Researchers from the Universities of Sheffield and Hertfordshire have revealed that quasars, the Universe’s brightest and most powerful objects, are ignited by colliding galaxies. Quasars can shine with the brightness of a trillion stars within a solar system-sized volume, yet the cause of their powerful emissions remained a mystery for 60 years after their discovery. By studying 48 quasar-hosting galaxies and comparing them to over 100 non-quasar galaxies, the team found that galaxy collisions funnel vast amounts of gas toward supermassive black holes at their centers. As this gas is consumed, it releases extraordinary energy in radiation, leading to the quasar phenomenon.
The study highlights that galaxies hosting quasars are approximately three times more likely to be in interaction or collision compared to other galaxies. Additionally, the ignition of a quasar can halt star formation in its host galaxy for billions of years by expelling gas. This research is crucial for understanding quasars’ roles in the cosmic history and could offer insights into the Milky Way’s future, especially regarding its eventual collision with the Andromeda galaxy in about five billion years. Quasars also serve as essential tools for astrophysicists in studying the early Universe.
