JWST First Images Revealed!. Are the beautiful colors…real? | by Michelle Cu | Jul, 2022

The first JWST images were finally revealed on 7/12! Here’s an explanation about the pictures!

left: Deep Field. right: Stephan’s Quintet (image: NASA)

The deep field picture was posted as a teaser image before the others were released. In the picture, you can see some galaxies distorted and forming a circle, that’s because of the gravitational lensing, which means that the gravitational forces were so strong that it creates some sort of magnifying glass to reveal smaller galaxies far away. Something special about Webb is that it is able to process several spectra from a single image, revealing the distance and chemical characteristics of stars and galaxies. With this feature, Webb found the oldest galaxy ever seen in the universe, the formation of this galaxy dates back to just 300 million years after the Big Bang, making it approximately 13.5 billion years old. This galaxy is called GLASS-z13, and can be found in the deep field image. It’s no more than a red blurry spot, but it’s still fascinating! Hubble has capture images of the deep field before, too, but the resolution was not as high, and the duration of imaging took weeks for Hubble while it only took around 12 hours for Webb.

The Stephan’s Quintet consists of 5 galaxies. One of the galaxies is much closer to us than the other four, which happen to be interacting with each other, causing it to stretch and change the shape of each galaxy.

left: Southern Ring Nebula. right: WASP-96b (image: NASA)

The Southern Ring Nebula is made mostly by gas and dust from dying stars in the middle. There are two stars in the middle, one much dimmer at the lower left side of the bright blue star. The dust and gas were mostly from the dimmer star. And the brighter star causes turbulance and creates the shape of the nebula.

The exoplanet’s spectrum may be a lot less exciting for those expecting to see vibrant images, but the graphic is a massive step forward in the studying of exoplanets. The gray lines shown in the picture are error bars presenting the uncertainty, and the blue line is a best-fit model that takes into account the data, the known properties of WASP-96 b and its star (e.g., size, mass, temperature), and assumed characteristics of the atmosphere. The spectrum data was collected by imaging the exoplanet crossing in front of a star, the light that travels through the atmosphere reveals the chemical compunds in it. The exoplanet was found to have water, and may even have clouds and haze!

Carina Nebula (image: NASA)

The Carina Nebula is my favorite image of Webb. The image shows the cliffs of the Nebula with thick gas and dust. While the Southern Ring Nebula shows the death of stars, this one is the star forming region.

image: ESA

Color of the Images

The most significant feature of Webb is the infrared imaging instruments. And the reason for being special is the fact that we would see what we couldn’t see. Our eyes can only process images through visible light, we couldn’t see them through infrared. Then…how are we able to see the images of Webb?

This contradictory thought leads to the truth that the colors of Webb images are not actually real. The images which were sent back from Webb come in as black and white, then the colors are added later on.

Broadband Color

Broadband color uses filters to turn black and white images to true colors — which is what you would see if your eyes are as powerful as the telescope.

Narrowband Color

Narrowband color is used for coloring the image to show the chemical subtance of the galaxy/nebula. For example, hydrogen and sulfer are seen in red, while oxygen is seen in green(blue-ish). When you combine these three filters, the resulting combination comes out to be in quite similar colors, which is not useful for visual analyzing. So the color of the elements will be changed into the chromatic order. Meaning the highest frequency(oxygen) will be assigned to blue, hydrogen will be presented as green, and sulfer would be red, just as it was before. The picture formed at the end would have more vivid colors than the one before.

The images of space are breathtaking, not just because the fascinating art, but also being an integral part of space exploration. Webb will continue to dive deep into the unknown of space, and facilitate the unveiling of more information about our galaxy and beyond.

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