TEONGRAV - Gravitational Wave Sources

The TEONGRAV group in Trento uses advanced numerical codes and powerful supercomputers to investigate the physics of neutron stars and black holes. These compact objects are strong sources of gravitational waves and may be behind some of the most energetic phenomena in the universe (e.g., gamma-ray bursts).

The Science

The TEONGRAV group of TIFPA works in the field of general relativity and computational astrophysics with the main focus on the dynamics and evolution of compact objects, such as neutron stars and black holes. Neutron stars are stars with masses of up to two times the mass of the Sun and a radius of approximately 10 km only. This implies a huge compactness and matter densities several orders of magnitude higher than what we can ever obtain here on Earth. The behaviour of matter at such high densities remains one of the main long-standing problems in astrophysics and nuclear physics; therefore, neutron stars represent an astrophysical laboratory offering a unique chance to study the behaviour of matter under these extreme conditions. These objects have been observed for years in the electromagnetic spectrum (from radio to gamma rays) and are often observed in binaries. In particular, the coalescence and merger of two neutron stars in a binary system is thought to be behind short gamma-ray bursts, powerful explosions in gamma rays observed by satellites such as Fermi and Swift. The same system also represents a very powerful source of gravitational waves, ripples in the fabric of spacetime that propagate at the speed of light and that will be detected for the first time in the next few years by ground-based detectors such as advanced Virgo in Italy and advanced LIGO in the USA. Studying the gravitational wave emission coming from these objects is one of the most effective ways to understand their nature and in particular their internal structure and composition. Numerical simulations by our group have the purpose of predicting the gravitational wave signal that these objects emit and how it is influenced by the neutron star internal structure (e.g., equation of state and magnetic fields). Moreover, our simulations allow to investigate the electromagnetic signals that these objects can emit and their possible connection with current observations of short gamma-ray bursts.
Another powerful source of gravitational waves is given by binary black hole systems. In particular, the merger of two supermassive black holes generates a strong gravitational wave signal that can be detected by future space-based detectors such as eLISA. Supermassive black holes are also surrounded by magnetized plasma that is responsible for strong electromagnetic emission. Such emission can allow us to detect these sources and identify accurately their position.

The TEONGRAV group performs state-of-the-art numerical simulations of these objects, employing powerful supercomputers and advanced numerical codes, which include the Einstein Toolkit and the Whisky code.
Some of our previous results have been also advertised by NASA, which realized the following videos for the general public:
• Binary Neutron Star Mergers http://youtu.be/ow9JCXy1QdY
• Binary Black Hole Mergers http://youtu.be/7y9AtdN4BlM


• Involved external institutions: /
• INFN groups: TIFPA, Milano Bicocca, Parma, Firenze, Roma “Sapienza”, Napoli
• Principal Investigator: Leonardo Gualtieri, Università “Sapienza”, Roma
• INFN Project: CSN IV
• Duration: not defined (2014 - )


• Local responsible for TIFPA: Bruno Giacomazzo
• Involved TIFPA people: Eloisa Bentivegna, Riccardo Ciolfi, Wolfgang Kastaun, Takumu Kawamura



Teongrav Numerical simulation of merging binary neutron stars (Giacomazzo B. and Perna R. 2013, ApJ Letters 771, L26)