Detection of circumstellar material in a normal Type Ia

http://xxx.lanl.gov/PS_cache/arxiv/p...707.2793v1.pdf

If the hydrogen line detected was supplied by a companion star, this also explains how other supernovae with primarily type Ia spectral signatures could have hydrogen emission lines in the spectra.

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

http://arxiv.org/PS_cache/arxiv/pdf/...708.0140v2.pdf

[B}Optical and Near-Infrared Observations of the Highly Reddened,
Rapidly Expanding Type Ia Supernova 2006X in M100[/b]

Highest observed velocity of the ejecta, and a slow decline in the Blue magnitude. This is a local event. If this were viewed from a cosmic distance before this local event occurred, how would this event be interpreted?

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Interesting, Jerry. Higher ejecta velocities mean higher temperatures, which means greater luminosity. It'll be nice to see one of these without the extra reddening which somewhat compensates things. That'll be trickier to fit for your average country bear. Thanks. Pete

__________________
A third rate theory forbids.
A second rate theory explains after the fact.
A first rate theory predicts.
A. Lomonosov

Distribution of 56Ni Yields for Type Ia Supernovae and Implications for Their Progenitors

Bo Wang1,2 ⋆, Xiang-Cun Meng1,2, Xiao-Feng Wang3,4 and Zhan-Wen Han1

Broadening the expected absolute absolute magnitude range of supernova Ia explosions greatly increased the probability that the most distant events we observe are very bright.

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Jerry. I'm not so sure the tacit assumption that an order of magnitude increase of nickel holds here. Once again, the relative distribution of ejecta is not isotropic (which would lead to spherical remnants), but polar preferential(which leads to prolate spheroids seen in the radio maps at Molonglo.).So, the expectation that more nickel seen from this viewing angle means more nickel seen over the entire fireball is not true. The galactic alignment of most progenitors due to galactic magnetic fields, which bears watching with Cepheids' pulsations too, means a viewing angle correction may be necessary. pete

__________________
A third rate theory forbids.
A second rate theory explains after the fact.
A first rate theory predicts.
A. Lomonosov

There is also the possibility that rotation inertia plays a roll; and there is the hypothesis of John Middleditch that virtually all supernovae a binary events that are differentiated primarily by viewing angle: New paper:

http://xxx.lanl.gov/PS_cache/arxiv/p...708.2263v1.pdf

The mainstream position remains that carefully characterized type Ia supernova are a special class of events in which the absolute magnitude is a function of strick mass and compositional boundaries. The observations noted in this thread do not support this simplistic approach in using supernovae to measure cosmic distance. Multiple parameterics come into play.

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

You confuse two different aspects of supernova research: 1) their composition, 2) their phenomenological properties.

Now undoubtedly, 1) causes 2). Yet different theories as to the nature of 1) do not actually change the observed results of 2).

Gravity could be caused by little elves, yet this would not change the measured properties of gravity. Similarly, type 1a supernovae could result when elves blow out their birthday-cakes. This would mean that there are all sorts of parameters: chocolate/vanilla cake, different frostings, the use of roman candles as well as normal candles, etc. The measured dispersion of these things remains the same, however.

Normalizing at a redshift of z=0.48 provides a balanced fulcrum with the specific set of supernova available at that time. As the population of higher redshift supernova observed increased, and these supernovae were added to the distribution, there was a possible trend towards smaller ‘stretch’ factors (personal private communication) and the data reduction method was abandoned.

To my knowledge, there has only been one study using stretch factors since 2002:

http://arxiv.org/PS_cache/astro-ph/p.../0607363v3.pdf

In this paper on supernova rise times, and they split the sample at a higher redshift (z=0.589) for statistical comparisons. Normalizing about a midpoint is an acceptable analytical technique when the baseline is uncertain, but it is fraught with potential errors. Specifically, off-setting biases will skew the slope of the curve, but provide the analyst with a false sense of security (been there, done that!). I think normalizing about the midpoint is inappropriate for any application where the underlying physics are not completely characterized. It should not be necessary when comparing supernova rise times: Either they are consistent at all redshifts (after time dilation corrections), or they are not.



I wish they would publish the raw curves - what is the distribution of the rise times before-and-after correction for time dilation, and before-and-after the stretch-factor normalization?

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Addressing, again, an old question of mine does not dismiss the confusion of your posts between actual observations and speculation about the composition.

Most of the time, this is a valid syllogism, but supernova research is exceptional. The essential assumption in using supernova as standard candles is that the mass of each-and-every 'type Ia' event is very near the Chandrashakar critical mass of 1.6 solar. In ~1994 Liebengut and others used this anticipated property to establish that there is time-dilation in the most distant supernova observations, the evidence of which is the much longer and therefore time-dilated light curves.

As a purely phenomenological assumption, this is no longer valid: We have seen light-curves in near-local supernova events that are longer than the light-curves available in 1994. So the question today should be: Are the more distant events more like the average, or more like the brightest and slowest burning of the locally-observed supernova events? This is where polarity, nickel content, expansion velocity, light curve shape, environment and other measurements of diversity in supernova events becomes critical. Once we know what makes some supernova events burn brighter and last longer, we can revisit the light curves of the most distant events and determine if they are truly time-dilated.

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

There is more to supernova work than light curves -- spectra provide a great deal of information about the physical properties of the ejecta. Using good spectra, one can answer some questions about symmetry, nickel content, expansion velocity, the environment, etc.

I suggest that you do some reading in the literature. Look to see how many of the distant events have well-measured spectra, and how those spectra compare to those of nearby events.

You have yet to provide one cosmological SNIa paper that relies upon this assumption. Why do you continue to make this claim?

http://arxiv.org/PS_cache/astro-ph/p.../0609616v1.pdf

The type Ia supernova SNLS-03D3bb from a super-
Chandrasekhar-mass white dwarf star

Frankly, this non-Standard Candle event blows-out the cosmological claims made using earlier supernova samples that did not anticipate superluminous events. We have no idea what percentage of the high redshift supernova observed are queer. What we do know is selection effects favor finding the brightest events at the greatest distances; meaning the high redshift sample may be absolutely saturated with over-brilliant supernovae.

In this later study (released today):

http://arxiv.org/PS_cache/arxiv/pdf/...709.0859v1.pdf

Some of the spectra are similar to the arch-type overluminous supernovae 1991T; yet the authors conclude they are all normal type Ia. None of the supernova spectra observed in this high redshift study are classified as underluminous or overluminous events; even though using current estimates of extinction, there should be a few subluminous events observed, and many overluminous events like the few we see in the local sample. Evolution is one possibility. Grossly underestimated extinction rates is another.

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

http://xxx.lanl.gov/PS_cache/astro-p.../9805201v1.pdf

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jwj

It's a big universe out there...is it really unwinding, really burning out?

Yes, that is a supernova paper that mentions some theoretical astrophysics about the object of study. Yet nowhere does the paper endorse or rely upon that hypothesis.

I assume that you read the paper, so do you continue to make this claim that SNIa cosmology relies on this theoretical model?

I also assume that you have noted that it is nine years old, and that most type 1a observations, including the must accurate and detailed ones, have happened since then.

__________________
Forming opinions as we speak

Newsgroups: sci.astro, alt.sci.planetary, sci.physics, sci.geo.geology
From: rgregorycl...@yahoo.com (Robert Clark)
Date: 8 Jan 2004 01:20:35 -0800
Local: Thurs, Jan 8 2004 5:20 am
Subject: Type I supernovae due to planetary impacts?

The news release below discusses observations of a companion star to a
Type I supernova. It mentions that there had been difficulty
confirming the theory that a companion star was necessary for Type I
supernova to occur.
This page also discusses the difficulty in confirming the theory for
Type Ia supernovae:

Source for major type of supernova explosions found
NATIONAL OPTICAL ASTRONOMY OBSERVATORY NEWS RELEASE
Posted: August 6, 2003
"The search for a progenitor for Type Ia supernovae has gone on for so
long that it almost became a point of embarrassment for scientists in
the field," Suntzeff notes. "Supernova 2002ic may not be the prototype
for all Type Ia's, but it is certainly the first crack in the puzzle."
http://spaceflightnow.com/news/n0308/06supernova/

I've been wondering if celestial impacts are common in stellar system
evolution:

From: Robert Clark (rgregorycl...@yahoo.com)
Subject: Re - Strangest Star known is the 'Talk of Astronomy'
Newsgroups: sci.astro, alt.astronomy, sci.physics, alt.fan.art-bell
Date: 2003-09-18 05:27:30 PST
http://groups.google.com/groups?selm...ing.google.com


Then the explosions seen in Type I supernovae may be due to impacts
of planets to their parent star. This would explain the high amount of
heavy metals seen in such explosions.
In these latest observations of companion stars to the supernovae,
this might be due to the rare cases of planetary systems in binary or
multiple star systems (the rarity being due to gravitational
instability.)


Bob Clark



************************************************** ***********************
European Space Agency
Science News Release SNR 1-2004
Paris, France 7 January 2004


First supernova companion star found


A joint European/University of Hawaii team of astronomers has for the
first time
observed a stellar 'survivor' to emerge from a double star system
involving an
exploded supernova.


Supernovae are some of the most significant sources of chemical
elements in the
Universe, and they are at the heart of our understanding of the
evolution of
galaxies.


Supernovae are some of the most violent events in the Universe. For
many years
astronomers have thought that they occur in either solitary massive
stars (Type
II supernovae) or in a binary system where the companion star plays an
important
role (Type I supernovae). However no one has been able to observe any
such
companion star. It has even been speculated that the companion stars
might not
survive the actual explosion ...


The second brightest supernova discovered in modern times, SN 1993J,
was found
in the beautiful spiral galaxy M81 on 28 March 1993. From archival
images of
this galaxy taken before the explosion, a red supergiant was
identified as the
mother star in 1993 -- only the second time astronomers have actually
seen the
progenitor of a supernova explosion (the first was SN 1987A, the
supernova that
exploded in 1987 in our neighbouring galaxy, the Large Magellanic
Cloud).


Initially rather ordinary, SN 1993J began to puzzle astronomers as its
ejecta
seemed too rich in the chemical element helium and instead of fading
normally it
showed a bizarre sharp increase in brightness. The astronomers
realised that a
normal red supergiant alone could not have given rise to such a weird
supernova.
It was suggested that the red supergiant orbited a companion star that
had
shredded its outer layers just before the explosion.


Ten years after this cataclysmic event, a European/University of
Hawaii team of
astronomers has now peered deep into the glowing remnants of SN 1993J
using the
NASA/ESA Hubble Space Telescope's Advanced Camera for Surveys (ACS)
and the
giant Keck telescope on Mauna Kea in Hawaii. They have discovered a
massive star
exactly at the position of the supernova that is the long sought
companion to
the supernova progenitor.


This is the first supernova companion star ever to be detected and it
represents
a triumph for the theoretical models. In addition, this observation
allows a
detailed investigation of the stellar physics leading to supernova
explosions.
It is now clear that during the last 250 years before the explosion 10
solar
masses of gas were torn violently from the red supergiant by its
partner. By
observing the companion closely in the coming years it may even be
possible to
detect a neutron star or black hole emerge from the remnants of the
explosion
'in real time'.


Given the paucity of observations of supernova progenitor systems this
result,
published in Nature on 8 January 2004, is likely to "be crucial to
understanding
how very massive stars explode and why we see such peculiar
supernovae"
according to first author Justyn R. Maund from the University of
Cambridge, UK.


Stephen Smartt, also from the University of Cambridge, says:
"Supernova
explosions are at the heart of our understanding of the evolution of
galaxies
and the formation of chemical elements in the Universe. It is
essential that we
know what type of stars produce them." For the last ten years
astronomers have
believed that they could understand the very peculiar behaviour of
1993J by
invoking the existence of a binary companion star and now this picture
has
proved correct.


According to Rolf Kudritzki from the University of Hawaii, "The
combination of
the outstanding spatial resolution of Hubble and the huge light
gathering power
of the Keck 10m telescope in Hawaii has made this fantastic discovery
possible."


Supernovae occur when a star of more than about eight times the mass
of the Sun
reaches the end of its nuclear fuel reserves and can no longer produce
enough
energy to keep the star from collapsing under its own immense weight.
The core
of the star collapses, and the outer layers are ejected in a
fast-moving shock
wave. This huge energy release causes the visible supernova we see.
While
astronomers are convinced that observations will match this
theoretical model,
they are in the embarrassing position that they have confidently
identified only
two stars that later exploded as supernovae -- the precursors of
supernovae
1987A and 1993J.


There have been more than 2000 supernovae discovered in galaxies
beyond the
Milky Way and there appear to be about eight distinct sub-classes.
However
identifying which stars produce which flavours has proved incredibly
difficult.
This team has now embarked on a parallel project with the Hubble Space
Telescope
to image a large number of galaxies and then wait patiently for a
supernova to
explode. Supernovae appear in spiral galaxies like M81 on average once
every 100
years or so. The team, led by Stephen Smartt, hope to increase the
numbers of
supernova progenitors known from 2 to 20 over the next five years.


Notes for editors


The team is composed of Stephen J. Smartt and Justyn R. Maund
(University of
Cambridge, UK), Rolf. P. Kudritzki (University of Hawaii, USA),
Philipp
Podsiadlowski (University of Oxford, UK) and Gerry F. Gilmore
(University of
Cambridge, UK).


Animations of the discovery and general Hubble Space Telescope
background
footage are available from
http://www.spacetelescope.org/video/heic0401_vnr.html


For more information, please contact:


Justyn R. Maund
University of Cambridge
Tel: +44 (0)1223 337544
E-mail: j...@ast.cam.ac.uk


Stephen Smartt
University of Cambridge
Tel: +44 (0)1223 766 651
E-mail: s...@ast.cam.ac.uk


Rolf. P. Kudritzki
Institute for Astronomy
University of Hawaii
Tel: +1 808 956 8566
E-mail: k...@ifa.hawaii.edu


Lars Lindberg Christensen
Hubble European Space Agency Information Centre
Garching, Germany
Tel: +49 89 3200 6306 (089 within Germany)
E-mail: l...@eso.org


[NOTE: Images supporting this release are available at
http://sci.esa.int/science-e/www/obj...objectid=34455 ]


************************************************** **********************

Here's an interesting paper:
SNLS Spectroscopy: Testing for Evolution in Type Ia Supernovae

There's a lot of up-to-the-minute details about careful observations. Basically it concludes:

__________________
Forming opinions as we speak

Or, in terms of what we might call the 'Jerry idea'*, a systematic study showing that local Ia SNe are not, phenomenologically, different from distant ones (assuming an appropriate LCDM model).

*Summarised, in language consistent with Jerry posts, as something like "high-z SNe are all radically different from low-z ones!" or "none of the observational results makes any sense at all!" Or, if you prefer, anti-confirmation bias on steroids.

Did you even read my quote from the paper?

Originally Posted by Jerry
"Most of the time, this is a valid syllogism, but supernova research is exceptional. The essential assumption in using supernova as standard candles is that the mass of each-and-every 'type Ia' event is very near the Chandrashakar critical mass of 1.6 solar."

If you are arguing that 'the essential assumption' is not grammatically similar to 'Theoretical models suggested'; you are still missing the point. The spectra of the most distant supernova are very noisy - Read the Broder et al paper referenced by Antoinseb - it is an necessary assumption of every paper using supernova Ia for cosmological purposes that the distant sample has the same light-curve length/ magnitude relationship as the local sample.

1991T was the very first supernova type Ia that did not seem to follow the magnitude/light-curve width relationship established for type Ia supernova, diveraging from the exist lightcurve/magnituded relationship by four sigma - it was much too bright for its light-curve width. Certain spectral features were noted in the 1991T spectra, and these were used to segregate a group of local supernova type Ia from the spectral group used as standard candles.

Broder et al notes that 5 or of the high redshift have been observed that seem to contain this same spectral feature, and Broder notes that this feature presents a challange to the interpretation of distant supernova light curves: Is the distant sample observed more like the superluminous event 1991T, or are they more like garden variety Ia supernova?

As stated by Broder:

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

Did I? Did you?

Your quote merely mentions that there is a theoretical model. It also mentions that there are empirical reasons for limiting SN Ia luminosity dispersion. If you bother to read the rest of the paper, or any other SN Ia paper, you will find that nothing rests on the theoretical model. Not even in that paragraph you quoted does anything rely on the theoretical model.

Indeed, the inference in the paper is the opposite of the one you imagine. That is, the authors are arguing from the empirical information on regularity to a possible explanation. They do not commit to the theoretical explanation, however.
This "assumption" can be tested by a variety of methods. Yet this assumption also does not rely on the theoretical model of the ultimate constituents of SN Ia events.

Yes it does!

The only exacting proof that the cosmic redshift is caused by relativistic expansion is the time-dilation measured in supernova light-curves. The theory redshifting is caused by relativistic expansion is completely dependent upon the theory that type Ia supernova events are caused by a white dwarf star accreting matter to a critical mass and exploding within a narrow range of light-curve widths and ~0.6 absolute magnitudes.

We know that gamma rays that we observe at cosmic distances are more powerful than the few that we have observed locally. Using current theories and methods for reducing the data, the most distant supernova events are interpreted as being 1-3 magnitudes dimmer than the brightest of the local supernova events. It is the theory that these type Ia explosions fall within a fairly narrow range of magnitudes that drives this conclusion.

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

Please provide a source for this proof. Such a proof is noticeably absent from your previous source and every other SN Ia paper that I have ever encountered. If you know of such a paper, why do you waste our time by providing sources without this argumentation. If you do not know of any such paper, why do you waste our time with these quite obvious falsehoods?
This theory is supported by observation, not by astrophysical theory. Again, please provide the sources that supposedly support this position.

Jerry said: "The only exacting proof that the cosmic redshift is caused by relativistic expansion is the time-dilation measured in supernova light-curves. The theory redshifting is caused by relativistic expansion is completely dependent upon the theory that type Ia supernova events are caused by a white dwarf star accreting matter to a critical mass and exploding within a narrow range of light-curve widths and ~0.6 absolute magnitudes."

Righ now we are limited in our ability to do astrophysics by the fact that all of our information about distant objects comes from electromagnetic waves. Actually, if and when gravitational waves from distant sources are detected they will provide independent confirmation of the expansion of the Universe. Once gravitational waves are used in tandem with electromagnetic waves to do cosmology it will be harder and harder to deny the expansion of the Universe. In fact, here is a paper which talks about gravitational wave measurements from distant sources being used to determine the hubble constant: "Determining the Hubble constant from gravitational wave observations" by Bernard F. Schutz

Abstract

"I report here how gravitational wave observations can be used to determine the Hubble constant, H 0. The nearly monochromatic gravitational waves emitted by the decaying orbit of an ultra−compact, two−neutron−star binary system just before the stars coalesce are very likely to be detected by the kilometre−sized interferometric gravitational wave antennas now being designed1−4. The signal is easily identified and contains enough information to determine the absolute distance to the binary, independently of any assumptions about the masses of the stars. Ten events out to 100 Mpc may suffice to measure the Hubble constant to 3% accuracy."

Due to, as Nereid so aptly puts it, Jerry's "anti-confirmation bias on steroids" Jerry will surely be much displeased if and when dark matter particles are discovered. He will be even more irked if the directly measured abundance of dark matter particles ends up matching the implied abundance as inferred from the CMB, galaxy cluster data, lensing, and supernovae observations. The direct detection of dark matter will largely make Jerry-like radical skepticism when it comes to cosmology even less tenable. Right now Jerry et al use our current ignorance of dark matter as an example of how cosmologists invent "theoretical entities" in an epicyclical manner to make up for the shortcomings of their existing theories. Once dark matter is discovered, if it is, Jerry will be forced to eat his words and his type of snide superiority-laden skepticism will become even more out of fashion than it already is.

So, the direct detection of gravitational waves and the direct detection of dark matter will both be sad days for Jerry. Of course, I am sure he'll fall back on the same kind of petty what if pigs could fly skepticism that he uses right now to try debunk the evidence, as there are people who right now dispute the roundness of the Earth (e.g. the Flat Earth Society), anthropogenic climate change, and the fact that the Earth revovles around the Sun. Except, the direct detection of these "free parameters" or "theoretical entities" will make Jerry's position even more untenable. Hence the title of this post, Jerry's worst nightmare. We shall see.

You seem to forget I have been wrong about many things - Mostly I was wrong when I used to chortle about how gravity waves would be found no later than the late nineteen eighties.

I monitor the gravity probe sites at least weekly, and always read papers that prove dark matter exists - so far, by reasserting dark matter is the difference between the motion we observe, and what Newtonian mechanics predict.

And I got this one right:

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

This is the spamming approach to scientific inference, then?

Well, we prefer to call it brainstorming, but spam is a better decription of that last post

Iapetus is a good example of something turning out to be quite opposite of what was expected, based upon current theory. It will be interesting to see how these new observations are integrated into the big picture.

It is ok to assume the latest constraints upon gravity waves mean we need to look harder, and that dark matter is a reasonable answer to missbehaving gravity, and that the extra bright and unusual supernova we see locally are not well represented in the distant sample. It is also ok to look at all of this not-so subtle evidence and say, perhaps the big picture is stunningly different, what was thought to be black on white is white on black. How did such a terrestrial looking moon end up orbiting Saturn? Is it made out of dirt, or covered with a thin chocolate shell?

See if you can find a good way to connect all of these dots.

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

I'm somewhat confused here.

Jerry, have you accepted that you were mistaken about the use of the white dwarf explosion theory?

No!

The evidence of time dilation and cosmic expansion found in supernovae explosions is directly tied to the assumption that

1) Supernova 'type Ia' represent a unique and readily discernable event.

2)The range of possible magnitudes is very small.

3) The light curve distribution is well-characterized.

4) Most of the time, when there is a supernova event with an exceptional light curve, magnitude; or both, there will be fundamental, detectable differences in the light curve and/or spectra that will not allow it to be confused with 'type Ia'.

5)Even though the spectra and light curves of very distant supernova are not as well defined as the local sample, it is possible to template the local sample and distant sample; and arrive at reasonably accurate conclusion as to whether the distant events are similar enough to the local events to make good assumptions regarding the magnitude of distant supernova.

This fifth caveat is dependant upon the theory that ALL redshifted events are time-dilated, and the only evidence of this is found in the light curves of type Ia. The argument is entirely circular; and wholly dependant upon the assumption, the theory, that a critical mass is involved. Otherwise, there is no justification whatsoever for assuming distant events have light curves that are the same length as local light curves before time dilation.

All of these assumptions are dependant upon the theory that Ia are unique because they are the explosions of white dwarf stars that accrete matter to a very specific mass. (I think I said 1.6solar, but the theoretical value is more like 1.4solar). This is spelled out quite clearly in Peebles or any text on cosmology. See Also Ned Wright's cosmology tutorial webpages:

http://casswww.ucsd.edu/public/tutorial/Distances.html

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

While I think very highly project to providing educational materials on this matter, in this case I feel the quote is going beyond the actual scientific papers, it seems. Of course, the source you provide is not Ned Wright. Rather it appears to be Gene Smith. (Unfortunately, Wright seems to make the same claim.) However, neither Smith nor Wright make the claim that this theory of the origin of the events plays any role in the cosmological use of the events. Indeed, if we had a good theory of the underlying nature of the events we could use this to further reduce dispersion.

Why don't any of the scientific journal articles you reference make use of this theory?

On another matter, I have PJE Peebles' Principles of Physical Cosmology in front of me, I can assure you that the references to white dwarfs in the text have nothing to so with supernova events. I'm not about to check the much earlier Physical Cosmology for references. Is there another text by Peebles that you are referring to? Or are you, once again, falsely assuming that this erroneous argumentation is in yet another scientific source where it is missing?