Application of Einstein’s Theory: Supernova Explosion Unveiled Through Uncommon “Cosmic Lenses”

Researchers have unearthed a unique gravitationally lensed supernova, named “SN Zwicky,” offering distinctive glimpses into the inner parts of galaxies, dark matter, and the processes of universal expansion. This breakthrough relies on gravitational lensing, a concept that intensifies the visibility of heavenly bodies, as propounded in Einstein’s theory of relativity.

Scholars acquire understanding about the expansion of the universe through gravitational lensing. This natural occurrence distorts space around galaxies, leading to the visual amplification of celestial entities.

In Einstein’s general theory of relativity, spacetime is a fusion of time and space. The theory posits that substantial objects, such as a galaxy or clusters of galaxies, can induce a curvature in spacetime. Gravitational lensing is a seldom observed but verifiable demonstration of Einstein’s theory; a large cosmic entity can markedly divert light as it journeys through spacetime, similar to a magnifying lens. Scientists can exploit the resultant visual aberrations when light from a more distant source traverses this lens to observe objects typically too remote and faint to detect.

A global consortium of scientists, involving University of Maryland astronomer Igor Andreoni, recently uncovered an exceptionally rare gravitationally lensed supernova, which they christened “SN Zwicky.” Located beyond 4 billion light years, the supernova was amplified nearly 25 times by a nearby galaxy acting as a lens. This discovery gives astronomers a singular chance to delve into the cores of galaxies, dark matter, and the mechanics fueling universal expansion. Their findings, encompassing an extensive analysis, spectroscopic data, and imaging of SN Zwicky, were published in the Nature Astronomy journal on June 12, 2023.

Delving into supernova Zwicky: originating from a small segment of the Palomar ZTF camera, one out of 64 “quadrants,” each hosting tens of thousands of stars and galaxies, the close-up reveals detailed explorations conducted with the larger and more precise VLT and Keck telescopes in Chile and Hawai’i respectively. The best-resolved Keck images display the four almost identical “replicas” of supernova Zwicky. These multiple images arise due to the distortion of space instigated by a foreground galaxy, also visible in the center and approximately midway between the site of the supernova explosion and Earth. Credit: J. Johansson

“The unearthing of SN Zwicky not only demonstrates the outstanding capabilities of contemporary astronomical tools but also signifies a substantial advancement in our pursuit to comprehend the fundamental forces molding our universe,” noted the paper’s chief author Ariel Goobar, who also heads the Oskar Klein Center at Stockholm University.

First detected at the Zwicky Transient Facility (ZTF), SN Zwicky quickly grabbed attention due to its exceptional brightness. Following that, employing adaptive optics tools on the W.M. Keck Observatory, the Very Large Telescopes, and NASA’s Hubble Space Telescope, the team noticed four images of SN Zwicky taken from distinct positions in the sky and verified that gravitational lensing was the cause of the supernova’s extraordinary luminosity.

SN Zwicky. Credit: Joel Johansson, Stockholm University

Andreoni, a postdoctoral associate at UMD’s Department of Astronomy and NASA’s Goddard Space Flight Center, elaborated that supernovae like SN Zwicky are vital for scientists to measure cosmic distances.

“SN Zwicky isn’t merely magnified by the gravitational lens, but also belongs to a category of supernovae known as ‘standard candles’ because their well-established luminosities enable us to estimate distance in space,” Andreoni clarified. “When a light source is further away, the light is dimmer, similar to observing candles in a dark room. By comparing two light sources in this way, we can obtain an independent measurement of distance without the need to directly study the galaxy.”

Apart from serving as a gauge for cosmic distance, SN Zwicky also paves the way for new research avenues for scientists investigating the properties of galaxies, including dark matter (which forms the majority of matter in the universe but does not absorb, reflect or emit light). Scholars also surmise that lensed supernovae like SN Zwicky could turn out to be very promising instruments for investigating dark energy (an enigmatic force opposing gravity and triggering the accelerated expansion of the universe) and refining current models detailing the expansion of the universe, including the computation of the Hubble constant—a parameter describing the rate at which the universe is expanding.

With the inauguration of the Vera Rubin Observatory in Chile on the horizon, Andreoni sees the team’s success in identifying and studying SN Zwicky as just the starting point. Still under construction, the new observatory is slated to commence full operations in 2024 and expand on the team’s findings as it takes multiple images of the entire visible sky to search for other supernovae and asteroids. Andreoni anticipates that the “big picture” strategy employed to locate SN Zwicky will persist in assisting scientists in amassing large quantities of data about celestial phenomena in the sky.

“This discovery lays the groundwork to discover more such rare lensed supernovae in forthcoming extensive surveys that will aid our study of transient astronomical events like supernovae and gamma ray bursts,” Andreoni commented. “We eagerly anticipate more unforeseen discoveries utilizing wide, untargeted optical surveys of the sky like the one that led us to identify SN Zwicky. With this method, we can delve into the transient sky with unparalleled depth.”

For a better understanding of how gravitational lensing functions, kindly watch the brief animation below:

Large-mass objects such as galaxies or clusters of galaxies distort the spacetime around them in a way that they can create multiple representations of background objects. This effect is termed strong gravitational lensing. Credit: ESA/Hubble, NASA

The paper, titled “Uncovering a population of gravitational lens galaxies with magnified standard candle SN Zwicky,” was published on June 12, 2023, in Nature Astronomy.

Reference: “Uncovering a population of gravitational lens galaxies with magnified standard candle SN Zwicky” by Ariel Goobar, Joel Johansson, Steve Schulze, Nikki Arendse, Ana Sagués Carracedo, Suhail Dhawan, Edvard Mörtsell, Christoffer Fremling, Lin Yan, Daniel Perley, Jesper Sollerman, Rémy Joseph, K-Ryan Hinds, William Meynardie, Igor Andreoni, Eric Bellm, Josh Bloom, Thomas E. Collett, Andrew Drake, Matthew Graham, Mansi Kasliwal, Shri R. Kulkarni, Cameron Lemon, Adam A. Miller, James D. Neill, Jakob Nordin, Justin Pierel, Johan Richard, Reed Riddle, Mickael Rigault, Ben Rusholme, Yashvi Sharma, Robert Stein, Gabrielle Stewart, Alice Townsend, Yozsef Vinko, J. Craig Wheeler and Avery Wold, 12 June 2023, Nature Astronomy.
DOI: 10.1038/s41550-023-01981-3

The research was underpinned by the National Science Foundation (Grant Nos. AST-2034437 and 1106171), the Knut and Alice Wallenberg Foundation (under Dnr KAW 2018.0067 and research project grant “Understanding the Dynamic Universe”), the Swedish Research Council (Project No. 201

Frequently Asked Questions (FAQs) about Gravitationally lensed supernova

More about Gravitationally lensed supernova

• Nature Astronomy: Uncovering a population of gravitational lens galaxies with magnified standard candle SN Zwicky
• Einstein’s Theory of Relativity: Space.com
• Gravitational Lensing: NASA Science
• Dark Matter: National Geographic
• Universe Expansion: Space.com