2024-01-01 22:27:32
NASA’s Fermi Gamma-ray Space Telescope has created a stunning all-sky time-lapse movie from 14 years of data, capturing the dynamic universe. It highlights the path of the Sun, the gamma-ray glow of the Milky Way, and distant galaxies known as blazars. The film reveals both the beauty and complexity of the cosmos, showcasing high-energy events occurring across the galaxy and beyond, including eruptions of supermassive black holes. (Artist’s concept.) Credit: Issues.fr.com
NASA’s Fermi Space Telescope presents a 14-year time-lapse film, revealing the dynamic universe through gamma-ray imaging. It highlights the Milky Way’s gamma-ray glow, solar flares, and distant galaxies powered by black holes.
The cosmos comes to life in an all-sky time-lapse movie made from 14 years of data acquired by NASA’s Fermi Gamma-ray space telescope. Our Sun, occasionally rising, serenely traces its path across the sky against a backdrop of high-energy sources within our galaxy and beyond.
“The Milky Way’s bright, constant gamma-ray glow is punctuated by intense, days-long eruptions of near-light-speed jets propelled by supermassive black holes at the hearts of distant galaxies,” said Seth Digel , senior scientist. at SLAC National Accelerator Laboratory in Menlo Park, California, which created the images. “These spectacular flares, which can appear anywhere in the sky, occurred millions or even billions of years ago, and their light barely reaches Fermi before our eyes. »
From solar flares to black hole jets: NASA’s Fermi Gamma-ray Space Telescope team has produced a unique time-lapse tour of the dynamic, high-energy sky. Judy Racusin, Fermi’s deputy project scientist, narrates the film, which compresses 14 years of gamma-ray observations into 6 minutes. Credit: NASA Goddard Space Flight Center and NASA/DOE/LAT collaboration
Gamma rays are the most energetic form of light. The film shows the intensity of gamma rays with energies above 200 million electron volts detected by Fermi’s Large Area Telescope (LAT) between August 2008 and August 2022. For comparison, visible light has energies between 2 and 3 electron volts. Brighter colors mark the locations of the most intense gamma ray sources.
“One of the first things that strikes your attention in the film is a source that scrolls steadily across the screen. This is our Sun, whose apparent motion reflects the annual orbital motion of Earth around it,” said Fermi deputy project scientist Judy Racusin, who recounts a tour of the film at NASA’s Goddard Space Flight Center in Greenbelt. , in Maryland.
Artistic conception of the Fermi Gamma-ray space telescope in orbit. Credit: NASA
Most of the time, the LAT detects the Sun weakly due to the impact of accelerated particles called cosmic rays – atomic nuclei moving at close to the speed of light. When they hit solar gas or even the light it emits, gamma rays result. Sometimes, however, the Sun suddenly brightens with powerful flares called solar flares, which can briefly make our star one of the brightest sources of gamma rays in the sky.
The film shows the sky from two different views. The rectangular view shows the entire sky with the center of our galaxy in the middle. This highlights the central plane of the Milky Way, which glows under gamma rays produced by cosmic rays hitting interstellar gas and starlight. It is also dotted with many other sources, including neutron stars and supernova remnants. Above and below this central band, we look out of our galaxy and into the larger universe, dotted with light sources and changing rapidly.
Most of them are actually distant galaxies, and they are best seen in a different view centered on the north and south poles of our galaxy. Each of these galaxies, called blazars, hosts a central black hole with a mass of a million Suns or more.
One way or another, black holes produce extremely fast jets of matter, and with blazars we are looking almost directly into one of these jets, a view that enhances their brightness and variability. “The variations tell us that something has changed in these planes,” Racusin said. “We regularly monitor these sources and alert other telescopes, in space and on the ground, when something interesting is happening. We need to be quick to detect these eruptions before they disappear, and the more observations we can collect, the better we will be able to understand these events.
Fermi plays a key role in the growing network of missions working together to capture these changes in the universe as they unfold.
Many of these galaxies are extremely distant. For example, light from a blazar known as 4C +21.35 has been traveling for 4.6 billion years, meaning that an eruption we observe today actually occurred while our Sun and our solar system were beginning to form. Other bright blazars are more than twice as distant and together provide striking snapshots of black hole activity throughout cosmic time.
Many short-lived events studied by Fermi, such as gamma-ray bursts, the most powerful cosmic explosions, are not visible in the time-lapse. This is the result of processing data over several days to refine the images.
The Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership managed by Goddard. Fermi was developed in collaboration with the U.S. Department of Energy, with significant contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.
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