Measuring cosmic distances is challenging, and astronomers rely on a variety of methods and tools to do so—collectively referred to as cosmic distance scales. One particularly important tool is Supernova type Ia, which occur in binary systems where a star (a white dwarf) absorbs matter from a companion (often a red giant) until it reaches the Chandrasekhar limit and collapses under its own mass. As these stars blow off their outer layers in a massive explosion, they temporarily overshadow everything in the background.
In a recent study, an international team of researchers led by Ariel Gubar of the Oscar Klein Center at Stockholm University discovered an unusual Type Ia supernova, SN Zwicky (SN 2022qmx).
In an unusual twist, the team observed “Einstein cross,” a phenomenon predicted by Einstein’s theory of general relativity, where the presence of gravitational lensing in the foreground amplifies light from a distant object. This was a major achievement for the team as it involved the observation of two very rare astronomical events that happened to coincide.
The team was made up of numerous researchers from Oscar Klein Centeron Kavli Institute of Cosmologyon Cahill Center for Astrophysicson Center for Infrared Processing and Analysis (IPAC), on Federal Institute of Technology in Lausanne (EPFL), at Center for Interdisciplinary Studies and Research in Astrophysics (Close Center for Astrophysical Research in LyonNASA Goddard, Space Telescope Science Institute (STScI) and numerous universities. Their research paper describing their findings recently appeared in Natural astronomy.
Initial detection was done using Transit facility Zviki at the Palomar Observatory in California. This facility is named after Fritz Zwicky, the astronomer who first theorized the existence of the Dark matter in the 1930s. A few weeks later, the team observed it with the adaptive optics (AO) of WM Keck Observatory atop Maunakea, Hawaii and A very large telescope (VLT) at the Paranal Observatory in Chile. Based on the observed brightness, Gubar and his colleagues hypothesized that they were observing a strong lensing effect.
These subsequent observations and images acquired by Hubble Space Telescope confirmed this theory by showing that the lensing effect in multiple images is the result of a foreground galaxy that magnifies the supernova by a factor of 25! This serendipitous discovery provides a host of opportunities for astronomers, including the ability to study SN Zwicky in more detail and further explore the mysteries of gravitational lensing.
As Goobar explained at Stockholm University press release“The discovery of SN Zwicky not only demonstrates the remarkable capabilities of modern astronomical instruments, but also represents a significant step forward in our quest to understand the fundamental forces shaping our universe.”
However, the implications of this go beyond these two phenomena. The study of Type Ia supernovae led astronomers to the realization that the cosmos is expanding at an accelerating rate. This discovery won the discovery team 2011 Nobel Prize in Physicswhich was divided between Saul Perlmutter (The Supernova Cosmology Project), and jointly between Brian P. Schmidt and Adam G. Reiss (The High-z Supernova Search Team). Observations of SN Zwicky could therefore help astronomers tackle the mystery of what drives this accelerated expansion.
“The exceptional magnification of SN Zwicky gives us an unprecedented chance to probe the properties of distant Type Ia supernova explosions, which we need when we use them to probe the nature of dark energy” said Joel Johansson, a postdoctoral fellow at Stockholm University and co-author of the study. It can also help astronomers pull back the curtain Dark matter and inform theories of how the universe will end (ie Big Crunch, Big Rip, Heat Death, etc.)