Runaway Black Hole Flees Behemoth Galaxy

Astronomers have spotted a supermassive black hole in a stripped-down galaxy racing away from a near-fatal close encounter in the center of a galaxy cluster.

It’s tempting to think of black holes as monsters, especially the supermassive variety. These beasts lurk at the centers of most galaxies and can be millions or even billions of times more massive than the Sun. When they eat, they feast — gobbling down gas then flinging radio-emitting jets out into intergalactic space.

So it’s a little odd that such a monster might be spotted running away, but that’s just what astronomers have found. In a recent search of nearby galaxies, Jim Condon (NRAO) and colleagues came upon a supermassive black hole stripped of most of its galaxy and fleeing from a big “Jabba the Hut”-type elliptical. The results have been accepted for publication in the Astrophysical Journal.

Predator Turned Prey

Condon started out trying to find supermassive black holes that didn’t live right in the centers of their galaxies. Galaxies are thought to grow in part by mergers with other galaxies. If that’s the case, the two black holes at the center of each galaxy would also have to unite, and that process might deliver a good kick to the resulting, larger black hole, shooting it off-center. Condon surveyed hundreds of nearby galaxies searching for this expected signature of galaxy mergers.

He didn’t find any. What he did find was even weirder — a galaxy on the run.

About 30,000 light-years from a brilliant, massive elliptical galaxy shone a surprisingly luminous source of radio waves. The source was too bright to be anything other than an accreting supermassive black hole. Yet it was much too far from the galaxy’s core to belong to it.

Condon and colleagues followed up with Hubble and Spitzer observations for a closer look. To their surprise, they found that the radio source sat in its own little galaxy, which has the mass of some 6 billion Suns — less than 1% of the Milky Way’s mass and atypically tiny to be hosting a supermassive black hole.

Hubble images also revealed a trail of ionized gas extending from the tiny galaxy to its much bigger sibling. The trail (and specific wavelengths of light that the trail emits) shows that the little galaxy is speeding away from the larger one at more than 2,000 kilometers per second (4.5 million mph). Whether it remains gravitationally bound or is heading out of the cluster toward intercluster space isn’t yet known.

A Close Encounter of the Galactic Kind

So what happened to this odd little galaxy? The scenario Condon’s team finds most likely is that the speedy galaxy was once a normal galaxy that fell into the gravitational well around the “Jabba the Hut” elliptical at the cluster’s center. It came very close to being destroyed, passing within 3,000 light-years of the elliptical’s core, but it managed to come out the other side of its slingshot pass. As it passed, gravitational tidal forces stripped away most of the galaxy’s stars and gas, but the very core of the galaxy — and its supermassive black hole — survived.

So now what? What’s left of the galaxy is still trailing debris and will eventually cease star formation. The supermassive black hole at its center may speed this process along if its radiation helps push gas out. In a billion years or so, the black hole probably will be invisible, wandering undetected through intergalactic space.

Watch Jim Condon explain the find:

Are there marauding black holes in the universe? Short answer: yes. For the long answer (and it's one you'll want to read), take a look at our special publication, Astronomy's 60 Greatest Mysteries.

One thought on “Runaway Black Hole Flees Behemoth Galaxy

  1. Yehiel Gotkis

    LikeBlack holes to pull-in the spacetime – Is it possible? Well, it looks like it is…

    Liquid vortex (LV) sheds light on the black holes (BHs) essentials.

    Gravity-driven liquid vortex – a generic analog of a cosmic black hole. Here is a few exciting things we can learn from it? Part 4 – Summarizing the most important points.

    Vortices could be found everywhere around us. Assuming different kinds of vortices possess common generics, we can get an insight in understanding the hardly observable ones, for instance BHs, by observing the easily observable ones, like LVs. Exploring LVs, also allows to run the observations with reasonable resources, in reasonable time, under variety of conditions and to observe the developments beneath the funnel bottom, which, in reference to the BHs, can be considered as an analog of the BH bottom.

    The LV I’ve observed was arranged to confine its developments in the thin surface layer thus making it to act as a two-dimensional one. The collection of LV videos could be accessed at YouTube under my name Yehiel Gotkis ( Please slow down the video rate as much as you can to see more details.

    Analysis of the observations leads to a shocking grasp questioning even the widely-adopted views on dark matter and dark energy.

    Observations, analysis, interpretations and conclusions.
    · The LV was emitting double-spiral waves known to carry momentum and associated kinetic energy transferable to other objects. The double spiral generation was induced by the spinning bottom asymmetry shaped as a distorted digit 8. The fact that generation of propagating away waves was caused by the spinning vortex asymmetry, in reference to the BH case, means that spinning BHs, being of even slightly asymmetric geometry, should generate/re-emit a part of the acquired mass/energy, as gravitational waves, back into the space. Which, in cosmic timescale, should make a significant amount of it, meaning that the Universe should be filled with energetic gravitational ripples. As the ocean surface ripples.

    · Also, the spinning double spiral wave profile, while swelling from the LV center, should oscillate, and it indeed does, which at some observation angles looks like wobbling (check, for example, “Liquid vortex upper double spiral wave generation” video \, providing a simple suggestion on interpretation of the Quasi Periodic Oscillation (QPO) phenomenon.

    · The LV observed was naturally pulling-in the water and whatsoever floating over it. In relation to the BHs, the upper water surface could be thought to be associated with the spacetime and the floating stuff – with the regular matter. So, for the spacetime/matter duo, as for the water/floating stuff,

    The spacetime and the matter are inherently engaged with each other.
    This engagement could be guessed of causing effects analogous to hydrodynamic drag and friction – gravitational drag and friction in BH case. Within the frame of this rationale (abbreviated as BHSSR, Black Hole Sucking Spacetime Rationale),

    The BHs are to be thought of pulling-in not only the matter but also the spacetime, whirling around the BH as liquid whirls around the LV.
    Intriguingly, the BHSSR allows to interpret the galaxy rotation curves anomaly and the Universe accelerated expansion with no necessity of introducing the two famous but still challenging to prove hypotheses:

    Existence of the dark matter
    As per the BHSSR, the pulled-in by the BH whirling spacetime can add additional momentum to the visible matter rotation in the BH proximity,

    Existence of the dark energy
    As per the BHSSR, at the galactic periphery, where the pulling-in force is diminished, the keeping on centrifugal force, induced by the spinning spacetime, accelerates the stars away from the galaxy center.

    · Another important LV occurrence is associated with the development of a galaxy-like spiral shape when a handful of shredded dry leaves was spread over the vortex area (video at

    The deep significance of this development stirred my mind and I would like to share it here:

    The floating leaves were arranging in a galaxy-like shape – what could drive the disarranged flock of intellectless dry leaves to organize themselves in a spiral shape? With the knowledge acquired about the LV, the answer is clear to me now…

    It is the water whirling around the LV, managing the floating stuff to form the spiral shape – it would not have formed spiraling if not governed by the whirling waters. This important deduction leads to an unambiguous conclusion: if in a system A made of non-continuous media a spiral structure is revealed, it must be postulated that there is an adjoined system B made of continuous media or containing a continuous media component (continuous media is essential for developing a vortex and an associated whirling activity). With relation to the galaxies, the only component to be considered as being continuous is the spacetime, which, being actuated by the BH vortex to whirlingly spin around and pulled into the BH, acts as the adjoined system B. So,

    The BH vortex actuates the spacetime to whirlingly spin around and flow into it, and the whirling spacetime, in its turn, directs the galactic regular matter to arrange itself in a spiral shape
    This concept provides explanations for numerous cosmic phenomena.

    And at the end I would like once again to emphasize on the spacetime/matter relations:

    The matter and the spacetime are adhered to each other as an inseparably engaged duo: where the spacetime there the matter. And vice versa.
    If for LV and BH vortices a number of conceptual features were found consistent it would be odd not to consider these vortices to be correlated, in general,
    This is it. Thank you for your attention.

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