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Thread: Excretion or accretion disc around the SMBH of Spiral galaxy?

  1. #31
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    Go to the Wiki AGN article linked in post 23 and scroll down to Models/Accretion disc. Here we have a paragraph that gives a brief, sketchy synopsis of the theoretical basis of accretion discs and their radiation. It mentions the possibility of absorption of the radiation by surrounding gas and dust, with reradiation in the infrared band. This could easily mask spectral features that otherwise could have been used to directly observe the Doppler shift of stuff that was spiraling into the black hole. My educated guess is that there are whole research papers on this topic stashed away in university astronomy libraries, where the professional researchers know where to find them. I don't think we can reasonably expect to find all of this readily available online.

    Dave Lee is referring to articles such as this one in attempting to defend his idea, and apparently is either missing or perhaps ignoring items in these articles which contradict him. Let me say that once again, absence of evidence is not necessarily evidence of absence.

  2. #32
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    Quote Originally Posted by Hornblower View Post
    <snip>
    Dave Lee is referring to articles such as this one in attempting to defend his idea, and apparently is either missing or perhaps ignoring items in these articles which contradict him. Let me say that once again, absence of evidence is not necessarily evidence of absence.
    Red highlighting added

    Though I have quoted Hornblower, this is a general concern to all members.

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  3. #33
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    Quote Originally Posted by Hornblower View Post
    From the various sources linked in this thread, it appears to me that the conditions are such that the in falling material is not giving us usable spectral features for determining the Doppler shift which would give us the smoking-gun radial velocity information. The absence of explicit verbalization of that detail in material that has become available online does not necessarily rule it out, at least as I see it, any more than our inability to directly observe the nuclear fusion in stellar cores would be grounds for rejecting it in theory. The latter was accepted in theory beyond a reasonable doubt long before we could detect neutrinos.

    Dave Lee, what is your hypothesis for the source of energy in AGNs? If you have already stated such a hypothesis, please direct us to it. I do not wish to try to tease it out of the jumble of stuff in this thread.
    Thanks for your important question.
    However, in order to answer this question, we need to have better understanding on accretion discs in AGN.
    So the questions should be:
    1. How do we distinguish between AGN which accretes mass from nearby gas clouds/stars (Accretion disc) to the one which generate new mass and blow it out (Excretion disc).
    The answer is:
    There are two key elements which are vital for the excretion disc:
    A. Temperature - above 10^7K.
    Let's assume that the nucleus accretes a gas cloud or a star. In this case, we need to estimate the accreted mass temp. So, let's assume that the star which is losing its mass is a Sun like star. On its surface, the temperature is about 5000K and in the core it is about 10^6K.
    As it is losing the outer layer to the other one, it is expected that the temp of the mass which is accreted into the accretion disc should be at about 5000K. In any case, it must be much below the 10^6K, unless it is losing its mass in a very dramatic and fast process.
    So, the temp of the mass in the accretion disc should give us a clear indication for the activity.
    At accretion disc (mass is in falling into the disc) - The expected temp of the mass in the disc should be significantly lower than 10^6K (even lower than 5000K). It is just a hot mass.
    However, at Excretion disc - As the process of new mass creation and fusion is based on very high temp, it is expected to find mass at a temp range of 10^7K to 10^9K. Therefore, we call it "Plasma".
    B. Orbital velocity.
    The orbital velocity of the plasma at the Excretion disc - At the most inwards side of the disc it is expected to have ultra high velocity - almost as high as the speed of light.
    At the accretion disc it is expected to see much lower orbital velocities.
    Those are the two key elements to distinguish between the two versions of discs (accretion or Excretion).
    2. what is the hypothesis for the source of energy in AGNs (for Excretion disc version)
    The excretion disc works under the supper gravity force of the SMBH as a massive magnetic accelerator.
    So, we actually transform the gravity force of the SMBH into massive magnetic accelerator which has the energy to create new mass. Therefore it is expected to see particles (as Quark, electron...) at the most inwards side of the excretion disc, and real atoms (or even molecular) as we move to the outwards side.

    Quote Originally Posted by Jean Tate View Post
    That link is broken for me; can you cite the actual paper please?
    https://academic.oup.com/mnras/artic...rectedFrom=PDF


    Quote Originally Posted by Jean Tate View Post
    Also, I don't understand why you think the reported observation is direct evidence of gas emission "from the outer part of the accretion disc"; can you give details please? Note: perhaps those details are in the paper you cite, but as your link doesn't work, I do not know what paper you're citing.
    It is stated clearly:
    "We present observations of the double-peaked broad H α profile emitted by the active nucleus of NGC 7213 using the Gemini South Telescope in 13 epochs between 2011 September 27 and 2013 July 23."

    Quote Originally Posted by Jean Tate View Post
    That AGNs seem to "emit" a lot of matter has been known for a long time. Perhaps the first discovery was double radio lobes, first associated with elliptical galaxies (I think the paper most often cited was published in the 1960s). And AGNs have been observed in ellipticals, lenticulars, and spirals (I'm not sure about irregulars), and even some dwarf galaxies.

    I don't understand why you seem to refer to only a very limited number of AGNs.
    Not all the AGN are the same.
    The main difference is in the accretion disc.
    Please see the above reply.

    Quote Originally Posted by Jean Tate View Post

    Can you explain, in detail, why you think "we should have direct observations of in falling matter" please (my bold)?
    How have your ruled out the possibility that such an absence is due to observational limitations? In particular, can you show - preferably in detail - that existing facilities could directly detect matter accretion onto the accretion disk in any galaxy (other than our own)?
    If we have the technology to see/observe a matter which is blowing out from the accretion disc, we also should have the technology to see a matter which is in falling to the accretion disc.
    Please also be aware that infalling matter should come with fireworks ("The mother of the fireworks"). If we can't see any gas cloud, star, planet, moon or even a tail falling in, than the only outcome is that there is no falling in.

    Quote Originally Posted by Jean Tate View Post
    Please show - preferably in detail - that these are capable of directly detecting matter "falling in" to the accretion disk of any AGN in any galaxy (other than the Milky Way).
    AGN means an Active GN. The word active means that it emits some sort of mass. So, in the same toke, if we can see in our technology all the variety of emissions (which I have discussed), than we should also see matter which is falling in (if there was any matter which is falling in). so simple as it is.

    Quote Originally Posted by Hornblower View Post
    Dave Lee is referring to articles such as this one in attempting to defend his idea, and apparently is either missing or perhaps ignoring items in these articles which contradict him. Let me say that once again, absence of evidence is not necessarily evidence of absence.
    I do not miss or ignore any item in any article which contradicts this ATM.
    Contradicts means - That we have direct observation on infalling matter. If it was stated somewhere, I would not even try to set any effort in this tread.
    In that article they highlight the possibility of absorption of the radiation by surrounding gas and dust, with reradiation in the infrared band.
    In other articles it is stated that they "believe", "estimate", "assume" that matter is infalling to the accretion disc.
    This doesn't contradict the ATM, as there is no direct observation for infalling matter (as you have already explained in one of your replies).
    I would love to have one direct observation which contradict this ATM.
    .
    Last edited by Dave Lee; 2018-Jul-30 at 07:31 PM.

  4. #34
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    Quote Originally Posted by Dave Lee View Post
    A. Temperature - above 10^7K.
    Let's assume that the nucleus accretes a gas cloud or a star. In this case, we need to estimate the accreted mass temp. So, let's assume that the star which is losing its mass is a Sun like star. On its surface, the temperature is about 5000K and in the core it is about 10^6K.
    As it is losing the outer layer to the other one, it is expected that the temp of the mass which is accreted into the accretion disc should be at about 5000K. In any case, it must be much below the 10^6K, unless it is losing its mass in a very dramatic and fast process.
    So, the temp of the mass in the accretion disc should give us a clear indication for the activity.
    At accretion disc (mass is in falling into the disc) - The expected temp of the mass in the disc should be significantly lower than 10^6K (even lower than 5000K). It is just a hot mass.
    However, at Excretion disc - As the process of new mass creation and fusion is based on very high temp, it is expected to find mass at a temp range of 10^7K to 10^9K. Therefore, we call it "Plasma".
    B. Orbital velocity.
    The orbital velocity of the plasma at the Excretion disc - At the most inwards side of the disc it is expected to have ultra high velocity - almost as high as the speed of light.
    At the accretion disc it is expected to see much lower orbital velocities.
    How on earth can you justify these statements about an accretion disk? The paper I pointed you towards, the one where you got the 10^9K temperature you were quoting earlier, was all about simulation of accretion disks and showed that current models of them yield much, much higher temperatures than you are now claiming. The orbital speeds are also well modelled and part of the mainstream. Either present published, detailed evidence to support your assertions about accretion disks or retract them. If this is your attempt to set up a test of your model it is deeply flawed.

    Quote Originally Posted by Dave Lee View Post
    It is stated clearly:
    "We present observations of the double-peaked broad H α profile emitted by the active nucleus of NGC 7213 using the Gemini South Telescope in 13 epochs between 2011 September 27 and 2013 July 23."
    I've already corrected your misreading of this once. H-alpha emissions are not gas emissions. In this case they are from gas in the accretion disk. It is not evidence for gas emission, it is evidence for a rotating disk of gas which becomes partially ionised at some radius.

    Quote Originally Posted by Dave Lee View Post
    If we have the technology to see/observe a matter which is blowing out from the accretion disc, we also should have the technology to see a matter which is in falling to the accretion disc.
    Please also be aware that infalling matter should come with fireworks ("The mother of the fireworks"). If we can't see any gas cloud, star, planet, moon or even a tail falling in, than the only outcome is that there is no falling in.
    I'll let Jean press you on this one but your claim about what we should be able to observe is glaringly illogical. As for the fireworks, you have been pointed to evidence of them in other galaxies. You have been pointed to estimates of the accretion rate of our galaxy and what it should mean observationally.

    Quote Originally Posted by Dave Lee View Post
    AGN means an Active GN. The word active means that it emits some sort of mass. So, in the same toke, if we can see in our technology all the variety of emissions (which I have discussed), than we should also see matter which is falling in (if there was any matter which is falling in). so simple as it is.
    That is not what active means at all. This is another of your redefinitions of a term. And your claims about observations are illogical, again. Jean has asked your for detailed explanations of what instruments and observations you believe should show matter infalling - I would like an answer to that too.

    As for things that contradict this ATM - again, that is not how it works. You need to show us that your idea is better than the mainstream because it has more predictive power. Given the number of physical laws broken by what you have proposed then rather compelling evidence is needed. So - still an open question - what are the compelling predictions made by your idea that cannot be accounted for by the mainstream models?

  5. #35
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    It appears that the key point in Dave Lee's opinions as presented in this thread is the apparent lack of any publication that presents evidence from which inward motion of stuff close to the black hole can be inferred. He insists that if we can observe evidence of the motion of the ejecta, we should be able to observe corresponding evidence of the stuff that is spiraling in. I stand by my hunch that the critical stuff is simply obscured by surrounding gas and dust, while polar jets are blasted out into regions where the view is unobstructed. I also see no need for a hypothesis of creating new matter to form the ejecta. All we need is plenty of energy, from whatever source, to propel existing matter out of the core.

    I would also like to see a technical description of how the core's gravity generates the magnetic accelerator in his latest model of an energy source.

  6. #36
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    Quote Originally Posted by Hornblower View Post
    It appears that the key point in Dave Lee's opinions as presented in this thread is the apparent lack of any publication that presents evidence from which inward motion of stuff close to the black hole can be inferred. He insists that if we can observe evidence of the motion of the ejecta, we should be able to observe corresponding evidence of the stuff that is spiraling in. I stand by my hunch that the critical stuff is simply obscured by surrounding gas and dust, while polar jets are blasted out into regions where the view is unobstructed. I also see no need for a hypothesis of creating new matter to form the ejecta. All we need is plenty of energy, from whatever source, to propel existing matter out of the core.

    I would also like to see a technical description of how the core's gravity generates the magnetic accelerator in his latest model of an energy source.

    An additional factor that must be taken into consideration is the rate of material joining the accretion disc is not required to be constant for any given epoch (indeed, as far as I am aware, there is no particular expectation that it would be).

    So the mainstream model is that a nucleus that was active but is now quiescent (as may well be the case for our own Milky Way) has simply exhausted the fuel that had been made available to it in earlier epoch(s). I would be interested in how Dave Lee's model (which as far as I understand it does not require a supply of infalling matter onto the accretion disc) accounts for periods of activity and quiescence - in his mechanism, what causes the production of "new matter" in the accretion disc to cease?

  7. #37
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    In my opinion we need to go back to Square One. This thread has become a hodgepodge of conflicting ideas and expressions thereof, and in hindsight I will acknowledge that I have not always adhered to the standards of this forum. For a fresh start I tried going back to some references linked in the first few posts, and many of the links did not work.

    Dave Lee, it appears that you are satisfied with a protostar model in which gas and dust are falling into the protostar. Please direct us to a reference that supports that satisfaction.

    It appears that you are not satisfied with an analogous AGN model in which gas is falling into the vicinity of a supermassive black hole. Please direct us to references that contribute to that dissatisfaction and explain why they do so.

  8. #38
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    Thanks for your replies, Dave Lee.
    Quote Originally Posted by Dave Lee View Post
    Thanks for your important question.
    <snip>
    That link is broken for me; can you cite the actual paper please?
    https://academic.oup.com/mnras/artic...rectedFrom=PDF
    Thanks.

    It's Schimoia+ (2017), "Evolution of the accretion disc around the supermassive black hole of NGC 7213", which is behind the MNRAS paywall; the arXiv preprint is arXiv:1708.03727.

    Also, I don't understand why you think the reported observation is direct evidence of gas emission "from the outer part of the accretion disc"; can you give details please? Note: perhaps those details are in the paper you cite, but as your link doesn't work, I do not know what paper you're citing.
    It is stated clearly:
    "We present observations of the double-peaked broad H α profile emitted by the active nucleus of NGC 7213 using the Gemini South Telescope in 13 epochs between 2011 September 27 and 2013 July 23."
    Yes, it does say that. In the Abstract.

    But did you read the paper itself?

    I cannot find anything on a direct observation; instead, what they did was construct a set of models, and from those draw conclusions about the nature of the accretion disk (and nuclear star cluster, mass of the SMBH, etc).

    So, please explain - in detail - how you concluded that Schimoia+ (2017) reports a direct observation. You may wish to answer my other questions first, then - from the paper - see that the spatial resolution of the pixels is, at the estimated distance of NGC 7213 (hint: it's huge).

    Not all the AGN are the same.
    The main difference is in the accretion disc.
    Please see the above reply.

    If we have the technology to see/observe a matter which is blowing out from the accretion disc, we also should have the technology to see a matter which is in falling to the accretion disc.
    Please also be aware that infalling matter should come with fireworks ("The mother of the fireworks"). If we can't see any gas cloud, star, planet, moon or even a tail falling in, than the only outcome is that there is no falling in.

    AGN means an Active GN. The word active means that it emits some sort of mass. So, in the same toke, if we can see in our technology all the variety of emissions (which I have discussed), than we should also see matter which is falling in (if there was any matter which is falling in). so simple as it is.

    <snip>
    I think there is a lot of confusion here, some of which may arise from different definitions, particular of "AGN" (you, Dave Lee, seem to be using one which differs greatly from the one(s) used in astronomy and astrophysics papers.

    Here are two questions which I think may help somewhat to clarify:

    JT01: what is a characteristic physical size of an accretion disk (e.g. in au or km)? Alternatively, what is a typical range for the size of accretion disks? If, in you ATM idea, this varies by type of the AGN the accretion disk is in, please quantify that variation.

    JT02: at distances of 1 Mpc, z (redshift) of 0.01, and 0.1, what is the angular size of a characteristic accretion disk?

  9. #39
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    I just now read an article about BL Lacertae, a monster AGN, in the latest Sky and Telescope. When it was discovered several decades ago, astronomers were perplexed because its spectrum had no emission or absorption lines, so there was no way of determining its redshift, if any. They could not tell whether it was an oddball object in our galaxy or an enormous beast vastly farther away, let alone try to tease out its internal pattern of motion. When the Hale telescope at Palomar finally showed some starlight from the host galaxy it became clear that it was a very remote object. My point here is that it may be the nature of the beast in general that there is no direct means of detecting the spiraling-in motion of the accreting material. Suppose that is the case. We can still do good science in inferring the motion from what we can observe, and be satisfied that the accretion model is a good one.

  10. #40
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    Quote Originally Posted by Jean Tate View Post
    Thanks for your replies, Dave Lee.
    It's Schimoia+ (2017), "Evolution of the accretion disc around the supermassive black hole of NGC 7213", which is behind the MNRAS paywall; the arXiv preprint is arXiv:1708.03727.
    Yes, it does say that. In the Abstract.
    Thanks for your confirmation.

    Quote Originally Posted by Jean Tate View Post
    But did you read the paper itself?
    I cannot find anything on a direct observation; instead, what they did was construct a set of models, and from those draw conclusions about the nature of the accretion disk (and nuclear star cluster, mass of the SMBH, etc).

    So, please explain - in detail - how you concluded that Schimoia+ (2017) reports a direct observation. You may wish to answer my other questions first, then - from the paper - see that the spatial resolution of the pixels is, at the estimated distance of NGC 7213 (hint: it's huge).
    In the article they explain how they isolate the AGN emission from the recorded data:

    "We extracted the nuclear spectra from our data using a window of 1.000×1.000 centered on the peak of the continuum emission."
    " In order to isolate the AGN emission we subtracted the contribution of the stellar population."
    If I understand it correctly, they have extracted this emission without the need for the Modeling.
    So, even without direct observation, they have found clear evidence that the accretion disc of the AGN at the center of the NGC 7213 spiral galaxy emits matter.
    What is wrong with that? Why can't we accept it as a solid evidence for the matter which is blowing outwards from the disc?
    They even call it in their own words: "Observation" just to highlight their full confidence in the discovery of AGN emission.

    To my best knowledge, there is no equivalent confidence for in falling matter to the accretion disc of Spiral galaxy.

    In any case, don't forget that we also have a direct observation for the Milky Way matter emission.

    Therefore, as long as we don't have an equivalent evidence and/or direct observation for in falling matter, we have to look for other alternative for the existence of the matter in the accretion disc of spiral galaxy.
    Quote Originally Posted by Jean Tate View Post
    Thanks for your replies, Dave Lee.
    I think there is a lot of confusion here, some of which may arise from different definitions, particular of "AGN" (you, Dave Lee, seem to be using one which differs greatly from the one(s) used in astronomy and astrophysics papers.
    There is no confusion at all. I only focus on spiral galaxy and some Spiral galaxies have AGN in their core.
    For example, in this article it is stated clearly: "The nucleus of NGC 7213 has been extensivelly studied in X-rays. XMM-Newton/BeppoSAX observations revealed that the AGN spectrum shows no significant Compton reflection component (Bianchi et al. 2003) – what is very peculiar among bright Seyfert 1 AGN’s."

    So, this is an excellent example of AGN in the core of spiral galaxy which blows out matter from the accretion disc. I'm quite sure that it isn't the only one in the whole universe with that kind of activity.
    .
    Quote Originally Posted by Jean Tate View Post
    Here are two questions which I think may help somewhat to clarify:
    JT01: what is a characteristic physical size of an accretion disk (e.g. in au or km)? Alternatively, what is a typical range for the size of accretion disks? If, in you ATM idea, this varies by type of the AGN the accretion disk is in, please quantify that variation.

    JT02: at distances of 1 Mpc, z (redshift) of 0.01, and 0.1, what is the angular size of a characteristic accretion disk?
    Why do you ask me those questions?
    I didn't set any sort of modeling. This data is needed to the one which is setting the modeling.
    In that article it is stated clearly that they have use modeling process.
    How could they set any sort of modeling without clear information about all your questions?
    I couldn't find any real answer for the estimated mass in the accretion disc, the minimal/maximal radius of the accretion disc and so on.
    In one article it was stated that the estimated mass in the accretion disc is 3 Sun Mass. In another article it was stated that there is a possibility that the accretion disc in the Milky way had accreted 10,000 sun mass in the past just to blow it out later on.
    So, if our scientists are so confused about the real size of the accretion disc, how could they set a modeling?
    What is the value of any modeling without the basic information on the accretion disc??
    Actually even when they discuss about the velocity, they didn't try to verify the different velocities based on the accretion radius. Just to remind you that in the most inwards side, the estimated velocity is almost as high as the speed of light.

    Quote Originally Posted by Shaula View Post
    How on earth can you justify these statements about an accretion disk? The paper I pointed you towards, the one where you got the 10^9K temperature you were quoting earlier, was all about simulation of accretion disks and showed that current models of them yield much, much higher temperatures than you are now claiming. The orbital speeds are also well modelled and part of the mainstream. Either present published, detailed evidence to support your assertions about accretion disks or retract them. If this is your attempt to set up a test of your model it is deeply flawed.
    We have already discussed about the modeling.
    I do not recall that there was any real information about the Minimal and maximal radius/estimated mass/Plasma structure per radius/temp per radius/velocity per radius/ and so on.. in the accretion disc of spiral galaxy.
    Without this vital information, how can we set any sort of modeling to protect out hypothesis?

  11. #41
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    Quote Originally Posted by Dave Lee View Post
    Thanks for your confirmation.


    In the article they explain how they isolate the AGN emission from the recorded data:

    "We extracted the nuclear spectra from our data using a window of 1.000×1.000 centered on the peak of the continuum emission."
    " In order to isolate the AGN emission we subtracted the contribution of the stellar population."
    If I understand it correctly, they have extracted this emission without the need for the Modeling.
    This is yet another example of where I think there's a basic break-down in communication.

    On the one hand, you are presenting an ATM model of something to do with AGNs (I think; I really don't know what your ATM idea is); on the other, you accept what's in a mainstream paper, without understanding it (apparently).

    For example (Section 2.1): "The scaled and corrected stellar population template was then subtracted from the nuclear spectrum in order to isolate the AGN emission." I think every astronomer or astrophysicist would say this clearly indicates the use of models, as does "The average extranuclear spectrum is only weakly “contaminated” by narrow emission lines which were excised by using a synthetic spectrum obtained from the application of the starlight-v04 spectral synthesis code of Cid Fernandes et al. (2005)"

    May I ask, how did you conclude that no modelling was involved?

    So, even without direct observation, they have found clear evidence that the accretion disc of the AGN at the center of the NGC 7213 spiral galaxy emits matter.
    What is wrong with that? Why can't we accept it as a solid evidence for the matter which is blowing outwards from the disc?
    They even call it in their own words: "Observation" just to highlight their full confidence in the discovery of AGN emission.
    Another example: the results and conclusions presented in Schimoia+ (2017) depend on long chains of evidence and logic, and models. You are presenting an ATM idea, which - by definition - involves using different evidence, logic, and models. Yet you have not specified which you are choosing to not accept (at least, not that I can tell).

    Putting this another way: if you accept all that is involved in arriving at one of the conclusions of Schimoia+ (2017), then you have no ATM idea at all (again as far as I can see).

    To my best knowledge, there is no equivalent confidence for in falling matter to the accretion disc of Spiral galaxy.
    And again, what work have you done to establish that any such "confidence" is within today's observational capabilities?

    In any case, don't forget that we also have a direct observation for the Milky Way matter emission.

    Therefore, as long as we don't have an equivalent evidence and/or direct observation for in falling matter, we have to look for other alternative for the existence of the matter in the accretion disc of spiral galaxy.
    Can you clarify what you mean please?

    For the record, it seems to me to be an example of the logical fallacy called "false dichotomy".

    There is no confusion at all. I only focus on spiral galaxy and some Spiral galaxies have AGN in their core.
    For example, in this article it is stated clearly: "The nucleus of NGC 7213 has been extensivelly studied in X-rays. XMM-Newton/BeppoSAX observations revealed that the AGN spectrum shows no significant Compton reflection component (Bianchi et al. 2003) – what is very peculiar among bright Seyfert 1 AGN’s."

    So, this is an excellent example of AGN in the core of spiral galaxy which blows out matter from the accretion disc. I'm quite sure that it isn't the only one in the whole universe with that kind of activity.
    Just a few posts ago you wrote (there are similar examples in your earlier posts):

    "Not all the AGN are the same.
    The main difference is in the accretion disc.
    "

    So without a lot of further clarification, it seems that your ATM idea incorporates something not found in any mainstream paper. So unless and until you clearly spell out what the characteristics of the different kinds of AGNs are (per your ATM idea, as presented in this thread), confusion will continue.

    Why do you ask me those questions?
    I didn't set any sort of modeling. This data is needed to the one which is setting the modeling.
    In that article it is stated clearly that they have use modeling process.
    How could they set any sort of modeling without clear information about all your questions?
    I couldn't find any real answer for the estimated mass in the accretion disc, the minimal/maximal radius of the accretion disc and so on.
    In one article it was stated that the estimated mass in the accretion disc is 3 Sun Mass. In another article it was stated that there is a possibility that the accretion disc in the Milky way had accreted 10,000 sun mass in the past just to blow it out later on.
    So, if our scientists are so confused about the real size of the accretion disc, how could they set a modeling?
    What is the value of any modeling without the basic information on the accretion disc??
    Actually even when they discuss about the velocity, they didn't try to verify the different velocities based on the accretion radius. Just to remind you that in the most inwards side, the estimated velocity is almost as high as the speed of light.

    <snip>
    It's your ATM idea, Dave Lee. Only you can provide answers on what its components are. If you can't answer questions asked of your own ATM idea, please say so.

    I look forward to your answers to my questions; here they are again:

    JT01: what is a characteristic physical size of an accretion disk (e.g. in au or km)? Alternatively, what is a typical range for the size of accretion disks? If, in you ATM idea, this varies by type of the AGN the accretion disk is in, please quantify that variation.

    JT02: at distances of 1 Mpc, z (redshift) of 0.01, and 0.1, what is the angular size of a characteristic accretion disk?

  12. #42
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    Quote Originally Posted by Dave Lee View Post
    It is vital to distinguish between accretion disc of Star to the accretion disc of SMBH in the core of Spiral galaxy. They have totally different characteristics. I wonder why our scientists put them in the same basket.
    In order to understand that issue we need to look again on the evidences:
    Accretion
    In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk.[1][2]
    Whether gas is collected around a star or a SMBH does not matter for the definition.

    Followed by some interesting but irrelevant literature and an "excretion" error. Excretion is a term used in biology, not astronomy. The astronomy term for gas being ejected from a accretion disk is emissions, as you know from what you have cited.

    ETA: Looking through your posts I do not see a clear explanation of your ATM idea. There are citations of mainstream literature and questions about mainstream science. My impression is that you think that the gas emitted from SMBH cannot be from the accretion disc. New matter is generated out of nowhere and SMBH push it out? This causes something to be different about AGN? So:

    IF01: Please present a clear description of your ATM idea, Dave Lee.
    Last edited by Reality Check; 2018-Aug-01 at 03:05 AM.

  13. #43
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    Quote Originally Posted by Reality Check View Post
    Accretion

    Whether gas is collected around a star or a SMBH does not matter for the definition.

    Followed by some interesting but irrelevant literature and an "excretion" error. Excretion is a term used in biology, not astronomy. The astronomy term for gas being ejected from a accretion disk is emissions, as you know from what you have cited.

    ETA: Looking through your posts I do not see a clear explanation of your ATM idea. There are citations of mainstream literature and questions about mainstream science. My impression is that you think that the gas emitted from SMBH cannot be from the accretion disc. New matter is generated out of nowhere and SMBH push it out? This causes something to be different about AGN? So:

    IF01: Please present a clear description of your ATM idea, Dave Lee.
    The ATM idea is as follow:

    1. It is related only for the accretion disc at spiral galaxy.

    2. Evidences -
    There is a direct observation of matter which is blowing out from the Milky Way accretion disc. The estimated total mass which had been blow out is 10,000 solar mass.
    There is also clear evidence that the accretion disc of NGC 7213 spiral galaxy is blowing matter from the outwards layer of the disc.

    3. There are no evidences or/and direct observations for:
    Any infalling of Stars/Gas cloud/ Tail of gas cloud/Rock or even stone to the accretion disc in the Milky Way.
    I have just found that in the article about NGC 7213 spiral galaxy that it might also have Gas cloud:
    https://arxiv.org/pdf/1708.03727.pdf
    "The CBC is evidence of additional gas at lower line-of-sight velocities than the gas in the accretion disk, probably orbiting the SMBH at distances beyond the disk."
    However, in the article they do not claim that this gas (cloud?) is falling in the accretion disc.

    So, if there is a gas cloud also around the SMBH in the NGC 7213, it does not show any signs of loosing mass to the accretion disc.

    4. Conclusions:
    There is not even one clear evidence for any sort of matter which is falling into the accretion disc of spiral galaxy, while we have direct observation (at least from the milky way) of excretion (blowing out) of 10,000 sun mass. Therefore, the only outcome is that the accretion disc must create new mass in order to support all the matter which had been (and is) excreted out.

    5. Disapprove the ATM
    The simple way to disapprove this ATM is by introducing evidences for in falling matter (Any sort of matter and at any quantity) into the accretion disc of any spiral galaxy.
    Last edited by Dave Lee; 2018-Aug-01 at 06:31 PM.

  14. #44
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    Quote Originally Posted by Jean Tate View Post
    If, in you ATM idea, this varies by type of the AGN the accretion disk is in, please quantify that variation.
    I have stated it before, and I will say it again. In this ATM I only focus on the accretion disc of spiral galaxy. Therefore, if there is AGN in a spiral galaxy - it is very relevant. All the other types of AGN are currently none relevant for our discussion. Unfortunately, the science does not give any specific information on AGN which is located in spiral galaxy.
    Therefore, the AGN by itself has no impact on the subject of this ATM

    Quote Originally Posted by Jean Tate View Post
    JT01: what is a characteristic physical size of an accretion disk (e.g. in au or km)?Alternatively, what is a typical range for the size of accretion disks?
    JT02: at distances of 1 Mpc, z (redshift) of 0.01, and 0.1, what is the angular size of a characteristic accretion disk?
    Those questions are none relevant to this ATM.
    I would love to know the answers for those questions and more than that. however, unfortunately the science doesn't give real answers for all the questions.

  15. #45
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    Quote Originally Posted by Dave Lee View Post
    The ATM idea is as follow:...
    The simple way to disapprove this ATM is by introducing evidences for in falling matter (Any sort of matter and at any quantity) into the accretion disc of any spiral galaxy.
    Dave, I worry that you continue to misunderstand that the burden of support is on your shoulders, and on your shoulders alone. Unless and until you provide affirmative support for your ATM position, it remains...unsupported. It is manifestly not our responsibility to disprove (although we may disapprove) your ATM proposition. The reason, as has been explained over and over again, is simply that failure to disprove your idea does not mean your idea is correct. There are many other possibilities that must also be considered, so even if the mainstream is wrong, somebody else's ATM idea could be the right one instead of yours.

    Becaue you seem to have a persistent misunderstanding about how logical proofs work. consider a simple example: If you were to assert that Santa Claus exists, our inability to disprove the existence of Santa Claus would not in any way mean that Santa Claus does exist. It would still be up to you to support your assertion; the failure of others to disprove your idea does not remove your burden.

    So please stop taking the position that others must disprove your proposition. The burden is entirely on you to provide affirmative support for your proposal.

    I, for one, would like you to answer the questions that have been asked, rather than evading them under the unilateral declaration that the questions are irrelevant. I find them highly relevant and ask you to reconsider your position.

  16. #46
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    Quote Originally Posted by Dave Lee View Post
    The ATM idea is as follow:

    1. It is related only for the accretion disc at spiral galaxy.

    2. Evidences -
    There is a direct observation of matter which is blowing out from the Milky Way accretion disc. The estimated total mass which had been blow out is 10,000 solar mass.

    <snip>
    Please provide a primary source for this assertion, particularly the “accretion disk” part.

    You may have, indirectly, considered Su&Finkbeiner (2012), “Evidence for Gamma-ray Jets in the Milky Way”; if so, please re-read it, particularly concerning “direct observation” and “Milky Way accretion disk”.

    I would also like you to answer the - many - other questions I’ve asked you, in this thread (other than those which you have already answered). Let me know if you’d like me to list the unanswered ones.

  17. #47
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    Quote Originally Posted by Dave Lee View Post
    I have stated it before, and I will say it again. In this ATM I only focus on the accretion disc of spiral galaxy. Therefore, if there is AGN in a spiral galaxy - it is very relevant. All the other types of AGN are currently none relevant for our discussion. Unfortunately, the science does not give any specific information on AGN which is located in spiral galaxy.
    Therefore, the AGN by itself has no impact on the subject of this ATM



    Those questions are none relevant to this ATM.
    I would love to know the answers for those questions and more than that. however, unfortunately the science doesn't give real answers for all the questions.
    Thanks for the clarification.

    Here is JT01 again, rephrased so that it is directly relevant to your ATM idea: What is the characteristic physical size of an accretion disk in a spiral galaxy?

  18. #48
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    Dave Lee, to convince me that infalling gas in an accretion disk is not a viable model for the energy source of an AGN, you need to do the following:

    1. Show that the Doppler shift, if observable, of core material rules out any inward motion.
    2. Show theoretically that radiation with some sort of observable Doppler-shiftable features is inevitable in such inflow.

    So far I have seen nothing of the sort.

    Whatever the source of energy is, I see no compelling need to propose the generation of new matter to account for ejecta from an AGN. With plenty of impetus, existing matter can be blown out. In your opinion, what am I missing?

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    And a direct question from me please:AF01. How was the accretion disc formed in the first place, if not through the aggregation of infalling matter? You are ascribing special properties to the central accretion disc in spiral galaxies, but how did that disc originally form, before it started churning out the "new" matter you claim it does?

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    OP banned due to an accumulation of infraction points, most recently for a pattern of evasiveness and refusal to answer questions. Thread closed.
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