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A method that significantly improves the measurement of the mass of black holes in the centers of galaxies

Prof. Hagai Netzer from Tel Aviv University, who participated in the research: The discovery will allow a better understanding of the connection between giant black holes and the galaxies in which they reside, especially in the early universe

A simulation of a supermassive black hole with an accretion disk around it. Image: NASA/JPL-Caltech.
A simulation of a supermassive black hole with an accretion disk around it. illustration: NASA / JPL-Caltech.

Giant black holes in the centers of galaxies have been known to scientists for decades. The current research in this field deals with the various relationships between them and their parent galaxies and their influence on the development of the galaxies starting from the time when they were first formed, when the age of the universe was less than a billion years.

Measuring the mass of black holes, using different methods, is a central tool in such studies and the degree of accuracy in such a measurement has many meanings. The most common method today is based on measuring the location and speed of gas clouds that are near "active" black holes - those that absorb material from the environment and in the process emit huge amounts of radiation into space that in many cases exceeds the amount of radiation emitted by all the stars in the galaxy. The limitations of the method stem, mainly, from only partial information on the location and mode of movement of those gas clouds.

In a new study published in the journal Nature Astronomy on Monday (November 20), a group of researchers proposes a new way to significantly improve the current method of measuring mass, relative to previous measurements. Among the researchers in the group are Professor Hagai Netzer from Tel Aviv University, Dr. Julián Mejía-Restrepo and Professor Paulina Lira from the University of Chile, Dr. Benny Trachtenbrot from the ETH Institute in Zurich and Dr. Dan Caplupo ( Dan Capellupo) from Magill University in Canada.

In an interview with the Hiden website, Prof. Netzer explains that in the future it will be possible to make such corrections to the old mass measurements of most active black holes. "This is an especially important discovery for those who work in the field and need it every day, who can now significantly improve the accuracy of the measurement, in this case of black holes in the centers of galaxies. "

"Until now, all those involved in the field have used a standard method that we developed in Israel many years ago and from time to time it is improved, but it has very large shortcomings. The biggest disadvantage is that it is the best possible but not accurate and this makes it difficult when you need sensitivity such as measuring the mass of the black hole in relation to the mass of the galaxy in which it is found."

Schematic description of the various regions near an active black hole (in the center of the figure in brown): a disk of hot gas (in yellow and red) with which the new mass measurement was made, and distant gas clouds (in brown) with which the previous measurements were made. Credit: Ricardo Ramirez.
Schematic description of the various regions near an active black hole (in the center of the figure in brown): a disk of hot gas (in yellow and red) with which the new mass measurement was made, and distant gas clouds (in brown) with which the previous measurements were made. Credit: Ricardo Ramirez.

As mentioned, the research is based on highly detailed spectral measurements, from the ultraviolet to the infrared, of about 40 active black holes residing in galaxies that are about 4 billion years old. The research was carried out with the help of giant telescopes at ESO's Southern Observatory. It allowed researchers to accurately map the emission emitted from a body known as an "adsorption disk" very close to the black hole and much closer than the gas clouds used for mass measurements. The researchers who analyzed the characteristics of the radiation found that it is possible to measure the mass of the black hole with great precision. This is another method, independent of the method that was accepted until now and was based on the movement of distant gas clouds. It makes it possible to calibrate and correct the measurement results of the old method so that the measured mass is more accurate.

. Prof. Netzer, who has been involved for many years in the development of methods for measuring the mass of black holes, believes that this will allow a better understanding of the way in which large black holes that developed in the young universe affected the young galaxies that formed at that time. In particular, one should expect a significant improvement in the understanding of the processes connecting the galaxies and the black holes in the young universe, when its age was less than 4 billion years. For example, the bigger the black hole and the more gas it absorbs, the greater the effect of the radiation emitted from the absorption disk on the environment. Such radiation can "cleanse" the galaxy of the gas clouds from which the galaxy's stars are formed and thus limit and even stop its development. "A more accurate measurement of the black hole's mass will allow for a better calculation of the process by which a small galaxy in the early universe turned into a giant galaxy in the current universe," explains Prof. Netzer.

How did you achieve this accuracy?
Prof. Netzer: "The idea is to measure the spectrum of radiation coming out of the material that surrounds it. The closest material is the accretion disk, where the material swirling around the black hole is concentrated. All the radiation we measure comes from this disk, because as we know the black hole itself does not radiate. In the existing method, the mass of gas clouds 10 times farther from the black hole relative to the disk was measured. We were able to use the accretion disk itself, i.e. the gas very close to the black hole to measure. We directly measured the valve of about 40 active black holes when the universe was about 4 billion years old. We measured with both methods, so now it is possible to calibrate the measurements already made with the old method, and to be more accurate in the masses of black holes in many galaxies throughout the universe.

"This discovery has important applications. We were particularly interested in what happened in the early universe, that is, in the initial evolution of galaxies, when the center of each galaxy has a black hole. The method can also be used for a similar measurement of the centers of much closer galaxies. The Milky Way and M87, a relatively close galaxy, have had good and accurate methods for a long time, so there is no point in using the new method - the mass of the black hole in the center of the Milky Way can be measured with an accuracy of 5% by observing the stars and gas surrounding it, but in distant galaxies, approximate methods must be used. , if we manage to measure the mass with an accuracy of 40-50% it is considered good.

"We were required to make observations of very high quality and with very sensitive spectroscopes. The observation required a lot of telescope time in eight meter telescopes. In the end, the effort paid off."

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21 תגובות

  1. To my father Blizovsky
    Just as I was reading articles, I browsed again to the interesting article of Professor Hagi Netzer and came across the last response of a commenter named Yehoshua. I have already encountered one Joshua who all he did was attack my words out of lust and stupidity. And I proved that he attacks my words pointlessly and it doesn't matter what I write. I took a paragraph from a book written by one of the greatest astronomers today and he attacked the things in a disgusting way just because he saw that my name was written in the title.
    If this is the same wild and screwed-up Joshua what he has done now is that he inserted his insulting response several weeks after we finished discussing the topic of the article to prevent us from noticing and responding. To prevent this kind of thing, Avi Blizovsky, you should register a list of recent comments. She is sorely missed by the commenters.
    Also, a comment that was said only to discredit has no place on a site like the science and I would be happy, my father, if you removed it.
    Good Day

  2. Yehuda
    First of all - I wrote several tens of light years. Please, pay attention to what you write...
    Second thing - you cannot bring quotes to strengthen your position, and after that write that you do not accept the quotes.

    And about Wikipedia. We don't know what happens to a black guy - and apart from you, no one claims otherwise. There are hypotheses and these hypotheses have predictions. If the predictions are fulfilled then the training in the hypothesis is strengthened.
    Regarding falling "into" a black hole, note that as a bystander - this does not happen at all 🙂 Due to the extension of time, it seems as if the body stops at the event horizon.

    Yehuda - I'm not a physicist, but I'm also not sure that the physicists are right in everything. Please don't decide for me what I think.
    You're not a physicist either, and you think you know better than these morons who invest their lives in them. And all this - when in your turn there are big contradictions, which you simply ignore.

  3. Dear Nissim
    I am not alone in my opposition to the concept of the "black hole" which for you is "the pinnacle of gravitational creation". There are many who, regardless of my theory, oppose the concept. Even on the Hebrew Wikipedia, the black guys are aware of the problematic situation, and I quote:-
    "There are two famous open questions related to black holes. It is known that behind every event horizon is a gravitational singularity - a point in space where the density is infinite because the mass is concentrated in one quantum point. The first question is the question of the correctness of the cosmic censorship hypothesis, according to which any singularity is hidden from us by an event horizon. The second question is related to finding a solution to the paradox of the destruction of the information resulting from this black blacks "evaporate" without losing information[. ” end quote.
    In my opinion, the first sentence in the quote from Wikipedia is also problematic: "It is known that behind every event horizon is a gravitational singularity" end of quote. In my humble opinion, nothing is known for sure about what happens after the event horizon, at most speculations. And to this I will also add my comments on the subject in response number one, and all these data increase the uncertainty of the "black hole" concept.
    You choose to accept the general approach, indeed it is a simple and effective solution and I assure you that even during an academic exam I would prefer to write the conventional opinion - the consensus regarding black holes. Simply, it is better not to argue with the examiner. But my personal opinion is different.
    The center of our galaxy is not a few light years away, but about 30,000 light years, but this is still a tiny distance compared to the other galaxies that are millions of light years away from us.
    You are fascinated by the achievements of the science of gravity and the theory of relativity, and it is true, there is something to be fascinated by, but let's not ignore the difficulties that some of them I brought up here.
    So that's my opinion.
    You call me "insolent", "shameless" and other things that I don't think are any of our business. But if that's your opinion, so be it.
    I don't want to argue about my theory because it is not relevant to the interesting article by Professor Hagi Netzer. Professor Hagi Netzer helped to develop a more accurate measurement method regarding black holes in the center of galaxies and I expressed my opinion about it.
    In conclusion, I will add that responding to you is like reaching a state of war. Is this the attitude you want?, isn't it better for us to be calm and not get dragged into slander. We are science lovers in general and astronomy in particular.
    Good day miracles

  4. Yehuda
    Have you changed your mind, and now you agree that we do know at the center of the galaxy? How many decades of light years away? And if so, why do you think there isn't a huge mass there? Remember – without mentioning your theory….

    I'll say it again - the idea of ​​a black hole comes from a scientific theory that predicted amazing things like the bending of light and the lengthening of time.
    And please, don't bring dark matter into the discussion - it has nothing to do with your claim.

    And you know, you're a little cheeky. You are not ready for me to mention your theory and not ready/able to defend it, and on the other hand you throw out "a black hole is your area of ​​low pressure". You dismiss all physics with such a delusional statement, and are surprised that you are enlightened? Have you no shame? 🙂

  5. for miracles
    It is explicitly written: "In distant galaxies, we must use approximate methods. If we manage to measure the mass with an accuracy of 40-50%, it is considered good." End quote. What do you take the particular case of our galaxy where you reach an accuracy of 5 percent deviation? In our galaxy even I saw from the movement of stars revolving around its center that it is four million solar masses. What bothers me is that with a little reading comprehension you could have seen the quote in the article. Just apply a comment?
    And as for dark matter, if you think it's okay not to mention it then be happy. I think it should have been addressed.
    It's almost half past two in the morning so good night Nissim

  6. Yehuda
    If you refer only to the content of the article, then I have 2 questions for you.

    1) What is dark matter relevant to the subject of the article? It is about measuring the mass, not the source of the mass.

    2) We will write in the article that the error in measuring the mass of "our" black hole is 5%. How is your understanding better than the author of the article, so that you can say that the mistake is 100%?

  7. Dear Nissim, Professor Hagi Netzer's article is interesting and raises many questions and I absolutely do not understand your stubbornness to drag me into a conversation about my theory. She is not the topic of discussion here and is not willing to be dragged into a conversation about her. It's sad that all you try to do is discredit and say that I'm completely wrong (?), disconnected from reality, that I discredit and belittle scientists (where did you see that?). The one who is disconnected is you who is bound to my theory (the devil knows why) and not to the subject of the discussion.
    So I understand that you have nothing to say about the uncertainty that exists in determining the mass of black holes which is the subject of the article.
    All the best, miracles and Shabbat Shalom

  8. Yehuda
    A scientific theory has to fulfill 4 conditions: explain the past, predict the future, have the ability to be refuted, and be without self-contradictions. You want to use the word prediction instead of prediction - please. I don't understand what exactly you object to.
    Regarding the ability to refute modern theories - you are completely wrong. In my opinion, it shows how disconnected you are from reality. Yehuda - your disdain for physicists is simply embarrassing!
    What do you think physicists do? let me tell you They look at the world, invent theories (leave me out of precision in words) - and try to disprove them!!!

    And you? I keep trying to tell you that you have a serious hole in the theory, and you ignore it. You ignore the fact that you have no explanation for phenomena such as the bending of light and the lengthening of time.
    You say that "the universe is simple", but without complicating your theory without an upper barrier, you are unable to explain the simplest phenomena.

    Maybe it would be helpful to answer my regular question? How do you explain gravity by elastic collisions?

  9. for miracles
    Where do you see that I mentioned my theory in my recent responses?? I'm only talking about the rules of conventional theories:- and the first or most important rule in science states:- if a theory or formula is assumed, it must be confirmed with measurements! Until then it's just an assumption, without measurements these are just words that are exaggerated in the space of the universe, therefore, the correctness of the theory or formula will only be where you measured and saw that it is correct therefore the theory or formula will not be absolute beyond the measurements and their accuracy! You cannot measure in the solar system and decide that the same thing will be in the whole universe to the extent of millions and even trillions!!!. It doesn't work that way. To draw conclusions from an apple falling in Newton's yard, regarding the behavior of black holes or galaxies??? I think this is exaggerated to the point of nausea. Again, this is not a new Judas theory, this is what I learned in high school. I also do not agree that teachings prophesy, only prophets or coffee connoisseurs prophesy, and not with great success. Hypothetical theories about what the situation could be in a place that we have not yet measured, but if the formulated behavior or the theory will be as predicted or "prophesied"?, only the measurements will prove this!
    Let's summarize: - The rules of science themselves state that the correctness is only where you measured. Keep this rule, it is the most important in science.
    Please respond gently. Shabbat is coming soon, the day of rest and patience.

  10. Yehuda
    The whole idea of ​​a black hole comes from a theory that predicted many results that are completely counter-intuitive. The argument that it doesn't fit your theory and is therefore wrong, in my opinion, doesn't exactly convince anyone.
    And on the other hand - your theory has no explanation for these phenomena, and it doesn't even make sense from a physical point of view.
    This brings me to another troubling conclusion...

  11. for miracles
    Surely a big star will shrink at the end of its life, but will it shrink to a black hole? I doubt it, the laws of physics have been measured and proven on the contraction of stars up to a certain degree, but beyond a certain degree of contraction there are no direct measurements to check the result. It is impossible to conclude without measurements, from the gravitation of a sun with a diameter of over a million km, to the behavior of a star with the same mass and a diameter of a few kilometers without measurements. Will the star shrink to the level of a neutron star or a white dwarf?, I believe so and there are measurements that hint at this such as the mass and behavior of Sirius B. Will it continue and shrink to a black hole?? Here I have already shown that the doubt has increased to one hundred percent and in fact the black hole is only a guess. Maybe a correct guess, because I don't have the measurements either, but when you come to the conclusion of singular points, my doubt skyrockets.
    This is my opinion and please respond gently it is only science

  12. for miracles
    So it is, that I doubt if in the black hole region there is a huge mass of millions of solar masses, I do not believe in black holes and singular points. I believe that the "black hole" is a low pressure area in the galaxy just like in a hurricane and gravity does not star in the galaxy. It only works between stars and planets and between nearby stars. But I could be wrong.
    Please respond gently
    Good Day

  13. Yehuda
    I absolutely agree about the last comments - it's really lacking.

    Regarding the other things: if you don't accept that the laws of physics work near huge masses, then why do you accept the idea that there are huge masses there? This is a conclusion from those laws of physics.

    What's more, your explanation that a black hole should also contain dark matter makes a lot of sense.

  14. I have two "disturbing" questions about the subject the article deals with.
    The first:- How is it possible that dark matter, which stars in the explanation of the rotation of every spiral galaxy, is not mentioned at all in the explanation of the mass of the black hole at its center? Wouldn't it be correct to assume that it explains most of the mass of the black hole just as it explains most of the mass of the galaxy to which the black hole belongs?
    The second question is: - Where is the great confidence that the laws of physics that we know from our backyard in the solar system with a mass of one sun will also be true near a mass of millions of solar masses near the black hole in the centers of the galaxies?
    It turns out, that if we add uncertainty arising from these two questions, to the uncertainty of about 50% that already exists with the more precise measurement that is being carried out now, it appears that we may have reached an uncertainty of.... One hundred percent?, so what could this say about the existence or non-existence of the black hole?
    Just a disturbing conclusion, so please respond gently, it's just science
    Yom Tov Hidan site, and thanks to Professor Hagai Netzer for an interesting article

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