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Blob
2006-Feb-23, 11:48 PM
Scientists are studying a strange explosion, detected with the Swift satellite, that appeared on February 18, 2006, about 440 million light years away in the constellation Aries.

The blast (GRB 060218) looks like a gamma-ray burst, however it may be the start of a supernova explosion.
The explosion was about 25 times closer and lasted 100 times longer than a typical gamma-ray burst.

Amateur astronomers in the Northern Hemisphere might be able to see it next week.

http://static.flickr.com/27/103590241_c448fc964f_m.jpg
Expand (http://static.flickr.com/27/103590241_c448fc964f_o.gif) 9 degree width map of Aries.
Position(2000): RA = 03:21:39.71 Dec = +16:52:02.6

Blob
2006-Feb-24, 12:50 AM
BTW, GRB 060218 is also known as Supernova 2006aj a type Ib/c explosion that was discovered near the centre of an anonymous galaxy in Aries.
It was at magnitude 18.2 at discovery.

http://mizar.as.arizona.edu/~grb/public/GRB060218/GRB060218_irg_clean.jpg

antoniseb
2006-Feb-24, 01:42 AM
Thanks Blob, this is another interesting item from Swift.

RussT
2006-Feb-24, 08:12 AM
This is from this site
http://grb.sonoma.edu/

This is what is said about the 06 02 18 Burst

Interestingly, Swift detected gamma rays from this same location over a month earlier, on January 17. Spectra taken of this event also show features similar to those seen in a supernova, when a massive star explodes. It seems likely that we are seeing a supernova-GRB connection, a rare event and one that is highly anticipated.


Then it says this about the 06 01 17 burst

There is also a bright galaxy very close to the position of the burst, and the redshift of this galaxy is z=0.042, indicating a distance of 562 million light years. That is actually very close for a GRB, which is consistent with the GRB brightness. However, estimates of the redshift of the GRB using other methods have yielded inconsistent results, with values ranging from z=0.45 (4.6 billion light years) to z=1.3 (8.8 billion light years). Hopefully follow-up observations will clear up this issue.

It is my contention that you have to be very careful when you are looking at all this. They say close to a galaxy, coincident with, apparently within etc, and then when you see the kind of redshift questionabilty here, you have to wonder how they can be making a galaxy or SuperNova conection at all.

Kullat Nunu
2006-Feb-24, 10:04 AM
Space.com news article (http://www.space.com/scienceastronomy/060223_explosion.html).

See also this article (http://skyandtelescope.com/news/article_1683_1.asp) by Sky & Telescope.

Blob
2006-Feb-24, 11:08 AM
Astronomers believe the bursts of radiation are emitted from a star about to implode; this may be a rare glimpse of a black-hole birth.

So far, the explosion looks like a "Type 1C" supernova. This means that the star has consumed all its nuclear fuel, leaving behind only an iron core.
In the 30-minute blast, the recorded Gamma rays did not show the usual pattern of short, sharp peaks; instead it rose smoothly.
That may indicate that the axis of the supernova is pointed away from Earth.

BTW, You'll need a least a 16” telescope to see it, though it may brighten considerably over the next week.

antoniseb
2006-Feb-24, 01:53 PM
Thanks for the pointers to the two articles. The S&T one gave some good details. I'm wondering of the January GRB was the same object, or a conincidence.

It is curious that this is so different from the usual GRBs we see, both in reduced luminosity and increased duration. It could be that this was slightly off-line, and that we were seeing the Gammas emitted as the beam plowed through clouds over an extended time, instead of all at once when the alignment is near perfect.

Alternatively, these 1c supernovae might NOT be the source for most GRBs.

peteshimmon
2006-Feb-24, 06:26 PM
I have interests in this subject as some may
remember. I have long wondered what detectors
were in space at the time of 1987a and if
checks were made for the time the neutrinos
passed.

Blob
2006-Feb-24, 07:21 PM
Hum,
New Scientist has a few comments and insights into the explosion
Link (http://www.newscientistspace.com/article.ns?id=dn8776&feedId=space_rss20)


@peteshimmon
Apart from hubble etc looking at it in Optical wavelengths (etc) there were only ground based Neutrino detectors for the explosion (newly deployed)
Link (http://zebu.uoregon.edu/~soper/StarDeath/nudetectors.html)

The Bad Astronomer
2006-Feb-25, 05:57 AM
This is from this site
http://grb.sonoma.edu/


I can't let this one go by: I write those synopses. :-) The site automatically gets the position and other basic info on a burst from Swift, but as astronomers observe it and send out emails, I read them and then write up the entries.

RussT
2006-Feb-25, 08:07 AM
Phil;

VERY COOL! I didn't realize that someone else was writting those (and obviously did not know it was you), and that you are just reporting what scientists have already written, and to be honest, the tone and caution in my post above also comes from reading "Many" abstacts that 'suggest' that any particular GRB is associated with a galaxy by saying it is 'coincident with', or appears to be part of, or the putative galaxy of GRB so and so, etc, etc. I have many more reasons if you wish to discuss them.

So what do you think about my concern with how some scientists are wording their reports or abstacts to suggest or otherwise assume that GRB's are associated with galaxies.

John Dlugosz
2006-Feb-27, 03:35 PM
I'm wondering about the "unnamed galaxy". Haven't they all, down to some dimness, been surveyed?

And wouldn't they give it a name as soon as it because interesting? How do you refer to it to other astronomers other than "the one over there" or "the host galaxy of (named event)"?

--John

RussT
2006-Feb-28, 02:46 AM
I'm wondering about the "unnamed galaxy". Haven't they all, down to some dimness, been surveyed?

And wouldn't they give it a name as soon as it because interesting? How do you refer to it to other astronomers other than "the one over there" or "the host galaxy of (named event)"?

--John

Atlas of the Universe

http://anzwers.org/free/universe/index.html

Shows that there are 350 billion Galaxies and 3.5 trillion Dwarf Galaxies, so when they are looking at "TRYING" to associate any GRB with a host galaxy, especially at high redshift, they do not have a name.

Fraser
2006-Feb-28, 05:04 PM
SUMMARY: NASA's Swift satellite is continuing to send back surprising information about gamma ray bursts. On February 18, 2006, it discovered something completely unique; a burst that originated 440 million light-years away and lasted about 30 minutes. This event is very similar to the more common bursts that have been seen in the past; however, it was about 25 times closer, and lasted 100 times longer than a typical burst.


View full article (http://www.universetoday.com/am/publish/swift_unusual_cosmic.html)
What do you think about this story? post your comments below.

ATKINS
2006-Mar-01, 11:12 AM
It is curious that this is so different from the usual GRBs we see, both in reduced luminosity and increased duration. It could be that this was slightly off-line, and that we were seeing the Gammas emitted as the beam plowed through clouds over an extended time, instead of all at once when the alignment is near perfect.

May we reasonably deduce that this type of low intensity GBR is so rarely observed precisely because of its low intensity, in other words that if it had been much further away, it would quite simply have gone unobserved? This would in turn suggest that this type of event may therefore be quite commonplace, especially in cases where intensity levels are even lower than that observed here.

As regards the idea that intensity and duration may in some way be linked to a GRB being "slightly off-line", do you mean that we only see the much more common, very short-duration, extremely intense GRBs because the Earth happens to be in the path of some kind of colimated jet emanating from the emitting object?

Sorry, I realize I am enlarging the discussion beyond the initial concern with GRB 060218, perhaps there is another thread for discussing GRBs in general which you could redirect me to. Thanks!

Don Alexander
2006-Mar-01, 12:33 PM
What Fraser presented here was the very Americano-centric PSU news release.

Here's the news release from the Swift site itself:

http://swift.gsfc.nasa.gov/docs/swift/news/2006/06-18.html

It makes mention of the fact that the supernova features in the spectrum were first detected by European astronomers in the GRACE collaboration with the VLT in Chile.

Way to go, Nicola!

See you in Nature.

Don Alexander
TLS Tautenburg, Germany

Fr. Wayne
2006-Mar-01, 01:57 PM
That the burst lasted so long will be a huge source of theoretical debate. Who could explain such a gamma ray phenomena? Very unique catch.

Duane
2006-Mar-01, 09:50 PM
I have merged the UT story into this thread, igven they are the same story and this thread was first.

RussT
2006-Mar-01, 10:11 PM
What Fraser presented here was the very Americano-centric PSU news release.

Here's the news release from the Swift site itself:

http://swift.gsfc.nasa.gov/docs/swift/news/2006/06-18.html

It makes mention of the fact that the supernova features in the spectrum were first detected by European astronomers in the GRACE collaboration with the VLT in Chile.

Way to go, Nicola!

See you in Nature.

Don Alexander
TLS Tautenburg, Germany

Don, when you click to the other links you get to this;

http://www.nasa.gov/images/content/143479main_GRB060218_clean.tif

The image in the middle is GRB06021618. So, it would appear there is another, even brighter and bigger one above it? Same configuration. And another above that without the middle bright spot. Also, do you know if the bright spot just right of GRB060218, is supposed to be the host galaxy, and has anything been said about the blue spot that that appears on the pic on the right that is left of the GRB?

peteshimmon
2006-Mar-01, 10:28 PM
When another GRB was seen in a galaxy in Leo
a few years ago, the afterglow morphed into
a Supernove. With my own ideas in mind I
figured some stars of the galaxy exactly in
front of the supernova might have "spalled"
high energy radiaion towards us caused by the
passage of the neutrinos through the star. That
there were several peaks suggested a number of
stars, some just off the supernova sightline.
Yhis gave a duration of a few seconds if I
remember. But 30 minutes? Well perhaps the
supernova is behind a globular cluster of
old stars. Thats my input for what it is worth.

Ara Pacis
2006-Mar-01, 10:49 PM
Could a companion star have possibly been pulled in, prolonging the energy release?

One question I have about GRBs. Do we only see them head-on (pole-on)? Would this mean that for every GRB we see there are many many more we don't see? Or might we be seeing most GRBs slightly off-axis somehow, maybe by refraction or reflectance off its ejected matter. If so, then might this recent long lived event be a rarer head-on perspective?

Blob
2006-Mar-01, 11:13 PM
has anything been said about the blue spot that that appears on the pic on the right that is left of the GRB?

Hum,
The tiny blue dot is GRB060218...

http://static.flickr.com/43/106522239_dfc07e0a1b_o.jpg

RussT
2006-Mar-01, 11:20 PM
Hum,
The tiny blue dot is GRB060218...


I see...Thanks Blob!

So what are the three circular orange objects, 2 with bright spots in the middle?

Blob
2006-Mar-02, 11:34 AM
So what are the three circular orange objects?

Hum,
they are just nearby stars (visible in a pair of large binoculars....)

RussT
2006-Mar-02, 12:07 PM
Ahh, I see now, however the top orange circle, with no bright spot in the middle, should be an item of interest, because I see nothing in the other pic to match it to. Do You?

Also, this GRB is probably, because of its longer than normal duration, the result of an AGN feeding episode.

Don Alexander
2006-Mar-02, 04:15 PM
Hello, all,

seems there has been quite a bit of discussion about this event...

@RussT:

The left image is from the Sloan Digital Sky survey, and shows the region months before the GRB/SN happened. The host galaxy is visible as a faint blue dot.

The right-hand image is taken by the UVOT telescope of the Swift satellite. UVOT has some peculiar optical "defects". Bright stars create these wavelngth-dependent halos - this is a three color image (UBV, I guess), and the halos are of different size in each color, creating monochromatic rings in the combined image. The "ring without a dot" is also an artifact, just as the faint line going through the bright stars. Ignore all this stuff.

Blob's picture points out the GRB/SN and it is easily seen that it is much brighter in the UVOT image than the host galaxy alone.

And this is definitely not an AGN episode!! The spectra clearly show an evolving hypernova (an extremely powerful supernova, in line with those detected in association with other GRBs), probably one of the most powerful ever seen.

Also, a note on GRB 060117. It is unclear what Swift detected here on the 17th of January, but the GRB info you quote from the GRB Real-Time Sky Map site definitely referes to another, real, GRB at a different location. (A very sad case, with an extremely bright afterglow, but it was so close to the sun that it was basically unobservable... :-( .)

@ Fr. Wayne and Ara Pacis: Yes, the anomalous GR emission is VERY unusual. Something like this has clearly never been seen before. If it had been a few times further away, Swift would never have been able to detect it. There is a lot of theory on the viewing-angle-dependency of GRBs, yes. The best theory today tells us that if we see a GRB a bit off-axis, we get what is called an X-ray Flash (XRF). These have softer peak energies (which is the case here) and have short, simple light curves (which is NOT the case here!!).

Recently, Lorenzo Amati et al. have shown that GRB 060218 is probably in accordance with the so-called "Amati relation", which would NOT be true for an off-axis event. Other evidence also shows that this may be on-axis. If so, it is completely unique.

@peteshimmon: Neutrinos hardly interact with matter, so even a strong burst of neutrinos will not create a gamma-pulse. Also, such a gamma-pulse would easily be absorbed by the star itself.

@Phil, the Bad Astronomer: You write those summaries?? LOL!!! I wrote someone at the site some months ago where it had been claimed that a redshift had been first measured by Keck, and actually it had been the VLT. Never got an answer...

Some updates, maybe, too: Swift UVOT detected a first peak in the optical/UV emission about ten hours after the burst onset. This peak spectrally looks like the Rayleigh-Jenas portion of a hot blackbody, with a peak in the ultraviolet. This is probably the "UV flash" of the supernova shock breakout - the point where the star actually ruptures and goes bang. This is the first time ever such a breakout has been observed in both the rising and the falling part.

The actual afterglow of this event seems basically non-existent.

Don Alexander
TLS Tautenburg, Germany

Fortunate
2006-Mar-02, 05:19 PM
Don Alexander
TLS Tautenburg, Germany

Thank you very much, Don Alexander. I would think more aspects will be clarified as time goes by and people have time to (observe? and) analyze further. If so, I would love to hear more.:)

Jerry
2006-Mar-02, 06:31 PM
What Fraser presented here was the very Americano-centric PSU news release.

Here's the news release from the Swift site itself:

http://swift.gsfc.nasa.gov/docs/swift/news/2006/06-18.html

It makes mention of the fact that the supernova features in the spectrum were first detected by European astronomers in the GRACE collaboration with the VLT in Chile.


It is curious that the "Americano" version does not even mention the connection and identification with a Ic supernova or hypernova. There is still some reluctance to accept the link.

As far as identification with a specific galaxy, the initial velocities of supernova bursts are so great, the redshift distance has to be considered preliminary until the mass involved in the explosion equilibrates a little.

peteshimmon
2006-Mar-02, 06:37 PM
Another sceptic eh:) Lets expand my suggestion.
The supernova may be just hundreds or even
tens of lightyears behind a globular cluster
consisting predominately of white dwarfs. The
neutrinos are high energy and high flux at these
distances. They will pass through the stars but
a fraction will react with the dense matter.
The idea is that the sheet of neutrinos as they
exit the star cause high energy radiation to
spall in our direction. And there will be lots
of them in a cluster. Finally there are
supernovae and supernovae. Hypernovae....I
think you call that hand waving:)

Don Alexander
2006-Mar-02, 07:44 PM
@Fortunate: Not much more observing time left. This field is near the ecliptic, and the sun is moving toward this location. In the next few weeks, it will sink into the soup near the horizon. Then only Swift UVOT and HST can observe in the optical.

@Jerry Jensen: Well, it does mention that this event is the precursor to a supernova. By the way, the Sky and Telescope article (link somewhere above) basically states that the SN spectral features were discovered by Caltech (Soderberg et al.), which is just plain wrong. The Caltech people were just intelligent enough to immediately submit something to the IAU circulars, which are read by a lot more people than the GCN circluars.

Concerning the redshift: First off, the first redshift identification by Mirabal and Halpern was made early enough that the SN features were not very visible (which prevented them from making the identification and thus claiming the discovery of SN2006aj...). Secondly, redshifts can always be derived by absorption lines. These are due to host galaxy gas in front of the SN, and are hardly affected by strong velocities. Finally, even the broad spectral features of the SN are symmetric, thus, the peak of these lines is at the host galaxy redshift.

@peteshimmon:
A) Globular clusters formed in the early universe when galaxy collision ignited so-called "super-starbursts" - basically creating highly concentrated dwarf galaxies. Such starburst have a special distribution of stellar masses, this is called the "initial mass function" - the IMF. You will produce few very massive stars and many low-mass stars (this phenomenon is seen in any large starburst observable today). The high-mass stars are gone by now, via supernovae and planetary nebulae. Today, globulars contain only stars less massive than the sun, but a lot of them, many more than even white dwarfs. So you will not get a globular cluster consisting of almost exclusively white dwarfs.
B) A supernova neutrino burst is probably emitted isotropically, so the neutrino flux is spread over the whole surface of an expanding sphere - this means the flux drops quickly with distance (r^-2 law). Globular clusters are large, dozens of light years in size. If the SN is close, only a few white dwarfs would lie along the line of sight. If the SN is distant, the flux is low.
C) White dwarfs are much denser than normal stars. While this increases there cross-section to neutrinos, creating more collisions per unit volume, gamma-rays will be immediately trapped. Even if the reaction takes place close to the surface of the dwarf facing us, the gamma ray will collide with many atoms, creating a random walk and an emission into a half sphere from the surface. Whatever remains of this radiation that actually is emitted toward us will be completely negligible.

Where did you get this wacky idea??

Just in case you've heard of supernovae being "driven" by neutrinos. This is not via the interaction between neutrinos and normal matter, but via neutrino-antineutrino annihilation - which does release quite a lot of energy. But this can only happen in the superdense shock fronts within the the collapsing star. (WAY denser than a white dwarf...)

Concerning the term "hypernova": This was introduced in 1998 by Bohdan Pacynski to describe extremely energetic supernovae with expansion speeds of about 30% light speed (ten times faster than typical supernovae). Not all Type Ib/c supernovae are hypernovae, and recently, Soderberg et al. showed (this is mentioned in the Sky & Telescope article) that even the few hypernovae they examined in the radio at late times did not feature GRB jets.

I think we can state: Every long GRB is associated with a hypernova, but not every hypernova with a long GRB. (Just to mention it, short GRBs are very probably neutron star mergers.)

Don Alexander
TLS Tautenburg, Germany

Ara Pacis
2006-Mar-02, 09:07 PM
Not much more observing time left. This field is near the ecliptic, and the sun is moving toward this location. In the next few weeks, it will sink into the soup near the horizon. Then only Swift UVOT and HST can observe in the optical.

Yet another reason to have several space telescopes in orbit around the sun away from earth.

peteshimmon
2006-Mar-03, 12:49 AM
Those are very interesting details, thanks.
As you are at the coal face so to speak I
will not try to teach you your job but they do
not rule out the idea as far as I can see. I
hope "wacky" indicates a slight, growing
appreaciation of the explanation. I read that
all six types of neutrino are in the burst
and perhaps white dwarfs act as catalysts to
recreate in a small way some of the things that
happened when they were created! I would say
a shock front is caused in the star that
causes material to spall from the exit side
temporally and give out X-rays as it falls
back on the surface. This could explain some
high energy bursts. But this is only one
mechanism I suspect. There are surely others!

RussT
2006-Mar-03, 08:59 AM
However, it may also be that GRBs originate from something that astronomers haven't considered yet.

hansgor
2006-Mar-03, 03:54 PM
Have some observation of the object,see:
http://sabbe.fragzone.se/KPO/grb060218.htm

Regards
h-g

hansgor
2006-Mar-05, 06:07 AM
One of the comparing stars for GRB060218 (mag.16.29) seems to be a variable star, if any have images of the area i will be happy to look at it.See:
http://sabbe.fragzone.se/KPO/grb060218c.htm

h-g

trinitree88
2006-Mar-05, 01:53 PM
B) A supernova neutrino burst is probably emitted isotropically, so the neutrino flux is spread over the whole surface of an expanding sphere - this means the flux drops quickly with distance (r^-2 law). Globular clusters are large, dozens of light years in size. If the SN is close, only a few white dwarfs would lie along the line of sight. If the SN is distant, the flux is low.

Don. I disagree on the isotropy of the prompt neutrino burst.:naughty:
1.Core collapse type 2 supernovae leave barrel shaped remnants, not spherical, as you would expect if the explosion was spherically symmetric (M.J. Kesteven, R.N. Manchester, Molonglo, NSW, Australian Journal of Physics)..48 0f 60 remnants definitively barrels..4 possible)..circa 1985.
2. Most supernova remnants whether type 2's or type 1a's are devoid of pulsars (Manchester also)..less than 5 in ~ 400.
3. High transverse velocity pulsars are seen, not associated with any nearby remnant(Lyne, Harrison, Cordes), though to be fair, they oft outlive the fairly short-lived remnants, suggesting ejection. (original asymmetrical ejections suggested by Schlovskii...circa 1976)
4.Pulsar ejection is a fundamental effect due to parity effects which are present in all weak interactions....supernovae no exception. The largest neutrino fluxes, and the strongest magnetic fields that naturally occur.
5. The nascent pulsar "birth" is almost certain to be accompanied by an asymmetry in the prompt neutrino burst, the and as a consequence of the massive pulsar acceleration....a gravitational wave.
6. Use of type1a's as standard candles fallaciously ignores luminosity vs viewing angle of the barrel shaped ejecta (I spoke to people in a position to use the info many years ago) ~14yrs.
7. Here's a prediction. If the long GRB's are truly from "beamed" supernovae...in all likihood the beam points in the birthward direction of the pulsar, as the shock front ruptures. Early neutrino beaming from that area losing neutrino opacity in the core shock bounce should precede a long GRB by only a few seconds statistically. Somebody ought to see if SuperKamiokande, SNO, MontBlanc, Dumand, Borexino, are set to observe statistical twitching precedent to Long GRB's.by 1-10 seconds..No? Pete.

hansgor
2006-Mar-07, 10:19 PM
Looks like this odd object did not get up to calculated mag of ~16.5 and also fading to soon, tonight down to mag~17.9
http://sabbe.fragzone.se/KPO/grb060218.htm
h-g

Don Alexander
2006-Mar-16, 07:32 PM
Hi, if anyone is still hanging around this forum:

The Swift Team has submitted its paper to Nature and placed it on astro-ph:

http://arxiv.org/pdf/astro-ph/0603279

I can wholeheartedly recommend anyone who is interested in this event to read this paper. It is not too technical in nature (slight pun intended) and both the presented data and the conclusions are superb.

Let's hope our own Nature paper turns out this well...

Also, today another paper:

http://arxiv.org/pdf/astro-ph/0603377

peteshimmon
2006-Mar-16, 08:15 PM
Is superb another word for true?:)

Blob
2006-Sep-01, 09:45 AM
Title: An optical supernova associated with the X-ray flash XRF 060218
Authors: E. Pian, P.A. Mazzali, N. Masetti, P. Ferrero, S. Klose, E. Palazzi, E. Ramirez-Ruiz, S.E. Woosley, C. Kouveliotou, J. Deng, A.V. Filippenko, R. Foley, J. Fynbo, D.A. Kann, W. Li, J. Hjorth, K. Nomoto, F. Patat, D. Sauer, J. Sollerman, P.M. Vreeswijk, E.W. Guenther, A. Levan, P. O'Brien, N. Tanvir, R.A.M.J. Wijers, C. Dumas, O. Hainaut, D.S. Wong, D. Baade, L. Wang, L. Amati, E. Cappellaro, A.J. Castro-Tirado, S. Ellison, F. Frontera, A.S. Fruchter, J. Greiner, K. Kawabata, C. Ledoux, K. Maeda, P. Moller, L. Nicastro, E. Rol, R. Starling
Comments: Final published version

Long-duration gamma-ray bursts (GRBs) are associated with type Ic supernovae that are more luminous than average and that eject material at very high velocities. Less-luminous supernovae were not hitherto known to be associated with GRBs, and therefore GRB-supernovae were thought to be rare events. Whether X-ray flashes - analogues of GRBs, but with lower luminosities and fewer gamma-rays - can also be associated with supernovae, and whether they are intrinsically 'weak' events or typical GRBs viewed off the axis of the burst, is unclear. Here we report the optical discovery and follow-up observations of the type Ic supernova SN 2006aj associated with X-ray flash XRF 060218. Supernova 2006aj is intrinsically less luminous than the GRB-supernovae, but more luminous than many supernovae not accompanied by a GRB. The ejecta velocities derived from our spectra are intermediate between these two groups, which is consistent with the weakness of both the GRB output and the supernova radio flux. Our data, combined with radio and X-ray observations, suggest that XRF 060218 is an intrinsically weak and soft event, rather than a classical GRB observed off-axis. This extends the GRB-supernova connection to X-ray flashes and fainter supernovae, implying a common origin. Events such as XRF 060218 are probably more numerous than GRB-supernovae.

Read more (http://arxiv.org/PS_cache/astro-ph/pdf/0603/0603530.pdf) (72kb, PDF)

peteshimmon
2006-Sep-02, 01:13 PM
So how many past grbs are now redesignated xrfs?