two supernovaes In a galaxy, and so far away that we see it as it did 10 billion years ago, it could be crucial in helping to reveal how fast the universe is expanding. The measurement has caused some tension in the scientific community.
The Hubble Space Telescope and the James Webb Space Telescope captured images of the galaxy and two supernovae.Galaxies become visible through power gravitational lensing effect — a phenomenon in which large amounts of mass, such as those found in galaxy clusters, can become distorted space This creates a “lens” shape that amplifies and distorts the light from more distant galaxies.
2016, Hubble Space Telescope The galaxy MRG-M0138 was imaged, but the images were not fully analyzed until three years later. MRG-M0138’s light is distorted into five separate images by the lens of the galaxy cluster MACS J0138.0-2155 (4 billion) light years Stay away from us. The images don’t look exactly like the galaxies we’re familiar with, as they are distorted into arcs due to imperfect lens conditions.
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However, while studying Hubble images in 2019, astronomers noticed a bright star Supernova In MRG-M0138. Type Ia supernovae are white dwarfeither by colliding with another white dwarf or by steal enough material From a close companion star.
But now, astronomers use James Webb Space Telescope (JWST) Found a second Type Ia supernovae in distant galaxies.
The first supernova was nicknamed “Requiem”; This second supernova is called “Encore”. MRG-M0138 is the most distant galaxy ever observed to host two Type Ia supernovae, which is, in fact, important in helping to solve perhaps the biggest mystery yet. cosmology Now.
When astronomers measure the expansion rate of the universe—a quantity we call the expansion rate of the universe Hubble constant – They get two incompatible values. Although on the surface, neither measurement appears to be in error, it is clear that neither can be correct. So either there’s an undetected error in our measurements, or there’s exotic new physics at work.
One way to measure the Hubble constant is by analyzing cosmic microwave background (CMB) Radiation left behind big Bang. The cosmic microwave background is patchy with tiny temperature differences that correspond to changes in the density of the original material that grew into the galaxies and galaxy clusters we see today.These changes and large-scale structures that we see in universe is directly relevant today and based on what we know Standard model In the field of cosmology, astronomers can use this connection to derive a value for the Hubble constant, which is equal to 67.4 kilometers (41.9 miles) per second per megaparsec. (A megaparsec is 3.26 million light years, so this means that every second, any given volume of space with a diameter of 3.26 million light years expands by 67.4 kilometers. )
However, Type Ia supernovae are also useful for measuring cosmic distances and the Hubble constant.That’s because they have a normalized maximum brightness From this we can judge their true intrinsic luminosity. We can then calculate their distance based on how bright or faint they appear to us.From there, astronomers can compare this distance to that of the supernova red shift, which measures the rate at which space is expanding, thereby stretching the wavelength of the light emitted by the supernova, resulting in the Hubble constant. The final calculation is done using the Hubble-Lemaître law, which states that the recessional velocity is equal to the distance times the Hubble constant. Using this method, the astronomers calculated 73.2 kilometers (45.5 miles) per second per megaparsec, which is greater than the value derived from the CMB.
However, the lensed supernovae in MRG-M0138 have the added advantage that they will appear in five different lensed images of the Milky Way.
“When a supernova explodes behind a gravitational lens, its light reaches Earth Justin Pirrell of the Space Telescope Science Institute and Andrew Newman of the Carnegie Institution for Science Observatory said in a joint study statement.
These paths vary in length, so supernovae may appear in images days, weeks, or even years apart.
“By measuring differences in the timing of supernova images, we can measure the history of the universe’s expansion rate, known as the Hubble constant, which is a major challenge in cosmology today,” Pierre and Newman said.
Lenticular supernovae are rarely discovered, with fewer than a dozen known. This makes the two Type Ia supernovae in MRG-M0138 particularly valuable.
However, there is a problem.Although most images of both supernovae have emerged, one is expected to have a longer light path based on light distribution models dark matter in the lens cluster. These final images are not expected to appear until the mid-to-late 2030s.
“Supernovae are usually unpredictable, but in this case we know when and where to expect to see the encore and the eventual occurrence of the encore,” Pierre and Newman said. “Infrared observations around 2035 will have a last hurray and produce new precise measurements of the Hubble constant.”
While the aging Hubble Space Telescope may no longer be active by 2035, JWST is expected to remain active. If so, and if it is able to detect the appearance of the final images of the Requiem and Encore, then the measurement of the Hubble constant they provide could help resolve whether the so-called Hubble tension is simply an experimental error or real phenomenon problem.
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