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Ministry Project: AYA 2013-40979-P

Funding body: MINECO. Plan Nacional de Astronomía y Astrofísica

Principal Investigators:

Subproject 1 (UV): Miguel Ángel Aloy Toras, José Antonio Font Roda

Subproject 2 (UA): José Antonio Pons Botella



We aim to deepen our knowledge of some of the most emblematic scenarios in Relativistic Astrophysics: relativistic jets in AGNs, microquasars, and GRBs, isolated neutron stars, and magnetars. These scenarios are characterized by the presence of relativistic flows, strong gravity, high-density matter, high-energy emission and ultra-strong magnetic fields (MFs).

To achieve our goals we will use both, state-of-the-art numerical modeling of (self-gravitating) relativistic fluid dynamics and MHD evolving, in the most general case, in dynamical spacetimes, as well as specific numerical tools to bridge the results of the simulations with astronomical data (electromagnetic and gravitational wave signals). Ultimately, our project can help interpreting the current observational data from a number of electromagnetic telescopes such as Radioastron, VLBA, EVN, and Fermi, and from new generation gravitational wave detectors like advanced LIGO, Virgo, KAGRA or the Einstein Telescope (in design phase). This challenging project requires a multidisciplinary perspective, coordinating the work of two groups with complementary expertise in Astrophysics, High- Performance Computing, Theoretical Physics and Applied Mathematics. The choice of the former scenarios is driven by the fact that they are hot topics, represent a breakthrough in their respective fields, are motivated by current astronomical observations and will have implications in the design of new observatories.

The combination of simulations with radiation transport permits linking the theoretical models of relativistic jets to their observation, which will allow us to tackle three areas, which are currently of interest: highenergy blazar emission, jetted tidal disruption events and gamma-ray burst (GRB) afterglows. Our research on extragalactic jets aims to understand the influence of MFs in morphology of pc- and kpc-scale jets. In the case of gamma-ray binaries, we expect to obtain information about the mechanisms leading to the observed gamma-ray flares. In the context of isolated neutron stars (NSs) we will consider different problems. The dynamics of the MF in the NS-core will be addressed. We will also employ as initial conditions for the long-term evolution of isolated NSs the results obtained from state-of-theart core collapse simulations.

We will also study non-axisymmetric oscillations of magnetar's models, which are directly selected by the magneto-thermal evolution combined with the analysis of QPOs as a model for observed features in giant flares of SGRs. The pioneering modeling of the X-ray emission in magnetar magnetospheres will produce the first selfconsistent description of the currents and the radiation transport in the surrounding of a magnetar, allowing to predict their persistent electromagnetic emission and to directly compare with the observations.

The development of instabilities in black hole-torus systems may yield relevant information on the GRB central engine and as a source of gravitational waves (GWs). Our new denoising algorithms for GW data will be applied to the S5-S6 LIGO runs in both the time and the frequency domain. The investigation of relativistic BZT fluids may open a new strategy to face the complexities associated with the thermodynamical properties of exotic states of dense matter in NS. Finally, the implementation of new 3+1 formulations of Einstein's equations in spherical coordinates may have a broad impact among Numerical Relativity practitioners.

KEY WORDS OF THE COORDINATED PROJECT: Relativistic flows, Magnetic Fields, Neutron Stars, Gravitational Radiation, Numerical Relativity

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