Supermassive black hole weighed using new scale

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Researchers have proposed a new means for getting a measure of just how massive supermassive black holes are.

They are known to exist at the centres of most galaxies, but a puzzle remains as to how they affect galaxy evolution.

The approach, published in Nature, infers a black hole’s mass from the speed of molecules swirling around it.

It could help weigh hundreds of nearby black holes. Its first use suggests a black hole in the NGC4526 galaxy has a mass 450 million times that of our Sun.

Only in a few dozen cases have the masses of supermassive black holes been estimated. Because they cannot be seen directly, astronomers have relied on guessing how large they are based on the motion of objects circling them.

Most estimates have come from gathering up starlight. This can be done by calculating how much faster the stars nearer the black hole are moving relative to those farther away.

However, that is an average measure, and the “random motions” of stars – not necessarily in the same direction as the swirling mass – blurs the measurement.

The movement of electrically charged gas can be tracked in the same way, with slightly less blurring due to random motion.

Written By: BBC News
continue to source article at bbc.co.uk

14 COMMENTS

  1. A more convenient unit of mass to express the weight of black holes is the mMIL. It’s easier to grasp than 150 billion times the mass of this or that, saves a lot of ink and will soon be the standard in many cosmological calculations.

    What is stands for? My Mother-In-Law.

  2. In reply to #1 by Sjoerd Westenborg:

    A more convenient unit of mass to express the weight of black holes is the mMIL. It’s easier to grasp than 150 billion times the mass of this or that, saves a lot of ink and will soon be the standard in many cosmological calculations.

    What is stands for? My Mother-In-Law.

    It’s like Frank Carson never left us. :)

  3. So if this increases the estimate for the heft of black holes, how much will it eat into the dark-matter and dark- energy fudges?

    Inferring the mass of a galaxy from its outermost stars’ orbital radii and speeds is the source of the dark matter problem, since “visible” mass is less than what is inferred from the strength of gravity. This definitely won’t touch dark energy; that’s another thing again. As for the dark matter case, since the NGC4526 galaxy has about 170 billion stars, this new estimate of the mass of its black hole only makes a small dent (if any) in the normal-dark matter percentage split.

  4. In reply to #3 by rjohn19:

    So if this increases the estimate for the heft of black holes, how much will it eat into the dark-matter and dark- energy fudges?

    Exactly my thoughts. I hope what they find dispels the theories entirely, requiring a fundamental reworking of how we understand gravity.

  5. “What we’d really like to understand is how these two components interact; why they care about each other at all. To do that, we need to be able to measure their masses, and compare them in all sorts of different galaxies. That will allow us to start answering these questions.”

    Isn’t this kind of research mindbogglingly awesome, 450 million times more massively interesting and useful than your dried up desert bush?

  6. In reply to #6 by HenMie:

    Isn’t this kind of research mindbogglingly awesome, 450 million times more massively interesting and useful than your dried up desert bush?

    I just long for the day I will see any topic here whatsoever, more so one having to do with science, complete its course without anyone mentioning religion, out of nowhere, for absolutely no darn reason.

    No offense, but some people here really seem they’re obsessed with this shit. It’s like they think about religion more often than your average priest.

  7. None taken! It just annoys me that a large percentage of the world population concerns itself , along with their priests, with made up nonsense while they should be putting their energies, mental and otherwise, to more worthy – and real – pursuits and wonders. Unfortunately, we live in the world in which all roads do lead to religion (not just the Roman one). Believe me, I live in hope that one day religion will take its rightful place – in history -and only then we will not have to even mention the dreaded thing!

    You are right – we probably do think more about it than your average priest; he will be too concerned about hiding the unsavoury details of his illegal ‘encounters’ now that he can be caught and punished at last. Oops, I mentioned it again…sorry! :)

    In reply to #8 by JoxerTheMighty:

    In reply to #6 by HenMie:

    Isn’t this kind of research mindbogglingly awesome, 450 million times more massively interesting and useful than your dried up desert bush?

    I just long for the day I will see any topic here whatsoever, more so one having to do with science, complete its course without anyone mentioning religion, out of nowhere, for absolutely no darn reason.

    No offense, but some people here really seem they’re obsessed with this shit. It’s like they think about religion more often than your average priest.

  8. In reply to #4 by Jos Gibbons:

    So if this increases the estimate for the heft of black holes, how much will it eat into the dark-matter and dark- energy fudges?

    Inferring the mass of a galaxy from its outermost stars’ orbital radii and speeds is the source of the dark matter problem, since “visible” mass is less than what is inferred from the strength of gravity. This definitely won’t touch dark energy; that’s another thing again. As for the dark matter case, since the NGC4526 galaxy has about 170 billion stars, this new estimate of the mass of its black hole only makes a small dent (if any) in the normal-dark matter percentage split.

    Not that there was much danger in that, as the split is grossly in favour of dark matter anyway (I think it was something like 90% of the universe’s mass being dark matter).

    Just out of interest, do all galaxies contain supermassive black holes, or are they restricted to certain types of galactic structure? The article mentions no current explanation for them, but I can imagine the astronomers have quite a few interesting theories about their formation.

    For instance, I remember watching a program about a decade ago in which they mentioned that the Milky Way had one in its centre, but also that there were hundreds of smaller ones in our galaxy alone. The Milky Way is not representative of all galaxies, though, so I wondered. If, say, supermassive black holes formed by tightly packed stars crunching into each other at the galactic disc’s hub, then maybe only older, larger, and denser galaxies contain them, and younger, smaller, or sparser ones don’t have them?

    I would look it up on Wikipedia, but my confidence in that site’s accuracy has diminished lately. Is it worth looking it up there, and if not, could you recommend anywhere else where I could brush up my knowledge (websites, magazines, etc.)? Popular science books on astronomy tend to discuss normal black holes more often than they discuss supermassive ones.

  9. The dark matter distribution is not likely to be affected by this. We have several ways of measuring the percentage of dark matter (measurement of the cosmic microwave background temperature anisotropy being an important one) that are independent of galaxy mass and how it is distributed.

    As far as how common are SMBHs? There seems to be a correlation between central bulge size of spiral galaxies and SMBH mass. So the larger the spherical buldge at the center of a spiral galaxy the more massive the black hole at its center.

    It is thought that every elliptical galaxy contains a super-massive black hole and irregular galaxies contain small or no super-massive black holes (not-so-super massive black holes?).

    It is likely the case that these super-massive black holes formed by the coalescence of black holes in galactic mergers; an evolution of galaxies by collision which goes very briefly as irregulars to spirals to ellipticals. This is all off the cuff and I’ll check back in perhaps with a more informed blurb when I’m not out drinking …which I am now. Now I’m off to discuss dark matter(s) with people in the pub.

  10. “They are known to exist at the centres of most galaxies, but a puzzle remains as to how they affect galaxy evolution.”

    I expect galaxies evolve by continuous constructing new stars, continuous growing black holes and mingling of neighbor galaxies.

  11. In reply to #12 by yash:

    I expect galaxies evolve by continuous constructing new stars, continuous growing black holes and mingling of neighbor galaxies.

    That covers quite a lot.

    There is more detail here:-
    http://en.wikipedia.org/wiki/Galaxy _formation_and_evolution

    It looks like the large galaxies have smaller satellite galaxies merging into them, with other large galaxies colliding and gradually merging over extended time periods. The universe as a whole may be expanding, but local groups of galaxies are converging!

    The Antennae Galaxies are a dramatic pair of colliding galaxies. In such a collision, the stars within each galaxy will pass by each other (virtually) without incident. This is due to the relatively large interstellar distances compared to the relatively small size of an individual star. Diffuse gas clouds, however, readily collide to produce shocks which in turn stimulate bursts of star formation.

    The bright, blue knots indicate the hot, young stars that have recently ignited as a result of the merger.
    Alt Text – (Right click and select “view image”)

    The Andromeda Galaxy will collide with the Milkyway in 3 to 5 billion Years.

  12. In reply to #13 by Alan4discussion:

    Thank you.

    “The universe as a whole may be expanding,”

    I like the using of the word “may be” here. I don’t like the word “definitely” or something like that which many friends are prefer to use.

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