Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Space simulations show that the Webb telescope can detect distant galaxies hidden in quasar glare

Space simulations show that the Webb telescope can detect distant galaxies hidden in quasar glare

High Redshift Quasar and Companion Galaxy

This artist’s illustration depicts two galaxies that existed during the first billions of years of the universe. The larger galaxy on the left hosts a glowing quasar at its center, whose glow is driven by hot matter around a supermassive black hole. Scientists estimate that the resolution and infrared sensitivity of NASA’s upcoming James Webb Space Telescope will allow it to detect a dusty host galaxy like this one despite the quasar’s spotlight. Credit: J. Olmsted (STScI)

Web observations will search for dusty galaxies from the first billion years of the universe.

The brightest objects in the distant young universe are quasars. These space beacons are powered by supermassive black holes, consuming material at breakneck speed. Quasars are so bright that they can overshadow their entire host galaxy, making it difficult to study these galaxies and compare them to galaxies without quasars.

A new theoretical study examines how well NASAforthcoming James Web Space Telescope, scheduled to launch in 2021, will be able to separate the light of the host galaxies from the bright central quasar. Researchers have found that the Web can find host galaxies that existed only 1 billion years after the Big Bang.

This video enhances a highly detailed simulation of the universe called BlueTides. Like Powers of Ten’s iconic video, each step covers a distance 10 times less than the previous one. The first frame covers about 200 million light years, while the fourth and last frame covers only 200,000 light years and contains two galaxies. The researchers used this simulation to study the properties of galaxies that contain quasars, bright galactic nuclei driven by the growth of supermassive black holes. Credit: J. Ni (Carnegie Mellon University) and L. Hustak (STScI)

Quasars are the brightest objects in the universe and among the most energetic. They overshadow entire galaxies with billions of stars. Supermassive Black hole lies at the base of every quasar, but not every black hole is a quasar. Only black holes, which feed the most insatiably, can feed the quasar. The material falling into the supermassive black hole heats up and causes the quasar to glow in the universe like a lighthouse.

Although quasars are known to be located in the centers of galaxies, it is difficult to say what these galaxies are and how they compare to galaxies without quasars. The challenge is that quasar reflections make it difficult or impossible to emit light to the surrounding host galaxy. It’s like looking directly at the car’s headlight and trying to figure out what car it’s attached to.

New study[1] suggests that NASA’s James Webb Space Telescope, due to launch in 2021, will be able to detect the host galaxies of some distant quasars, despite their small size and blackout dust.

Simulated infrared images from Web and Hubble

These simulated images show how the quasar and its receiving galaxy will appear on the upcoming James Webb Space Telescope (top) and the Hubble Space Telescope (bottom) at infrared wavelengths of 1.5 and 1.6 microns, respectively. The larger Web mirror will provide more than four times the resolution, which will allow astronomers to separate the light of the galaxy from the irresistible light of the central quasar. The individual images cover about 2 arcseconds in the sky, which is a distance of 36,000 light-years with a redshift of 7. Credit: M. Marshall (University of Melbourne)

“We want to know in which galaxies these quasars live. This can help us answer questions like: How can black holes grow so big so fast? Is there a connection between the mass of the galaxy and the mass of the black hole we see in the nearby universe? “said lead author Madeleine Marshall of the University of Melbourne in Australia, who conducted her work at the ARC Center for Excellence in All Astrophysics in 3 dimensions.

The answer to these questions is challenging for a number of reasons. In particular, the farther a galaxy is, the more its light is stretched to longer wavelengths than the expansion of the universe. As a result, the ultraviolet light from the accretion disk of the black hole or the young stars of the galaxy shifts to infrared wavelengths.

In a recent study[2], astronomers used NASA’s close infrared capabilities Hubble Space Telescope to study famous quasars in the hope of noticing the surrounding brilliance of their host galaxies without significant discoveries. This suggests that dust in galaxies obscures the light of their stars. Webb’s infrared detectors will be able to peek through the dust and reveal hidden galaxies.

“Hubble just doesn’t go far enough in infrared light to see the host galaxies. The Web will really excel here, “said Roger Windhorst of Arizona State University in Tempe, co-author of the Hubble study.

To determine what Webb is expected to see, the team used a state-of-the-art computer simulation called BlueTides, developed by a team led by Tiziana Di Mateo of Carnegie Mellon University in Pittsburgh, Pennsylvania.

“BlueTides is designed to study the formation and evolution of galaxies and quasars during the first billions of years in the history of the universe. Its large space volume and high spatial resolution allow us to study these rare quasar hosts on a statistical basis, “said Yuain Ni of Carnegie Mellon University, who is leading the BlueTides simulation. BlueTides provides good agreement with current observations and allows astronomers to predict what the Web should see.

The team found that quasar-accepting galaxies are usually smaller than average, covering only about 1/30 of the diameter of Milky Way although it contains almost as much mass as our galaxy. “The host galaxies are surprisingly small compared to the average galaxy at this point in time,” Marshall said.

The galaxies in the simulation also tend to form stars quickly, up to 600 times faster than the current rate of star formation in the Milky Way. “We have found that these systems are evolving very fast. They are like premature children – they do everything early, “explained co-author Di Mateo.

The team then uses these simulations to determine what Web cameras will see if the observatory studies these remote systems. They found that distinguishing the host galaxy from the quasar would be possible, though still challenging due to the small size of the galaxy in the sky.

“The Web will find the opportunity to observe these very distant host galaxies for the first time,” Marshall said.

They also consider what Web spectrographs can derive from these systems. Spectral studies that separate the incoming light into its constituent colors or wavelengths will be able to reveal the chemical composition of the dust in these systems. Learning how heavy elements they contain can help astronomers understand their history of star formation, as most chemical elements are produced in stars.

The Web can also determine whether or not receiving galaxies are isolated. The Hubble study found that most quasars have detectable satellite galaxies, but cannot determine if those galaxies were actually nearby or were random superpositions. Web’s spectral capabilities will allow astronomers to measure the redshifts, and hence the distances, of these obvious satellite galaxies to determine if they are the same distance as the quasar.

Ultimately, Web observations should provide a new insight into these extreme systems. Astronomers are still struggling to figure out how a black hole can grow to weigh a billion times more than our Sun in just a billion years. “These big black holes shouldn’t have existed so early because there wasn’t enough time for them to become so massive,” said co-author Stuart White of the University of Melbourne.

Future studies of quasars will also be fueled by synergies between a number of upcoming observatories. Infrared research with the European Space Agency’s Euclid mission, as well as the Vera C. Rubin Earth Observatory, National Science Foundation / Department of Energy, is currently under construction for the Cerro Pachón in the Atacama Desert in Chile. Both observatories will significantly increase the number of known distant quasars. These newly discovered quasars will then be explored by Hubble and Webb to gain new insights into the formative years of the universe.


  1. “Host galaxies of z = 7 quasars: predictions from the BlueTides simulation” by Madeline A Marshall, Yueying Ni, Tiziana Di Matteo, J Stuart B Wyithe, Stephen Wilkins, Rupert AC Croft and Jussi K Kuusisto, October 5, 2020, Monthly notices of the Royal Astronomical Society.
    DOI: 10.1093 / mnras / staa2982
  2. “Limit ultraviolet emission in the dead frame of the 6 quasar hosts in far infrared light” by MA Marshall, M. Mechtley, RA Windhorst, SH Cohen, RA Jansen, L. Jiang, VR Jones, JSB Wyithe1, X. Fan, NP Hathi, K. Jahnke, WC Keel, AM Koekemoer, V. Marian, K. Ren, J. Robinson, HJA Röttgering, RE Ryan Jr., E. Scannapieco, DP Schneider, G. Schneider, BM Smith and H. Jan , August 27, 2020, The Astrophysical Journal.
    DOI: 10.3847 / 1538-4357 / abaa4c

The simulation of Bluetides (project PI: Tiziana Di Matteo from Carnegie Mellon University) was conducted at the Blue Waters Sustainable Petascals Computing Facility, which is supported by the National Science Foundation.

The James Web Space Telescope will be the world’s leading space observatory when it launches in 2021. The Web will unravel the mysteries of our solar system, look beyond distant worlds around other stars, and explore the mysterious structures and origins of our universe and our place. in him. Webb is an international program run by NASA with its partners ESA (European Space Agency) and the Canadian Space Agency.

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