Super-massive and Small Black Holes Both Suck


Sorry, couldn’t resist that title. Astronomers studying black holes are able to “see” them due to the fact that the gas getting sucked in gets extremely hot and emits X-rays. These X-ray pulses are commonly seen among smaller black holes, but until now, had not been detected from super-massive black holes. But astronomers using the XMM Newton X-ray satellite have discovered a strong X-ray pulse emitting from a giant black hole in a galaxy 500 million light years from Earth, created by gas being sucked in by gravity. “Scientists have been looking for such behaviour for the past 20 years and our discovery helps us begin to understand more about the activity around such black holes as they grow,” said Dr. Marek Gierlinski from Durham University. Gierlinski and his colleagues say this finding is the “missing link” between small and super-massive black holes.

The astronomers were looking at the center of the galaxy REJ1034+396 galaxy and found that X-rays are being emitted as a regular signal from the super-massive black hole. They say the frequency of the pulse is related to the size of the black hole. “Such signals are a well known feature of smaller black holes in our Galaxy when gas is pulled from a companion star,” said Gierlinski. “The really interesting thing is that we have now established a link between these light-weight black holes and those millions of times as heavy as our Sun.”

The scientists hope future research will tell them why some super-massive black holes show this behavior while others do not. Most galaxies, including the Milky Way, are believed to contain super-massive black holes at their centers.

The researchers, who publish their findings in the journal Nature on September 18, say their discovery will increase the understanding of how gas behaves before falling on to a black hole as it feeds and develops.

Source: Durham University

14 Replies to “Super-massive and Small Black Holes Both Suck”

  1. Once again, an intriguing find. Those more au fait with the physics should keep watching this & cjeck out the publication.

  2. Just curious, why it was so hard to find them to begin with for the SMBH and what did they do differently here to find it from one?

  3. I like the title!

    I am curious. Did astonomers really think that the behavior of small black holes would change as they became supermassive? I guess I always thought that the supermassive blackholes had cleared out their surrounding areas (explaining their size) and that’s why it was hard to detect x-rays (they didn’t look active).

    Something that I thought was very interesting is that the article mentioned a link between the size of the blackhole and the frequency of the X-Rays. If true, that would be a fantastic way to measure a black hole’s size. I’m also wondering how the size would affect the frequencies that are emitted.

    Cool article!

  4. Thomas,
    Visually locating black holes would be a very difficult chore; they are relatively small and since they don’t reflect light we typically only see them when something near them is affected by it.
    You can notice a star or multiple stars orbiting a location with seemingly nothing there; is an indicator
    Gravitational lensing or distortion of light around a black hole is an indicator
    When gases get near a black hole, they speed up to a point where they get very very hot and in many cases throw off X-rays.

    Yes, there are some differences between SMBH and smaller black holes, as this subject obvously points out.

    I think you are on target about the activity around SMBH along the lines when they reach their maximum size; we’ll have to keep watching to see if this gets proven.

    Find out some more differences between the sizes and you will figure out the answer to your final question, or you can pursue what sort of things affect the wavelength size and frequency of xrays!

  5. Hey Nancy, thanks for the article. I think the title is fine. I do have a small quibble though. When we say that gravity “sucks” we reinforce a common misconception among the public; namely that gravity from a black hole can somehow actively grab you and suck you in (perhaps something like an octopus with its tentacles). In fact, material simply falls into the black hole under the influence of gravity.

    I’ve been battling this misconception for a long time. When I would ask my students what would happen to the Earth of the Sun was suddenly (and magically) turned into a black hole, the vast majority say we would be sucked in. Of course, we wouldn’t. The gravity of a 1 solar mass object 1 AU away does not depend on the physical size of that object. Or put another way, the Earth cannot tell that the Sun is not already a black hole.

    The difference between being sucked and falling is kind of subtle, I guess, but there is a difference. For people who don’t know a lot about physics, the difference can interfere with their understanding of gravity.

    On the other hand, when I teach about the cosmic acceleration, one of my favorite lines is that now we know that gravity doesn’t just suck, it also blows! It’s generally good for a least a small snicker, even from the kids sleeping in the back row.


    K. McLin
    NASA E/PO Group
    Sonoma State University

  6. I was going to ask about what is the frequency of the waveform you show in the illustration until I read Phil’s clarification. But I would still like to see an example of a plot of one of the smaller black hole’s waveform output. Like the one that Phil says varies many times a day. But he says pulses, and you are showing a sine wave. Or tell me where to go to look at the waveform. Thanks.

  7. RL:
    “I am curious. Did astonomers really think that the behavior of small black holes would change as they became supermassive?”
    I agree RL. I would think it doesn’t matter how “big” a black hole is, be it super or tiny. They all suck!!

  8. I “cjeck’ed out the publication” even though I’m not “more au fait with the physics” – “an intriguing find” indeed. 😉

    A little fun w/ words.

  9. RL – just to clear something up, when they talk about frequencies, they mean ‘temporal frequencies, i.e. the time-scale of the X-ray pulsations, not the actual frequency or equivalently the energy of the X-rays. The idea is that the time between pulses is related to the time which material takes to orbit round the black hole, for bigger black holes it takes longer to do this, hence the dependence on mass.

    Thomas – in short, they got lucky! These pulsations are quite rare in the stellar mass black holes, and in many active galaxies they would probably be too slow to easily observe anyway (you’d need a really long observation). But this galaxy evidently has a small enough black hole that you can see enough pulsations in a single day to clearly say they are there, that combined with the existence of this rare phenomenon in this particular galaxy explains why they had to get to looking at this one before they found this phenomenon. I should also add that they also did the hard job of doing a really good and thorough analysis!

  10. Hi Kevin-
    Great to hear from you! In the different work that you and I do, we both have the challenge of needing to grab people’s attention (suck them in, so to speak) and explaining details in an interesting way. I know sometimes (I hope not too often!) the technicalities can get a little lost along the way. It’s a fine line sometimes, but of course, our main goal is to get people interested in science and then inform and educate (me on the inform side, you on the educate!) Keep up the great work you do!


  11. My two cents:

    Yes, the title is cool!. I have always thought all black holes are of the same size – matter collapsing to a point or – singularity. More massive? Yes, but larger? No.

    However, when we discuss the size of a black hole, we would be talking about the “event horizon” – the point outside the black hole where the escape velocity equals the speed of light, which would tell us how massive a black hole is..

  12. hi
    this article is nice article but every black hole at its younger stage sucks gas to form into a super massive .Even black hole at our milky way galaxy emits high amount of x-rays.Any ways good to know about it

  13. if it sucks even x-rays in wouldnt it also suck in radio waves. Thus wouldnt it make it difficult to search the stars for radio signals from other worlds?

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