May 30th: Chasing a Runaway Black Hole

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Podcaster: Richard Drumm
Title:
Space Scoop: Chasing a Runaway Black Hole

Organization:365 Days Of Astronomy

Link : astrosphere.org ; http://unawe.org/kids/unawe1711/

Description: Space scoop, news for children

A new member joining the dwarf planet family very soon – an object called 2014 UZ 224 and nicknamed ‘DeeDee’, short for Distant Dwarf.

Each week we will have a random drawing for a prize package from our sponsor. Enter the code for this week into this site: https://cosmoquest.org/achievements/code for a chance to win.

This week’s code is 0F7Brm. Enter it into the website to unlock the achievement and enter the contest.

Bio: Richard Drumm is President of the Charlottesville Astronomical Society and President of 3D – Drumm Digital Design, a video production company with clients such as Kodak, Xerox and GlaxoSmithKline Pharmaceuticals. He was an observer with the UVa Parallax Program at McCormick Observatory in 1981 & 1982. He has found that his greatest passion in life is public outreach astronomy and he pursues it at every opportunity.

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Transcript:
This is the 365 Days of Astronomy Podcast. Today we bring you a new episode in our Space Scoop series. This show is produced in collaboration with Universe Awareness, a program that strives to inspire every child with our wonderful cosmos.

Chasing a Runaway Black Hole

What’s invisible, 160 million times more massive than the Sun, and on the move?

A newly discovered runaway supermassive black hole!
Supermassive black holes are just what their name suggests: really, really massive black holes.

They can grow up to billions of times more massive than the Sun, possess immense power and have extreme eating habits. They’ll devour stars, rocky planets, even light — nothing is off the menu.

While smaller black holes can be caught wandering between the stars, supermassive black holes are normally only found at the very center of galaxies.

Which is why a team astronomers conducted a systematic search to spot a supermassive black hole moving away from the center of its galaxy.

When I read the scientific paper that the team produced, I was pleasantly surprised to find that I knew 3 of the members. My friends Dr. George Privon, Dr. Aaron Evans and the fabulous Dr. Sabrina Stierwalt all contributed to the team effort.

In addition to other observatories, the astronomers used the space-based Chandra X-Ray Observatory’s Advanced CCD Imaging Spectrometer or AICS instrument.

They gathered the data on the elliptical galaxy & its SMBH, together called
CXO J101 527.2+625 911.

It’s located in the direction of the familiar northern constellation Ursa major, the Big Bear, which is also called the Big Dipper.

Following a trail of clues, the astronomers may have figured out what caused this unusual behavior. The galaxy containing this black hole was involved in a collision with another galaxy, millions of years ago.

The two galaxies eventually calmed down & merged together to form one enormous elliptical galaxy, both bringing with them their own supermassive black hole or SMBH. The pretty spiral shapes were unfortunately lost in the chaos of the galaxy merger.

But the combined galaxy couldn’t host two black holes. The immense gravity of these objects pulled them towards each other, closer and closer, until they eventually crashed and merged into one.

This violent collision then sent gravitational waves – warps in spacetime – crashing through the Universe.

Now, I just said ‘Gravitational waves’. The term ‘gravity waves’ has already been taken by the field of fluid dynamics. An example of a gravity wave is the ocean waves you see at any beach. So we now have to say gravitational wave when we’re talking about the spacetime event.

Anyway…
If these waves are emitted more strongly in one direction than another, the combined black hole would have been sent in that opposite direction, an effect called “recoil” that was first hypothesized by Dr. Asher Peres in 1962.

We see the same thing when a rocket launches. Exhaust gases coming out of the engine nozzle at high speed push towards the Earth and propel the rocket in the opposite direction, towards the sky. For every action there’s an equal and opposite reaction, don’t you know.

This would have given the newly formed black hole such a large kick that it would have pushed it out from the galaxy’s center! This is exactly what the team of astronomers found when they looked at the Chandra and Hubble data.

Data from the Keck telescopes in Hawaii and the Sloan Digital Sky Survey, called SDSS, also helped confirm the conclusion.

There were 2 bright spots in the center of the galaxy. The exact center was the crowded zone of stars that typically reside in galaxy cores. This is the geometric centroid of the galaxy.

The other bright spot was the SMBH. It was 3,000 light years out of place. It’s offset to the north relative to the nucleus of the galaxy.

This bright spot was also an emitter of X-rays, which is what SMBHs do. The SMBH also is moving differently from the galactic center, which also supports the recoil theory.

The velocity of the SMBH here is only about 10% of escape velocity, so it’s not going anywhere. It is probably oscillating back & forth through the galaxy core. The oscillations are likely being gravitationally dampened and will eventually cease.

If the conditions had been just right, with the masses large enough and spin axes aligned just so, in what the team of astronomers called the “superkick configuration”, the SMBH would have been ejected from the galaxy altogether!

Hey, Here’s A Cool Fact:
Our Solar System lies 25,000 light years from the core of our Galaxy and our supermassive black hole, called Sagittarius A*. The core of our galaxy is in the direction of the constellation Sagittarius, and is visible in the summertime. The brighter stars have a pattern that resembles a teapot!

Bertrand Russell would be amused, knowing that Russell’s teapot was real after all!

Thank you for listening to the 365 Days of Astronomy Podcast!

End of podcast:

365 Days of Astronomy
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The 365 Days of Astronomy Podcast is produced by Astrosphere New Media. Audio post-production by Richard Drumm. Bandwidth donated by libsyn.com and wizzard media. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org.  This year we will celebrate more discoveries and stories from the universe. Join us and share your story. Until tomorrow! Goodbye!

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