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Astronomers solve the mystery of small galaxies with Monster Black Holes



Paul M. Sutter is astrophysicist at Ohio State University host of Ask a Spaceman and Space Radio and author of [19659003] Dein Place in the universe . Sutter contributed this article to Space.com's Expert Voices: Op-Ed & Insights .

Almost every galaxy in our universe seems to have a huge black hole at its center, including our own Milky Way galaxy. The event Horizon Telescope has recently taken a picture of the one in the Jungfrau Galaxy at a distance of 55 million light-years. That's nice. And as soon as you get over this surprising fact, another one appears. There is a very strange relationship between the mass of the black hole in the center of a galaxy and the properties of the galactic host. For example, the bigger the galaxy is, the larger the black hole. However, there are some strange exceptions to this general trend, and astronomers studying these weirdnesses can uncover a crucial link between the development of black holes and galaxies.

Related: Images: Black Holes of the Universe

A Dark Beginning

If you're wondering which ones have come first, the galaxy or its Black Hole is the answer: We do not know it. At some point in the distant past ̵

1; about 13.5 billion years ago, when the stars formed for the first time – galaxies and huge black holes seemed to have formed relatively at the same time. However, whether huge black holes began to germinate in still young galaxies or galaxies fused around small black holes, a close personal relationship was established very quickly.

Astronomers believe that there is regular communication and interaction between giant black holes and their galaxies . The bigger the galaxy is, the more material there is and the more material there is, the more fuel there is to feed the ever-gaping gullet of the huge black hole. But when they eat black holes, they become active. Gas swirls around with intense energies as it falls into the event horizon. Part of this gas heats up and emits powerful rays that escape from the environment. In other cases, the gas may spin around the outside edges of the black hole without collapsing, forming long rays that extend thousands of light-years into the surrounding medium.

As you can imagine, a lot of energy is poured into the neighborhood of the black hole. This energy heats the surrounding gas and the now-hot gas barely tends to sink into the middle where it could risk encountering the black hole. If the gas stays safely away, the black hole can not eat and thus stabilizes in size.

However, if the galaxy gets bigger, it can push more gas in the middle, overwhelming all concerns, and give the black hole a new meal properly accompanied by a new feedback episode, the continued growth of the black hole prevented from getting out of hand.

As galaxies grow, their black holes grow gradually. Small galaxies have small black holes, and large galaxies have large black holes.

Except for those who do not.

Related: Black Hole Quiz: How well do you know the strangest nature? Creations?

Secrets of the Blue Nuggets

Some galaxies harbor extremely large black holes, far beyond the trends set by their brothers. How did these black holes get so big if the galaxies they house did not really have enough material to make them that way?

The answer could, according to a recent study stem from a particular type of galaxy known as a blue nugget. That's right, blue nugget. It's a kind of galaxy, and I do not invent that name.

Blue nugget galaxies are only very far away, which means that they were a feature of the much younger universe and have not drifted around to this day. Blue nuggets are, as the name implies, blue and small. They are relatively small galaxies with an exceptionally high star formation rate. Forming like crazy stars, these galaxies tend to make more large, light blue stars than the average and give them the color of their namesake, fed by nearby gas streams that pump material into the undersized galaxy and increase its star formation rate.

Feed the Machine

But this inflow of raw material comes at such an early age cost. With all the activity forming in the center of a massive black hole, far larger than expected from such a young galaxy. And this devouring black hole breaks out all over the blue nugget galaxy, blocking further star formation. Since the galaxy is so small, this feedback affects not only the nucleus, but the whole, and stops the growth of this galaxy too young.

The population of stars that was born early makes it so The nugget is beautiful and blue and eventually dies. It leaves only old, small, dark red stars with very little new activity and transforms this galaxy into what is affectionately known as a red nugget. And because of this early activity, it has an exceptionally large central black hole.

Could this really be the story behind these weird galaxies and their big black holes? We have only a handful of examples of such extreme cases, so without further data it is difficult to draw firm conclusions. And yet, this story is convincing and could give an indication of the current story between the black holes in their galaxies.

You can download the study "Supermassive Black Hole Demographics: Evading M – σ" for free on the online preprint site arXiv .

You can listen to the Ask A Spaceman podcast in iTunes and on the Internet at http://www.askaspaceman.com . Post your own question on Twitter with #AskASpaceman or by following Paul @PaulMattSutter and facebook.com/PaulMattSutter . Follow us on Twitter @Spacedotcom or Facebook .


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