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Feb 17, 2024

James Webb Space Telescope Captures Images of Irregular Galaxy NGC 6822

The James Webb Space Telescope has released a series of new images showcasing the dusty and irregular galaxy NGC 6822. Situated at a relatively close distance of 1.5 million light-years from Earth,

The James Webb Space Telescope has released a series of new images showcasing the dusty and irregular galaxy NGC 6822. Situated at a relatively close distance of 1.5 million light-years from Earth, this galaxy is of particular interest due to its low metallicity.

Metallicity refers to the abundance of heavy elements in a galaxy, excluding hydrogen and helium. Early galaxies primarily consisted of hydrogen and helium, leading to low metallicity. Over time, heavier elements were formed within stars and then dispersed throughout the universe during supernova events.

The images were captured by the Near-InfraRed Camera (NIRCam) and the Mid-InfraRed Instrument (MIRI), both mounted on the James Webb Space Telescope. NIRCam observes in the near-infrared spectrum and is suitable for observing the densely packed field of stars within NGC 6822, while MIRI is highly sensitive to the gas-rich regions of the galaxy.

Researchers from the James Webb Space Telescope combined the observations from NIRCam and MIRI to create a composite image that highlights features such as dust clouds and areas of active star formation. By utilizing different parts of the electromagnetic spectrum, the two instruments are able to capture different details of the galaxy.

The MIRI image reveals regions of dust more prominently in the mid-infrared, with cooler dust appearing blue and warmer dust appearing orange. Additionally, different colors can help differentiate between nearby and distant galaxies, with nearby galaxies appearing green and distant galaxies appearing orange. An orange ring shape near the bottom center of the image represents the remnant of a supernova.

On the other hand, the NIRCam image allows for the identification of thousands of stars that are challenging to observe in the MIRI image. This is achieved by peering through the dust, with brighter stars appearing blue and fainter stars appearing red.

For a slider comparison of the MIRI and NIRCam images, interested individuals can visit the Webb website.