Using the Very Large Telescope located on Cerro Paranal, a research team of researchers have discovered that smaller galaxies, (those containing a lower proportion of metals), are capable of generating a greater number of supernova explosions from massive stars.
06 / 11 / 2023
More than a hundred galaxies were observed by an international research team that recently released a study on the so-called “gravitational collapse supernova rate”, which is a measure of the number of stellar explosions produced at the end of the life of stars with masses greater than eight times the mass of the Sun.
The study was led by astronomer Thallis Pessi, currently a doctoral student within the Astrophysics program at the Institute of Astrophysical Studies that is part of Diego Portales University (IEA UDP), and was published in The Astrophysical Journal Letters. The observations were obtained with the MUSE instrument at the Very Large Telescope, located on Cerro Paranal, in the Atacama Desert, Chile. The MUSE instrument is an integral field spectrograph and obtains an image in which each pixel is a spectrum. This gives us much more information about galaxies than a single image, such as the chemical composition of the star-forming regions where massive stars are born.
Analysis of these observations allowed scientists to conclude that there is a correlation between the presence of metals, (all elements heavier than helium), in galaxies and the relative number of gravitational collapse supernovae they produce. In smaller galaxies, that is those with a lower proportion of metals and where fewer new stars form, this rate is considerably higher than, for example, in the Milky Way. On the other hand, larger and more massive galaxies, those with more heavy elements, produce fewer gravitational collapse supernovae in proportion to the massive stars they form.
“This is unexpected,” explains Pessi. “It is usually thought that all regions where massive stars form have a similar capacity to produce gravitational collapse supernovae, and our results show something different,” he adds. Astronomer José Luis Prieto, director of the IEA UDP and co-author of the study, explains that “if 100 massive stars are formed in our galaxy, in the Magellanic Clouds – small galaxies close to the Milky Way – those same 100 stars would produce 10 to 15 times more supernova explosions. It’s not a subtle difference: in fact, it’s a pretty significant factor.” The results of this study could have implications for our understanding of the supernova explosion mechanism of massive stars.
Along with Pessi and Prieto, astronomers from the European Southern Observatory (ESO), the University of Warwick (United Kingdom), the Ohio State University (United States), the National Autonomous University of Mexico, the U. of Turku (Finland), and other institutions were involved in the study.
You can review the full publication at the following LINK