Re: Swift Data rules out beamed theory


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)

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."

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.

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.

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.

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.

George


Here we have proof confirming all my earlier predictions that grbs are
proof that GR can be violated.

TITLE: GCN GRB OBSERVATION REPORT
NUMBER: 5131
SUBJECT: VLT optical spectroscopy of GRB 060512
DATE: 06/05/14 17:34:10 GMT
FROM: Rhaana Starling at GRACE/U of Amsterdam
<starling@xxxxxxxxxxxxxx>

R. Starling (Amsterdam), C.C. Thoene, J.P.U. Fynbo (DARK),
P. Vreeswijk (ESO) and J. Hjorth (DARK) report on behalf of
a larger collaboration:

We observed the optical transient of GRB 060512 (first reported
by Cummings et al. GCN 5117) with the ESO FORS1 Long Slit
Spectrograph under poor observing conditions, beginning at
2006-05-13 02:06:43 UT with an exposure of 2x1800s.
The spectrum covers the range 3850-8750A.

Preliminary analysis shows the afterglow to be blue, consistent
with the magnitudes given in De Pasquale & Cummings (GCN 5130).

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.

We thank the staff and observers at ESO Paranal.



TITLE: GCN GRB OBSERVATION REPORT
NUMBER: 5145
SUBJECT: GRB 060512: TNG optical spectroscopy
DATE: 06/05/16 16:48:31 GMT
FROM: Daniele Malesani at SISSA-ISAS,Trieste,Italy
<malesani@xxxxxxxx>

S. Piranomonte (INAF/OARm), E. Maiorano (INAF/IASF Bo), V. D'Elia
(INAF/OARm), N. Masetti (INAF/IASF Bo), F. Fiore (INAF/OARm), D.
Malesani (SISSA/ISAS), G. Mainella, A. Magazzu' (INAF/TNG), report on
behalf of a larger collaboration:

We observed the optical transient of GRB 060512 (Cummings et al. GCN
5117; Mundell et al., GCN 5119) with the 3.6m TNG telescope located in
the Canary Islands. Two mid-resolution spectra (~10 A FWHM) were
obtained with TNG+DOLoRes, starting on 2006 May 13.0423 UT, for a total

exposure time of 40 minutes. The spectra cover the range 4000-8000 A.

Inspection of the spectrum does not reveal any obvious absorption
system. We find no signs of the continuum break around 4800 A reported
by Starling et al. (GCN 5131). Our spectrum shows a continuum extending

blueward down to ~4000 A (the limit of our grism), suggesting z < 2.3.

We thank the observing staff at TNG.

This message can be cited.



regards
Sean

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