James Webb Space Telescope Feed Post

Webb Researchers Discover Lensed Supernova, Confirm Hubble Tension

A New H0pe? Scientists are using Webb to measure the expansion of the universe, by pointing it at a gravitationally lensed supernova SN H0pe. The light from this exploding star has been bent and magnified by a galaxy cluster between it and us. Supernova H0pe was discovered when scientists saw three points of light in a Webb image of a galaxy cluster that were not present in the Hubble data. The dots (circled in the inset box) are a special type of supernova that has a known luminosity. Each “dot” shows the supernova at a different point in time. Imagine sitting at a vanity with a trifold mirror so that there are three of you. Add in a time delay so that in the right mirror you are lifting a comb, in the left you are combing, and in the middle, you are putting the comb down. Having “trifold” images of this supernova allow scientists to use the time delays, its distance, and the gravitational lensing properties to calculate a value for the Hubble constant: the rate at which the universe is expanding. The value for the Hubble constant obtained using this method matches other measurements in the local universe. More observations of Supernova H0pe, one of the most distant of its kind, will help further our understanding of this fundamental parameter of the universe. Read more: blogs.nasa.gov/webb/2024/10/01/webb-researchers-discover-... Note: this science is in progress and not yet peer-reviewed. Image Credit: NASA, ESA, CSA, STScI, B. Frye (University of Arizona), R. Windhorst (Arizona State University), S. Cohen (Arizona State University), J. D’Silva (University of Western Australia, Perth), A. Koekemoer (Space Telescope Science Institute), J. Summers (Arizona State University). Image description: This picture is set into two equal frames, left and right. Both are set on a black backdrop full of luminous bright spiral galaxies of varying size, glowing bright white, yellow and orange. Many of these galaxies are either clustered together, or overlapping each other visually, adding layers of scale to the image. In the middle of the left frame, two bright prominent orange galaxies appear to be stretched out into long tendrils pointing north and south that appear roughly one third the size of the frame, much unlike the usual spiral form of galaxies in space. These two orange elongated galaxies are the focus of this image, while many different colored galaxies populate the background. The left frame has a square inset, highlighting one of the two elongated orange prominent galaxies which is the focus of the image. This shows the magnifying effect a foreground cluster can have on the distant universe beyond, known as gravitational lensing. The lens, consisting of a cluster of galaxies that is situated between the supernova and us, bends the supernova’s light into multiple images. To achieve three images, the light traveled along three different paths. Since each path had a different length, and light traveled at the same speed, the supernova was imaged in this Webb observation at three different times during its explosion.The right panel zooms in on the long orange filament, revealing three focal points of concentrated light that have been marked with circles. Analyses confirmed that these dots corresponded to an exploding star, one with rare qualities. First, it’s a Type Ia supernova, an explosion of a white dwarf star. This type of supernova is generally called a ‘standard candle,’ meaning that the supernova had a known intrinsic brightness. Image & Description by NASA