Abstract The Laser Interferometer Space Antenna (LISA) will be a transformative experiment
for gravitational wave astronomy, and, as such, it will offer unique opportunities to address …

Abstract The Galactic Center (GC) of the Milky Way, thanks to its proximity, allows to perform
astronomical observations that investigate physical phenomena at the edge of astrophysics …

The spin of the massive black hole (BH) at the center of the Milky Way, SgrA*, has been
poorly constrained so far. We place an upper limit on the spin of SgrA* based on the spatial …

The motion data of the S-stars around the Galactic Centre gathered in the last 28 yr imply
that Sgr A* hosts a supermassive compact object of about, a result awarded with the Nobel …

The ongoing monitoring of the Galactic center and Sgr A*, the central supermassive black
hole, produces surprising and unexpected findings. This goes hand in hand with the …

The close neighborhood of a supermassive black hole contains not only the accreting gas
and dust but also stellar-sized objects, such as late-type and early-type stars and compact …

Precise measurements of the stellar orbits around Sagittarius A* have established the
existence of a supermassive black hole (SMBH) at the Galactic centre (GC). Due to the …

The center of the Milky Way hosts the closest supermassive black hole, Sgr A*. Decades of
near-infrared observations of our Galactic Center have shown the presence of a small …

Despite the huge improvements guaranteed by future GRAVITY observations of the S0-2
star, these will not be able to unveil the fundamental nature, whether black hole or …

After giving a short overview of previous results on constraining of Extended Gravity by
stellar orbits, we discuss the Schwarzschild orbital precession of S2 star assuming the …