SCIENCE ALERT
Measuring cosmic distances is challenging, and astronomers rely on multiple methods and tools to do it – collectively referred to as the cosmic distance ladder.
One particularly crucial tool is type Ia supernovae, which occur in binary systems where one star (a white dwarf) consumes 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 outshine everything in the background.
In a recent study, an international team of researchers led by Ariel Goobar of the Oskar Klein Centre at Stockholm University discovered an unusual type Ia supernova, SN Zwicky (SN 2022qmx).
In an unusual twist, the team observed an “Einstein ring“, an unusual phenomenon predicted by Einstein’s theory of general relativity where the presence of a gravitational lens in the foreground amplifies light from a distant object.
This was a major accomplishment for the team since it involved observing two very rare astronomical events that happened to coincide.
Their research paper that describes their findings recently appeared in Nature Astronomy.
The initial detection was made using the Zwicky Transient Facility at the Palomar Observatory in California. This facility is named in honor of Fritz Zwicky, the astronomer who first theorized the existence of dark matter in the 1930s.
A few weeks later, the team observed it with the adaptive optics (AO) at the W.M. Keck Observatory atop Maunakea, Hawaii, and the Very Large Telescope (VLT) at the Paranal Observatory in Chile. Based on the observed brightness, Goobar and his colleagues hypothesized that they were observing a strong lensing effect.
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These follow-up observations and images acquired by the Hubble Space Telescope confirmed this theory, showing that the multiple-image lensing effect resulted from a galaxy in the foreground that magnified the supernova 25 times!
This fortuitous discovery presents numerous opportunities for astronomers, including the ability to study SN Zwicky in greater detail and further investigate the mysteries of gravitational lenses. As Goobar explained in a Stockholm University press release:
