Goethe Universität

May 9, 2024 | academic.oup.com | Goethe Universität |Università di Perugia

Binary-black-hole (BBH) mergers can take place close to a supermassive black hole (SMBH) while being in a bound orbit around the SMBH. In this paper, we study such bound triple systems and show that including the strong gravity effects of describing the SMBH with a Kerr metric can significantly modify the dynamics, as compared to a Newtonian point particle description of the SMBH. We extract the dynamics of the system, using a quadrupole approximation to the tidal forces due to the SMBH.

Jan 27, 2024 | academic.oup.com | Goethe Universität

The development of a neutrino moment based radiative-transfer code to simulate binary neutron-star mergers can easily become an obstacle path because of the numerous ways in which the solution of the equations may fail. We describe the implementation of the grey M1 scheme in our fully general-relativistic magnetohydrodynamics code and detail those choices and strategies that could lead either to a robust scheme or to a series of failures.

Jan 9, 2024 | link.aps.org | Goethe Universität |East Lansing

We study linear perturbations against static spherically symmetric background configurations of general relativity with a real scalar field (SF), which is minimally coupled with gravity; it is nonlinear due to the presence of the self-action potential. The background solutions have a naked singularity at the center of the configuration. The focus is on the stability of the background and fundamental frequencies of the quasinormal modes (QNM) of the axial perturbations in the Regge-Wheeler gauge.

Dec 11, 2023 | academic.oup.com | Carnegie Mellon |Universität Würzburg |Goethe Universität |Max-Planck-Institut für Radioastronomie

In this paper, we introduce a novel data augmentation methodology based on Conditional Progressive Generative Adversarial Networks (CPGAN) to generate diverse black hole (BH) images, accounting for variations in spin and electron temperature prescriptions. These generated images are valuable resources for training deep learning algorithms to accurately estimate black hole parameters from observational data.

Nov 27, 2023 | academic.oup.com | Goethe Universität |Campus UAB

It is widely accepted that supernovae (SNe) are a possible final stage of the life of massive stars and white dwarfs in close binary systems; they are observationally classified as type-I (SNe I) or type-II (SNe II) depending on whether they are hydrogen-poor or hydrogen-rich, respectively. SNe are usually discovered by untargeted wide-field surveys and they can be identified in their local environment performing differential photometry (see also section 2 and Kessler et al.