The scientists compared the position and velocity measurements from Gravity and Sinfoni, along with the measurements taken during previous observations of S2, with the predictions of Newtonian gravitational physics, the general theory of relativity and other theories of gravity.
The team used the Sinfoni instrument to measure the velocity of S2 relative to Earth.
"Our first observations of S2 with GRAVITY, about two years ago, already showed that we would have the ideal black hole laboratory," Frank Eisenhauer, principal investigator of GRAVITY and the SINFONI
spectrograph, added in the statement.
To get insight into the various processes of galaxy mass assembly, the Mass Assembly Survey with SINFONI
in VVDS (MASSIV) aims at probing the kinematical and chemical properties of a significant and representative sample of high-red-shift (0.9 < z < 1.8) star-forming galaxies.
The team used SINFONI to measure the motion of S2 towards and away from Earth and the GRAVITY interferometric instrument to make extraordinarily precise measurements of the position of S2 in order to define the shape of its orbit.
'During the close passage, we managed not only to precisely follow the star on its orbit, we could even detect the faint glow around the black hole on most of the images.' By combining the position and velocity measurements from SINFONI and GRAVITY, as well as previous observations using other instruments, the team could compare them to the predictions of Newtonian gravity, general relativity and other theories of gravity.
The study, titled "Medium-resolution integral-field spectroscopy for high-contrast exoplanet imaging: Molecule maps of the beta Pictoris system with SINFONI
," was published June 11 in the (http://dx.doi.org/10.1051/0004-6361/201832902) journal Astronomy & Astrophysics.
Distant galaxies like the ones in the survey are just tiny faint blobs in the sky, but the high image quality from the VLT used with the SINFONI
instrument means that the astronomers can make maps of how different parts of the galaxies are moving and what they are made of.
The team compared the position and velocity measurements from GRAVITY and SINFONI respectively, along with previous observations of S2 using other instruments, with the predictions of Newtonian gravity, general relativity and other theories of gravity.
The team used SINFONI to measure the velocity of S2 towards and away from Earth and the GRAVITY instrument in the VLT Interferometer (VLTI) to make extraordinarily precise measurements of the changing position of S2 in order to define the shape of its orbit.
Team leader Stefan Gillessen, from the Max Planck Institute for Extraterrestrial Physics in Germany, said, "The gas at the head of the cloud is now stretched over more than 160 billion kilometers around the closest point of the orbit to the black hole." The astronomers were able to observe the event by training VLT's SINFONI
instrument onto the area around the black hole for 20 hours.
"This study has only been possible because of the outstanding performance of the SINFONI
instrument on the VLT.