of the equations of motion of these "measure fields" leads to the spontaneous breaking of the scale invariance. A dilaton field with exponential potentials is added and coupled to the different measures. In the effective Einstein frame, potentials for the dilaton with flat regions appear, if curvature square terms are introduced, two flat regions appear, one capable of describing inflation and the other describing the slowly accelerated phase of the present universe. These models allow non singular cosmologies of the emergent type. In the context of the late universe, it is shown that the scale invariance is responsible for the avoidance of the 5th force problem that could have appeared in connection with the nearly massless dilaton. Also a see saw cosmological mechanism that could explain the smallness of the present vacuum energy can be formulated. Finally these techniques have been used to formulate scale invariant extensions of the Standard Model.

Divergence-type hyperbolic theories for ultrarelativistic fluids (STARS)

• Marcelo Enrique Rubio (IATE - CONICET)

In this talk I will present a novel theory with the aim of describing the dynamics of ultrarelativistic fluids considering dissipative effects up to second order. The problem of achieving a covariant relativistic extension of the equations that describe non-relativistic dissipative fluids constitutes a very active area of current research, given that a well-posed and causal theory of viscous fluids is essential for a better description of several astrophysical problems, as for example the coalescence of compact objects, which constitute nowadays the main source of gravitational wave production. After mentioning previous attempts for covariant extensions of viscous fluids, we will present a proposal for the study of the dynamic evolution of ultrarelative fluids. Then, we will show how to implement the equations of the theory numerically, using the Kurganov-Tadmor centered method, which allows capturing discontinuous solutions that simulate shock waves, and show some simulations in the one-dimensional case.

Susceptibilities of strongly interacting matter in a finite volume (STARS)

• Christian Spieles (Frankfurt Institute for Advanced Studies (FIAS))

We investigate possible finite-volume effects on baryon number susceptibilities of strongly interacting matter. Assuming that a hadronic and a deconfined phase both contribute to the thermodynamic state of a finite system due to fluctuations, it is found that the resulting shapes of the net-baryon number distributions deviate significantly from the infinite volume limit for a given temperature T and baryochemical potential μ_B. In particular, the constraint on color-singletness for the finite quark-gluon phase contribution leads to a change of the temperature dependence of the susceptibilities in finite volumes. According to the model, the finite-volume effect depends qualitatively on the value of μ_B.

Directed, elliptic and triangular flow of free protons and deuterons in Au+Au reactions at 1.23 A GeV (STARS)

• Paula Hillmann

Recently, the HADES experiment at GSI has provided preliminary data on the directed flow, $v_1$ elliptic flow, $v_2$ and triangular flow, $v_3$ of protons in Au+Au reactions at a beam energy of 1.23 A GeV. Here we present a theoretical discussion of these flow harmonics within the UrQMD transport approach. We show that all flow harmonics, including the triangular flow, provide a consistent picture of the expansion of the system, if potential interactions are taken into account. Cluster formation has a large contribution to the physics of collective flow. Therefore, the flow of deuterons and free protons are compared. Investigating the dependence of the flow harmonics on the nuclear interaction potentials it is shown that especially $v_3$ can serve as a sensitive probe for the nuclear equation of state at such low energies. The triangular flow and its excitation function with respect to the reaction-plane were calculated for the first time and indicate a complex interplay of the time-evolution of the system and the initial conditions at low beam-energies. Our study also indicates a significant softening of the equation of state at beam energies above E lab > 7 A GeV which can be explored by at the future FAIR facility.

Delta mass shift as a thermometer of kinetic decoupling in Au+Au reactions at 1.23 AGeV (STARS)

• Tom Reichert (Institut für Theoretische Physik, Goethe Universität Frankfurt)

The HADES experiment at GSI will soon provide data on the production and properties of ∆ baryons from Au+Au reactions at 1.23 AGeV. Using the UrQMD model, we predict the yield and spectra of ∆ resonances. In addition we show that one expects to observe a mass shift of the ∆ resonance on the order of 40 MeV in the reconstructable ∆ mass distribution. This mass shift can be understood in terms of late stage ∆ formation with limited kinetic energy. We show how the mass shift can be used to constrain the kinetic decoupling temperature of the system.

The phase diagram of the Polyakov-Nambu-Jona-Lasinio approach (STARS)

• Joerg Aichelin (Subatech/CNRS, France)

Recently we succeeded, by introducing an interaction between the gluon mean field (presented by the a function of the Polyakov loop) and quarks, to reproduce the lattice equation of state for zero chemical potential with the Polyakov-Nambu-Jona-Lasinio model. Also, entropy density, interaction measure, energy density and the speed of sound are quite nicely reproduced. Even the first coefficient of the Taylor expansion of the lattice data with respect to the chemical potential is in the error bars of the lattice calculations. These findings are of great importance for future studies of heavy ion reactions because the Polyakov-Nambu-Jona-Lasinio model can be extended to finite chemical potentials (where lattice calculations are not possible) without introducing any new parameter. In addition, it shows at large chemical potentials a first order phase transition. It provides therefore a basis for theoretical studies in the energy range of the future FAIR and NICA facilities where one expects that heavy ion collisions are characterized by a large chemical potential. It may also serve as a equation of state for gravitational wave studies.

Exploring the partonic phase at finite chemical potential within an extended off-shell transport approach (STARS)

• Elena Bratkovskaya (GSI, Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany and Institute for Theoretical Physics, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany)

We extend the Parton-Hadron-String Dynamics (PHSD) transport approach in the partonic sector by explicitly calculating the total and differential partonic scattering cross sections as a function of temperature $T$ and baryon chemical potential $\mu_B$ on the basis of the effective propagators and couplings from the Dynamical QuasiParticle Model (DQPM) that is matched to reproduce the equation of state of the partonic system above the deconfinement temperature $T_c$ from lattice QCD. The novel transport approach (PHSD5.0) thus incorporates no additional parameters compared to the default version PHSD4.0. We calculate the collisional widths for the partonic degrees of freedom at finite $T$ and $\mu_B$ in the time-like sector and conclude that the quasiparticle limit holds sufficiently well. Furthermore, the ratio of shear viscosity $\eta$ over entropy density $s$, i.e. $\eta/s$, is evaluated using the collisional widths and compared to lQCD calculations for $\mu_B$ = 0 as well. We find that the novel ratio $\eta/s$ does not differ very much from that calculated within the original DQPM on the basis of the Kubo formalism. Furthermore, there is only a very modest change of $\eta/s$ with the baryon chemical $\mu_B$ as a function of the scaled temperature $T/T_c(\mu_B)$. This also holds for a variety of hadronic observables from central A+A collisions in the energy range 5 GeV $\leq\sqrt{s_{NN}} \leq$ 200 GeV when implementing the differential cross sections into the PHSD approach. We only observe small differences in the antibaryon sector (${\bar p}, {\bar \Lambda}+{\bar \Sigma}^0$) at $\sqrt{s_{NN}}$ = 17.3 GeV and 200 GeV with practically no sensitivity of rapidity and $p_T$ distributions to the $\mu_B$ dependence of the partonic cross sections. Small variations in the strangeness sector are obtained in all studied collisional systems (A+A and C+Au), however, it will be very hard to extract a robust signal experimentally. Since we find only small traces of a $\mu_B$-dependence in heavy-ion observables - although the effective partonic masses and widths as well as their partonic cross sections clearly depend on $\mu_B$ - this implies that one needs a sizable partonic density and large space-time QGP volume to explore the dynamics in the partonic phase. These conditions are only fulfilled at high bombarding energies where $\mu_B$ is, however, rather low. On the other hand, when decreasing the bombarding energy and thus increasing $\mu_B$, the hadronic phase becomes dominant and accordingly, it will be difficult to extract signals from the partonic dynamics based on "bulk" observables.

Deuteron production in heavy ion collisions (STARS)

• Marcus Bleicher (Uni Frankfurt)

In this talk, we discuss UrQMD phase-space coalescence calculations for the production of deuterons. We compare with available data for various reactions from the GSI/FAIR energy regime up to LHC. It is found that the production process of deuterons, as reflected in their rapidity and transverse momentum distributions in p+p, p+A and A+A collisions at a beam energies starting from the GSI energy regime around 1 AGeV and up to the LHC, are in good agreement with experimental data. We further explore the energy and centrality dependence of the d/p ratios. Finally, we discuss anti-deuteron production for selected systems. Overall, a good description of the experimental data is observed. The results are also compatible with thermal model estimates. We also discuss the production of hypermatter within the same approach and find sizable production rates at FAIR.

One-loop divergences in 7D Einstein and 6D conformal gravities (STARS)

• Danilo Diaz (Universidad Andrés Bello)

Within the context of AdS/CFT Correspondence, we first compute one-loop infrared (IR) divergences of 7D Einstein Gravity in a certain Poincaré-Einstein background metric. We compute then the one-loop ultraviolet (UV) divergences of 6D Conformal Gravity on the boundary. We verify the equality of the above results that stems from the IR-UV connection of the duality dictionary. Key ingredients are heat kernel techniques, factorization of the boundary higher-derivative kinetic operator for the Weyl graviton on the 6D boundary Einstein metric and WKB-exactness of the Einstein graviton in the chosen 7D Poincaré-Einstein background. In all, we elucidate the way in which the 6D results containing the type-A and type-B conformal anomalies for the Weyl graviton are encoded in the 7D "hologram" given by the fluctuation determinant for the Einstein graviton. We finally discuss possible extensions to include higher-spin fields.

Generalized SU(2) Proca inflation (STARS)

• Yeinzon Rodriguez Garcia (UAN & UIS (Colombia))

The generalized SU(2) Proca theory is the only modified gravity theory, nowadays, able to accommodate in a natural way a configuration of vector fields which is compatible with the homogeneous and isotropic nature of our Universe. In previous works, we have been able to uncover a self-tuning mechanism that drives an eternal slow-roll inflationary period for an ample spectrum of initial conditions. We have made a little and justified modification to the action so that the mentioned self-tuning mechanism is preserved but now the inflationary period has a graceful exit and is long enough to solve the classical problems of the standard Cosmology. The action is free of tachyonic, ghost, and Laplacian instabilities, and, in addition, provides a non-anomalous speed for the gravity waves. The usual naturalness problem of the primordial inflation in this scenario is, therefore, essentially absent.

Lie-Backlund transformations for residual symmetries in General Relativity (STARS)

• Miguel Angel Marquina Carmona (CINVESTAV IPN)

Lie-Backlund transformations have been used to extend the criteria proposed by Ayón-Beato and Velázquez-Rodríguez for characterizing the residual symmetries of the gravitational ansatz developed according to Lie-point transformations. We found that non-local Lie-Backlund transformations allows us to obtain the more general residual symmetries of the metric. We present the generalized criteria for finding all residual symmetries for any metric ansatz in general relativity.

Correlation functions of sourced gravitational waves in inflationary scalar vector models. A symmetry based approach (STARS)

• Josue Motoa Manzano (Universidad del Valle)

In this work we use the correspondence between a field theory in de Sitter space in 4-dimensions and the dual conformal field theory in an euclidean space in 3-dimensions, to compute the form of two and three point correlation functions of scalar-tensor perturbations. To this end, we use an inflationary model, in which the inflaton field is interacting with a vector field trough the term $f(\phi)\left(F_{\mu \nu}F^{\mu \nu}+\kappa\tilde{F}_{\mu \nu}F^{\mu \nu}\right).$ The first step of this method consist in to solve the equations of motion for the fields in the de Sitter 4D space-time, then evaluate this solutions in super-Hubble scales and compute the conformal weight of the projection of this fields in the 3D space. In a second stage, we propose a general form for the correlators, which involve scalar, vector and tensor perturbations and, using the first step result, find its momentum dependence by imposing that those are invariant under dilatations and special conformal transformation (SCT). As a result, we find the form for the different Spectrums of the tensor perturbations and for the a mixed Bispectrum coming from the vacuum and for the vector perturbations. They show to be in agreement with the results in the literature.

The symmetry energy in neutron stars: constraints from GW170817 and direct Urca cooling (STARS)

• David Edwin Alvarez Castillo (JINR)

In this contribution I will review the state of the art measurements for the symmetry energy from both astrophysical and terrestrial laboratories. In particular the recent detection of gravitational radiation from the GW170817 event shed light on the properties of the neutron star equation of state, thus comprising both the study of the symmetry energy and stellar radius. Furthermore, I shall address the question on the possibility of a universal symmetry energy contribution to the neutron star equation of state under restricted Direct Urca cooling. When these two aspects are combined, powerful predictions for the neutron star equation of state are obtained.

Stueckelberg-Horwitz-Piron (SHP) classical mechanics with evolving local metric (STARS)

• Martin Land (Hadassah College)

Stueckelberg-Horwitz-Piron (SHP) theory is a framework for posing classical and quantum relativistic physics in canonical form with an external parameter of evolution $\tau$. SHP electrodynamics generalizes Maxwell theory by allowing the four-vector potential to depend on $\tau$ and introducing a scalar gauge potential $a_5(x,\tau)$ associated with this $\tau$-dependence. As a result, current conservation, wave equations, and other scalar expressions suggest a formal 5D symmetry that breaks to tensor and scalar representations of O(3,1) in the presence of 4D matter. Following a similar approach, this electrodynamic theory has recently been extended to non-abelian gauge symmetries and to the classical and quantum many-body problem in curved 4D spacetime with local metric $g_{\mu\nu}(x)$, for $\mu,\nu = 0,1,2,3$. In this talk we examine another extension of classical SHP mechanics by allowing the local metric to be $\tau$-dependent and introducing new metric components associated with $\tau$ evolution. In order to obtain a reasonable prescription for this generalization, consistent with an extended equivalence principle, the breaking of formal 5D tensor symmetries must be treated in detail. This extension permits us to describe particle motion in geodesic form with respect to a dynamically evolving background metric. As an example, we consider the field produced by a $\tau$-dependent mass $M(\tau)$, first as a perturbation in the Newtonian approximation and then for a Schwarzschild-like metric. As expected, the extended Einstein equations imply a non-zero energy-momentum tensor, representing the flow of mass energy corresponding to the changing source mass. Moreover, the Hamiltonian (the scalar system mass) is driven by terms proportional to $dM / d\tau$ and is not conserved. In $\tau$-equilibrium, this system becomes a generalized Schwarzschild solution for which the extended Ricci tensor and mass-energy-momentum tensor vanish.

On the dynamics of rotationally supported galaxies (STARS)

• Ramzi Suleiman (Triangle Research & Development Center)

A recent finding, based on empirical data of 153 rotationally supported galaxies, with very different morphologies, masses, sizes, and gas fractions, revealed that the baryonic and the dark matter in galaxies are strongly coupled, such that, if the first is known, the second follows and vice versa. Here, we propose a completely theoretical analysis of the dynamics of rotationally supported galaxies, which results in the same conclusion. We find that the relationship between baryonic and dark matter densities at any radius r is governed by the law, ρ(r)_M + ρ(r)_DM = ρ_0, where ρ(r)_M, and ρ(r)_DM are, respectively, the densities of matter and dark matter at radius r, and ρ_0 is the density at the galaxy’s center. Strikingly, we also found that the radius r_s, at which the rotation velocity is equal to half of its maximal value (or alternatively the radius r_c at which the baryonic matter density is equal to half of its density at the galaxy’s center) constitutes a vivid signature of the galaxy, in the sense that it reveals rich information about the galaxy’s dynamics, including the distribution of its matter and dark matter and their total amounts in the galaxy.

A hybrid model for pulsar evolution (STARS)

• Zhi Fu Gao (Xinjiang Astronomical Observatory, Chinese Academy of Sciences)

The combined effects of both the standard magnetic dipole model and the composite neutron superfluid vortex model on the energy loss rate of neutron stars and pulsar spin down are simultaneously taken into account to study the evolution of neutron stars on the P-Pdot diagram. The evolution path of each neutron star is dictated by a particular mechanism in our hybrid model in different parameter spaces and the valley of each curve is the most possible place for a neutron star to be observed since this is the place which corresponds to the minimum value of the evolution speed (i.e. the time derivative Pdot). In other words, pulsars would distribute around these valleys on the P-Pdot diagram. The combined model can be fitted very well with observation to yield the interesting results:(1) the suppressed region in the lower-right part of the diagram can be explained by neutrino cyclotron emission from the 1S0 neutron superfluid vortexes in neutron stars. (2) All radio pulsars that were identified with super strong magnetic fields with field strength beyond the critical quantum magnetic field before are now all lying inside the critical magnetic field line in our model. (3) The peak of neutron star magnetic fields (logB) distribution revels a gaussian distribution in our model whereas the statistics of the simple magnetic dipole model results in a distribution with non-symmetrical peak.

Efficient cosmic-ray acceleration at reverse shocks in supernova remnants (STARS)

• Satoru Katsuda (Saitama University)

When a supernova explodes, a blast wave is generated and propagates into the ambient medium, whereas the deceleration of the ejecta by the ambient medium induces an inward-propagating shock wave, the so-called reverse shock (RS). If the RSs can efficiently accelerate cosmic-rays, then they can be important production sites of heavy-element cosmic-rays. We present evidence for efficient cosmic-ray acceleration at reverse shocks in young Galactic supernova remnants including Cassiopeia A and RCW 86, based on recent X-ray observations with Chandra.

Crustal torsional oscillations inside the deeper pasta structures (STARS)

• Hajime Sotani (National Astronomical Observatory of Japan)

The quasi periodic oscillations (QPOs) observed in the soft-gamma repeaters are generally considered as a results of the global oscillations of the neutron stars. In this study, we first take into account the torsional oscillations excited in the tube and bubble phases, which can be excited independently of the oscillations in the phases of spherical and cylindrical nuclei, and successfully identify the observed QPO frequencies with such torsional oscillations. The resultant neutron star models are consistent with the mass formula for low-mass neutron stars and the constraint by the gravitational waves from the merger of the neutron star binary, GW170817.

Gravitational wave emitted from core-collapse supernovae (STARS)

• Tomoya Takiwaki (Tomoya)

Gravitational wave signal from core-collapse supernova is the key to understand the mechanism of core-collapse supernovae. The evolution of the frequency of the signal tells us the property of neutron star and information of the accretion flow near the neutron star. In this study, I will introduce the gravitational waveform based on our recent 3D simulations and discuss what information extracted from the signal.

Cosmic matter in the laboratory - Investigating neutron star core densities with FAIR (STARS)

• Christian Sturm (GSI Helmholtzentrum fuer Schwerionenforschung)

The Facility for Antiproton and Ion Research, FAIR, is presently being constructed adjacent to the existing accelerator complex of the GSI Helmholtz Centre for Heavy Ion Research at Darmstadt/Germany, expanding the research goals and technical possibilities substantially. The worldwide unique accelerator and experimental facilities of FAIR will open the way for a broad spectrum of unprecedented fore-front research supplying a large variety of experiments in hadron, nuclear, atomic and plasma physics as well as biomedical and material science which will be briefly described in this presentation. Emphasis will be put on the investigation of the highest baryon densities accessible in the laboratory by relativistic nucleus-nucleus collision at FAIR energies, probing strongly interacting matter under extreme conditions as we expect inside neutron stars.

Predictions of the pseudo-complex theory of gravity for EHT observations: Observational tests (STARS)

• Thomas Boller (MPE Garching)

A modified theory of gravity, avoiding singularities in the standard theory of gravitation, has been developed by Hess \& Greiner, known as the pseudo-complex theory of gravitation. The pc-GR theory shows remarkable observational differences with respect to standard GR. The intensity profiles are significantly different between both theories, which is a rare phenomenon in astrophysics. This will allow robust tests of both theories using Event Horizon Telescope (EHT) observations of the Galactic Center. We also predict the time evolution of orbiting matter. In this paper we summarize the observational tests we have developed to date. In case that the EHT data are public, we will discuss their implication on the pc-GR theory.

Comparison of the predictions of the pc-GR to the observations of the EHT (STARS)

• Peter Hess (Universidad Nacional Autónoma de México)

The observation predictions of the pseudo-complex General Relativity, related to the structure of an accretion disk, are compared to the reported observations of the Event Horizon Telescope.

Physics and astrophysics with the Pierre Auger Observatory (STARS)

• Rogerio de Almeida (Universidade Federal Fluminense)

One century after the discovery of cosmic rays, the origin of ultra high energy cosmic rays still remains enigmatic. Taking data since 2004, the Pierre Auger Collaboration has been expanding our knowledge about these cosmic particles with energies much higher than what LHC can achieve. Although some intriguing questions have been answered, some of the mystery still persists. The focus of this presentation is on the most recent results on ultra-high energy cosmic rays obtained with the Pierre Auger Observatory  with emphasis on the anisotropy studies of the arrival directions of the most energetic particles.

CPT violation due to quantum decoherence tested at DUNE (STARS)

• Félix Napoleón Díaz Desposorio (Pontificia Universidad Católica del Perú)

In this work we study the intrinsic CPT violation in the neutrino oscillations phenomena produced by quantum decoherence as sub-leading effect. In the usual representation, we find that only fifteen elements of the decoherence matrix violate the CPT symmetry intrinsically. We find exact solutions for the CPT asymmetry function in vacuum . We define an observable $\mathcal{R}$ to make predictions of this model for the future Long-Baseline experiment, DUNE. We found values of the decoherence parameters with $5 \sigma$ of discrepancy to standard physics which are allowed by the current experimental limits, suggesting hints for new physics by this model in the context of future experiments. arXiv:1811.04982

Non-linear electrodynamics for astrophysical plasmas (SMFNS)

• Marcelo Enrique Rubio (IATE - CONICET)

In this work we study the initial value problem of a non-linear extension of classical Electromagnetism, known as "Force-Free Electrodynamics" (FFE). The FFE equations describe the dynamics of a diluted plasma near the event horizon of a rotating black hole. In these astrophysical regions, magnetic fields dominate the dynamics when compared with the matter that constitutes those plasmas, giving rise to an decoupled description for Electromagnetism. As a starting point, we consider a covariant formulation of the FFE theory in terms of two scalar potentials, known as "Euler potentials", which allow a very elegant and precise geometric interpretation of it. The ease of formulating FFE in terms of two potentials lies in the fact that, being the only dynamical variables, it provides an optimal scenario for its numerical implementation. In this work we show that this formulation is weakly hyperbolic, which means that the system does not have a well posed initial value problem in the usual sense. In this way, it is not possible to guarantee uniqueness or continuity during the dynamic evolution, which implies that this formulation is not convenient for numerical simulations.

Modeling anisotropic magnetized compact stars with $\gamma$ metric: the white dwarfs picture (SMFNS)

• Diana Alvear Terrero (ICIMAF)

Magnetic fields introduce an anisotropy in compact stars’ equations of state by splitting the pressure into two components, one parallel and the other perpendicular to the magnetic field. This suggests the necessity of using structure equations accounting for the axial symmetry of the magnetized system. We consider an axially symmetric metric in spherical coordinates, the $\gamma$-metric, and construct a system of equations to describe the structure of spheroidal compact objects. In this way, we connect the geometrical parameter $\gamma$ linked to the spheroid’s radii, with the source of the anisotropy. So, the model relates the shape of the compact object to the physics that determines the properties of the composing matter. To illustrate how our structure equations work, we present magnetized white dwarfs structure and discuss the stability of the solutions. The results are obtained for magnetic field values of $10^{12}$G, $10^{13}$G and $10^{14}$G, in all cases with and without the Maxwell contribution to the pressures and energy density. This choice allows to have two sets of EoS, one featuring $\gamma>1$ and other with $\gamma<1$ .

Magnetic field effects on Bose-Einstein condensate stars (SMFNS)

• Gretel Quintero Angulo (Facultad de Física, Universidad de La Habana)

We study magnetic field effects on the Equations of State (EoS) and the structure (mass-radius relation) of Bose-Einstein Condensate (BEC) stars, i.e. a compact object composed by a gas of interacting spin one bosons formed up by the pairing of two neutrons. To include magnetic field in the star description we suppose that particle-field and particle-particle interactions are independent, and consider two situations, one where the magnetic field is constant, and another where it is produced by the bosons. Magnetic field presence splits the pressure of the boson gas in two components, one parallel and the other perpendicular to field direction. At low densities and/or strong fields the smaller pressure might be negative, making the boson system unstable. This imposes a lower limit to the central mass density of the star in a way that, the stronger is the magnetic field, the denser has to be star to support its mass against collapse. Since the anisotropy in the pressures implies that the resulting star is not spherical, to compute the mass-radius relation we use the recently found γ-structure equations that describe axially symmetric objects provided they are spheroidal. The obtained BEC stars are, in general, less massive and smaller than in the non-magnetic case, being magnetic field effects more relevant for low densities. When the magnetic field is produced by the bosons, the inner profiles of the fields are determined self consistently as a function of the star inner radii, its values being in the orders expected for compact stars.

Thermodynamic properties of a magnetized neutral vector boson gas at finite temperature (SMFNS)

• Lismary de la Caridad Suárez González (Instituto de Cibernética Matemática y Física,Habana, Cuba)

We study the thermodynamic properties of a neutral vector boson gas in presence of a constant magnetic field at finite temperature. The study has been done considering relativistic and non-relativistic bosons. In general, one of the most outstanding properties of magnetized bosonic systems is the occurrence of Bose-Einstein condensation (BEC) and Bose-Einstein ferromagnetism: in the condensed state, the gas shows a spontaneous magnetization. The main purpose of this work is to study the effect of temperature on the equations of state for that matter that allows more accurate descriptions of compact objects, specifically of neutron stars, which might contain spin-1 bosons formed up by two paired neutrons. As a limit case we study the structure of stars fully composed by matter in this form.

Modeling anisotropic magnetized strange quark stars (SMFNS)

• Samantha López (ICIMAF)

When studying the structure of magnetized compact objects, the anisotropy in their equations of state (EoS), due to the magnetic field, must be taken into account. This anisotropy consists in the splitting of the pressure in two components, one parallel and the other perpendicular to the magnetic field. In this work, we compare the size and shape of magnetized strange quark stars using three different sets of structure equations. First, we solve the standard isotropic Tolman-Oppenheimer-Volkoff equations for the parallel and perpendicular pressures independently. Then, we obtain the mass-radii curves of the magnetized strange quark stars using axially symmetric metrics in cylindrical and spherical coordinates, this last one called the gamma-metric. The differences between the results obtained in each case are discussed.

The magnetized photon time delay and Faraday rotation (SMFNS)

• Adrian William Romero Jorge

We study the propagation of photon in magnetized vacuum and medium, taking into account radiative corrections. We describe both time delay and Faraday rotation, with the aim of applying the results to astrophysical context.

The mathematical description of the influence of the expansion of the Universe on the metric of a black hole (SMFNS)

• Adrian Linares-Rodríguez (Universidad Central "Marta Abreu" de Las Villas, Santa Clara ci)

The existence of black holes has its analytical argumentation in Einstein's field equations. The first solution of general relativity that would characterize a black hole was found by Schwarzschild in 1916. Since then, these cosmic objects are being studied and investigated in their various variants: Scwartzshild, Kerr, Reissner-Nordström, Kerr-Newman, and others. The no-hair theorem states that a black hole has only three independent properties: mass, charge and angular momentum and is characterized by producing intense gravitational fields. On the other hand, the existence in the Universe of a dark material component of the repulsive type against the attractive action of gravitation can be represented by the quintessence. The effect of the quintessence surrounding the black hole is then introduced. Ordinarily, an additional element within the stress-energy-moment tensor of the Einstein field equations is introduced. The mathematical description of this problem is complicated, in general. In this investigation, we have chosen to use a variant in which the effect of the quintessence is introduced as a perturbative action in the metric of the ordinary black hole introducing the time-dependent scale factor. The Einstein field equations are obtained using the perturbed metric and the results obtained correspond to those obtained by the ordinary way.

Extending observations to distances larger than 10 kpc should resolve the anomaly of a galaxy lacking dark matter (SMFNS)

• Ramzi Suleiman (Triangle Research & Development Center)

We investigated the claim that galaxy NGC 1052-DF2 lacks dark matter. For this purpose, we constructed a novel, theory-based computer simulation of the dynamical interaction of matter and dark matter in a prototypical ellipsoid galaxy and utilized it to predict the distributions of dark matter in a galaxy as a function of the galaxy’s core radius and maximal rotation velocity. We ran the simulation using the parameters of NGC 1052-DF2 as well as the parameters of six other UDGs from the Coma cluster and seven dSph galaxies from the local group. For each galaxy, the simulation was run in steps of 2 kpc up to 100 kpc from the galaxy center. Inspection of the distributions of matter and dark matter generated by the simulated, as a function from distance r, reveals the following: (1) Consistent with the ΛCDM paradigm, all the tested galaxies, including galaxy NGC 1051-DF2, are predicted to be dark-matter-dominated. (2) The reported lack of dark matter within r ≤ 10 kpc is supported by the simulation results. However, this result is an aftermath of conducting a “shortsighted” observation for only r < 10 kpc. (3) Consistent with ΛCDM models, the bulk of dark matter at galactic scales resides at the galaxies’ halos. (5) The core radius of a galaxy is predictor of the proportions of matter and dark matter in the galaxy.

Homogeneity of the universe emerging from the Equivalence Principle and Poisson equation: A comparison between Newtonian and MONDian cosmology (SMFNS)

• Eduardo Guendelman (Ben Gurion University)

A correspondence between the Equivalence principle and the homogeneity of the universe is discussed. We show that under the Newtonian gravity, translation of co-moving coordinates in a uniformly expanding universe defines a new accelerated frame. A consistency condition for the invariance of this transformation yields the second Friedman equation. All these symmetries are lost when we modify Newton’s second law and/ or the Poisson equation. For example by replacing Newton’s second law with non-linear function of the acceleration, as Modified Newtonian Dynamics (MOND) suggested, the concept of relative acceleration is lost. As a consequence the homogeneity of the universe breaks. Therefore MOND which changes Newton’s second law or a QUAdratic Lagrangian (AQUAL) which changes the Poisson equation are not complete theories and they should be amended to preserve the cosmological principle. Only locally could MOND be used as a toy model, but not as a global theory which should describe a universe in large scales.

A study in progres about a dynamical gravastar solution (SMFNS)

• Duvier Fontanella (ICIMAF)

We present the state of research devoted to investigate the consequences of a formerly proposed regular solution at the origin for the Einstein-Klein-Gordon equations. We implement a match with the Schwarzschild solutions with a zero scalar field outside a spherical region. The configuration of fields are used as a first step in an iterative process to calculate the vacuum expectation value of the energy-momentum tensor, aiming at further solving the Einstein semi-classical equation. The result shows the quantum corrections to the previous solution. It is expected that further steps in the iterative process will regulate the previous solutions, by leading to the convergence of the iterative solution. The first step in the iteration solution and an explicit dependence of the expectation value of the energy-momentum tensor with the metric are found.

Perturbations to planetary biospheres due to high energy muons from cosmic ray bursts originated in neutron star mergers (SMFNS)

• Rolando Cardenas (Universidad Central ''Marta Abreu'' de Las Villas)

In this work a mathematical model for aquatic photosynthesis, modified by some of us to include particulate ionizing radiation, is used to assess the perturbations that muons coming from neutron star mergers could make to this biological process. It is then shown that neutron star mergers not too far from inhabited rocky planets have the potential to considerably deplete their aquatic photosynthesis. Some remarks concerning the affectation on other types of subsurface life are also done, and by extension some considerations on habitability of the Milky Way are presented.

Z production in pPb and PbPb collisions at 5.2 TeV (STARS)

• Dario Ramirez Zaldivar (InSTEC, Havana University)

There is a growing interest in the exam and analysis of results in the ALICE, ATLAS and CMS detectors in asymmetric systems (pPb) due to the possibilities of establishing some references for PbPb collisions and to gain insight into the behavior of the medium itself. The analysis of data in both cases can allow the understanding of the PDFs under different regimes. The study of the initial state in proton-lead collision at 5.02 TeV using Drell-Yan process was chosen because the inclusive lepton production is a clean process independent of the color degree freedoms. For the study, it was considered an extension of the Glauber model to express the cross-section. Under this approach, we can examine the initial vertex of the hard process described by sigma_pp and apply the usual calculation through the factorization theorem. In particular, we focused on the analysis of the pT distribution and compared the role of different factorization schema in the behavior of the distribution at low pT.

Towards the measurement of the anisotropic pressures effects in magnetized quantum vacuum (SMFNS)

• Hugo Celso Peréz Rojas (ICIMAF)

Starting from the fact that vacuum pressure orthogonal to a constant magnetic field is negative, whereas along the field is positive, we estimate the shift of frequency for radiation moving in these directions to first order in α at small fields as compared to the Schwinger critical field Bc, and suggest ideas for its experimental test. For fields of order of or greater than 2Bc we briefly discuss the arising of an imaginary part on the vacuum energy, meaning its instability at such fields. We propose an heuristic model of bosonic electron-positron bound state leading to a ferromagnetic quantum phase transition of vacuum at critical fields 2Bc.