Black holes, the all-consuming beasts of our universe, are poorly understood yet constantly fascinating objects. Every day’s a school day with these gargantuan gravitational monsters, and this week is no exception: NASA’s Jet Propulsion Laboratory (JPL) has announced the detection of a major flare that’s been seen escaping one, created by a previously unseen mechanism.
Something strange happened to the supermassive black hole Mrk 335 in the ancient past. 324 million years ago, a violent, energetic tremor shook this object in the Pegasus constellation, and only now the radiation from it has reached two of NASA’s detectors on Earth: the Nuclear Spectroscopic Telescope Array (NuSTAR), and Swift.
Ancient, supermassive black holes have features called accretion discs. As cosmic material falls into this orbiting ring of matter, the debris loses vast amounts of gravitational energy. This is then converted into thermal energy that is radiated back out into the universe as high-energy bursts.
In this regard, Mrk 335 has been a relatively calm object in the recent past. “Something very strange happened in 2007, when Mrk 335 faded by a factor of 30. What we have found is that it continues to erupt in flares but has not reached the brightness levels and stability seen before,” said Luigi Gallo, the principal investigator for the project at Saint Mary's University, in a statement.
In September 2014, however, Swift caught the first half of a huge flare; later, when NuSTAR was quickly programmed to look at the same corner of the night sky, it caught the second half of the outburst.
Supermassive black holes also tend to have another feature called a “corona,” a plasma cloud of highly energetic particles that generate X-rays, a type of radiation also detected during this recent flare. There are two possible formation mechanisms for the corona, known colloquially as the “lamppost” and “sandwich” models. In the former, the coronas are compact light sources sitting above and below the black hole; in the latter, the corona is spread out more diffusely, enveloping the accretion disc like slices of galactic bread.
Remarkably, Mrk 335’s new flare appears not to be generated by the accretion disc, but instead from the actual ejection of the corona, and the new data received by NASA’s two detectors seems to support the lamppost model.
“The corona gathered inward at first and then launched upwards like a jet,” said Dan Wilkins of Saint Mary’s University in Halifax, Canada, lead author of a new paper on the results appearing in the Monthly Notices of the Royal Astronomical Society, in a statement. The corona ejection was traveling at 20 percent of the speed of light; as it rushed towards us, its incredible speed began to warp its properties, brightening it in a relativistic effect called Doppler boosting.
“This is the first time we have been able to link the launching of the corona to a flare,” said Wilkins. The reason for the initial shifting of the corona, however, remains a mystery.
Image credit: The purple corona of this supermassive black hole gathered inwards before being violently ejected towards Earth. NASA/JPL-Caltech