[evan_au]

We can clearly see our accretion disc, we also can measure the plasma temp and monitor its structure and velocity.
We also clearly see matter that is ejected from this accretion disc.
Therefore, if any sort of gas is drifting inwards, we have to see it.

I'm afraid that you are starting from some false assumptions.
- Despite our galactic SMBH being "only" 28,000 light-years away, we can't actually see it.
- This is because it is shrouded by all the dust and gas that fills the plane of our galaxy.
- This dims visible light by a factor of a trillion, and higher frequencies by an even bigger factor.
- So the accretion disk at the center of the galaxy is only visible at radio frequencies. Until the Event Horizon telescope announces some results, we won't be able to see any gas swirling inwards.
- In infra-red wavelengths, astronomers can see some very bright stars orbiting the SMBH. But these are not part of the accretion disk (at least, not yet...)
- So I'm afraid that we can see the center of other galaxies better than we can see our own.
See: https://courses.lumenlearning.com/astronomy/chapter/the-center-of-the-galaxy/

I only focus on the accretion disc around SMBH in the core of a massive spiral galaxy (as the milky way galaxy).
...(The galaxy in the video) is quite small galaxy and it is not clear if it has any spiral arms or the requested hot plasma.

The galaxy in the video is a very distant galaxy, so it might look small in the sky.
But it hosts a SMBH about 25-30% the size of our own.
Like most SMBH, this one was quiet, until a star wandered too close and was disrupted, producing a temporary accretion disk of plasma. So it meets your criteria.

...But I don't see what the spiral arms of the galaxy have to do with the accretion disk of the SMBH in the center?

[Dave Lev (OP)]

...But I don't see what the spiral arms of the galaxy have to do with the accretion disk of the SMBH in the center?

Spiral galaxy is a leading force in our Universe.
There are billions of spiral galaxies in our Universe.
All of them have hot plasma in their accretion disc.
With regards to the Milky Way;
Few years ago, our scientists were expecting to see a nice fireworks as one of the Gas came closer to the SMBH in our galaxy. Somehow, The SMBH had refused to eat that gas cloud.
However, the Milky Way is just one spiral galaxy. We monitor many others.
Did we ever see any sort of fireworks while they eat some sort of gas cloud or star?

- So I'm afraid that we can see the center of other galaxies better than we can see our own.

If we can see the center of other spiral galaxy, did we ever found a gas cloud/star that drifts inwards to the accertion disc?
If no, could it be that the accretion disc of spiral galaxy is different from all the others?
Let's focus on Hydrogen and molecular ejection from spiral galaxies:
The Milky way ejects molecular stream - If I recall correctly the estimated mass in this stream is about 10,000 sun mass, while the total mass in the accretion disc is only three Sun mass.
So, how could it be that an aria which has only 3 Sun mass can supply a constant stream of 10,000 suns mass?
Our scientists want to believe that the mass in the accretion disc of spiral galaxy is coming from a nearby gas cloud.
However, as you have already advised, we didn't find YET any evidence for that.
Let's look at Andromeda:
http://holographicgalaxy.blogspot.com/2012/06/streaming-hydrogen-gas-bridge-connects.html
"Streaming Hydrogen Gas Bridge Connects Andromeda and M33 Galaxies Together".
Could it be that this stream of gas had been generated in the accretion disc of the galaxies - especially by Andromeda as it is a very massive spiral galaxy?
M51 spiral galaxy:
https://www.sciencedaily.com/releases/2018/05/180516144619.htm
"What it was turned out to be a massive cloud of ionized hydrogen gas spewed from a nearby galaxy and then essentially "cooked" by radiation from the galaxy's central black hole."
"The discovery of the giant gas cloud, first observed by Watkins in 2015 and announced by Mihos on Twitter in April, potentially provides astronomers around the world with an unexpected "front row seat" to view the behavior of a black hole and associated galaxy as it consumes and "recycles" hydrogen gas."
In this case our scientists have an excellent view -  "front row seat". They see clearly the gas cloud that had been ejected from the galaxy. They speak about "consumes and "recycles" hydrogen gas".
Therefore, it is also expected to see where this recycle gas is coming from. They should see the gas cloud as it drifts to the accretion disc.
If they don't see it, could it be that this "recycles matter" is actually a new matter which had been generated in the core of those spiral galaxies?
The space is full with mass. Actually the number of stars in the open space is higher than the total number in the whole galaxies together (or at least equal).
Our galaxy crosses the space at ultra high velocity. Never the less, not even a single star can penetrate the galaxy due to its incredible gravity force. The gravity of the galaxy clears its path in space.
Therefore, all the stars in the galaxy and around the galaxy are moving with the galaxy.
Hence, could it be that this is one more indication that all the matter in our galaxy had been created by the galaxy?

The galaxy in the video is a very distant galaxy, so it might look small in the sky.

If that galaxy is located so far away, how can we see a star that is drifting inwards to the accretion disc?

 

[evan_au]

If I recall correctly the estimated mass in this stream is about 10,000 sun mass, while the total mass in the accretion disc is only three Sun mass.

According to this 2013 article, astronomers are debating the size and orientation of any jet emanating from our galactic black hole:
https://www.scientificamerican.com/article/milky-way-black-hole-jet/

Ignoring our galaxy, I don't think that there is a conflict between 3 solar masses in the accretion disk and 10,000 solar masses in a jet. On my wall calendar I have an image of Hercules A, which shows radio jets extending maybe 30 times the width of the visible galaxy. This represents the operation of a jet over billions of years, which could easily have spat out the mass of 10,000 stars.

However, the matter in an accretion disk today is transient, and will mostly be swallowed by the black hole (it migrates inwards), with a small percentage spat out in a jet. So it is possible that an accretion disk which contains only 3 solar masses today could have fed a jet containing 10,000 solar masses - it depends on the residence time in the accretion disk.

From this distance, we can't tell if a jet is continuous (this requires a regular source of matter to feed it) or "bursty" (just becomes active when a star gets too close and is disrupted).

Astronomers think that a supermassive black hole could grow at an average rate of around 1 solar mass per year - but again, it could be very bursty.
See NASA student tutorial: https://spacemath.gsfc.nasa.gov/Modules/8Mod9Prob3.pdf

Our galaxy crosses the space at ultra high velocity. Never the less, not even a single star can penetrate the galaxy due to its incredible gravity force.

Have a look at Stellar streams.

These are groups of stars (some streams equivalent to 200 million suns) which are in orbit around the center of the Milky Way, in highly inclined orbits. They routinely penetrate the galactic disk, and come out the other side.

They are thought to be remnants of smaller galaxies that have ventured too close to our galaxy and been torn apart, much like a meteor shower spreads out along the path of a comet.
https://en.wikipedia.org/wiki/List_of_stellar_streams

[Dave Lev (OP)]

One simple question:
Do you agree that so far we couldn't find even one real evidence that the accretion disc at ANY spiral galaxy in the Universe accretes mass from outside?

[evan_au]

Do you agree that so far we couldn't find even one real evidence that the accretion disc at ANY spiral galaxy in the Universe accretes mass from outside?

I don't agree.

We live in a spiral galaxy, the "Milky Way galaxy". Where we live can be considered as the outer parts of the accretion disk around the supermassive black hole at the heart of our galaxy.

The Milky Way is in the process of accreting the Large and Small Magellanic clouds (dwarf galaxies).

The Milky Way has already accreted several dwarf galaxies, and these are slowly having their velocities randomised by gravitational interactions with stars in the main disk of the galaxy.

This is the same process that happens with atoms in the accretion disk immediately surrounding a black hole, except that one occurs by gravitational interactions on a scale of hundreds of millions of years (ie the timescale of one orbit around the galaxy), while atomic interactions close to the black hole occur on timescales of days or weeks (ie the timescale of one orbit around the black hole).

Have a look at Stellar streams.

I heard today that the Gaia spacecraft has revealed the presence of numerous new stellar streams close to Earth.

Gaia precisely measures the position of stars near the Earth, using the parallax technique.
- The first data release gave the precise position of nearby stars
- The second data release (a year later) allowed the motion of these stars to be calculated
- Software picked up a number of known stellar streams, plus some new ones passing near the Sun
- For more distant stars, Gaia only detects motion across the sky. A companion project measures the radial velocity of these stars using doppler shift from ground-based telescopes. This will allow detection of more distant stellar streams.
- I expect that extra data releases over the next 3 years will reveal even more stellar streams.
See: https://www.cosmos.esa.int/web/gaia/iow_20180930

[Dave Lev (OP)]

I don't agree.

We live in a spiral galaxy, the "Milky Way galaxy". Where we live can be considered as the outer parts of the accretion disk around the supermassive black hole at the heart of our galaxy.

The Milky Way is in the process of accreting the Large and Small Magellanic clouds (dwarf galaxies).

The Milky Way has already accreted several dwarf galaxies, and these are slowly having their velocities randomised by gravitational interactions with stars in the main disk of the galaxy.

This is the same process that happens with atoms in the accretion disk immediately surrounding a black hole, except that one occurs by gravitational interactions on a scale of hundreds of millions of years (ie the timescale of one orbit around the galaxy), while atomic interactions close to the black hole occur on timescales of days or weeks (ie the timescale of one orbit around the black hole).

Thanks
So, if I understand you correctly, there are several indirect evidences for the accretion process in the Milky Way.
Stellar streams and Dwarf galaxies are few examples for those indirect evidences of the accretion process.
We assume that in a similar process, Atoms accretes into the accretion disc, but there is no direct evidence for that.
Therefore, so far there is not even a single direct evidence for any sort of Gas cloud/star.../Atom that accretes directly into the accretion disc of the Milky Way or of any other spiral galaxy in the whole Universe.
Do you agree with that?

[Dave Lev (OP)]

We don't have direct evidence for any sort of matter that falls into the accretion disc. However, there are several direct evidences for particles stream that are ejected from the heart of our galaxy and other spiral galaxies:
https://www.scientificamerican.com/article/milky-way-black-hole-jet/
"X-ray and radio observations offer the best evidence yet that, as long suspected, high-energy particles stream from the heart of our galaxy"
"Such jets are common throughout the universe, and most suppermassive black holes are thought to produce them."
"..scientists have detected a weak jet emanating from the black hole at the center of the nearby galaxy M81.."
So, we see clearly that the accretion disc of spiral galaxy ejects high-energy particles stream.
We see it at the Milky Way and at many other spiral galaxies.
Now let's assume that the current hypothesis that the accretion disc get's its matter from outside.
Our scientists estimate that the SMBH increase its mass by one sun mass every year.
So, in the last 10,000 Years due to this activity, our SMBH in the Milky Way should have to eat those 10,000 sun mass from the aria next to the accretion disc. After 1 Million years it should eat 1 Million sun mass from the galaxy. After 1 Billion years it should eat 1 Billion sun mass from the galaxy.
This is just the mass which the SMBH must consume for itself.
Hence, after so long time of eating the matter from the galaxy, it is expected to find that there is no matter near the accretion disc.
However, in only day light from the black hole, there is an estimated matter of 10,000 sum mass.
There is another issue - New star production.
https://en.wikipedia.org/wiki/Baby_Boom_Galaxy
"The Baby Boom Galaxy has been nicknamed "the extreme stellar machine" because it is seen producing stars at a rate of up to 4,000 per year (one star every 2.2 hours). The Milky Way galaxy in which Earth resides turns out an average of just 10 stars per year.[4]"
So, how could it be that our SMBH eats one sun mass per year, produces 10 stars per year, ejects that kind of high-energy particles stream, and - we see that the galaxy center is still full with mass?
Could it be that the only solution for that is - new mass creation?

[evan_au]

The Milky Way galaxy in which Earth resides turns out an average of just 10 stars per year...
So, how could it be that our SMBH ... produces 10 stars per year?

The new stars tend to be produced in cold molecular dust clouds.
However, the center of the Milky Way galaxy has a very high density of stars, and the energy of the central accretion disk will tend to disperse any cold gas clouds.

So most of the new stars will tend to be outside the central bulge of the galaxy.
See: https://en.wikipedia.org/wiki/Star_formation
And, by the way, new stars form by a process of accretion.

So, how could it be that our SMBH eats one sun mass per year... and - we see that the galaxy center is still full with mass?

As a general rule, the central SMBH of a galaxy has a mass of around 0.1% of the mass of the central bulge of the galaxy.
So the SMBH could keep eating for billions more years, and still the center of the galaxy would still be full of mass.

[Dave Lev (OP)]

So most of the new stars will tend to be outside the central bulge of the galaxy.
See: https://en.wikipedia.org/wiki/Star_formation
And, by the way, new stars form by a process of accretion.

In the following article it is stated that most of the Milky Way's star formation activity is taking place at the 5-kpc center ring. We also see at this center large fraction of the molecular hydrogen present in the Milky Way:

https://en.wikipedia.org/wiki/Milky_Way

"The bar may be surrounded by a ring called the "5-kpc ring" that contains a large fraction of the molecular hydrogen present in the Milky Way, as well as most of the Milky Way's star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of the Milky Way.[106] X-ray emission from the core is aligned with the massive stars surrounding the central bar[99] and the Galactic ridge."

As a general rule, the central SMBH of a galaxy has a mass of around 0.1% of the mass of the central bulge of the galaxy.
So the SMBH could keep eating for billions more years, and still the center of the galaxy would still be full of mass.

Let's make a simple calculation:
In 12 Billion years (the Min. age of the Milky Way) it is estimated that based on one sun mass per year, the SMBH should eat about 12 Billion star mass from its nearby aria.
Out of the estimated 400 billion stars in the galaxy, 12 Billion stars means 3%.
There are only 0.1% of the total star mass in the bulge. Therefore, the SMBH has to eat 30 times the total mass in the bulge during its life time while still keeps it full with mass.
So, I still wonder how could it be that after eating all of this matter just for self consuming, plus all the requested matter for the jet stream, there are still so much matter in that 5KPC ring and especially in the one light ring of the bulge (10,000 Sun mass).
I know that we shouldn't think in a logic way when we look at our Universe.
However I wonder what is the benefit for the Milky Way to set most of its star formation activity in the center just to eat them all.
Don't you think that something must be wrong in our hypothesis?
Do you agree that so far there is no direct evidence for any sort of mass that accretes directly into the accretion disc of spiral galaxy?
How long do we still have to wait until our scientists will understand that there is a possibility that the SMBH doesn't eat any mass from its spiral galaxy or disqualify that idea by direct evidence?

[Dave Lev (OP)]

I have proved that Atom is a cell of Energy:

https://en.wikipedia.org/wiki/Gluon
"A gluon is an elementary particle that acts as the exchange particle (or gauge boson) for the strong force between quarks"
"Gluons are actually just bosons, since they are the equilibrium force between the two quarks, which together form a triumvirate, and thus the energy force of the boson is in the form of a gluon, and thus the quarks become stable. They cannot separate unless something greater is capable of separating the quarks from each other, and so the gluon appears to hold these forces together. In fact it is just a type of energy while the two smaller forces, the quarks (also forms of energy) can unite under a single force, and this is the gluon's job."

the Gluons is a type of Energy while the Quarks are also forms of energy.
Therefore, the mass in the proton represents Energy.

We know that in Atomic bomb we actually convert some mass in the Atom into Energy.
Let's assume that the SMBH eats stars.
However, in the accretion disc we don't see any star. We actually see some sort of particles..
So, the accretion disc breaks the Stars into Atoms and then breaks the Atoms into particles. During this process, it increases its temp to 10^9 c. Therefore, we actually see a transform of mass into energy. Some sort of Atomic bomb in full activity.
Actually, if we break the protons we get the Gluons & Quarks. Those Gluons are by definition Energy and they can't exist without the proton Envelope.
Therefore, once we break the proton to particle, 99% of the proton must be converted into energy by definition.
Somehow it seems to me that at this temp it must break down also the remaining quarks.
So, if the accretion disc accretes mass from outside, it should convert 100% (or at least 99%) of the mass into energy.
Hence, do you agree that after the accretion process and converting mass into Energy, nothing (or almost nothing) would be left to be ejected out from the accretion disc and in the same token nothing would get into the SMBH itself?
Therefore, do you agree that the only feasible process in the accretion disc that can set that hot Molecular jet stream must be based on converting the energy in the Mighty SMBH gravity force into Atoms and Molecular instead of converting Atoms into energy?

I personally don't see any logic in the following accretion process:
The Milky Way sets most of the star formation activity in the center of the galaxy.
Then it accretes those new born stars to the accretion disc, breaks them down to Atoms and breaks their atoms into particles and energy.
After this long process it starts the opposite process:
It creates back the protons/ neutrons from the particles that had been survived, and then creates new Atoms and molecular. Then it blows them away in some sort of hot molecular stream.
This molecular stream should set a molecular gas cloud. In this gas cloud new stars will be born just to be eaten again by the accretion disc.
Is it real???

[Dave Lev (OP)]

I hope that by now we agree that new Atom creation in the Accretion disc of Spiral galaxy is feasible.
Based on the SMBH mighty gravity force, Magnetic/electric power, Ultra velocity of the plasma (0.3 Speed of light) and High temp (10^9 c), new particles might pop up in the innermost side of the accretion disc. Those particles will be transformed into new Atoms and Molecular as they drift outwards and eventually be ejected as a hot jet stream from the accretion disc.
That ejection process is very critical.
I wonder why this hot jet stream is ejected from the accretion disc.
We know that the moon is drifting outwards from Earth and the Earth is drifting outwards from the Sun.
Actually, all the planets and most of the moons (except of one or two) in the solar system are drifting outwards.
Some might claim - tidal.
But, could it be that it is more than just "tidal"?
Could it be that something is missing in Newton and kepler formula?
Could it be that Time is missing?
The Moon is drifting away from the Earth by only few centimeters per cycle. However, each cycle takes one Month. Therefore, during our life time it might be very difficult to notice any real change.
Hence, Newton law works Ok for this orbital cycle.
Never the less, any particle which orbits around the SMBH at almost the speed of light sets several cycles per day.
So, could it be that even if it drifts only few millimeter per cycle, during our life time it might complete the full cycle from new born particle at the inner most side of the accretion disc, to Atom/molecular in the outer most that is ejected from the accretion disc in a hot jet stream?
So, could it be that in most of the orbital cycles - drifting outwards is dominant?
If so, this outwards drifting phenomenon is critical for our understanding how spiral galaxy really works.
We have to find the time effect on Newton law.
As the Milky Way must generate 12 new stars per year, could it be that this represents the minimum mass production of the accretion disc in the galaxy?
However, there is only three sun mass in the plasma.
So how could it be that so low mass quantity can generate so high mass?
The answer is: "gluon"
We know that 99% of the proton/Neutron mass is gluon while only 1% represents the quarks.
Therefore, any particle during the transformation process to Atom gets the gluon energy and increases significantly its mass?
So, do you agree that with only three sun mass of quarks it is feasible to generate new molecular stream with almost 300 Sum mass?

[evan_au]

Could it be that something is missing in Newton and kepler formula?
Could it be that Time is missing?

Newton's and Kepler's formulas both explicitly include time in determining the motion of point masses.

However, distributed masses like the Earth, Moon or an accretion disk follow more complex laws that depend on factors like density and viscosity.

So, could it be that in most of the orbital cycles - drifting outwards is dominant?

Ignoring galactic collisions (and their subsequent black hole mergers), which muddy the picture considerably....

A spiral galaxy will feed matter into its central black hole, which will take on the dominant angular momentum of the galaxy.
The spin axis of the black hole will align with the spin axis of the galaxy.
The accretion disk will also have the same axis, and will form a pancake shape parallel to the galaxy itself.

However, the matter ejected from the black hole does not lie in the plane of the accretion disk, but at 90 degrees to it, along the poles of the black hole.

While "drift outwards" could occur temporarily in accretion disk after a bright flare, that is possible only because the accretion disk is in orbit around the equator of the black hole.

"Drift Outwards" cannot occur to matter at the poles, as this is not in orbit around the black hole. It must be blasted outwards, at speeds far faster than the 0.3c of the inner accretion disk. The mechanisms which cause this are a bit mysterious, but are thought to relate to magnetic fields trapped in the plasma of the accretion disk, much like a Coronal Mass Ejection occurs on the Sun.

As the Milky Way must generate 12 new stars per year, could it be that this represents the minimum mass production of the accretion disc in the galaxy?

Astronomers see clouds of cold hydrogen gas falling down onto the lane of the galaxy from the intergalactic medium.
Some of this could have originated in polar jets from our own SMBH. or from another galaxy. This supply of fresh gas is the raw material of new stars.

[Dave Lev (OP)]

"Drift Outwards" cannot occur to matter at the poles, as this is not in orbit around the black hole. It must be blasted outwards, at speeds far faster than the 0.3c of the inner accretion disk. The mechanisms which cause this are a bit mysterious, but are thought to relate to magnetic fields trapped in the plasma of the accretion disk, much like a Coronal Mass Ejection occurs on the Sun.

Astronomers see clouds of cold hydrogen gas falling down onto the lane of the galaxy from the intergalactic medium.
Some of this could have originated in polar jets from our own SMBH. or from another galaxy. This supply of fresh gas is the raw material of new stars.

Wow!!!
Thanks for the great answer.
That answer proves that the magnetic force around the SMBH is absolutely HUGE!!!
It actually gives higher confidence for the idea that new matter is created at the accretion disc.
Please let me know if the following meets the evidences that we have:

The Magnetic force around the accretion disc traps the Atom which had been drifted out from the accretion disc and boosts it upwards at 0.8 c. (Faster than the orbital velocity, which is 0.3 c)
However, why this magnetic force traps only the Atom/Molecular at the outer side of the disc? Why not from inside of the accretion disc?
I assume that gravity force is the ultimate answer for that as follow:
F = G * M * m / R^2
M = The mass of the SMBH
m = The mass of the particle/Atom/Molecular.
The meaning is that when the particle is located at the inwards side of the accretion disc, the gravity force on that particle is higher than the magnetic force. However, as the particle drifts outwards, its gravity force decreases. Only at the most outwards side of the accretion disc, the magnetic force becomes higher than the gravity force. At that radius, the particle had already been transformed into Atom or Molecular. Therefore, the magnetic force traps that new born Aton/Molecular and lifts it up at 0.8 c.
It also proves that nothing can get into the accretion disc.
Any atom from outside would be lifted up into that hot jet stream.
The magnetic force can't distinguish between Atom which is just drifting outwards from the accretion disc to the one that is coming from outside the disc.
Both of them will be lifted at 0.8 speed of light.
Therefore, the Huge magnetic force around the accretion disc is used as a shield which prevents any sort of mass accretion from outside.
That proves that the accretion disc doesn't accrete any mass from outside.
From now on we must call it excretion disc.
Do you agree with that?

[Dave Lev (OP)]

Astronomers see clouds of cold hydrogen gas falling down onto the lane of the galaxy from the intergalactic medium.
Some of this could have originated in polar jets from our own SMBH. or from another galaxy. This supply of fresh gas is the raw material of new stars.

Let's try to understand that important activity;
The magnetic force blows up at almost the speed of light all the matter which had been ejected from the excretion disc of spiral galaxy.
At that point the matter is very contaminated. It includes all the variety of Atoms (Hydrogen...Gold..) and molecular (water...) but also all the particles which had not been fully transformed into Atoms. Those particles could contaminate any new formed star.
However, as the hot stream goes upwards, the magnetic power is decreasing. Therefore, at some point, the gravity force of the Galaxy pulls the atoms and molecular back to the lane of the galaxy
Never the less, all the other particles which didn't complete the transformation cycle continue to go upwards due to their tinny size comparing to Hydrogen Atom.
So, the magnetic force which blows the matter upwards, set some sort of cleaning activity to the matter which had just been created at the excretion disc.
This reminds me the way how do we clean wheat.

There is another benefit for this process - Temperature decrease
The Plasma temp is 10^9. It is too hot to be used as a raw material for new star.
However, this upwards magnetic blow up process decreases the temp to a relatively lower temp.
It also stops at once any fusion activity in the hot matter which had been ejected from the excretion disc.

So, do you agree that as the matter is falling down onto the lane of the galaxy we can claim that this activity "supply of fresh gas (Clean and at lower temp.) which is used as raw material of new stars"?

[Dave Lev (OP)]

Astronomers see clouds of cold hydrogen gas falling down onto the lane of the galaxy

Few year ago (2014), our scientists thought that the source for the gas cloud is a massive disc stars:
https://www.mpg.de/8777573/gas-cloud-galactic-centre
"A likely source for both G1 and G2 could then be clumps in the wind of one of the massive disk stars, which could have been ejected some 100 years ago close to the apocentre of the G2 orbit. Another possible explanation that has been suggested recently would be a large star, enveloped by an extended gas cloud. Based on the current VLT data, however, this model is highly unlikely.
Astronomers are nevertheless puzzled why they have not yet detected increased Xray emission from the gas cloud near the black hole."
I hope that by now they already know that the new matter is coming from the excretion disc of the galaxy.
Therefore, our scientists shouldn't be so "puzzled".
The black hole has no intention to eat any new matter which it just drifts out from its excretion disc.
Do you agree that the mighty magnetic shield around the excretion disc protects the core from any accretion activity?