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Fraser
2007-Jun-12, 04:25 PM
Gamma ray bursts are the most powerful explosions in the Universe, emitting more energy in an instant than our Sun can give off in its entire lifetime. ...

Read the full blog entry (http://www.universetoday.com/2007/06/12/gamma-ray-bursts-eject-matter-at-nearly-the-speed-of-light/)

trinitree88
2007-Jun-12, 06:02 PM
Gamma ray bursts are the most powerful explosions in the Universe, emitting more energy in an instant than our Sun can give off in its entire lifetime. ...

Read the full blog entry (http://www.universetoday.com/2007/06/12/gamma-ray-bursts-eject-matter-at-nearly-the-speed-of-light/)

Fraser. I believe the ESO has been pre-empted on this by the Work of Peter Nissenson and Costas Papaliolios, in 1988. As has been previously stated in my posts on supernovae, they prefer a prolate spheroidal ejection symmetry, in a surprising turn on their favored equatorial escape velocities. Following Supernova 1987a, these two gentlemen found that speckle interferometric images of the remnant yielded a mysterious "Spot" escaping at relativistic velocities. Widely ridiculed in the press at the time, as Son of Supernova, and an artifact of their image processing, Mssrs. Nissenson and Papaliolios stuck to their guns. They later showed, with improved image processing algorithms, that a second jet was formed also, and published the result also.
Strange, what garnered them ridicule in 1988, is now state-of-the-art, coming out of the ESO. (I've worked briefly with Peter....one of the most meticulous experimentalists I've ever seen...). It'd be nice to see him get credit for his discovery, superceding this blog by almost twenty years.....or is this going to go under the "Some are more equal than others"clause in physics....too? Ah Ah Ah. Ahhh. :shifty:Pete.
see:http://www.astro.uiuc.edu/mcnews/newsletters/newsletter32/newsletter32.html

Northwind
2007-Jun-13, 07:16 AM
It'd be nice to see him get credit for his discovery, superceding this blog by almost twenty years.....or is this going to go under the "Some are more equal than others"clause in physics....too?


It does appear that something is on the change in the "mainstream" :lol: It's getting very hard now to hide the inconsistencies and outright lies!

If Tt88 had not bought this to our attention, the ESO would be credited with this discovery!

And I am reading the title right, that it's matter that it's ejecting?

trinitree88
2007-Jun-13, 08:33 AM
snippet:

And I am reading the title right, that it's matter that it's ejecting?

Northwind; A spherically symmetric explosion would give a fireball that follows inverse square law meticulously. Eventually, the expanding ejecta with escape velocity will cool, thin, and reveal the pulsar. No asymmetry, no movement of center of mass. No movement of center of mass, no gravitational wave.
This is rare. The shapes of SN remnants, whether 1a, or 2's....are predominantly barrels. Many are empty...(~495/500...Kesteven). Free floating, high transverse velocity pulsars, young and old are found, in absentia of remnants. The birth kicks, predicted by Schlovskii (circa 1976)...are seen (Bailes).That speaks of asymmetry. When that happens, the envelope opens up on one side. The gamma ray burst is emitted from a beamed birthing. The jets, slightly asymmetrical, emerge at relativistivc velocities. Even the neutrino burst will have an asymmetry due to parity effects in weak interactions. They are universal there. The argument for inverse square law fails the morphological characteristics of the known remnants, (Molonglo, Kesteven, Manchester, et al ),and the transverse velocities seen, requiring polarimetric data to characterize it properly as it depends on viewing angle. (This was communicated to Kirshner et al following the 1992 Vassar AAPT Meeting by T. Nicastro, and others.). Patience. Pete.

Mortac
2007-Jun-13, 12:29 PM
What would happen if one of these would hit the Earth straight on?

John Mendenhall
2007-Jun-13, 02:14 PM
What would happen if one of these would hit the Earth straight on?

Luckily, a really improbable event.

With respect to Trinity's post, incorrect crediting is a widespread problem. There may be an opportunity, with the Internet available, to fix things. For example, Jupiter's rings were predicted on the basis of observation of shadows decades before Voyager, and the idea was poopoo'ed.

Argos
2007-Jun-13, 02:18 PM
What would happen if one of these would hit the Earth straight on?

Actually, it happens all the time, since we can detect them. ;)

John Mendenhall
2007-Jun-13, 02:22 PM
Actually, it happens all the time, since we can detect them. ;)

The gamma rays, not the pulsar, right?

Don Alexander
2007-Jun-13, 02:48 PM
Hm, what you all seem to be missing is that SN1987A had nothing to do with Gamma-Ray Bursts. This was a subliminous Type II SN with a blue supergiant progenitor, while GRBs originate in Type Ic SNe deriving from stripped-envelope Wolf-Rayet Progenitors. Also, they are associated with the formation of black holes, not neutron stars.

D. A. Kann
Thueringer Landessternwarte Tautenburg
PhD student, Gamma-Ray Burst Afterglow Collaboration at ESO

trinitree88
2007-Jun-13, 03:49 PM
Hm, what you all seem to be missing is that SN1987A had nothing to do with Gamma-Ray Bursts. This was a subliminous Type II SN with a blue supergiant progenitor, while GRBs originate in Type Ic SNe deriving from stripped-envelope Wolf-Rayet Progenitors. Also, they are associated with the formation of black holes, not neutron stars.

D. A. Kann
Thueringer Landessternwarte Tautenburg
PhD student, Gamma-Ray Burst Afterglow Collaboration at ESO

Don. At least some evidence exists for correlation of GRB's and type 2's. I'd be quite surprised, (but wrong ) if they only occur in a subset of type 1's. With the annihilation of electron/positron pairs occuring wholesale in the core collapse, sure to create gamma rays, and the rapid deformation of the nascent fireball, for them all to attenuate to x-rays, and on down seems unlikely at best. see:http://apod.nasa.gov/apod/ap030414.html
pete

stevenspray
2007-Jun-13, 03:54 PM
Yeah I wonder what is meant by ''matter'' in that blog? Matter is defined to have mass and this mass is been ejected at almost the speed of light!! How 'big' can one assume this mass to be? Surely it should be ripped appart by traveling at nearly the speed of light?


What would happen if one of these would hit the Earth straight on?

What would happen then if this ejected ''matter''(Not photons) hits the earth? (Not that we are in danger of this)

Jerry
2007-Jun-13, 04:20 PM
Hm, what you all seem to be missing is that SN1987A had nothing to do with Gamma-Ray Bursts. This was a subliminous Type II SN with a blue supergiant progenitor, while GRBs originate in Type Ic SNe deriving from stripped-envelope Wolf-Rayet Progenitors. Also, they are associated with the formation of black holes, not neutron stars.

see http://arxiv.org/PS_cache/astro-ph/pdf/9904/9904147v2.pdf

A Possible Lateral Gamma-Ray Burst Jet from Supernova 1987A

Also

http://arxiv.org/PS_cache/arxiv/pdf/0705/0705.3846v1.pdf

The SN 1987A Link to Gamma-Ray Bursts

The gamma ray burst associated with 1987A was relatively small, but the link is quite undeniable. No one knows for certain what the source is of the most powerful gamma rays. The latest GLAST papers indicate there is not always an observable optical counterpart...but whether this is real, or due to optical opacity in the source galaxy is somewhat up in the air.

Tree, I have heard that Peter Nissenson and Costas Papaliolios had their funding pulled after publishing such a foolish result. (My notes say Nilsson, so I wonder if I have the right 'apple'). It is not uncommon for the ESA to claim firsts that are actually seconds, thirds or fifths.

jonnyz
2007-Jun-13, 04:22 PM
Yeah I wonder what is meant by ''matter'' in that blog? Matter is defined to have mass and this mass is been ejected at almost the speed of light!! How 'big' can one assume this mass to be?

Thats exactly what i was wondering! Funny thing i was reading ABHOT yesterday...
"Because of the equivalence of energy and mass, the energy which an object has due to its motion will add to its mass. In other words, it will make it harder to increase its speed. This effect is only really significant for objects moving at speeds close to the speed of light. For example, at 10 % of the speed of light an objects mass is only 0.5% more than normal, while at 90% of the speed of light it would be more than twice its normal mass. As an object approaches the speed of light, its mass rises ever more quickly, so it takes more and more energy to speed it up further. It can in fact never reach the speed of light, because by then its mass would have become infinite, and by the equivalence of mass and energy, it would have taken an infinite amount of energy to get it there. For this reason, any normal object is forever confined by relativity to move at speeds slower than the speed of light. Only light, or other waves that have no intrinsic mass, can move at the speed of light."pg21

So is the 'matter' ejected radiation?

Jerry
2007-Jun-13, 05:13 PM
So is the 'matter' ejected radiation?
No. The matter is matter with humongus linear kinetic energy. It is emitting radiation that is highly blue shifted, relative to the position of the source galaxy. There is considerable room for debate about whether a conventional mechanism could be responsible for accelerating matter to this potential, or if new physics are required.

Don Alexander
2007-Jun-13, 06:31 PM
Okay, I assume I'll soon be labeled one of those braindead scientists who do not accept that alternative theories are the truth...

trinitree88 writes:

> Don. At least some evidence exists for correlation of GRB's and type 2's.

Really? Please, give me some citations. There are four spectroscopically confirmed supernovae associated with GRBs (SN 1998bw/GRB 980425, SN 2003dh/GRB 030329, SN 2003lw/GRB 031203, SN 2006aj/XRF 060218), and several more cases where the spectra are not good enough for classification. In all four cases, SNe of Type Ic (not even Ib) were found. Actually, I'm co-author on the Nature paper on the discovery of SN 2006aj, so I know a little bit what I'm talking about.

Here's a good review of the topic:

http://arxiv.org/abs/astro-ph/0609142

> With the annihilation of electron/positron pairs occuring wholesale in the
> core collapse, sure to create gamma rays,

Actually, it's the other way around. The extremely dense and hot accretion disk creates a relativistic neutrino/anti-neutrino wind which then creates an electron-positron pair production plasma. Any gamma-rays produced here have no chance of getting outside. The GRB itself is not produced until the jet is way outside the star, by the acceleration of electrons in collisionless shocks in the jet. These electrons spiral along field lines and produce synchrotron radiation which they emit into a strongly collimated cone (relativistic beaming). Independent of how this jet was accelerated, this is known as the "standard fireball model". It's quite accepted theory.

> see:http://apod.nasa.gov/apod/ap030414.html

Um?? Quoting... APOD?? First of all, the picture has absolutely nothing to do with GRB 030329. Secondly, the supernova associated with GRB 030329 was clearly of Type Ic.

Check out:

http://arxiv.org/abs/astro-ph/0306347
http://arxiv.org/abs/astro-ph/0304173
http://arxiv.org/abs/astro-ph/0307435
http://arxiv.org/abs/astro-ph/0309555

Jerry writes:

> see http://arxiv.org/PS_cache/astro-ph/p.../9904147v2.pdf

Thanks for the link. This is actually published in ApJ, so it can't be that stupid. But still, it's only a theoretical model to a few data points with large errors...

> The gamma ray burst associated with 1987A was relatively small,

Um, there was no GRB associated with SN 1987A?? There were detectors orbiting Earth that would have caught it, but nothing was measured.

> but the link is quite undeniable.

Really?? Some observations claim to see something what might be jetted emission. I've been working in the GRB field for some years now and this was the first time I heard of it. What does that tell us??

> The latest GLAST papers indicate there is not always an observable optical > counterpart...

What does this have to do with GLAST?? GLAST is not even launched yet... Do you mean Swift?? The problem of the "dark bursts" has existed long before Swift. I have worked on it myself.

> but whether this is real, or due to optical opacity in the source galaxy is
> somewhat up in the air.

True, it's as yet unsolved. Here's a super-recent paper on one dark burst that can be explained very well by a large amount of dust in it's host:

http://arxiv.org/abs/0706.1518

> No. The matter is matter with humongus linear kinetic energy.

Actually... It is still unclear if the jet is matter-dominated (electron-positron plasma) or Poynting-flux dominated (pure radiation field).

> There is considerable room for debate about whether a conventional
> mechanism could be responsible for accelerating matter to this potential,
> or if new physics are required.

The concrete workings of the central engine are still not fully understood, true. The favored model is the Blandford-Sznajek mechanism, in which energy is extracted from a rapidly spinning black hole by magnetic fields that permeate the event horizon and are thus "spun up". Matter moving along these magnetic fields would probably form polar jets. But accretion disc winds and neutrino emission probably also play an important role. The physics is so messy that no one can numerically model the whole process with today's computers.

Hope this answers some questions.

Alex

PS.: Can someone teach me the command to make these nice quote boxes?? I'm an idiot when it comes to HTML...

Argos
2007-Jun-13, 07:05 PM
PS.: Can someone teach me the command to make these nice quote boxes?? I'm an idiot when it comes to HTML...

Even my blind grandma can do it with a single hand...:)

Use:
Insert text

RussT
2007-Jun-13, 10:39 PM
PS.: Can someone teach me the command to make these nice quote boxes?? I'm an idiot when it comes to HTML...

Even my blind grandma can do it with a single hand...:)

Use:

This is simply "Unkind"!!! And uncalled for!

Don, I too had difficulties with this when I first came here.

The [......] QUOTE inside the [] needs to be all CAPS and the [/.....] also all CAPS. That puts whatever you want to quote in the box.

And if you are quoting something 'someone' said you...
use the QUOTE=name] with the [ in front of the QUOTE of course.


with the [/ in caps at the end.

Argos
2007-Jun-14, 02:16 PM
This is simply "Unkind"!!! And uncalled for!

??????Donīt you have sense of humor???????? :)


The [......] QUOTE inside the [] needs to be all CAPS and the [/.....] also all CAPS.

No, it is not necessary.

trinitree88
2007-Jun-14, 04:35 PM
Don Alexander. 1. I'm a little confused by the expression..."creates a relativistic neutrino/anti-neutrino wind"...as neutrinos are only distinguishable from anti-neutrinos by being massless and always traveling at c, wouldn't the expression only pertain to massive neutrinos (which are not as yet incontrovertibly proven ?)....which are not distinguishable from their anti-particles?
2. If NASA erred in their identification of text in APOD...that'd be one more error to correct, to be sure.
3. as a point of order...Why is a hypernova classified 1c, with a core collapse like a type 2? The original 1a was for binary red super/white dwarf companion. The original type 2 core collapse. Why not 2b,2c for a hypernova? The nomenclature, using 1c seems to create unnecessary confusion....what's the rationale there?
pete

Don Alexander
2007-Jun-14, 05:22 PM
Thanks, first of all, to Argos and RussT


1. I'm a little confused by the expression..."creates a relativistic neutrino/anti-neutrino wind"...as neutrinos are only distinguishable from anti-neutrinos by being massless and always traveling at c, wouldn't the expression only pertain to massive neutrinos (which are not as yet incontrovertibly proven ?)....which are not distinguishable from their anti-particles?

Well, now, first of all, I deem the evidence for a non-negligible mass of neutrinos to have become quite convincing. Everything points to neutrinos being able to transform into other types of neutrinos, and this is only possible if they have mass. In the equation that regulates this, there is a trigonometric function multiplied by the mass. Set the mass to 0, and the varying term disappears, no transformations are possible.

On the other hand, you do touch a point. It is still unknown if neutrinos are Dirac or Maiorana particles. Possibly, neutrinos and anti-neutrinos are identical. But there are indications that neutrinos and anti-neutrinos have different chiralities.

I basically stated "neutrino/anti-neutrino wind" because particle production from photons always produces particles and their anti-particles to preserve certain quantum numbers. This is very obvious in electron/positron production, as photons are chargeless, and thus we must have charges of +1 and -1 to produce 0. But there are also things like lepton numbers, and in the case of neutrinos, these should also be preserved, and photons, being bosons, have lepton number 0, similar to the case of charge.


2. If NASA erred in their identification of text in APOD...that'd be one more error to correct, to be sure.

Well, at the time that APOD came out, the analyses were probably still quite preliminary.


3. as a point of order...Why is a hypernova classified 1c, with a core collapse like a type 2? The original 1a was for binary red super/white dwarf companion. The original type 2 core collapse. Why not 2b,2c for a hypernova? The nomenclature, using 1c seems to create unnecessary confusion....what's the rationale there?

Very good point! The problem is that initially, supernovae were classified by their spectra, at a time when no one really even knew what a supernova was. Type I SNe had no lines of hydrogen, Type II SNe did. Type Ib/c also have no lines of hydrogen in their spectra, so they were lumped into the Type I category. But of course Type Ia (thermonuclear runaway detonation of a white dwarf reaching the Chandrasekhar mass) and Type Ib/c + Type II (core collapse of massive stars) are quite different phenomena...

So, basically, it's a historic artifact and a mess.

Hope this clears things up.

Alex

One Skunk Todd
2007-Jun-14, 07:28 PM
Need to change the direction of the slash mark [/quote] not [\quote] to make it work.

Nick4
2007-Jun-15, 06:17 AM
What would happen if one of these would hit the Earth straight on?

There are always particals hitting the earth going about the speed of light they go right through it and you.