The first observations made by the James Webb Space Telescope were released live on NASA TV on July 12 at 11:30 PM Korean time (July 12, 10:30 AM EST). There are five publicly available high-resolution images and spectral spectra: the SCAMS 0723 galaxy cluster, the hot gas exoplanet WASP-96b (spectral spectrum), the NGC 3132 nebula known as the Southern Ring Nebula, Stephan’s Quintet, and the Carina Nebula. The edge of NGC 3324 includes the ‘Cosmic Cliff’. (See related article – ‘James Webb Space Telescope Reveals First Observation Results’)
In the James Webb Space Telescope Observation Interpretation series, we dig through high-resolution images one by one to find out what the pictures mean and what James Webb’s plans for the future of celestial bodies are. James Webb’s fifth image is a group of five galaxies called Stephan’s Quintet, which became a hot topic because it was possible to grasp hints about the evolutionary process of galaxies that had not been seen before.
→ This is a continuation of the first part. (View related article – ‘How the Galaxy Evolution Proceeds Part 1’)
One of the brightest single objects in the universe, and a very active supermassive black hole, a quasar has only been found at great distances. This indicates that they were born in a relatively early universe. This is because the farther away the celestial body is, the longer it takes for light to reach our eyes, and the older the image can be observed.
First quasar 3C 273 discovered © ESA/Hubble
Although more detailed observations are possible as we come to more recent universes, these quasars are observed at a rather low frequency, and quasars have not been found in more recent universes. Through this, it can be predicted that the quasars in the early universe are no longer active due to changes in the environment of the expanding universe, and it can also be inferred that the difference in density between the present universe and the past is very different. Thus, it is thought that dense galaxies, such as Stefan’s quintet, were more likely to have appeared in the early universe, where quasars existed. In particular, it is known that there is a supermassive black hole with a mass of 24 million solar masses emitting light energy equivalent to 40 billion suns in the NGC 7319 galaxy.
Gas around black hole revealed
The MRS (Medium-Resolution Spectrometer), a spectrometer constituting the MIRI instrument, observed the active galactic nucleus of the NGC 7319 galaxy in detail. The above spectrometer has the function of integral field units (IFU) consisting of a camera and a spectrometer, and shows the spectral feature image of the galactic nucleus called “Data Cube” in detail. Similar to magnetic resonance imaging (MRI), this is a shooting that can cut and decompose (“slice and dice”) one piece of information into many images. This allows astronomers to figure out the structure of space and calculate the velocity of that structure. For reference, the above speed is measured by the wavelength shift of a specific emission line.
The gas surrounding the black hole is revealed. © JWST/NASA, ESA, CSA, STScI
MRS captured gas ionized by powerful winds and black holes near the active galactic nucleus of a supermassive black hole at a previously unstudied wavelength. In the lower part of the picture above, the blue part shows the movement of ionized gas toward us, and the orange part shows the movement of ionized gas away from the observer.
In particular, argon and neon are highly ionized by strong radiation from supermassive black holes and wind, and are found in superheated gases. In addition, observations through molecular hydrogen lines indicate that they are observed in the center of galaxies, where cooler, denser gases are found. (Go to high resolution image)
Schematic of gas near an active black hole
The image below shows the active galactic nucleus of the NGC 7319 galaxy taken with NIRSpec (Near Infrared Spectroscopy). An integrated field device, also a combination of a camera and a spectrometer, is used to provide a data cube, which reveals the composition of hot gases in the vicinity of an active black hole. Of note, the bright and active nucleus itself has been removed from this image to better show the structure of the surrounding gas.
Gas diagram of an active black hole © JWST/NASA, ESA, CSA, STScI
The picture above shows some of the main emission lines that can be seen in NIRSpec, and through this, various gases can be identified. First, the hydrogen atom is shown in blue and yellow, and the structure of the outflow can be traced. In addition, observations of iron ions in blue-green color can be traced to the presence of hot gases, and observations of cold, dense hydrogen molecules, shown in red, can be traced to the vicinity of the ejection gas and fuel reservoirs of black holes. (Go to high resolution image)
Gas diagram of an active black hole © JWST/NASA, ESA, CSA, STScI
The above image detailing the gas composition near the supermassive black hole of the NGC 7319 galaxy is also observed by MRS. The observations above show that the black hole is surrounded by silicate dust, which resembles beach sand, but is much smaller. It also shows that the top of the black hole (top right diagram) is made up of hot, ionized gases including iron, argon, neon, sulfur and oxygen. Studying multiple emission lines of the same element with different degrees of ionization is very helpful in understanding the nature and origin of the eruption. On the other hand, the spectrum below (bottom right) shows that the supermassive black hole is rich in cold, dense molecular hydrogen and silicates that absorb light from the central region of the galaxy. (Go to high resolution image)
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