The Webb telescope was designed to investigate a formative and mysterious era which reaches back to about 500 million years after the Big Bang in an area of the Universe where progenitors of galaxies like the Milky Way were born. With a giant mirror and infrared sensors Webb can see the most distant, and thus earliest, galaxies. What we see on the picture below has long been transforming into something else. Again: an archaeological finding from a past we can hardly grasp. An astronomer’s team from the Columbia University in the USA has re-examined images of 4.000 new-born galaxies observed by the telescope at the dawn of time.
I identify with the astronomers, who like archaeologists consider the Webb findings, dug out by a cinematic device and recomposed to understand our past.
These images show the position of the most distant galaxy discovered so far within a deep sky Hubble Space Telescope survey called GOODS North (Great Observatories Origins Deep Survey North). The survey field contains tens of thousands of galaxies stretching far back into time. The remote galaxy GN-z11, shown in the inset, existed only 400 million years after the Big Bang, when the Universe was only 3 percent of its current age. It belongs to the first generation of galaxies in the Universe and its discovery provides new insights into the very early Universe. This is the first time that the distance of an object so far away has been measured from its spectrum, which makes the measurement extremely reliable. GN-z11 is actually ablaze with bright, young, blue stars, that appear red in this image because their light was stretched to longer, redder, wavelengths by the expansion of the Universe.
Black Hole’s Impact on Its Galaxy
The young host galaxy, called GN-z11, glows from such an energetic black hole at its center. Black holes cannot be directly observed, but instead they are detected by the tell-tale glow of a swirling accretion disc, which forms near the edges of a black hole. The gas in the accretion disc becomes extremely hot and starts to glow and radiate energy in the ultraviolet range. This strong glow makes it possible for astronomers to detect black holes.
GN-z11 is a compact galaxy, about one hundred times smaller than the Milky Way, but the black hole is likely harming its development. When black holes consume too much gas, it pushes the gas away like an ultra-fast wind. This wind could stop the process of star formation, slowly killing the galaxy, but it will also kill the black hole itself, as it would also cut off the black hole’s source of food.
The team analyzed the images of galaxies in a patch of sky smaller than a full moon, known as the Extended Groth Strip. The images were obtained by an international collaboration called the Cosmic Evolution Early Release Science survey (CEERS). The technology and the way data and findings are read from the Webb Telescope are immensely interesting, as they speculate on objects that existed at the origin of time, namely galaxies and hydrogen and oxygen atoms.
(source: New York Times article 05.01.2024 The Early Universe Was Bananas)
New Era in Astronomy
Roberto Maiolino, Professor of Experimental Astrophysics at the Cavendish Laboratory and at the Kavli Institute for Cosmology, University of Cambridge, says that the gigantic leap forward provided by JWST makes this the most exciting time in his career: It’s a new era: the giant leap in sensitivity, especially in the infrared, is like upgrading from Galileo’s telescope to a modern telescope overnight. Before Webb came online, I thought maybe the universe isn’t so interesting when you go beyond what we could see with the Hubble Space Telescope. But that hasn’t been the case at all: the universe has been quite generous in what it’s showing us, and this is just the beginning.
Maiolino says that the sensitivity of JWST means that even older black holes may be found in the coming months and years. Maiolino and his team are hoping to use future observations from JWST to try to find smaller seeds of black holes, which may help them untangle how black holes might form: whether they start out large or they grow fast.
(Credit: SciTechDaily.com)
