James Webb Telescope will help us to study remote quasars: Scientists

NASA is planning to launch the James Webb Space Telescope nearly at the end of this year. A team of NASA scientists will train the Telescope on six of the most distant and luminous quasars. With the help of the telescope, they will study the properties of these quasars and their host galaxies, and how they are interconnected during the first stages of galaxy evolution in the very early universe. In addition, the team will also use the quasars to examine the gas in the space between galaxies, particularly during the period of cosmic reionization, which ended when the universe was very young. For the task, the scientists will use the Webb telescope’s extreme sensitivity to low levels of light and its superb angular resolution.

Scientists say peering deep into the universe is like looking back in time. The light from those distant quasars that the telescope receives had begun its journey billions of years ago, when the universe was very young. It took billions of years to arrive here as they the quasars are billions of light years away from us. Do what we see through the telescope is the remote past, not today.

Citing to Santiago Arribas, a team member and a research professor at the Department of Astrophysics of the Center for Astrobiology in Madrid, Spain, reports say that all those quasars scientists are studying existed very early, when the universe was less than 800 million years old, or less than 6 percent of its current age. So those observations give us the opportunity to study galaxy evolution and supermassive black hole formation and evolution at these very early times.

The light from these very distant objects has been stretched so dramatically that it is shifted out into the infrared when it arrives to us. But the Webb is equipped with infrared-tuned instruments and it is uniquely suited to studying this kind of light.

The quasars the team are going to study are among the brightest as well as the most distant objects in the universe. These quasars have the highest black hole masses and also the highest accretion rates. The accretion rate means the rate at which material falls into the black holes.

Scientists say they are interested in observing the most luminous objects as the very high amount of energy that they’re generating down at their cores should lead to the largest impact on the host galaxy. They say that they want to observe those quasars at the moment when they’re having the largest impact on their host galaxies.

When matter is accreted by the supermassive black hole, as reported, an enormous amount of energy is released. That energy heats and pushes the surrounding gas outward, generating strong outflows that tear across interstellar space like a tsunami, wreaking havoc on the host galaxy.

According to the scientists, outflows play an important role in galaxy evolution. Gas fuels the formation of stars, so when gas is removed due to outflows, the star-formation rate decreases. In some cases, outflows are so powerful and expel such large amounts of gas that they can completely halt star formation within the host galaxy.

Moreover, they also think that outflows are the main mechanism by which gas, dust and elements are redistributed over large distances within the galaxy or can even be expelled into the space between galaxies. According to them, this may provoke fundamental changes in the properties of both the host galaxy and the intergalactic medium.

As neutral gas between galaxies made the universe opaque to some types of light, the view was much unclear when the universe was very young– more than 13 billion years ago. Later, in course of hundreds of millions of years, the neutral gas in the intergalactic medium became charged or ionized, making it transparent to ultraviolet light– the Era of Reionization.

To study to find the factor that led to the reionization that created the ‘clear’ conditions detected in much of the universe today is the priority of Webb. It will peer deep into space to gather more information about this major transition in the history of the universe. As mentioned by scientists, the observations will help us understand the Era of Reionization, which is supposed to be one of the key frontiers in astrophysics.

The team of scientists is said to use quasars as background light sources to study the gas between us and the quasar, using the technique called imaging spectroscopy. After determining whether the gas is neutral or ionized, scientists will learn how neutral the universe is and how much of this reionization process has occurred at that particular point in time.

As reported, the James Webb Telescope is an extremely sensitive telescope able to detect very low levels of light. This is important, because even though the quasars are intrinsically very bright, the ones this team is going to observe are among the most distant objects in the universe. The James Webb Space Telescope will be the world’s premier space science observatory when it launches in 2021. Scientists claim that Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it.

Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

Source: NASA

  • June 24, 2021
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Universe & Existence