Re: Swift Data rules out beamed theory


"sean" <jaymoseley@xxxxxxxxxxx> wrote in message
news:1148036676.322202.287090@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

George Dishman wrote:
sean wrote:
...
George dishman wrote in an earlier article...


Take care Sean, I'm not saying the spectra
are definitive or unambiguous, I haven't seen
many and I can't remember the papers I saw to
check whether they were SWIFT grism spectra or
ground based folllow-ups. What I am saying is
that Lyman break data are pefectly valid as a
rough indicator which when combined with ground
data, which is also valid, has allowed the
redshift of many GRBs to be deterined. It may
be less than half as you say, but even that
contains many which are definitely at high
redshift so I think that rules out your local
source idea.

George

If I can respond with some of the latest data from
GRB research. Here are 2 recent gcn posts.
The first claims to supply Lyman break evidence in
optical spectra.

No it doesn't. What it says is quite clear:

"We observed the optical transient of GRB 060512
... under POOR OBSERVING CONDITIONS ...

We report a break in the continuum around 4800A
and bluewards which, IF IDENTIFIED as the onset
of the Lyman-alpha forest, indicates a redshift in the
range z ~ 2.7-2.9. The signal-to-noise is TOO LOW to
allow identification of further lines."

(My emphasis)
Im aware of the seeing conditions in that gcn. After all I posted it
here.

Then that should have been the end of it.

But let me put it this way. If they didnt think that their observation
indicated z ~ 2.7-2.9 then why did they post that in their gcn?

Because it is what they observed. They are scientists,
they make measurements and the publish what they get.
If they published something other than what they
measured, you would (rightly) acuse them of faking
their data. If they didn't publish, there would be
questions as to why they used up valuable telescope
time and produced nothing.

No Matter what spin you try to put on this the plain fact of it is that
they observed a spectra and felt there was strong enough indication
to merit a gcn posting saying there is a Lyman break at 4800A. If there
was no evidence of a break Im sure they would not have mentioned it.

Then they would be treated as frauds. If a break
is evident in the data, then they should publish
it. The whole reason for publishing is so that
others can check. That is exactly what happened.

And that contradicts the other gcn redshift. Thats called ambiguity,

No, it is called doing their job correctly. You
don't seem to understand how this works. The point
of the SWIFT project and GCN system is that it gets
very sketchy data on transient events distributed
very rapidyl, these aren't formal papers that have
been checked for months and published in a journal.

You omitted the previous GCN 5130 which said:

"The detection in the U, B and V, together with the
non-detection in the UV filters, may indicate that the
redshift of this burst is less than approximately 2.5."
Include that gcn if you like but its not an earth based spectra
observation which is what I claimed were ambiguous. Nor is it a
what I refer to as a continuum spectra.
It is 6 seperate exposures at 6 seperate times in 6 seperate filters.
Anyways it too contradicts the findings in 5130. Incidentally, thats
what `ambiguous` means.
The second contradicts this
lyman break evidence that you so love to cite.
It seems that in grb060512 at least we have evidence
that so called Lyman break proof claimed in one
spectra is no longer apparent in another later spectra.

Wrong, what you have is evidence that spectra
obtained under "poor observing conditions" as a
result of which the "signal-to-noise is too low to
allow identification of further lines" must be treated
with care, and now you should understand why it
is a requirement of most scientific work that results
be duplicated.
`Treated with care` doesnt mean discard, if the data
doesnt fit your argument. You argument is emotive and
not rational. The gcn clearly states the Lyman break
is seen at 4800A.

No it doesn't, it says there is a break in their
spectrum and at 4800A and that _IF_ it is a Lyman
break then it implies a certain red shift. I know
you would like it to say something else but we can
all read it for ourselves.

This is exactly what I call ambiguous earth based redshift
evidence. Here we have two spectra contradicting each other

No you don't. What you have is one spectrum
possibly obtained through broken cloud with an
apparent break which the authors were careful to
qualify by clearly stating the visibility problem.
The second spectrum obtained under clearer
skies does not show a break.
Let me see, regardless of seeing conditions you have
one spectra that says z,2.5 and one that says z~2.7-2.9.
Thats called ambiguity isnt it?

No, it's called you inventing conclusions to suit
your own ends.

They certainly contradict
each other. If the seeing conditions were too poor Im
sure the gcn would not have been posted.

Too poor perhaps, but it's a judgement as what is
good enough. They published with a warning which
was the responsible way to handle it. You choose
to ignore that warning.

In other words the grb has no obvious redshift contrary to
all yours and Craigs arguments.

It is not contrary to our arguments at all.The Lyman
forest is caused by the light passing through regions
of hydrogen between us and the source. Those
regions are patchy and there may not be any hydrogen
along the path so you don't always get a break, more
so for low z sources. The argument was that in those
high z cases where a break IS seen then it is still a
"spectral" measurement contrary to your view, and
it is still a perfectly valid measure of red shift where it
is available.
Yes it *is* contrary to your arguments. You claimed that there was
no ambiguity in redshift determination.

I have said that some red shifts can be determined
unambiguously. Some are unambiguously while others
cannot be determined at all.

Ive now cited at least 2 and can find more if neccesary.
And dont forget I can also use these
same spectra to show that the grb is indeed local by comparing the
profile and spikes favourably to a solar spectra. In fact there is an
example at my website. So at the very least one has to accept that
spectra of grb
afterglows can be used to support both my theory and beamed theory.

No, I am waiting for you to take all the data on all
the GRBs that have red shifts that are considered
unambiguous and show that your theory can explain
the specific measurements.

Hence I made the prediction that a Swift spectra would support my theory
better and settle the debate. Unfortunately Swift does not supply optical
spectra as I had originally hoped.

I agree it would be nice to have the UVOT grism
data but you still have to explain the terrestrial
data obtained in good seeing conditions.

And six exposures in six seperate
filters at six seperate times is not what I call a continuum spectra.
Otherwise you should be able to identify spikes and lines from a
set of UVOT exposures. Can you ? No.
Maybe in time the red shift of GRB 060512 will be found
and maybe it won't but that's not really important, what
you should be considering is those high GRBs for which
firm evidence does exist because unless you can show
they are wrong, they falsify your claim that GRBs are local.
I can show that they (spectra) are ambiguous and I can show that they
can be used to show that the grb is local at my website. Furthermore I
can use the ALL swift UVOT
observations to confirm an earlier prediction that the afterglow would
peak and decay later in longer wavelengths.

I'll leave Craig to answer that if h's around.
Last I saw he was trying to get you to state
clearly the equation for that but it was a year
or more ago so you may have done so since.

George


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