Using NASA’s Chandra X-ray Observatory and NSF’s Karl G. Jansky Very Large Array (VLA), astronomers have found that H1821+643 — the nearest quasar hosted by a galaxy cluster, at a distance of about 3.4 billion light-years — is less influential than many giant black holes in other galaxy clusters.
Quasars are a rare and extreme class of supermassive black holes that are furiously pulling material inwards, producing intense radiation and sometimes powerful jets.
Known as H1821+643, this quasar is about 3.4 billion light-years from Earth and contains a 4-billion-solar-mass black hole.
Most growing supermassive black holes pull material in less quickly than those in quasars.
Astronomers have studied the impact of these more common black holes by observing ones in the centers of galaxy clusters.
Regular outbursts from such black holes prevent the huge amounts of superheated gas they are embedded in from cooling down, which limits how many stars form in their host galaxies and how much fuel gets funneled toward the black hole.
Much less is known about how much influence quasars in galaxy clusters have on their surroundings.
“We have found that the quasar in our study appears to have relinquished much of the control imposed by more slowly growing black holes. The black hole’s appetite is not matched by its influence,” said Dr. Helen Russell, an astronomer at the University of Nottingham.
To reach this conclusion, Dr. Russell and colleagues used Chandra to study the hot gas that H1821+643 and its host galaxy are shrouded in.
The bright X-rays from the quasar, however, made it difficult to study the weaker X-rays from the hot gas.
“We had to carefully remove the X-ray glare to reveal what the black hole’s influence is. We could then see that it’s actually having little effect on its surroundings,” said Dr. Paul Nulsen, an astronomer at the Harvard & Smithsonian’s Center for Astrophysics.
Using Chandra, the astronomers found that the density of…
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