The Milky Way is a pretty big one, but still fairly quiet.
The last word I would use to describe it is quiet. Even though it looks weird through a small telescope, you can see it in radio waves and X-rays.
The fifth-brightest galaxy in the sky can be seen from the southern hemisphere using just binoculars, because it is close to us. The huge black hole at its core is feeding gas and dust into its maw, which is what we call an active galaxy. The material forms a disk around the black hole that gets hot, and the magnetic fields near the center form two tornadoes. The material is launched away from the black hole at terrifyingly high speeds, forming a pair of jets in opposite directions.
The amount of material shot out is three times the mass of the Sun is ejected every year. 6 octillion tons is 6,000,000,000,000,000,000 tons of material per year. The mass of the Earth firing away every 30 seconds is what you prefer.
Holy sucks.
The mass is being accelerated to tens of thousands of kilometers per second, so the energy behind it all is immense. Our universe is quiet.
The jets start to slow and go into lobes, like a Q-tip. It can be hard to see the gas in the jets and lobes due to their large size. A team of astronomer used the new Murchison Widefield array in Australia to take a look at the universe.
The image covers 16 times the width of the Moon in the sky, from tip to tip. 1.6 million light years is equal to the distance from Cen A. The jets are foreshortened from perspective because they are aimed at an angle toward us.
It is a dot in the center of the image because the galaxy is 1/6th of a degree wide. The MWA observations allow details to be seen on a scale of a few thousand light years, so that the gas dynamics can be seen.
Right away you can see that the northern and southern parts are different. The visible light images show that it looks like an elliptical galaxy but it has a broad dust lane across it. If an elliptical collided with a dusty spiral, it would have an odd appearance. If the collision dumped a lot of gas to the north that would have impeded the flow of the northern jet and created all those interesting features there, the southern lobe would be intact and featureless.
The astronomer think they have found a very interesting process in the images. The gas in the jets is very hot, and slams into cold gas farther out, creating denser knots and heating it up enough to generate X-rays. The X-ray and radio emission is anti-coincident, so where one is bright the other is dark, because of the magnetic fields being compressed. Electrons spin around the field lines like beads on a wire.
Most of the gas in the jets is lost to space. A small fraction of it cools down, forms clouds, and then rains down onto the galaxy itself. They could return to the black hole in the center and help keep the process going. The model of how that works is complex, but it seems to describe what we see in Cen A.
It is one of the Universe's most powerful ironies that can draw material in at fantastic rates but also power some of the most energetic phenomena in the universe. Light can't escape if it gets too close to a black hole, but it can escape from farther out.
We can see quasars and blazars in the observable Universe, but there are no details about them. We get a chance to see it up close, in detail if needed, but also take a wide view and see what it does on a larger scale, with one in our back yard like this. We can get a more complete picture of how these objects behave, and that will lead to millions of other such galaxies spread throughout space.
If the black hole is spinning rapidly, the jets may be focused on it. It drags the fabric of spacetime around like a whirlpool, which can launch material away.
All Rights Reserved © 2024
