Mar 22 2008
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Followup: naked eye gamma-ray burst
This is just a quick followup to the news of the naked-eye GRB from a few days ago. I’ve been getting email and seeing things popping up in other astroblogs, so I figured I’d chime in.
I want to mention that given the distance and brightness of the burst, it is most likely the single most luminous event ever witnessed by humans. I think that’s somethin’ right there.
NASA issued a press release, and pretty quickly, which is good. I’m not surprised: it was written by my old friend Bob Naeye, who works for NASA public outreach at Goddard Space Flight Center. Bob has written and/or edited for every major astronomy magazine in this country, it seems like, and he was my editor for a couple of years with Astronomy magazine. To this day he is one of if not the finest editor I’ve ever had. Plus he’s just a nice guy. 
The image above is from Swift: it was taken by the X-Ray Telescope on board the satellite mere minutes after the burst was detected. Having seen a few Swift X-ray images, let me say that that sucker was bright. Very cool.
In news from the ground: Pi of the Sky is a GRB hunting robotic telescope in Poland, and it has great images and animations of the GRB seen as it was on the rise, even as Swift was detecting the gamma rays. This is a very cool idea: telescopes on the ground with very wide fields of view look at the same part of the sky at the same time as Swift. Remember, Swift is a satellite in low Earth orbit, and it sees a large portion of the sky at once. When gamma rays from a GRB are detected by Swift, it immediately (in a few seconds!) sends down the rough coordinates of the burst so other telescopes can observe it as quickly as possible — many GRBs fade to invisibility in seconds. So a telescope looking at the same part of the sky as Swift cuts down even those precious seconds, getting the burst simultaneously in optical light as Swift sees the gamma-rays.
In this case, it paid off incredibly: they caught the burst actually getting brighter, which is rare all by itself. But to have that happen with a burst of this distinction, well, that’s a major coup. Hats off to the astronomy folks in Poland for getting this. Of course, they gave us Copernicus, so they have a long history in ground-breaking astronomy.
Reports are pouring in from all over the world (and I mean all over and above it), and at the moment it’s mostly technical data: brightness, spectra, and so on. I suspect in the next few days a more coherent picture of this burst will emerge, but it will get better when it fades enough to look for the host galaxy — the galaxy in which the burst occurred. Sometimes the galaxy can be seen well enough to show that the burst came from a place in it where stars are actively being born. That implies this was a young supermassive star that exploded, the kind that doesn’t live long enough to wander out from its stellar nursery. Spectra of the galaxy can give an idea of the chemical content of it, how much of elements like iron and calcium can be seen, hinting again at physical conditions in the galaxy.
Like I said last time, we still have big questions about these titanic events, and the more images and spectra we have, and the more brains we have looking at them, the better.
What star in bootes was the gamma rayPhil ? ?
The single most luminous event ever witnessed by humans! WOW! I like the comment at the end of the NASA report that the increased gamma ray burst activity marked the passing of Sir Arthur C. Clarke the day before.
I think that it’s safe to say, given the magnitude of this event, this event was not the explosion of a star that is visible from earth. If it were, we would almost certainly be dead (buy Phil’s next book for more details
). So when it is said that the GRB occurred in the constellation Bootes, what they mean is that the GRB happened in the same direction as the constellation Bootes, but much, much, much farther away.
Using spectroscopy, the distance to the GRB was measured at about 7 billion light-years (IIRC). Our galaxy is only 100,000 light-years across, and 7 billion light-years is about halfway across the entire observable universe. As Ian said, it came from the same direction as Bootes, but the stars in Bootes are within our galaxy.
This just in from BZRA (Bad Zeta Reticulan Astronomer):
I want to mention that given the distance and brightness of the burst, it is most likely the single most luminous event ever witnessed by Zeta Reticulans. I think that’s somethin’ right there.
Hi Phil, just wondering, is the ‘ray-like’ structure apparent in the picture of the burst that you posted real or is it an artifact of the optics or camera?
“when it fades enough to look for the host galaxy ”
That’s pretty amazing, actually. The GRB was brighter than the output of the entire galaxy? Impressive…. most impressive.
We caught this one 14 min after the burst, and it was STILL 13th mag. Incredible. I just wish we had nothing better to do with our telescopes than follow Swift around the sky all night - then maybe we would have been more successful in Swift Cycle 4.
Couple of quick questions:
- Could one or more of the extinction events that plagued Earth’s past history have been triggered by one of these babies?
- And if so, would there be any tell-tale signs that would allow us to study and detect them?
My guesses regarding answers to these would be “yes” and “no”, but they’re just guesses.
Talk about old news, didn’t this happen billions of years ago? Sorry, bad joke.
Also, and I’m being half-serious, billions of living creatures could have been potentially killed by this event, so I think a moment of silence is in order.
Please forgive me if the answer to this question can be found in the articles and comments. If it is, I missed it.
Was this GRB observed in a known galaxy (obviously not the Milky Way)? Or do we now know the location of a previously unknown galaxy because of this GRB?
J. D.
Phil,
I’d like to point out a small error in your post. That image is an X-ray image of the burst, taken with the Swift XRT. However it was not taken “minutes after the burst”, it was actually taken starting over an hour after the burst. When Swift first slewed to the burst, it was so bright that the XRT had to take data in a special fast readout mode that sacrifices imaging for timing. Shortly before this XRT does take a short (0.1s in this case) exposure of the field to localize the burst, but that is not the image above!
Sorry for being pedantic
SkepticTim: The structure in the image is purely due to the XRT’s optics, in this case the support structure of the grazing incidence mirrors. GRBs are too far away to have any discernible structure.
I wrote a little article of my own about this, and included the supposition that this was the brightest event ever seen by human beings, the miost distant object ever (potentially) seen by the naked eye and the idea that it was “Arthur’s farewell” signal. I hope I got all my facts right - feel free to comment here.
I’m still gobsmacked at the idea that I could have looked up and seen an actual event occurring half way across the known universe!
Dear Earth,
Sorry. Too much lighter fluid. You know how it is.
Sincerely,
The people of Haleakala*
*(yes, it’s just a coincidence)
When you consider this event and WR-104 ( http://www.universetoday.com/2008/03/03/looking-down-the-barrel-of-a-gamma-ray-burst/ ) together, I start feeling a tad uncomfortable.
Where did the burst happen? North Hemisphere, South? Constellation?
An interesting thought - all Intelligent civilizations on our level would probably their own SWIFT in the sky. It’s kind of neat that this is something for sure other races all over the universe have gotten excited about, along with the human race.
[…] the BABlogger says… Posted on March 22, 2008 by DW In a supplemental regarding the GRB, Phil wrote, “…given the distance and brightness of the burst, it is most likely the […]
Kevin F: The “Pi of the Sky” page Phil links to has a “scientific” data link at the top. At the bottom of that page is a SIMBAD link for the position in the sky Right Ascension 14h32′23″, Declination +36°16′ which puts it well into the northern sky up near the “top right-hand” side of main part of Bootes. Hence the mention of this constellation in the first few comments.
The single most luminous event ever witnessed by humans?
I see only two realistic explanations:
1. This is definitely the sign of the end times. All the previous ones didn’t work out I know - but this is CERTAINLY it.
2. It could be some Amanda Tapping type scientist chick blowing stars up to protect the Earth from alien invasion. I mean think about it. We just happen to see such a huge explosion at this point in history? What are the odds?
I think the SG-1 series is based on reality, and the show is a Wormhole X-treme style double-bluff by the government. And Wormhole X-treme itself a triple-bluff to throw us off the track. It’s the only reasonable explanation.
Phil is probably in on it, by the way. That’s why he goes to so much trouble to show photos of people with his books. We are supposed to believe that lots of people are buying them, and that’s where his money comes from - not a big fat cheque from NASA.
dr_lha: Thanks, I thought that was likely, but I’ve been retired from active astrophysics for a a long time and things have changed.
Yes, a moment of silence for all those prokaryotes that died on a galaxy far, far away
An obvious nitpick, for the record:
I’m sure it’s not the brightest ever event seen by naked-eye (or could have been seen, it still seems unknown whether anyone was actually looking at the time), just the brightest in the last few years we know about.
And a question:
The NASA page, and the previous page it links to, both say that what’s visible is the afterglow caused by the high energy jets from the (supposed) collapsing star heating up the gas surrounding the GRB. I’d have thought that the afterglow would emit light in all directions, not just the directions of the jets.. is that wrong?
You know, I have no science training in University. My college training is in Theology.
But… when I read something like this, all I can say is, “Wow”! There are really no other words to describe the awesomeness of the Universe.
Many months ago I said that I looked at Saturn’s rings. We have Hubble’s pics. But, please, if you have even a small telescope, take the time to find Jupiter, or Saturn, or Mars….
A few years ago when Mars was at it’s closest, I took my then 5 or 6 year old daughter out and aimed my small Meade 3.5 inch scope at Mars. I could ACTUALLY see the Ice-caps! later I showed her Jupiter and her 4 moons, then Saturn…. Real time! I was able to show my daughter the wonders of the Universe. My ex is taking them to church and stuff, ( I used to be a minister, but have “fallen”. That’s fine. I have no problem teaching my daughter what I believe, yet respecting what her mother, who knows zilch about science anyway, believes. I have the unique advantage of knowing, in a limited sense, both sides of the coin. At this point my oldest is more interested in Hannah Montana than the latest Mars update! My youngest is developmentally delayed (Down syndrome).
I guess I want to thank BA for showing me, and in turn, through me, my kids the wonders of Space! BA you are one of my heroes!
One more thing… Maybe you will be hearing my last name in the future, but not my first. It may be my daughter’s. She could be a part of the first mission to Mars! But it could easily be your child! Whatever your religious beliefs, or lack of, please take the time to show your kids the wonders of this Solar system, this Galaxy and this Universe!
i guess this has been a “rant”? But BA, thanks for bringing the wonder of this weird, wonderful, and seemingly infinite Universe home to us! I really appreciate your love of what you do! Thanks, from the bottom of my heart!
I’m not sure how, or if you celebrate Easter, but I hope the Easter Bunny drops many chocolate eggs on you, Mrs. BA, and the little BA!
Sorry - can’t resist posting this. Enjoy.
The Greatest SF Story Ever Told
(A Pantoum Tribute to “The Star” by Arthur C. Clarke)
They knew their time had come at last
They understood all things must cease
Their faithful sun was dying fast
They must resign themselves to peace.
They understood all things must cease
Their mighty empire would be lost
They must resign themselves to peace
There would be none to count the cost.
Their mighty empire would be lost
They hoped their art would all be saved
There would be none to count the cost
They locked their treasures deep in caves.
They hoped their art would all be saved
They held each other in their grasp
They locked their treasures deep in caves
Their star pulsed out its dying gasp.
They held each other in their grasp
They knew God would remember them
Their star pulsed out its dying gasp -
Its light was seen in Bethlehem.
© Elwood Herring 26 Feb 2000
[…] Bad Astronomy has a pretty good writeup on the matter, with more information on the satellite used, including the following information: Swift is a satellite in low Earth orbit, and it sees a large portion of the sky at once. When gamma rays from a GRB are detected by Swift, it immediately (in a few seconds!) sends down the rough coordinates of the burst so other telescopes can observe it as quickly as possible — many GRBs fade to invisibility in seconds. So a telescope looking at the same part of the sky as Swift cuts down even those precious seconds, getting the burst simultaneously in optical light as Swift sees the gamma-rays. […]
Apparently five GRBs went off on the day of Arthur C. Clarke’s death, including that especially gigantic one. Given that these things probably kill life on every planet within tens of thosands of light-years of them, I found myself thinking of Clarke’s famous story “The Star”.
Clarke’s story was decent enough, but guys, stars that are primaries of habitable planets don’t go nova. Trust me on this. I know 8,000 SF stories from 1950 to 1980 were about habitable planets threatened by their suns going nova, but it doesn’t really happen. Let me know if you want a quick precis of how stellar evolution works and why sunlike stars can’t go nova.
Barton Paul Levenson: I (and I suspect most people who post here) know all about stellar evolution, and we also know good SF when we read it. We are able also to distinguish fact from fiction. Clarke’s short story was an excellent work that drove home the concept that the universe has no pity, and no intelligence controlling it. The contention that habitable planets don’t orbit suns that go nova is irrelevant, whether true or not (what do you think will happen to our own Sun in a few billion years anyway? Not that we’ll be around to worry about it.)
The point is also put across eloquently in Terry Pratchett’s story “Hogfather” where towards the end of the book Death explains wearily:
“Take the universe and grind it down to the finest powder, and sieve it through the finest sieve, and then show me one atom of justice, one molecule of mercy. And yet, you try to act as if there is some ideal order in the world. As if there is some, some rightness in the universe, by which it may be judged.”
btw I also like the Twilight Zone version of Clarke’s story, in which some sort of poetic consolation is suggested to account for the tragedy of the event. Makes you think.
Another point I intended to mention in my previous post was the inescapable fact that when that GRB went pop it would have wiped out any alien civilizations around it within a huge sphere many tens or even hundreds of light years across. It was THAT big. You didn’t have to be on a planet orbiting the actual star that exploded to get burned. So Arthur C. Clarke’s story is still 100% valid in my opinion. If you believe that there really is life out there, it is a nigh-on certainty that there is now slightly less life in the vicinity of GRB080319B.
In the earlier thread on the GRB I said:
“People talk as if it were a fact that GRBs give off their energy in beams (rather than in every direction). I know there was some evidence for beaming recently (I think it was a paper in Nature or Science), but my impression was that the evidence was somewhat sketchy. Has there more evidence generated for the hypothesis that GRBs give off their energy in beams? Just looking at the NASA photograph, it looks like the thing was giving off energy in every direction. Would it take a force much more powerful than the burst itself to direct all that energy into beams?
Thanks for any insight …”
Dr_LHA responded:
“Mark: GRBs basically have to be beamed, otherwise the amount of energy they give off would be too large to explain.”
Thanks for responding Dr. LHA. That’s the impression I’d gotten also, i.e. the evidence for beaming is scant, but they MUST be beamed otherwise we have no explanation for them. This is pet peeve of mine so excuse me while I climb onto my soapbox …
“Ahem … All conveyors of science to masses out there in world … PLEASE STOP DOING THIS!!” That is, please stop giving people the impression that we understand things that we don’t, and then add little qualifiers like “of course there are some details that haven’t been worked out yet …” This is a curiosity KILLER to aspiring future scientists. I remember asking probing questions about gravity and electons and such to my high school physics teacher. He gave the impression that all this stuff has been figured out but it was much too difficult for me to understand. That basically killed the curiosity and interest I had. If he had instead said something like, “nobody really understands these things at the most fundamental level, we need people with an interest in these things to study them and figure them out” who knows how my career would have been different. It seems apparent to me that all we have with regards to GRBs is a couple of barely tenable HYPOTHESES about what causes them. These hypotheses are probably totally unable to explain the beaming of GRBs (which everyone agrees must be occurring because otherwise we would have no explanation for these things – anybody spot the logical inconsistency here?)
So, if it is true, please just say, “We have no idea what can cause a burst of energy this big. We have a couple of seriously deficient hypotheses that people are working on.”
Again, I ask. If the amount of energy put out by these things is what makes them difficult to understand, then how does “beaming” solve the problem since it would take more energy to concentrate a beam than is in the beam itself?
I’ll shut-up now and let someone with more knowledge correct/enlighten me.
Thanks
@Barton…
Better would have ben “civilization threatened by nearby star going supernova/GRB.” Then we could have our cake and nuke it, too!
(My coat? the liquid nitrogen one on the far end.
Man, that’s cool….)
There is quite a bit of evidence of beaming, actually. There is a phenomenon called the jet break, where the material in the beam suddenly slows and the angle of beam widens. This has been seen in many many GRBs, and is excellent evidence that the energy is focused into beams and not emitted in all directions.
Mark: My explanation was not meant to contain all the arguments for why there are jets are present in GRBs. It is merely one of the simplest arguments for them, i.e. that an object at such a distance could not physically output the amount of energy required if the GRB output its energy uniformly in all directions.
Although its true that GRBs are still poorly understood, as Phil states there are many phenomenological characteristics in GRB afterglows that point towards there being jets in the system.
I would point out that I am not a GRB theorist, but know many that are and the concept to beaming and jets in GRBs is non-controversial these days.
I’m familiar with the “no molecules of justice” mode of thought; it’s something we hear constantly from the likes of Richard Dawkins. It’s wrong, though. Justice can be real even if it’s not made of molecules. Ditto love. And God. If you want to live without those things, feel free, but don’t claim that your nihilism is somehow backed by science.
I wonder how many alien philosophers were explaining how the universe was finely and intelligently tuned to be a hospitable place for conscious life, when they were hit by this?
By the way, the GRB came from roughly the direction of USNOA2 1200-07324239, near the Bootes Void.
http://server6.sky-map.org/starview?object_type=1&object_id=1148174927
“Again, I ask. If the amount of energy put out by these things is what makes them difficult to understand, then how does “beaming” solve the problem since it would take more energy to concentrate a beam than is in the beam itself?”
For an isotropic (i.e., in all directions equally) radiator we have:
F = P / (4*pi*r^2)
where F is power flux (watts per square meter), P is power (watts), and r is distance (meters)
For a tightly focused beam:
F = P / (Sigma*r^2)
where Sigma is the solid angle (steradians) of the beam. Or:
P = Sigma*F*r^2
Sigma = 2*pi*(1 - cos(0.5*theta))
where theta is the full beam width (radians)
For small theta we use a Taylor series approximation:
P = 0.25*pi*theta^2*F*r^2
Thus, if you cut the beam width in half the power needed to produce the given flux (i.e., brightness) goes down by a factor of four. So small beams are good to project power a long way. Hope that helps.