An international team of astronomers has managed an incredible feat. They have peered into the very heart of a quasar and discovered temperatures much higher than physicists thought were possible for this kind of object.
The analysis, published in the Astrophysical Journal Letters, takes full advantage of a radio astronomy trick. By looking at the same object with two different and distant telescopes, you can combine the data and produce an image with a much higher resolution.
The researchers used the Russian radio space telescope, RadioAstron, which orbits almost as far as the Moon and combined it with the Arecibo telescope in Puerto Rico, as well as other telescopes in Germany, the continental US, and Mexico to construct a virtual telescope 170,000 kilometers (106,000 miles) across.
This allowed them to look at the incredibly bright quasar 3C 273 and the supermassive black hole that is powering it. The telescopes were able to observe a region that is 2.7 light-months across, which, since the galaxy is 2.4 billion light-years from Earth, is equivalent to seeing a golf ball on the Moon.
The observations themselves are impressive but what the astronomers found is even more spectacular. Based on the brightness, the object must have a temperature of 40 trillion Kelvin (72 Trillion °F). According to present theories, the maximum allowed temperature from a quasar emission should be 1 trillion kelvin.
"Temperatures this high test our understanding of the physics in the vicinity of supermassive black hole at the heart of 3C 273," said Dr. Tapasi Ghosh, the Very-long-baseline Interferometry (VLBI) staff astronomer at the Arecibo Observatory, in a statement. "We hope that Arecibo-RadioAstron observations of other sources will help shed light on this mystery."
The supermassive black holes at the center of quasars are surrounded by a bounty of material being pulled apart by the intense gravity of the region. But it’s not just gravity. Black holes have enormous magnetic fields that accelerate charged particles, which end up emitting what we call synchrotron radiation.
This idea is crucial to our understanding of quasars but 3C 273 is suggesting that it might not deliver a complete picture of what these cosmic monster can do.
"We conclude that it is difficult to interpret the data in terms of conventional incoherent synchrotron radiation," added lead author Dr. Yuri Kovalev of the Lebedev Physical Institute in Moscow.