Saturday 22 March 2025
Astronomers have long been fascinated by galaxy mergers, those cosmic collisions that can spark the birth of new stars and supermassive black holes. But what happens when two galaxies collide, their gas and dust swirling together in a chaotic dance? A team of scientists has recently shed light on this process, using cutting-edge observations to map the molecular gas at the heart of a dual quasar system.
The object of their study is J0749+2255, a pair of quasars that are thought to be the result of a galaxy merger around 2.17 billion years ago. Quasars are incredibly luminous objects powered by supermassive black holes at the centers of galaxies, and dual quasars like J0749+2255 are rare and intriguing phenomena.
Using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile, the researchers observed the molecular gas surrounding the quasars. They detected carbon monoxide (CO), a common molecule found in interstellar space, which can be used to infer the properties of the gas. The CO signals revealed a complex morphology, with two distinct components: a slow-moving, diffuse gas and a fast-moving, turbulent gas.
The researchers suggest that this turbulence is likely driven by the merger itself, as the gas is stirred up by gravitational forces and interactions between the galaxies. This turbulence can lead to the formation of stars, which in turn can fuel the growth of the supermassive black holes at the heart of the quasars.
One of the most striking aspects of the observation is the sheer scale of the molecular gas reservoir. The researchers estimate that there are tens of billions of solar masses worth of gas present, a staggering amount that could support the formation of thousands of stars over time. This suggests that galaxy mergers may play a crucial role in regulating star formation and black hole growth across cosmic history.
The findings also have implications for our understanding of quasar evolution. Quasars are thought to be powered by supermassive black holes, which grow through the accretion of gas and dust from their surroundings. In the case of J0749+2255, the dual quasars may be fueled by the merger-induced gas reservoir, which could help explain why these systems are so luminous.
The study is a testament to the power of modern astronomical instrumentation, which allows us to peer into the distant past and uncover the secrets of galaxy evolution.
Cite this article: “Galaxy Mergers Unleash Turbulent Gas Reservoirs”, The Science Archive, 2025.
Galaxy Mergers, Quasars, Dual Quasars, Alma Telescope, Molecular Gas, Carbon Monoxide, Star Formation, Black Hole Growth, Cosmic History, Galaxy Evolution
