Analysis of the galaxy ESO 243-49 in multiple wavelengths has detected the signature of hot stars swirling around a midsize black hole, highlighted by the white circle on this Hubble Space Telescope image. Astronomers say the readings suggest that the black hole is actually part of the leftovers from a dwarf galaxy that crashed into the bigger galaxy and disintegrated.

Astronomers have reconstructed what they think is a galactic crash scene, with a rare breed of black hole left behind amid a dwarf galaxy's wreckage. The Hubble Space Telescope played a key role in the accident investigation.

The black hole was detected three years ago in the edge-on spiral galaxy ESO 243-49, about 290 million light-years from Earth, and raised a question that's been bugging astronomers ever since.

The theoretical scenario for creating black holes through the collapse of stars is well-known. But scientists are just beginning to figure out how galaxy formation can lead to the creation of supermassive black holes that are millions or billions of times heavier than the sun. This particular black hole, designated HLX-1, was even more of a puzzler: It's about 20,000 times as massive as our sun, a kind of midsize monster that's rarely seen in our celestial neighborhood.

The astronomer who led the HLX-1 search effort, Sean Farrell of the University of Leicester and the Sydney Institute for Astronomy, took a closer look at the black hole with the aid of imagery in ultraviolet, visible and infrared wavelengths from Hubble, as well as X-ray imagery from NASA's Swift satellite. Now he and his colleagues are suggesting that the midsize black hole is a leftover from a dwarf galaxy's unfortunate encounter with the much bigger galaxy less than 200 million years earlier.

They came to that conclusion based on observations of light toward the reddish side of the spectrum — so much red light that it can't be explained just by the blaze of material falling into the black hole. Farrell and his colleagues think the light is coming from a cluster of hot stars surrounding the black hole.

"The fact that there’s a very young cluster of stars indicates that the intermediate-mass black hole may have originated as the central black hole in a very low-mass dwarf galaxy," Farrell said in a news release from the European Space Agency's Hubble team. "The dwarf galaxy was then swallowed by the more massive galaxy."

As the dwarf galaxy was ripped apart, the black hole and some of its surrounding material would have survived.

The researchers say it's not yet clear what will happen to the black hole. It might spiral into the center of ESO 243-49, merging with the supermassive black hole that's already there. Or it might settle into a stable orbit in the bigger galaxy's outer environs. Either way, the X-ray emissions that brought the black hole to light in the first place will eventually fade away.

The findings from Farrell and his colleagues were published today by The Astrophysical Journal, and the team will continue watching HLX-1 for more clues.

Looking beyond just one intermediate-mass black hole, the astronomers say the case of HLX-1 sheds light on the bigger mysteries surrounding the formation of those supermassive, galaxy-scale black holes. Most theorists surmise that big galaxies — and the big black holes at their centers — are built up gradually through the merger of smaller galaxies. This research supports that view.

Our own Milky Way galaxy might well go through the next phase of the merger process in a few billion years, when it's due to mix it up with Andromeda and create a bigger behemoth nicknamed "Milkomeda."

More about galaxy mergers:

• Twisted galaxy warped by 'stealth merger'
• Almost every galaxy has had a major collision
• Galactic merger could boot our solar system
• NASA spots most crowded space collision ever
• Black hole knocked off its axis by galaxy collision
• Cosmic Log archive on galaxies | black holes

In addition to Farrell, authors of "A Young Stellar Population Around the Intermediate Mass Black Hole ESO 243-49 HLX-1" include M. Servillat, J. Pforr, T.J. Maccarone, C. Knigge, O. Godet, C. Maraston, N.A. Webb, D. Barret, A. Gosling, R. Belmont and K. Wiersema.

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

Paris Observatory

Computer simulations show how the Andromeda Galaxy and Magellanic Clouds formed from the collision of two massive galaxies in the Local Group 6 billion years ago.

The Andromeda Galaxy and the Magellanic Clouds -- the Milky Way's most prominent galactic neighbors –- took on their current shape because of a huge collision between two galaxies billions of years ago, according to new numerical simulations.

Our celestial neighborhood, known as the Local Group includes nearly 40 galaxies in all. But it's dominated by two giant spiral galaxies: Andromeda and our own Milky Way. Researchers have long thought that Andromeda -- which is 2.5 million light-years away in the constellation of the same name -- formed from a mash-up of two galaxies of smaller mass. To get at the details surrounding the galactic merger and its consequences, a team of astronomers led by the Paris Observatory's Francois Hammer modeled the galaxy's structural evolution.

The team was able to reproduce most of the Andromeda Galaxy's peculiar properties, such as its large, thin disk and massive central bulge. That lent confidence to an analysis indicating that the two galaxies – one slightly more massive than our Milky Way and the other a third as massive –- started to merge about 9 billion years ago. The mash-up was complete about 3.5 billion years later.

The researchers noted in a news release that the collision must have been particularly violent to generate the rotation required to form the Andromeda Galaxy's giant disk.

The simulations also predict that an amount of mass equivalent to one-third that of the Milky Way could have been expelled during the interaction through the formation of gigantic tidal tails –- thin, elongated regions of stars and interstellar gas. The gas within one of these tails may have formed the Magellanic Clouds, which today are satellite galaxies attached to the Milky Way.

The implication is that the Large and Small Magellanic Clouds were actually space invaders from the galaxy next door, coming at us at a velocity of 620,000 mph (1 million kilometers per hour).

"If confirmed, these results may have important consequences in cosmology, by supporting both the hypothesis that most spiral galaxies have been formed by mergers, and the prediction that many dwarf galaxies may originate from tidal tails during such events," researchers said in the news release.

The team's results are being reported in two research papers, published by The Astrophysical Journal and Astrophysical Journal Letters.

More information on Andromeda and the Magellanic Clouds:

• Milky Way, Andromeda had similar origins
• Andromeda is a cannibal and heading our way
• Collision caused rings around Andromeda
• New Hubble photos show galaxy collisions
• Milky Way clouds are speeding through space
• Galactic neighbors are just passing through

"Does M31 Result From an Ancient Major Merger?" is being published in the Dec. 10 issue of The Astrophysical Journal, with Hammer as well as Y.B. Yang, J.L. Wang, M. Puech, H. Flores and S. Fouquet listed as authors. Yang and Hammer are the authors of "Could the Magellanic Clouds Be Tidal Dwarves Expelled From a Past-Merger Event Occurring in Andromeda?" -- which was published Nov. 20 in Astrophysical Journal Letters. Yang and Wang represent the National Astronomical Observatories of the Chinese Academy of Sciences, and the other researchers are from the Paris Observatory.

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

L. Calcada / ESO

An artist's impression shows the young galaxy UDFy-38135539 gathering up the hydrogen and helium gas surrounding it and forming many young stars. Astronomers have determined that UDFy-38135539 is the most distant known galaxy.

Astronomers have confirmed that an incredibly faint galaxy in the constellation Fornax is the most distant known object in the universe, shining more than 13 billion light-years away and reflecting an era when stars were just beginning to emerge from a cosmic fog.

The galaxy, known as UDFy-38135539, is one of several super-distant objects picked out from the Hubble Ultra Deep Field, the most sensitive snapshot ever taken of deep space. In time, astronomers may well spot objects that are even farther away, but this particular galaxy was the first of its type to go through the arduous process of having its measurements checked.

In fact, the astronomers behind the observations say they couldn't have seen UDFy-38135539 unless there were other, fainter galaxies nearby to help clear out the space around it. "Without this additional help, the light from the galaxy, no matter how brilliant, would have been trapped in the surrounding hydrogen fog, and we would not have been able to detect it," Durham University's Mark Swinbank said in a news release from the European Southern Observatory.

The ESO researchers, led by Matt Lehnert of the Observatoire de Paris, published their findings in this week's issue of the journal Nature. Those findings shed unprecedented light (so to speak) on a mysterious period in the development of the universe, about 600 million years after its big-bang origin, when the radiation of the first stars began clearing out the neutral hydrogen that filled the infant universe. That process, known as reionization, transformed the cosmos from an opaque haze to the mostly empty space we know today.

"Measuring the redshift of the most distant galaxy so far is very exciting in itself, but the astrophysical implications of this detection are even more important," Nicole Nesvadba of France's Institute d'Astrophysique Spatiale said. "This is the first time we know for sure that we are looking at one of the galaxies that cleared out the fog which had filled the very early universe."

Further observations are likely to flesh out the scientific story of how the universe emerged from its dark ages.

G. Illingworth / UCO-Lick and UCSC / NASA / ESA / HUDF09

The Hubble Ultra Deep Field shows several candidates for breaking observational distance records, but confirming those distances is difficult. The inset picture highlights the galaxy UDFy-38135539, which is the farthest observed object to have its distance confirmed.

How the measurement was done
The story of UDFy-38135539 begins with last year's release of the latest Hubble Ultra Deep Field imagery, captured using the Hubble Space Telescope's brand-new Wide Field Camera 3. Astronomers checked the spectral signatures of thousands of faint objects in the picture, looking for the telltale signs of extreme redshift -- that is, a shift in the spectrum that is linked to how far away an object is in our expanding universe.

The ESO astronomers found several galaxies that had their light shifted so far to the red side of the spectrum that they knew those galaxies had to be incredibly distant. Numerically speaking, their redshift had to be greater than 8. But how much greater?

To figure out the precise redshift number, the astronomers booked 16 hours of time on the ESO's Very Large Telescope in Chile, which is equipped with an ultra-sensitive infrared spectroscopic instrument called SINFONI. After weeks of data analysis, the team ran the numbers and came up with a redshift of 8.55. That meant the galaxy was farther away than the most distant previously known galaxy (redshift 6.96) as well as the most distant previously known object (a gamma-ray burst at redshift 8.2).

That redshift means the light left the galaxy when the 600-million-year-old universe was in its era of reionization. But based on the models for the development of galaxies, UDFy-38135539 would not have had enough power at that time to clear out enough empty space for the light to shine through as it did. That's why scientists suspect that other, undetected galaxies were helping to clear out the bubble of space.

In a Nature commentary, Michele Trenti, an astronomer at the University of Colorado's Center for Astrophysics and Space Astronomy, hailed the results as "a fundamental leap forward in observational cosmology." He noted that there was "robust statistical confidence" that the team's interpretation was correct, with only a 0.1 percent chance that the interpretation of the galaxy's spectrum was incorrect.

Trenti said the study "opens up exciting proects for spectroscopy of high-redshift objects" -- not only using the data currently at hand, but also drawing upon future studies to be conducted by Hubble and its successor, the James Webb Space Telescope, as well as the European Extremely Large Telescope.

Q&A with the research team's leader
The leader of the research team, Matt Lehnert of the Observatoire de Paris, answered a couple of my follow-up questions in an e-mail exchange:

Cosmic Log: Could you explain why this observation is so difficult? Of course the faintness of the galaxy is one of the big issues, but I understand that the high redshift is another big issue.

Matt Lehnert: You are correct, it is not only the faintness.  It becomes increasingly difficult because the night sky becomes brighter (which causes more background noise), contains a plethora of emission lines caused mainly by OH molecules in the upper atmosphere of the earth, and light is increasingly absorbed due to many molecules and other complex interactions. We cannot overcome all of these problems. Light lost is light lost.  Having a very efficient spectrograph helps. 

SINFONI is certainly that.  Perhaps the best currently available. You also have to have good data reduction software.  It's not very romantic, but removing those night sky lines is tricky -- they are strong, much, much stronger than the signal, and they vary with time.  Because they are bright, they add lots of noise, but much of that "additional" noise is due to improper removal.  My colleague, Nicole Nesvadba, has literally developed an excellent set of tools for extracting the most out of these data.

Q: Could you please also talk about the significance of the conclusions you reached on the galaxy's place in the epoch of reionization. I understand that the luminosity from the galaxy alone wouldn't have been enough to allow the redshifted photons to escape, and that the assumption is that there were surrounding smaller galaxies that aided in "carving" out a suitable bubble of ionized hydrogen gas. Does this fit with the existing models for galaxy formation during that epoch, or does it rule out any models that theorists have come up with? What do scientists hope to gain by learning more about the reionization epoch?

A: Well ... I always believe that models should be tested with results!  Astronomy is still an empirical science and so much of what we model is based on observational results.

The underlying physics is very complicated.  For example, we really do not have a robust picture of how individual stars form.  As you might imagine, since galaxies are made up of stars, and are to some extent defined by these stars, it is difficult to understand how galaxies form without this essential understanding of how stars form.  Having said all of that, our current models do in fact predict that reionization was mostly due to numerous faint objects and that the first places to be reionized were the ones that had higher densities of objects.  Was it a surprise for me? Yes. Was it a surprise for all astronomers? No way!

What we hope to learn is, what types of galaxies were really responsible and in fact, were only galaxies responsible? There are other ideas, mini-quasars -- small black holes that accrete matter and contribute, to decaying particles, to several other [ideas that have been] at least proposed if not all that plausible.

We would like to know how reionization proceeded. Was it in fits and starts? Did it start in regions of the highest densities and then proceed to the lowest?  How long did it take?  How did this gas cool to form the first galaxies, and how did galaxy formation change because the universe was reionized?

These first galaxies literally changed the state of the universe.  It was most neutral -- composed mainly of hydrogen and helium atoms -- to mostly ionized between galaxies -- composed mostly of protons, electrons, and helium nuclei (although helium re-ionization came later at lower redshifts).

It is a great challenge to understand how did these humble galaxies, humble because they are small, low-mass galaxies, change the state of the universe?  It's an exciting puzzle and a challenge to our understanding of physics.

Correction for 11 p.m. ET: I originally wrote that the galaxy was seen as it was 600,000 years after the big bang, but the figure is actually 600 million years. Sorry for putting the decimal point in the wrong place, and thanks to those who pointed out the error.

In addition to Lehnert, Nesvadba and Swinbank, the authors of "Spectroscopic Confirmation of a Galaxy at Redshift z=8.6" include Jean-Gabriel Cuby, Simon Morris, Benjamin Clement, C.J. Evans, M.N. Bremer and Stephane Basa.

Connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter. You can also check out "The Case for Pluto," Alan's book about the controversial dwarf planet and the search for new worlds.