Quasars are the brightest sources of light in the universe, powered by supermassive black holes that reside at the centers of galaxies. Their extreme brightness comes from accretion disks – vast amounts of gas and dust swirling around the black hole. Thanks to gravitational attraction, these disks accelerate and heat up, creating immense amounts of radiation. Recent observations from the James Webb Space Telescope (JWST) have revealed quasars whose influence was so powerful that it practically "killed" their host galaxy, limiting the formation of new stars.
Lonely quasars: Unexpected discoveries
One of the surprising discoveries in recent research has been the presence of quasars that appear to be almost completely isolated in the early universe, without many neighboring galaxies that could provide them with the "fuel" for their growth. In fact, astronomical models predicted that the earliest quasars should have formed in the densest regions of the universe, rich in gas and dust. However, recent observations using the James Webb Telescope reveal that some quasars, like J1007+2115, exist in relatively empty regions of space.
These discoveries shed new light on the understanding of supermassive black hole formation and challenge scientists to reconsider how such objects could grow without nearby sources of material. There is a possibility that the galaxies surrounding these quasars are actually hidden behind dense clouds of dust, making them invisible to telescopes of ordinary sensitivity. Researchers hope that additional observations, particularly with JWST, will allow for deeper insights through this cosmic veil of dust [16].
Quasar winds: Forces that reshape galaxies
One of the key features of quasars is their ability to produce "quasar winds." These winds are extremely powerful, traveling at speeds of up to 7.6 million kilometers per hour, and can eject large amounts of gas and dust from the galaxy, resulting in "starvation" for new star formation. The quasar winds originating from objects like J1007+2115 carry material equivalent to the mass of 300 suns each year. These winds not only halt the growth of the supermassive black hole but also significantly slow down the formation of new stars in the surrounding galaxies.
This leads to the concept of "dead galaxies" – galaxies that were once active but have now stopped producing new stars due to a lack of necessary resources. The galaxy currently surrounding the quasar J1007+2115 is likely such an example; it was once rich in activity, but the quasar winds have largely depleted its material, preventing further growth and the formation of new stars [17].
Early formation of black holes: Collapse of massive stars
Another theory that comes into play to explain how supermassive black holes were able to form so quickly after the Big Bang is the direct collapse of massive stars. According to recent findings, the first supermassive black holes likely formed from the collapse of enormous stars that did not explode as supernovae but instead collapsed under their own gravity into intermediate-mass black holes. This formation process allowed for the very rapid growth of these objects, as they began to consume surrounding material immediately after collapsing.
Moreover, these early stars formed in "mini-halos" of matter and dark energy, which enabled them to achieve masses thousands of times greater than our sun. Unlike today's generations of stars that are exposed to intense radiation and shock waves from neighboring supernovae, these early stars were not subjected to those factors, allowing for the formation of much more massive black holes.
Star formation "inside out": New insights from JWST
Recent observations from JWST have also uncovered an unusual mode of star formation in early galaxies – from the "inside out." Researchers have noted that in one early galaxy, just 700 million years after the Big Bang, stars formed first in the center and then gradually spread to the edges. This pattern of star formation differs from what is observed in today's galaxies but confirms theoretical models that predicted such dynamics.
These observations are crucial as they allow astronomers to "check their homework" – comparing actual data with theoretical predictions to gain a deeper understanding of how galaxies evolved in the first few hundred million years after the Big Bang. The formation of stars in these early galaxies likely went through several phases, including the accretion of gas toward the center, ultimately shaping the present-day cores of galaxies.
Continuation of research and future prospects
Scientists plan further observations to understand exactly what happened in the early stages of the universe and how galaxies evolved into the large structures we see today. With the help of JWST, additional research on quasar winds and their roles in both the formation and destruction of galaxies is planned. The goal is to comprehend how these cosmic giants contributed to the evolution of the universe while also uncovering how the supermassive black holes themselves developed and grew to enormous sizes.
Creation time: 21 October, 2024
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