Quasars that shut off
The uncertainty of science: Astronomers have discovered a class of quasars that suddenly turn off, something that no theory had predicted possible.
LaMassa, an astronomer now at the Space Telescope Science Institute, was mystified. Until that moment in 2014, she, like so many others, had expected quasars to be relatively stagnant. “Then you see these drastic changes within a human lifetime, and it’s pretty cool,” she said.
Confusion turned into excitement, and a hunt began to find more of these oddities. Although less luminous examples had already been seen, astronomers wanted to know if changes as dramatic as the one LaMassa discovered were common. It was no straightforward task, given that surveys tend not to go back and look at objects they have previously observed. But astronomers searched through archived data and discovered 50 to 100 more of what became known as “changing-look quasars.” Some of these have dimmed substantially more than LaMassa’s first example. Others have transitioned in the space of a month or two. And others, after disappearing, have reappeared again.
“It’s clear that the reason we weren’t finding these objects before is that we weren’t looking for them,” said Eric Morganson, an astronomer at the University of Illinois.
The article does a fine job of explaining the whole problem, including outlining the theories now being posited to explain these events. Bottom line: the universe is always more complicated that expected by initial observations.
The uncertainty of science: Astronomers have discovered a class of quasars that suddenly turn off, something that no theory had predicted possible.
LaMassa, an astronomer now at the Space Telescope Science Institute, was mystified. Until that moment in 2014, she, like so many others, had expected quasars to be relatively stagnant. “Then you see these drastic changes within a human lifetime, and it’s pretty cool,” she said.
Confusion turned into excitement, and a hunt began to find more of these oddities. Although less luminous examples had already been seen, astronomers wanted to know if changes as dramatic as the one LaMassa discovered were common. It was no straightforward task, given that surveys tend not to go back and look at objects they have previously observed. But astronomers searched through archived data and discovered 50 to 100 more of what became known as “changing-look quasars.” Some of these have dimmed substantially more than LaMassa’s first example. Others have transitioned in the space of a month or two. And others, after disappearing, have reappeared again.
“It’s clear that the reason we weren’t finding these objects before is that we weren’t looking for them,” said Eric Morganson, an astronomer at the University of Illinois.
The article does a fine job of explaining the whole problem, including outlining the theories now being posited to explain these events. Bottom line: the universe is always more complicated that expected by initial observations.