Large Bipolar radio bubbles in the Galactic Centre

[Buzz Bloom]

TL;DR

Inflation of 430-parsec bipolar radio bubbles in the
Galactic Centre by an energetic event

From Nature: volume 573, pages235–237 (2019)
https://www.nature.com/articles/s41586-019-1532-5

I confess that I am unable to understand the technical presentation in this article. I am hoping that someone at PF will be able to respond with a simplified summary about what this article is describing.

Quote from Abstract
The Galactic Centre contains a supermassive black hole with a mass of four million Suns within an environment that differs markedly from that of the Galactic disk. Although the black hole is essentially quiescent in the broader context of active galactic nuclei, X-ray observations have provided evidence for energetic outbursts from its surroundings. Also, although the levels of star formation in the Galactic Centre have been approximately constant over the past few hundred million years, there is evidence of increased short-duration bursts, strongly influenced by the interaction of the black hole with the enhanced gas density present within the ring-like central molecular zone at Galactic longitude |l| < 0.7 degrees and latitude |b| < 0.2 degrees.
. . .
We postulate that the progenitor event was a major contributor to the increased cosmic-ray density in the Galactic Centre, and is in turn the principal source of the relativistic particles required to power the synchrotron emission of the radio filaments within and in the vicinity of the bubble cavities.

 

[stefan r]

The main article is behind a pay wall. Here is one on Archive.

My impression from the abstract is that the authors deliberately avoided specifying what happened. They are reporting that the time is several million years ago. The magnitude of the explosion is 10⁴⁶ Joules. They just want to report on the size and shape of the bubble. The bubble is about the same size in both directions and the radio and x-ray bubble shapes match. From that they conclude that it was created by a single event.

We can contemplate various scenarios. Suppose Wily Coyote sets a trap for road runner at the galactic center. If he uses sticks of TnT he needs a billion solar masses. A rock fall trap is more promising since the rocks can fall into the black hole and road runner is likely to use the black hole for gravity assist. If 11% of the rest mass of the rock is converted to energy then Coyote needs a 10³⁰ kg (1 solar mass) rock. If Coyote used antimatter he would have needed to use 50 Jupiter masses of it.

There is a cluster near the galactic center that could have formed 7 million years ago.