Oliver Bernie, an astronomer at CNRS and head of an observation program for the telescope, commented on the first images of the James Webb Space Telescope (JWST), published today by the American Space Agency (NASA), European (ESA) and. Canadian (ASC).
You’ve finally been able to see the first image of the James Webb Space Telescope (JWST) launched last December. What do you think?
Olivia Barney. It’s very moving! These images are remarkable, whose depth and subtle details have never been found before with previous terrestrial and space observations such as Hubble. The first results show significant sensitivity, about 6 to 10 times higher than before. This is either to observe very distant objects like primitive galaxies or to see objects that are close to us but very poorly illuminated, such as in the formation of stars or planets. On the other hand, there is a lot more information in these images for the 6.5 meter diameter mirror of James Webb thanks to its high resolution. Clearly, in terms of detail, it’s like moving from an Impressionist painting to a realist style.
The galaxy cluster SMACS 0723 is so huge that it distorts and extends light from objects behind it. In addition to JWST’s capabilities, it makes it possible to observe galaxies that are extremely distant and have very little illumination, thus offering “the deepest image of our universe,” Olivia Bern suggests.
JWST observes visible radiation but mainly in infrared. Why?
OB Infrared corresponds to longer wavelengths than visible spectral structures. Observing infrared makes it possible to go further back in the past of the universe and see the galaxies formed in the first epoch of the universe.
In terms of details, it’s like moving from an Impressionist painting to a realistic style.
In fact, as the universe expands, the light signal of these first galaxies shifts strongly towards red and leaves the visible spectrum. So to understand the nature of the first stars to exist in the universe and the way they formed just after the Big Bang about 13.5 billion years ago, we must look for their light in infrared.
The deep field of distant galaxies seen in this picture perfectly illustrates this power of JWST. These wavelengths also make it possible to observe newborn stars or planets, for example, through the dust and gas cocoons that surround them.
Located in the constellation of Wales, about 2,000 light-years from Earth, the Southern Ring Nebula is a planetary nebula. It is an extended cloud of gas and dust, expelled by a star towards the end of life that gives birth to the visible white dwarf in the center. “The quality of the details is amazing: you can see a completely granular texture that was invisible before,” Olivier Barney encourages.
Do scientists use these images for their research?
O.B. These images show information that uses false colors to make them aesthetically pleasing to the naked eye. Scientists do not use these color images directly to work. They are mainly interested in the data collected by each filter in the telescope, on the specific wavelengths for images or through the data SpectrographOffA spectrograph is an instrument that separates light into a spectrum of frequencies. This spectrum contains the unique signatures of atoms and molecules, allowing them to be identified.. It gives information about the temperature, density and chemical composition of the observed objects and sometimes their movements. We can thus guess which physical phenomenon there is in the game.
The JWST Exoplanet WASP-96b has unveiled the chemical structure of the atmosphere, a gas giant that orbits half the mass of Jupiter and its stars, located 1120 light-years from Earth (in the constellation of Phoenix), in less than 4 days. The spectrum reveals water in different states at different depths of the atmosphere, “which proves the impressive power of the instrument! 6, rejoiced in Olivia Bern.
But James Webb doesn’t just have a scientific mission. With great images that move and touch ordinary people, the way the Hubble Telescope humanity represents the universe has had a powerful effect on the collective imagination around the universe we live in. This is a fundamental role, at least as important as the scientific discovery that JWST must continue. I bet with my colleagues that the images aired today would have a consent to Hubble’s work and the Carina Nebula which proves me right!
But space agencies are now also broadcasting data that will be invaluable to you. Can you explain?
OB Today, agencies broadcast these admirable images but also all the observations and data created during the test episode. The latter has an important scientific interest. In fact, they will allow us to evaluate the quality of various instruments and test the data processing algorithms we have prepared. The rest of us, astronomers and astrophysicists, can’t wait to finally do some science with this telescope that we’ve been waiting for decades!
Your own observations will be from 10 September to 3 October. What do you want to analyze and how is JWST a resource for your project?
O.B. Our team is made up of three leaders: Els Peters of the University of Western Ontario in Canada, the Emily Hubert Institute for Space Astrophysics, and me.
For the Orion Nebula study we received 40 hours of observation. Locations are expensive: for this first wave of projects, only thirteen have been selected worldwide.
The trio coordinates an international team of about 150 people from 18 countries, with a strong team of about thirty researchers. We have received 40 hours of observations to study the Orion Nebula, a cloud of gas and dust at the center of the constellation of the same name. Locations are expensive: for this first wave of projects, only thirteen have been selected worldwide, i.e. approximately one lucky candidate for every ten candidates, and we are the only program with major responsibilities for France.
The group of galaxies, 290 million light-years away, is Stefan Quintet, the first compact group of four interacting galaxies, and a galaxy on another plane discovered in 1877. That’s awesome! », Comments Olivier Berné.
The Orion Nebula is interesting in two cases. First, it is at least partially representative of the environment in which the solar system was formed, a region of star and planetary formation. So studying it will allow us to better understand the structure of the sun and the planets that surround the earth such as the earth.
On the other hand, distant galaxies observed by James Webb make many stars during their evolution. Their infrared radiation is therefore affected by the light signals received from the Orion Nebula. The difference is that Orion is close enough that different regions of the nebula can be observed with different physical parameters (temperature and density of the gas, the rate of formation of them and the energy of the radiation field, etc.). Our project is therefore to provide models that connect to the shape of the light signal obtained with these parameters, a standard that would make it possible to interpret signals received from distant galaxies. We have been preparing this project for almost ten years, and the observations made will remain at the center of our research for several years! 3
A giant in the service of knowledge
The JWST is the largest and most powerful space telescope ever launched. It is designed to better understand our solar system, to observe distant worlds around other stars, to explore the origins of the universe. This is the result of an international partnership between NASA, ESA and CSA. ESA thus provided two of James Webb’s four scientific instruments: the NIRSpec spectrograph and the 50% Miri spectrograph and imager. Several laboratories affiliated with CNRS participated, such as the Laboratory for Space Studies and Instrumentation in Astrophysics (LACIA), the Marseille Astrophysics Laboratory (LAM) or the Space Astrophysics Institute (IAS). The telescope was launched on a rocket on December 25, 2021 5 in Ariadne From the European Space Center in French Guiana. With its 6.5-meter-wide mirror, it is now in orbit around Lagrange Point L2 in the Sun-Earth system, located 1.5 million kilometers from the Earth, opposite the Sun. 3
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The James Webb Telescope is exploring the ancient universe