Astronomers discover three merging supermassive black holes

Using telescopes on Mauna Kea in Hawaii, astronomers have discovered three different galaxies that have pairs of supermassive black holes at their center, with all three likely to merge at some point in the future.

First the scientists used the Subaru Telescope to survey more than 34,000 known quasars, high energy supermassive black holes.

The team identified 421 promising cases. However, there was still the chance many of these were not bona-fide dual quasars but rather chance projections such as starlight from our own galaxy. Confirmation required detailed analysis of the light from the candidates to search for definitive signs of two distinct quasars.

Using Keck Observatory’s Low Resolution Imaging Spectrometer (LRIS) and Gemini Observatory’s Near-Infrared Integral Field Spectrometer, Silverman and his team identified three dual quasars, two of which were previously unknown. Each object in the pair showed the signature of gas moving at thousands of kilometers per second under the influence of a supermassive black hole.

From this survey work they now tentatively estimate that only 0.3% of all known quasars are likely made up of a binary, which in turn gives them a rough estimate of how often galaxies with such supermassive black holes collide and merge. This in turn helps them develop theories on galaxy formation.

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.

Combined Earth-Space radio array discovers superhot quasar interior

The uncertainty of science: Data obtained by combining four ground-based radio telescopes with the Russian orbiting RadioAstron 10-meter radio telescope have detected temperatures of 10 trillion degrees in the quasar 3C 273, a hundred times hotter than predicted possible by theory.

Supermassive black holes, containing millions to billions times the mass of our Sun, reside at the centers of all massive galaxies. These black holes can drive powerful jets that emit prodigiously, often outshining all the stars in their host galaxies. But there is a limit to how bright these jets can be – when electrons get hotter than about 100 billion degrees, they interact with their own emission to produce X-rays and Gamma-rays and quickly cool down.

Astronomers have just reported a startling violation of this long-standing theoretical limit in the quasar 3C 273. “We measure the effective temperature of the quasar core to be hotter than 10 trillion degrees!” comments Yuri Kovalev (Astro Space Center, Lebedev Physical Institute, Moscow, Russia), the RadioAstron project scientist. “This result is very challenging to explain with our current understanding of how relativistic jets of quasars radiate.”

In addition, the higher resolution of the radio images produced by this space/ground-based array was good enough to see the effect produced by the structure of the interstellar material between here and the quasar.

A quasar shuts down

Astronomers have identified the first quasar to change its energy output.

Quasars are massive, luminous objects that draw their energy from black holes. Until now, scientists have been unable to study both the bright and dim phases of a quasar in a single source. As described in an upcoming edition of the Astrophysical Journal, Yale-led researchers spotted a quasar that had dimmed by a factor of six or seven, compared with observations from a few years earlier.

It is also believed that quasars are the central supermassive black holes at the center of these very distant and ancient galaxies. Knowing how these black holes change can tell us something about the behavior of Sagittarius A*, the generally quiet central black hole in the Milky Way.

Two newly discovered supermassive black holes weigh in as the heaviest known

Two newly discovered supermassive black holes weigh in as the heaviest known.

One of the newly discovered black holes is 9.7 billion solar masses and is located in the elliptical galaxy NGC 3842, which is the brightest galaxy in the Leo cluster of galaxies that sits 320 million light years away in the direction of the constellation Leo. The second is as large or larger and sits in the elliptical galaxy NGC 4889, which is the brightest galaxy in the Coma cluster about 336 million light years from Earth in the direction of the constellation Coma Berenices.

It is believed that these heavy supermassive black holes are the kind that produced quasars in the early universe.

The most distant quasar ever found

Astronomers have found the most distant quasar ever, and are baffled by its existence.

The light from the quasar started its journey toward us when the universe was only 6% of its present age, a mere 770 million years after the Big Bang, at a redshift of about 7.1 [3]. “This gives astronomers a headache,” says lead author Daniel Mortlock, from Imperial College London. “It’s difficult to understand how a black hole a billion times more massive than the Sun can have grown so early in the history of the universe. It’s like rolling a snowball down the hill and suddenly you find that it’s 20 feet across!”