Every galaxy holds a black hole whose gravitational field is extremely intense. However, that gravitational field affects only a small region around the center of the Universe.
According to theories, the growing black holes generate enough energy to heat up and drive out the gas within galaxies to great distances. Observing and describing how this energy interacts with galaxies and changes their development is a fundamental question in present-day Astrophysics.
In a new study, scientists have determined the effect of black holes on the satellite galaxies around the host galaxies. They tried to see whether the matter and energy emitted from around these black holes can alter the evolution of the galaxies.
For this work, they used Sloan Digital Sky Survey to analyze the properties of the galaxies in thousands of groups and clusters.
Annalisa Pillepich, a researcher at the Max Planck Institute for Astronomy (MPIA, Germany) and co-author of the article, said, “Surprisingly, we found that the satellite galaxies formed more or fewer stars depending on their orientation with respect to the central galaxy.”
Using the cosmological simulation of the Universe called Illustris-TNG, scientists understood the geometrical effect on the properties of the satellite galaxies. The simulation shows a clear modulation of the star formation rate in satellite galaxies depending on their position with respect to the central galaxy.”
The results suggest that there is a particular coupling between the black holes and their galaxies. This coupling expels matter to great distances from the galactic centers and can even affect the evolution of other nearby galaxies.
Ignacio Martín Navarro, a researcher at the Instituto de Astrofísica de Canarias (IAC), said, “So not only can we observe the effects of central black holes on the evolution of galaxies, but our analysis opens the way to understand the details of the interaction.”
“This work has been possible due to collaboration between two communities: the observers and the theorists which, in the field of extragalactic Astrophysics, are finding that cosmological simulations are a useful tool to understand how the universe behaves.”
- Martín-Navarro, I. et al. Anisotropic satellite galaxy quenching modulated by black hole activity. Nature (2021). DOI: 10.1038/s41586-021-03545-9