Equations of state of dense matter play a key role in neutron star modelling. Well constructed equations of state must be constrained by nuclear physics experiments, and multi-messenger observations. But they must also be designed with the same nuclear model for the high density, and the low density part of the star. Yet, non-unified equations of state can be abundantly found in the...
For the past two decades, flares (i.e. outbursts of radiation) have been observed from the centre of the Milky Way where a massive compact object of 4.2 millions solar masses resides at only 8.3 kpc. This makes this object called Sgr A* the closest supermassive black hole candidate to Earth and an unique laboratory for relativistic astrophysics. Recent observations have shown that the source...
The future mission LISA will observe gravitational waves in a frequency range going from 10-4 to 10-1 Hz through three satellites orbiting in a heliocentric orbit. It is expected that this mission will detect the orbit of solar mass star orbiting around the compact object at the center of the Milky Way, Sagittarius A*. Depending on the orbit and the star’s mass, the gravitational waves emitted...
Optical interferometry just recently came to an age with the transformative results brought up by GRAVITY at the VLTI, on topics such as exoplanets, active galactic nuclei (AGN) and the Galactic Center. The next stage is already upcoming with GRAVITY+, a series of upgrades of the instrument and the infrastructure. With laser-assisted, extreme adaptive optics for each unit telescope and...
The continuous monitoring of stellar orbits in the Galactic Centre over the past few decades revealed the massive central object Sgr A at their shared focal point (→ Nobel prize 2020). These and other observations (orbits of hot flares, black hole shadow) are in best agreement with the notion of Sgr A being a massive black hole of about 4 million solar masses. Assuming the black hole model,...
Recent years have seen a renewed interest in analytical treatments of the two body problem in gravity. This is mainly due to the recent detections of gravitational waves from binary coalescences. Lately, many tools originating from particle physics and QFT have been utilized for the analytic solution of the two-body problem in gravity such as EFT methods and modern methods for Scattering...
The many recent detections of gravitational waves (GWs) of binary black hole (BBHs) mergers have opened the way for future multimessenger campaigns. One expected result, not achieved yet, is the co-detection of electromagnetic (EM) radiation from a BBH merger system together with its GW inspiral emission, detectable for stellar-mass BHs with LIGO/Virgo, intermediate-mass BHs (and stellar-mass...
