For more than 30 years, the Hubble Telescope has provided images of galaxies from the near infrared through the ultraviolet to the visible region. In the James Webb era, NASA spent six days reminding us what we owed Hubble on this issue. Here is the continuation of the article that we dedicated to the Festival of Galaxy Images.
Here is the second part of the article dedicated to NASA Week, which each day painted a quick portrait of one of the galaxies observed with the Hubble Telescope while it is still active to reveal secrets of the Kingdom of Nebulae , which were opened there a little less over a century ago by Edwin Hubble.
The Hubble telescope once again shows us an image of a galaxy discovered by British astronomer William Herschel. He observed NGC 1087 in the constellation Whale in 1785. But as always, it was only through the work of astronomers in the 1930s and beyond that we discovered that this spiral galaxy is located about 80 million light-years from the Milky Way and is about 87,000 light-years in diameter.
NGC 1087 is one of the barred spirals and the image above shows it in false colors as seen by Hubble’s instruments in ultraviolet, visible and near-infrared light. According to the accompanying NASA press release, the dark red streaks are cold molecular gas, the raw material from which stars form. The bright pink spots mark areas where new stars are forming, characterized by the presence of ionized hydrogen, oxygen and sulfur. The bluer regions are home to hot young stars that formed earlier in the life of this galaxy.”
The galaxy NGC 6951, pictured below, is a type II Seyfert galaxy (named after the American astronomer Carl Keenan Seyfert, who began studying it seriously in 1943) with a supermassive black hole at its center, surrounded by a ring of stars, gas and dust. It has a diameter of about 3,700 light-years and is said to have formed between 1 and 1.5 billion years ago. But their discoverers, the French astronomer Jérôme Coggia in 1877 and the American astronomer Lewis Swift in 1878, could not have known this, just as this spiral, which we can observe in the constellation Cepheus, was about 78 million light-years from the Milky Way .
The entire galaxy is about 75,000 light-years in diameter and is visible from the Northern Hemisphere, as explained in NASA’s press release, which also states that we can see turbulent regions of gas in the Hubble image in visible and infrared light, which are shown in dark red. surrounding bright blue pinpricks that are star clusters.
Notably, NGC 6951 has been the site of at least six supernovae discovered in the last 25 years.
As a cosmic photographer, NASA’s Hubble Space Telescope has taken more than a million photos documenting the universe. These images illustrate, explain and inspire us with their magnificence. But how are these images captured and processed?
This incredible video explains how Hubble images are captured and processed. To get a reasonably accurate French translation, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then click on “Subtitles” and finally “Auto-translate”. Select “French”. © NASA’s Goddard Space Flight Center
NGC 4654 is one of the galaxies that can be observed in the Virgo Cluster. It lies about 55 million light-years from Earth. Because it lies just north of the celestial equator, it is visible on Earth from the Northern Hemisphere and most of the Southern Hemisphere. Obtaining this false-color photo required images from the Hubble Space Telescope taken in visible, ultraviolet and infrared light.
NGC 4654 appears to have had a gravitational interaction with the companion galaxy NGC 4639 about 500 million years ago. We suspect that its movement through the galaxy cluster’s millions of Kelvin plasma puts a pressure on it that tends to strip it of its gas content, resulting in a long, thin trail of hydrogen gas on the southern side of the galaxy, as explained in NASA’s press release . Curiously, the rate of star formation remains comparable to that of other galaxies, despite this process of gas depletion, which tends to rule out the possibility of gravitational collapse of matter, creating open clusters of young stars.