Unveiling the Birth of Massive Galaxy Clusters: ALMA's Discovery of Hot Gas in the Spiderweb Galaxy

 Utilizing the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers discovered a substantial reservoir of hot gas in the still-forming galaxy cluster surrounding the Spiderweb galaxy, marking the most distant detection of such hot gas to date. Galaxy clusters are among the largest known objects in the universe and this finding, published in Nature, unveils the early stages of their formation.

Galaxy clusters host numerous galaxies and contain a vast "intracluster medium" (ICM) of gas that exceeds the mass of the galaxies themselves[1]. While much of the physics of galaxy clusters is understood, observations of the initial ICM formation phases are limited[1]. Galaxy clusters are massive enough to gather gas that heats up as it falls towards the cluster[3].

Researchers detected the ICM of the Spiderweb protocluster through the thermal Sunyaev-Zeldovich (SZ) effect[2]. By measuring the SZ effect's shadows on the cosmic microwave background, astronomers can infer the existence of hot gas, estimate its mass, and map its shape[1]. The study found that the Spiderweb protocluster contains a vast reservoir of hot gas at a temperature of several tens of millions of degrees Celsius[1]. This discovery indicates that the Spiderweb protocluster is expected to transform into a massive galaxy cluster in around 10 billion years, increasing its mass by at least a factor of ten[1].

These findings lay the groundwork for synergies between ALMA and ESO's upcoming Extremely Large Telescope (ELT), which will revolutionize the study of structures like the Spiderweb[1].

References: [1] Astronomers witness the birth of a very distant cluster ... [2] ALMA Detects Huge Reservoir of Hot Gas in Very Distant ... [3] Astronomers Witness Birth of Distant Galaxy Cluster in ...