Over the last three decades, the Hubble Space Telescope has revealed some of the most enigmatic secrets of the universe—be it spiral galaxies located millions of light-years away from earth or portraits of Jupiter’s storms. But come October 2021, the mantle of discovering galactic secrets will be passed on to the James Webb Space Telescope.
And, as a new study suggests, the James Webb Space Telescope will be able to reveal the host galaxies of some distant quasars despite their small size and obscuring dust. Quasars are some of the brightest objects in the universe. According to an official Nasa statement, they are bright enough to outshine entire galaxies made up of billions of stars. “A supermassive black hole lies at the heart of every quasar, but not every black hole is a quasar,” the statement explains. “Only the black holes that are feeding most voraciously can power a quasar. Material falling into the supermassive black hole heats up and causes a quasar to shine across the universe like a lighthouse beacon.”
Computer simulations led by Madeline Marshall, a PhD candidate at the University of Melbourne in Australia, showed that while Hubble can't see galaxies currently hidden by these quasars, the James Webb Telescope will be able to get past the glare. For a recent study, published in The Astrophysical Journal in August, Marshall collaborated with researchers from the US, China, Germany and the Netherlands. They used the near-infrared capabilities of the Hubble to study known quasars in hopes of spotting the surrounding glow of their host galaxies. “Hubble simply doesn’t go far enough into the infrared to see the host galaxies. This is where Webb will really excel,” Rogier Windhorst of the Arizona State University in Tempe, a co-author on the Hubble study, was quoted as saying in the Nasa statement.
For the second part of the research, Marshall and rest of the team used a state-of-the-art computer simulation—called BlueTides—to determine whether Webb's cameras would be able to spot these distant systems. BlueTides is developed by a team led by Tiziana Di Matteo at Carnegie Mellon University in Pittsburgh, Pennsylvania. “BlueTides is designed to study the formation and evolution of galaxies and quasars in the first billion years of the universe's history,” said Yueying Ni of Carnegie Mellon University, who ran the simulation. They found that distinguishing the host galaxy from the quasar would be possible, although still challenging due to the galaxy’s small size on the sky. The findings of this study were published in the Monthly Notices of the Royal Astronomical Society earlier this month.
Ultimately, Webb’s observations should provide new insights into these extreme systems, the Nasa statement explains. Further studies on quasars are expected in the near future through collaborations between some upcoming observatories, the statement adds. Infrared surveys with the European Space Agency’s Euclid mission as well as the ground-based Vera C. Rubin Observatory, which is currently under construction in Chile, could significantly increase the number of known quasars in the universe. These newfound quasars would then be examined by Hubble and Webb to get new insights of the universe’s formative years.
FIRST PUBLISHED17.10.2020 | 07:30 PM IST