This defintely deserves its own thread!

Here are the relevent posts in order.

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RussT
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Everything is, as it should be, otherwise, it wouldn't be!

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RussT
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Everything is, as it should be, otherwise, it wouldn't be!

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RussT
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Everything is, as it should be, otherwise, it wouldn't be!

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RussT
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Everything is, as it should be, otherwise, it wouldn't be!

Sorry if you got that impression SM, but you have totally misunderstood my intensions.

The first link I got on that was Wiki, which is why I linked the lower article. But I then realized that that was Universe Today, and so felt it important to link the original Chandra release, so everyone could see the 'Top in their field' direct remarks, without being edited by another science writer.

I also felt that it was important to give different sources so any 'uncertainties'
or in my estimation 'misinterpretations' could possibly be easier for others to see.

Any other "Pro's" want to add their quick evaluations?

Here are the 3 links again.

http://en.wikipedia.org/wiki/SN_2006gy

http://www.universetoday.com/2007/05...est-supernova/

http://www.nasa.gov/mission_pages/ch...supernova.html

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RussT
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Everything is, as it should be, otherwise, it wouldn't be!

No pro here. But what needs to be added? after StupendousMan pointed out, "This supernova was classified as a Type II event... consistently."

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Everyone is entitled to his own opinion, but not his own facts.

I think this is the big story here:

"In terms of the effect on the early universe, there's a huge difference between these two possibilities," said Smith. "One pollutes the galaxy with large quantities of newly made elements and the other locks them up forever in a black hole."

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Everyone is entitled to his own opinion, but not his own facts.

It has also been pointed out, consistently, that this is much, much brighter than your garden variety type II supernovae, surpassing all type Ia supernovae in brilliance, and even though there is a hydrogen envelope, many phases of the spectral development have been more like a 'type Ia' than a 'type II'. This is exceedling strange from the prospective of what normally separates a type II from a type Ia. It is not enough to write it off as weird: It is weird in a way that, at very high redshift, it could easily be mistaken as a type Ia with a much lower absolute magnitude. The potential here, is that these kind of events completely compromise cosmology developed using type Ia as standard candles.

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jwj

It's ok not to know. We should try harder to find out.

Is this consistently in agreement with current thinking?

Are there NEW physics here? IE;...

And, based on this, and that the star supposedly fully exploded, without leaving a black hole, can we safely say that this was NOT "Beamed"?

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RussT
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Everything is, as it should be, otherwise, it wouldn't be!

I've just read two preprints on SN 2006gy which show in detail the spectrum of this supernova, and supernovae of other types:

http://xxx.lanl.gov/abs/astro-ph/0612617
http://xxx.lanl.gov/abs/astro-ph/0612408

The spectra of SN 2006gy are dominated by a blue continuum and strong H-alpha emission line, at early times and for many weeks after maximum light. They are not at all like the spectra of normal Type Ia supernovae.

Since neither the light curve, nor the spectra, of SN 2006gy are similar to those of Type Ia supernovae, and since this event is unprecedented -- and hence very very likely one of a very rare class of events -- your claim

has no evidence to support it.

Smith, Li, Foley, Wheeler, Pooley, Chornock, Filippenko, Silverman, Quimby, Bloom and Hansen conclusion is that this was not a type II event, not mine! Also, from the same reference:

Ofek et als proposal, not mine. If Ofek is correct, and an event like this was viewed from the 'SNe Ia' side, the hydrogen lines would likely not be visible. If this were the case, it would be much more like an overly-bright SNe Ia than your garden variety type II - the evidence definitely supports my variation on this theme, if both sets of authors are partially correct.

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jwj

It's ok not to know. We should try harder to find out.

Jerry has claimed that the peculiar SN 2006g, and other events like it, might be confused with ordinary Type Ia SNe at large distances, and thus introduce errors into cosmological calculations.

I have written that this event was never confused with an ordinary Type Ia supernovae, and that others like it would not be, for two reasons: its spectrum is unlike that of an ordinary Type Ia (SN 2006gy shows a blue continuum and strong H-alpha emission near maximum light), and its light curve is also unlike those of Type Ia events (being much more luminous and slower to decline).

I provided two preprints to buttress my claims.

Jerry replied -- see his message preceding this one -- with two points. He states that Smith et al. reject the hypothesis that SN 2006gy was a "Type IIa" supernova. Yes, that's right, and it supports my claims. A "Type IIa" supernova refers to the thermonuclear explosion of a white dwarf which happens to be surrounded by a very dense circumstellar envelope. Smith et al. show that this is unlikely in the case of SN 2006gy from an energetic standpoint, and because it is inconsistent with the X-ray emission detected by Chandra. They prefer a model in which a very massive star with a considerable hydrogen envelope explodes, perhaps within a dense circumstellar medium. In other words, Smith et al. see the evidence pointing towards a core-collapse SN, albeit a peculiar one. Not a Type Ia event. Not only was this event called "Type II" from the start, from an observational point of view, it now seems most likely to have been a Type II core collapse from a theoretical point of view.

That is what I claimed: this was not a Type Ia, nor would it be confused with one.

Jerry also notes that Ofek et al. (the other preprint) suggest that this might have been a Type Ia thermonuclear explosion which occurred within a dense circumstellar medium. However, had he gone on to read the paper, he would have seen that Ofek et al. also reject this hypothesis and suggest that the event was due to the core-collapse of a massive star. So, although they considered a Type Ia-type explosion from a theoretical point of view, they also rejected it.

Neither of the papers supports Jerry's claims.

I'm getting really tired of spending time replying point-by-point to correct Jerry's incorrect claims. I think I may just quit -- what's the point?

Gentlemen, Gentlemen and Ladies;

You are BOTH missing the point entirely!

Yes, Jerry is "Stuck" on 1a's, but he has been partially right all along.

SM, why didn't you respond to my questions above?

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RussT
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Everything is, as it should be, otherwise, it wouldn't be!

What do those questions mean? Why do any of those questions matter?

But why did they reject the possibility that this unusual event does not involve a Ia event with a stellar companion?

What they are saying is that this explosion was too bright to be a textbook type Ia, therefore it could not be one. But that is my argument: It can only be a binary event with a Ia type as one of the core components, if the textbook is wrong about the total energy that a type Ia, as defined by spectral energy distribution, can muster in a binary system. If, in a similar instance, both binary parents happen to be white dwarf stars, this type of event could be exceptionally bright and have an exceptionally long light curve, but not reveal a hydrogen envelope.

This event was many, many times brighter than a typical type II supernova (which are not typically as bright as type Ia), so if luminocity is a criteria for rejecting the supposition that it is a type Ia, luminocity should also be an acceptable criteria for rejecting the notion that this is a type II event.

Clearly this event was too bright to be a garden variety type Ia or type II. Like every other hypernova event, it casts a shadow upon all of the assumptions that are necessary to conclude that type Ia supernova represent a unique class that is easily descernable from other events at high redshifts. Since the hypernova class of events are up to two orders of magnitude brighter than type Ia, over time, we should expect hypernova events to dominate the most distant, magnituded - limited sample of observations. Otherwise, it should be strongly suspected that the absolute magnitude of the most distant events is underestimated.

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jwj

It's ok not to know. We should try harder to find out.

Luminosity is only one of the defining parameters. SN2006gy had hydrogen in it spectra and a brighter/longer duration light curve than SN1a.

SN2006gy is by no estimate a “typical” event.

While the spectra data is sufficient to dismiss the event as a type I, all the evidence combined would tend to suggest an atypical type II event. Perhaps even a new class of type II.

Or can you provide conclusive evidence to demonstrate otherwise?

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"I just have not come across anything that explains what I am trying to suggest."
- EU proponent not wanting credit for statement

Since all supernova with hydrogen envelopes are classified as type II, this event is type II. However, in formulating this definition, it was assumed that if the hydrogen envelope was still intact, there could not be such an energetic (thermal nucleur(?)) event, eclipsing type Ia events in absolute magnitude. A new class seems appropriate. IIp3?

I think Smith et al put it best:

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jwj

It's ok not to know. We should try harder to find out.