Crab pulsar beams most energetic gamma rays ever detected from a pulsar

The Crab Nebula in the constellation of Taurus

On October 5, 2011, an international collaboration of astrophysicists announced that they had detected pulsed gamma ray emission from the Crab pulsar having the same period as the Crab pulsar.  Using the VERITAS Cherenkov telescope array in Arizona, they detected gamma ray energies in the range of 100 – 400 billion electron volts, higher than anything previously observed from a pulsar and so energetic that current pulsar cosmic ray acceleration models fail to explain it.

Earlier this year, astronomers announced that they had detected a gamma ray flare from the Crab Nebula that was produced by cosmic ray electrons having energies of up to 10 quadrillion electron volts.  See story at:  This is 100,000 times greater than the gamma ray energies observed to come from the Crab pulsar.  A conservative estimate would place the particle energies involved in producing the Crab Nebula flare as being several orders of magnitude higher than the particle energies inferred from the pulsar’s gamma emission.  So as concluded earlier, it is unlikely that the Crab pulsar is responsible for the Crab Nebula’s gamma emission.

Changes in the angular size of the Crab pulsar

Related to the earlier posting about the gamma ray flare observed in the Crab remnant, it is worth mentioning the findings of astronomer A. G. F. Brown published in 1976:

Brown made interplanetary scintillation observations of the Crab pulsar at a radio frequency of 81.5 MHz and found that over a four year period between 1971 and 1975 the angular diameter of the Crab pulsar radio source increased over three fold from 0.2±0.1″ of arc to 0.7±0.1″ of arc.  The angular diameter of a pulsar’s radio image is determined by the amount of scattering its radio signal experiences as it encounters electrons in the interstellar medium.  A larger radio image diameter implies greater scattering which in turn implies greater interstellar electron concentration.  Brown ruled out changes in the solar plasma as being responsible for the change.  He also finds it unlikely that it is caused by changes in scattering in the immediate vicinity of the pulsar.

I would suggest that these changes in interstellar medium scattering are produced by the superwave that is now passing through the Crab nebula’s vicinity and which can change the electron density encountered along the line of sight to the Crab pulsar.

Explaining the ring-like waves of X-ray emission around the Crab pulsar

X-ray map of the inner portion of the Crab Nebula.

Credit: NASA/CXC/MSFC/M.Weisskopf et al & A.Hobart

Click below to view video

In a recent comment, gmagee inquired about the rings of X-ray emission that are seen to be expanding away from the Crab pulsar and whether this activity might be more likely interpreted as being intrinsic to the pulsar wind rather than to an impacting galactic cosmic ray volley.  This ring motion was reported in the news today, one story appearing in PhysOrg (
In answer to this question, I would respond, no.  The expanding ring of emission is most likely produced by the superwave, not by the Crab pulsar.  Much of the misconception on interpreting this phenomenon concerns the all too common belief that the Crab pulsar lies near the geometrical center of the Crab Nebula.  This misconception is perpetuated not only in technical papers but in media news reports such as the above cited report.  To the contrary, as I had proposed in chapter 5 of my 1983 Ph.D. dissertation (see in particular pp. 179 – 180 of the dissertation update), a careful analysis of the kinematics of the Crab pulsar and of the high velocity filaments traveling outward from the explosion center shows that the Crab pulsar is most likely situated at the forefront of the Nebula (4 – 5 light years from the center) and is traveling almost directly towards us at ~1500 km/s (2° angle deviation from our line of sight).  Only when viewed in projection from our vantage point does it “appear” to lie at the geometrical center of the Nebula.  I would rather not go into the details of this explanation here since it is rather extensive, but refer readers to my dissertation.  Also the peripheral nebular placement of the Crab pulsar is to a much less extent dealt with on page 74 of Decoding the Message of the Pulsars.  Other reasons why the pulsar is not the source of the cosmic rays energizing the Crab Nebula are given in my dissertation, in my 1987 Earth, Moon, and Planets paper, and in chapter 10 of my book Earth Under Fire.

This high velocity scenario I am proposing suggests either that 1) the Crab supernova explosion was asymmetrical in such a manner as to eject its central neutron star outward in our direction, or 2) that the Crab neutron star progenitor was part of a close binary and that its partner star destroyed itself in the explosion and simultaneously ejected and propelled its neutron star partner outward along the pulsar’s current trajectory.  Examples of such hyperfast pulsars are PSR B1508+55 and B1757-24.  An example of B1757-24 is shown in the image below.  If this were the Crab pulsar, we would be far off to the right viewing the pulsar and its nebula face on.

Pulsar B1757-24 in the constellation of Sagittarius

As I pointed out 28 years ago in my dissertation, an impacting superwave would create a bow shock region around the Crab pulsar.  Hence waves of superwave cosmic rays hitting this shock region, travelling way from us into the plane of the sky at the Crab location, would give the appearance to us of concentric rings of X-ray emission expanding away from the Crab pulsar as they proceded in the anticenter direction to the rear of the pulsar.  The shock front generating these moving X-ray rings (in the vicinity of the Nebula’s luminous wisps) may not necessarily correspond with the shock region that I have suggested is responsible for producing the gamma ray synchrotron emission flares.  There may be several such emission nodes in the supernova shell that would be emitting high energy radiation.  But they may not necessarily all be at the same distance relative to a given cosmic ray front in the superwave.  So although the Crab pulsar X-ray rings and the gamma ray flares are both being energized by superwave cosmic rays, they would not necessarily be impacted simultaneously by a given front.  This would explain why no correlative results are seen for the two emission phenomena.

[I would like to point out here that in giving the above explanation I am not constructing a model a posteriori to  fit the data.  My model was proposed 28 years ago and I see no reason to change it.  I am simply explaining how this apriori proposed model would produce the observed results.  In short, findings which astronomers say seem very mysterious, are seen not really to be that mysterious after all.]


Viewing coherent gamma synchrotron emission from the Crab Nebula

In a comment to the previous posting, gmagee has asked why a superwave hitting the entire remnant would  cause us to see a flare, given that the remnant is many light years in size.  He wonders why the emission due to a brief rise in superwave cosmic ray intensity would not average out over the entire remnant, thus preventing us from seeing an intensity change lasting only a few days.

The reason is that we are seeing gamma radiation from a very small area of the Nebula.  We don’t see the majority of the gamma ray emission radiated by the entire Nebula during a gamma ray flare; we only see the gamma emission that is directed precisely in our direction.  In other words, this gamma emission is coherent synchrotron emission, rather than incoherent synchrotron emission.  Consider that the cosmic rays producing this gamma emission are normally considered to have energies of between 1015 to 1016 ev.  This means that the cosmic ray electrons have Lorentz factors (γ) of between 109 and 1010.  Electrons of such high energy beam their gamma synchrotron emission in a narrow cone in the forward direction of their travel where the cone aperture has a half diameter of: θ =  1/γ radians = 10-9 – 10-10 radians.  This equals just 0.2 to 0.02 milliarc seconds!  So when these gamma rays are orbit around magnetic field lines encountered in the Crab’s magnetized plasma sheath, they will beam their radiation in a very limited direction which we will see only when those electrons are aimed towards us in their gyration orbit.  A deviation of more than this angle and their radiation will be entirely invisible to us.  The actual radiation cone that will be beamed out will be wider than this because the superwave cosmic rays impacting the Nebula will have some degree of angular dispersion.  Let us say that the incident volley has an angular variation of 1 degree of arc.  Then cosmic ray electrons spiralling around Nebula field lines a short distance away which beam their radiation, let us say two degrees away from our line of sight will be totally invisible to us.
If you calculate the depth of the Nebula in the line of site (considering that the superwave cosmic rays are travelling away from us toward the Galactic anticenter) then this calculates to d = r (1 – cos θ), where r = 4 light years, the approximate radius of the Nebula.  For θ = 1 degree this calculates to 0.0006 ly, or a depth of 0.2 light days.  So variations in cosmic ray intensity lasting 1 light day or more should certainly be reflected in gamma ray intensity variations of comparable duration.

In 1977 W. Kundt wrote that the incoherent synchrotron emission can only account for ~1% of the optical luminosity in the Crab Nebula’s wisp region and neither can it account for the 1% fraction of the optical emission which is circularly polarized.  This led him to propose that the Crab Nebula was being energized by a cosmic ray “beam” that was producing coherent synchrotron emission, the mechanism we are proposing above.  In particular, he proposed that the emission was being produced by stimulated synchro-Compton emission being beamed toward the observer.  As I pointed out in 1983 (p.177 – 179 of my Ph.d. dissertation), this emission is most likely stimulated by superwave cosmic rays propagating along our line of sight toward the Galactic anticenter and impacting the Crab Nebula.  The pulsar is an unlikely origin for the beamed emission comiing from the wisps since the vector from the pulsar to the wisps makes a large angle with respect to our line of sight.  The superwave source is left as the more plausible alternative.

Kundt, W. “The Wisps in the Crab Nebula: A Cosmic Laser?” Astronomy and Astrophysics 60 (1977):L19.


Crab Nebula flares again

Update to our previous posting about gamma ray flares being observed from the Crab Nebula, ongoing evidence that the nebula is being impacted by superwave cosmic ray electrons.

The Crab Nebula in the constellation of Taurus

BBC News story news story

On April 12th, 2011, the Crab Nebula emitted a gamma ray flare lasting six days that was five times more intense than any of the others that were previously observed and 30 times brighter than the nebula’s normal gamma ray intensity.  On April 16th an even brighter flare occurred but faded out over a period of two days.

As stated in the previous post, I had predicted this high energy variability of the Crab Nebula almost 30 years ago in my Ph.d dissertation and in a subsequent 1987 journal publication.  It is only recently with the launching of the Swift gamma ray telescope that regular measurements of the Crab Nebula at gamma ray frequencies have been made possible.  As I proposed then, the Crab Nebula’s unusually strong luminosity does not originate from its associated neutron star but from a volley of galactic cosmic rays that are striking it face on.  Since this volley can change its intensity quite rapidly, so too the intensity of the Crab Nebula’s emission will change in step.  This would be most noticeable at gamma ray frequencies since the very high energy cosmic rays producing the gamma synchrotron radiation lose their energy quite rapidly, hence intensity changes become more noticeable than at, for example, optical frequencies where the lower energy cosmic rays have lifetimes of many years and hence smooth out any flare activity.

Current claims that the flares are attributable to the Crab’s neutron star are entirely off the mark.  In fact, there is no evidence of any correlated activity in the immediate vicinity of the Crab pulsar.  For example, NASA scientist Martin Weisskopf who was part of a team observing the pulsar with the Chandra X-ray telescope is quoted as stating:

 “Thanks to the Fermi alert, we were fortunate that our planned observations actually occurred when the flares were brightest in gamma rays,” Weisskopf said. “Despite Chandra’s excellent resolution, we detected no obvious changes in the X-ray structures in the nebula and surrounding the pulsar that could be clearly associated with the flare.”

Astronomers are currently at a loss to explain what they are seeing simply because they are ignorant of the superwave theory.  Do your part and inform them.

Gamma/X-ray source GRB 110328A still active

In response to Nick Darby’s comment on the previous post, a few days ago I checked with one of the Swift team astronomers, Jamie Kennea, who said that the source is “still well detected.” Swift observes this source daily and posts the data on the following page on their website ( Enter 110328A in the homepage search box and refer to found links. As seen from the X-ray light curve posted at, the source is still very active with no indication it is dying down, as some astronomers had expected; see graph below.

BAT X-ray intensity from GRB 110328A as of May 10, 2011

This shows that as of the date of this May 10th posting quasar source GRB 110328A has been active for one and a half months. So time is rapidly running out for the black hole snack theory. Those wishing to follow its progress on the Swift website, note that the source is also referred to as Swift J164449.3+573451.

GRB 110328A: First ever observation of a newly formed quasar!

Nascent Quasar GRB 110328A

When a formerly quiescent galactic nucleus is observed by astronomers to suddenly begin radiating high energy emission, it is probably natural for them at first to avoid interpreting the sighting as the birth of a quasar and instead propose something on a far smaller less dramatic scale.  Knowing very well the psychology of his astronomer peers, Sir Fred Hoyle forsaw a similar sighting downplay in his science fiction story The Inferno (1973). His story was about astronomers first sighting the explosion of our own galactic nucleus, its sudden activation into the quasar state.  A passage from his book describes how some members on the astronomical discovery team at first wrongly concluded that what they had discovered was a supernova explosion:

“Except this supernova does seem unusually bright,” interjected Tom Cook.
“Has brightened up still more,” announced Bill Gaynor, who had just come in. “Didn’t go to bed. I stayed up till it rose—in the east, about an hour ago.”
“What is it now?”
“I’d say about minus eight.” [25 times brighter than Venus]
There was a whistle around the common room.
“More like a bloody quasar than a supernova,” muttered someone.
A long silence followed this remark. It was broken by Almond. “Which would explain something that’s been worrying the hell out of me.”
“What’s that, Dr. Almond?” Gaynor asked, his eyes red with lack of sleep.
“Why the position of the thing is so precisely the same as the Galactic center. It’s obvious really, isn’t it? The center of the Galaxy has blown up.” Almond’s deep voice was grave as he made this pronouncement.

The Inferno, Sir Fred Hoyle and Geoffrey Hoyle
passage quoted in Earth Under Fire by P. LaViolette

We may be seeing the same sequence of events playing out in real life with the discovery of the source GRB 110328A which may actually prove to be a quasar, the first ever to be seen turning on.  The initial appearance of this X-ray and gamma ray source was first detected by the Swift telescope on March 28, 2011.  It was found to be located at the center of a galaxy in the constellation of Draco situated about 3.8 billion light years away (z = 0.35).

Seeing that the source continued its highly energetic activity even days afterward, astronomers began to realize that what they had been observing was something other than a mere gamma ray burst (GRB).  Most gamma ray bursts, on the other hand, last from a minute or so to several hours at most.  But in seeking an alternate interpretation, astronomers have leaned towards the less dramatic and proposed that we are observing a “supermassive black hole” that is in the process of tidally disrupting and consuming a passing star.

For example, on April 14th, after the source had been active for over two weeks, astronomers Almeida and De Angelis proposed just this in a paper they had submitted for publication to Astronomy and Astrophysics journal.  They propose that we are seeing a black hole having a mass of ~107 solar masses ripping apart and consuming a red giant star of mass 0.5 to 5 solar masses which had happened to orbit too close to it.  They state that if their theory is correct, we should expect that the intense X-ray emission from GRB 110328A to not last more than a few weeks to a few months, i.e., the time taken for the red giant star’s mass to become completely consumed.  In fact in their April 14th paper to Astronomy and Astrophysics, they state that the emission should be seen to begin to fade within a few days to a few months.

Now more than a week has passed since the date they posted their paper, so the predicted lower limit of a “few days” has been well exceeded.  If the source continues its current variable activity after a few months from now, then like Dr. Almond in Hoyle’s novel, astronomers will be forced to consider the inevitable, that what we are seeing is more like a “bloody quasar” than the transitory burp of a black hole!

I predict that GRB 110328A is a quasar and that we just happen to be viewing it at a point in its cycle when it has happened to turn on.  I would prefer not to call it a supermassive black hole as has become customary in astronomy for the reason that I don’t believe in the existence of black holes.  I prefer to use the more neutral term galactic core or alternatively supermassive mother star.  Here are some facts to consider that favor the interpretation that GRB 110328A is a quasar:

1) the X-ray emission is coming from the exact center of the host galaxy, hence from its core.  Similarly, quasars are known to be galactic nuclei in their active state, hence a galactic core observed during its active phase.

2) the average long-term emission coming from GRB 110328A is seen to have an intensity in the range of what is observed to come from a quasar.  That is, quasars typically have X-ray luminosities that range from 1043 to 1048 ergs/s whereas Almeida and De Angelis report that this object has an average X-ray luminosity of about 2.5 X 1047 erg/s.  So GRB 110328A is near the upper end of the quasar luminosity range.

3) Whereas the X-ray luminosity from quasars is observed to erratically vary by many fold over a period of anywhere from hours to weeks, similarly the emission from GRB 110328A has been observed to vary erratically on a timescale of a few hours to a day, very similar to a more rapidly varying quasar.

4) Like a quasar, GRB 110328A emits synchrotron radio emission.  Radio emission from this source was reported on April 11th by Brunthaler et al.

X-ray intensity light curve for source GRB 110328A

X-ray intensity lightcurve for quasar PDS 456.

Considering that we may be observing for the first time the onset of a quasar, there are several interesting things that we can learn from GRB 110328A.
First we can get an idea about the rapidity of the onset of the quasar state.  The observed event occurred without prior warning and reached maximum intensity within 15 minutes.  I have previously stated that we could expect a similar sneak attack from the core of our own Galaxy.  (GRB 110328A instead lies several billion light years away.  So we need not worry about it.)
Second, when it initially turned on, its luminosity was about 20 times greater than the value it attained days later.  At its initial onset it achieved a luminosity of around 5 X 1048 ergs/s in two peak events separated a day apart.  Hence in its first days it would have been one of the most luminous quasars in the sky.  This is very significant.  For it implies that a first strike from our own galactic core may deliver its most deadly effects in the first day or two, with intensities an order of magnitude greater than what we would later be exposed to.

We will keep you updated with more as this story unfolds.  Meanwhile, for those interested about the core explosion phenomenon, click here.  For those who might have doubts that GRB 110328A is an example of a supermassive black hole tidally disrupting a passing star, and who might be interested in learning of an alternative way to conceive of the supermassive objects that form the cores of galaxies, click here.  For evidence that the core of our own Galaxy is most likely not a supermassive black hole, but a mother star, visit our subquantum kinetics forum ( and in particular the posting entitled “Evidence Against Black Hole in Galactic Core“.  Further evidence against the black hole theory is discussed in the books Subquantum Kinetics and Genesis of the Cosmos.

Is the Crab Nebula being energized by a superwave?

The Crab Nebula in the constellation of Taurus. Courtesy of NASA

In his 1983 Ph.D. dissertation, Paul LaViolette presented the novel theory that most of the radiation coming from the Crab Nebula is not due to cosmic ray emission coming from the Crab pulsar, but rather is produced by a cosmic ray electron volley (a galactic superwave) that is currently propagating toward the galactic anticenter and impacting the remnant face on.  He theorized that these superwave cosmic rays are currently being captured by the magnetized plasma forming the Crab remnant which causes them to emit synchrotron radiation, thus illuminating the nebula.

Recent observations of the occurrence of gamma ray flares in the nebula help support LaViolette’s theory.  Measurements made with the Fermi Gamma Ray Space Telescope have shown that in February 2009 the Crab nebula gamma ray intensity rose by a factor of four over a 16 day period before subsiding back to background levels.  Also on September 2010 its gamma ray intensity rose six fold over a 4 day period.  Details of this are reported in the February 2011 issue of Science magazine.

The cosmic rays producing this gamma emission have such high energies that they cannot travel further than 0.1 light years.  So if the cosmic rays had originated from the Crab pulsar, all of their emission would have had to come from a region 0.2 light years in diameter centered on the pulsar.  However, the Crab pulsar may be ruled out as being the source of these cosmic rays since observations with the Jodrell Bank radio telescope have shown that during these flares there was no change in the pulsar’s radio flux intensity, pulse shape, or rate of pulse period increase; see report in the Astronomer’s Telegram.

Furthermore the astronomers who studied these flares were puzzled by the finding that these gamma flares were necessarily produced by cosmic ray electrons having energies of 10 quadrillion (10 million billion) electron volts.  These were the highest energy cosmic rays ever observed that were able to be traced to a specific astronomical object.  The problem is that astronomers have no idea how a pulsar, like that associated with the Crab nebula, could have accelerated cosmic ray electrons to such a high energy, and have accomplished this acceleration so rapidly.  They say the discovery challenges all theories about how cosmic ray particles are accelerated (see story in Science Daily).

This mystery is easily solved if the cosmic rays producing this gamma ray emission originated from the energetic cosmic ray source residing at the center of our galaxy and are part of a superwave currently impacting the Crab remnant, as suggested by LaViolette.  The flare would indicate that we happened to observe the remnant at a time when it was being impacted by a higher than normal density of ultra relativistic galactic cosmic ray electrons.  As noted from observations of active galactic nuclei, cosmic ray emission intensities can vary considerably.  With this model, the relativistic electrons producing this gamma emission would not be coming from a point source in or near the nebula but would be entering diffusely over the entire nebula.  In the standard explanation, the high energy electrons would be limited to a 0.2 light year diameter region centered on the pulsar before exhausting all of their energy.  According to the superwave theory, these electrons would produce emission covering a much larger region most probably centered on the remnant’s X-ray emission region that would not necessarily be centered on the pulsar.  It would most likely coincide with the X-ray emission that is located to one side of the pulsar.

The other unusual finding reported lately is that the Crab Nebula has been gradually dimming.  Sandberg and Sollerman have found that the optical and infrared emission from the Crab Nebula has been gradually declining in intensity by about 0.7 ± 0.4 % per year (2.9 ± 1.6 mmag/yr) over the past 20 years.  From 2006 to 2009 an even larger increase of about 2% per year is indicated.  Also more recently, besides the discovery of the gamma ray flares, scientists have found that the gamma ray emission intensity from the Crab Nebula has been declining quite rapidly.    Observations with the Fermi gamma ray telescope indicate that since the summer of 2008 its gamma ray intensity has declined about 7%; see stories in e Science News and Before It’s News.  In fact, they have found that its gamma emission has brightened and dimmed three times since 1999 on a timescale of about three years.

Astronomers have been puzzled by this variability since the standard theory predicts that the Crab pulsar radio intensity should show a corresponding decline in intensity, or corresponding variations, but as mentioned above, the pulsar’s intensity instead remains relatively constant.  The superwave theory is not similarly troubled by such intensity variations.  In fact, long-term changes in intensity would be entirely expected as the superwave propagates through the remnant.  Eventually, sometime perhaps within the next millennium or so, after the superwave has completely passed through the nebula on its journey away from the GC, the Crab nebula will cease to shine as it now does.  Its source of illumination will essentially be shut off.

Events triggered by the 40,000 year BP superwave

OC inquired:

“Do you think the C 40,000 BC superwave event had anything to to do with this?  Significant new information shows that the Campanian Ignimbrite (CI) eruption from the Phlegrean Fields, southern Italy, was much larger than hitherto supposed and in fact one of the largest late Quaternary explosive events.  The eruption can be dated to 40,000 calendar years ago, within the interval of the so-called Middle to Upper Paleolithic ‘transition’.  Its position can be precisely correlated with a number of other environmental events, including Heinrich Event 4 (HE4), the Laschamp excursion, and a particular cosmogenic nuclide peak.”

Yes, many of the events you describe here would have been caused by the 40,000 years before present superwave.  Actually the Vostok ice core indicates that the beryllium-10 concentration peak (the cosmogenic nuclide peak) began its rise around 45,000 years before present (B.P.), or around 43,000 years B.C; see the Vostok Be-10 chart below.

Earth's cosmic ray exposure based on the Vostok beryllium-10 deposition rate record

The 40,000 superwave passage date that I had estimated from the observed polar azimuthal extent of the Fermi bubble relative to the galactic plane was based on the assumption that we lie 23,000 light years from the Galactic center.  Other astronomers prefer to use a slightly greater distance estimate of 26,000 light years.  If we were to instead use the 26,000 light year distance value, we would then calculate a superwave passage date of 45,000 years B.P.  So we can say that the Fermi gamma ray bubble predicts that its associated superwave would have passed the Earth between 40 and 45 thousand years ago.

Looking at the Cariaco Basin radiocarbon record, we see that there was also a pronounced and prolonged rise in the atmosphere’s radiocarbon excess.  This began around 44,000 years ago and peaked around 40,000 years ago; see graph below.

Radiocarbon record from the Cariaco Basin ocean sediment core (Hughen, et al. 2004). Arrows indicate times of rapid increase in C-14 excess.

This too was likely due to the arrival of superwave cosmic rays from the Galactic center.  At no time in the past 50,000 years did Earth experience such a pronounced and prolonged rise in atmospheric C-14 concentration.  The superwave would have injected cosmic dust into the solar system and this would have aggravated the Sun causing an increase in severe solar storms.  So it is not surprising that we find the Laschamp excursion coinciding with this event.  Also Heinrich event H5 occurred in the midst of this event (42,000 to 43,000 years B.P.).  As I describe in my dissertation update, Heinrich events mark times of pronounced glacier wave activity when sudden climatic warming caused mountainous waves of glacial meltwater to sweep across the ice sheets and out into the ocean, depositing continental debris far out to sea.  This would be another symptom of a superwave passage.  It is difficult to tell if the CI volcanic eruption was also causally associated with the superwave passage.  For a causal connection one might either look to isostatic changes due to ice sheet thickening or thinning, or to gravity wave effects.

OC further inquired:

“Regarding the beryllium-10 concentration peaks (please remember I’m not a scientist), there is one around the time of the Toba super-volcano explosion … roughly 73,000 BC as well.  What could be said about that event with relation to a superwave event (gravity wave connected?), or do we know?”

This is an interesting observation.  Two major volcanic eruptions appear to correlate with the dates of major Be-10 peaks in the Vostok record, i.e., with passage dates of major superwaves.  It would be interesting to do a complete statistical analysis of volcanic eruption dates to see if a sound correlation is found with Be-10 peak dates.  I have not done this.

P. LaV.