GRB Visible Halfway Across the Universe

by Paul Gilster on March 21, 2008

The recent news of a record-setting gamma ray burst (GRB) in a distant galaxy doesn’t just raise eyebrows. It practically singes them. Occurring in the midst of a 24-hour period that saw five gamma ray bursts (a story in itself), the burst called GRB 080319B was picked up by the Swift satellite on March 19 and traced to the constellation Boötes. The afterglow brightened to magnitudes between 5 and 6, meaning that in dark locations, people with normal vision could have seen the burst remnant with the naked eye.

How extreme was this burst? Ponder the implications of what Derek Fox (Pennsylvania State University) has to say:

“These optical flashes from gamma-ray bursts are the most extreme such phenomena that we know of. If this burst had happened in our galaxy it would have been shining brighter than the Sun for almost a minute — sunglasses would definitely be advised.”

Brighter than the Sun. All of this makes the optical afterglow of GRB 080319B 2.5 million times more luminous than the brightest supernova ever recorded. It is the most intrinsically bright object ever seen. With a redshift of 0.94, the burst can be traced to a distance of 7.5 billion light years, so we’re talking about seeing something with the unaided eye that occurred more than halfway across the visible universe.

Record-setting GRB

I loved what Swift science team member Judith Racusin said in this NASA news release. Noting that the mammoth burst was one of four detected on March 19, the grad student made the obvious connection: “Coincidentally, the passing of Arthur C. Clarke seems to have set the universe ablaze with gamma-ray bursts.” It’s hard to imagine anything that would have pleased Clarke more than having the heavens come alive with unimaginable energies on the day he left us.

Image: The extremely luminous afterglow of GRB 080319B was imaged by Swift’s X-ray Telescope (left) and Optical/Ultraviolet Telescope (right). This was by far the brightest gamma-ray burst afterglow ever seen. Credit: NASA/Swift/Stefan Immler, et al.

Thus do records fall. Until the 19th, the most distant object visible with the naked eye was the galaxy M33, some 2.9 million light years away. Peter Mészáros (Penn State), who leads Swift’s theory team, notes that such bursts may be formed from a massive stellar explosion that culminates in a black hole or neutron star. The optical brightness created by this one may have been the result of unusual circumstances:

“When the jet that formed during the explosion of the star slammed into surrounding gas clouds, shock waves were generated that heated the jet. The exceptional brightness of this burst requires the jet to have just the right combination of magnetic fields and velocity, which occurs very rarely.”

Further analysis of the data should tell us much more. Interestingly, one of the theories accounting for the unusual brightness is that the awesome energies of the burst were concentrated in a jet that happened to be pointed directly at the Earth. One can only imagine the result of a jet like this pointed at a biosphere no more than a few light years from the object in question. Whatever that object may have been.

For while the exploding star theory makes sense, other phenomena cannot be ruled out. We do know that gamma ray bursts are remarkably common, occurring about once a day in the form of flashes of gamma radiation arriving from all directions of the sky. The Swift satellite’s instruments allow Earth- and space-based instruments to target the afterglow of such bursts quickly, while providing redshift and lightcurve information. Be sure to check out this video of Swift’s operations. Penn State offers an excellent and detailed backgrounder on GRBs as well.

Supernova remnant

GRB studies have advanced rapidly in the past decade, following a long period in which the events were considered deeply mysterious. Military satellites monitoring compliance with the Nuclear Test Ban Treaty began to report the bursts in the late 1960s. In fact, there was a brief but pulse-quickening period when some theorized they were evidence of extraterrestrial civilizations (a theory quickly abandoned). By 1995, the Compton Gamma-Ray Observatory had collected data on 3000 bursts, showing they were being picked up from all directions in the sky.

Image: A composite Chandra X-ray (blue) and Palomar infrared (red and green) image of the supernova remnant W49B. Recent evidence has suggested that a gamma ray burst was associated with this remnant. Credit: X-ray: NASA/Chandra X-ray Center/Spitzer Science Center; Infrared: Caltech/Palomar.

Understanding the mechanisms at work has occupied scientists ever since, with great attention paid to GRB afterglows. Swift has provided a leap forward by localizing the afterglows almost immediately after their detection in gamma and X-rays. An emerging question: Are GRBs possible sources of gravitational waves? One mechanism that could explain some bursts is the merger of two neutron stars, or a neutron star and a black hole, both events considered candidates for generating such waves. With Swift at work and LIGO (Laser Interferometric Gravitational Observatory) searching for them, the potential link between gravitational waves and gamma ray bursts offers rich grounds for future research.

Hans Bausewein March 21, 2008 at 12:18

“Coincidentally, the passing of Arthur C. Clarke seems to have set the universe ablaze with gamma-ray bursts.”

It’s amazing that the GRB knew 7.5 billion years ago, that Arthur C. Clarke would die on the day its light would arrive on a tiny planet that did not even exist when the GRB went off.

(same or similar for the other 4)

It tells more about the human mind’s ability to see coincidences ;)

(or *did* the rays from GRB 080319B kill Arthur? Who knows?)

philw1776 March 21, 2008 at 13:48

Speaking of LIGO, seems as if the instrument is still too insensitive to pick up putative gravitational waves. It’s been operational for over 5 years now with no papers on G wave detection.

fitz March 21, 2008 at 19:28

“Speaking of LIGO, seems as if the instrument is still too insensitive to pick up putative gravitational waves. It’s been operational for over 5 years now with no papers on G wave detection.”

I suppose non-detection is significant as well. Too bad there’s
not one common process within its present detection ability. Billions of
dollars later comes the realization they should have waited for more advanced
technology or space based system.

James M. Essig March 21, 2008 at 21:37

I had a few musings on just how large of single explosions of real matter based human and or ETI devices might be produced. The following examples are far larger than any thing we have ever witnessed except the Big Bang.

A thermonuclear device with the mass of about 10 EXP 6 solar masses in the form of a rotating toriod with a diameter of about 6 billion kilometers could be gradually spun up until it reached the end of construction and a rotation velocity of several hundred kilometers/second. White dwarf dense toriodal material would allow for a thin aspect ratio toriod to reduce gravitational/rotational induced tidal forces which otherwise could tear the ring apart. A rotational velocity of say 500 km/second would permit the fusion energy yield to be efficiently stored at about 5,000 times greater than that of the rotational kinetic energy. Much more massive fusion rings are in theory possible. Using matter/antimatter toroidal configurations made of solid neutronium and antineutronium, devices with a mass of 10 EXP 14 solar masses with a sub black hole enclosed volume density and a radius of 20 lightyears might in theory be constructed. This would yield enough energy to vaporize an amount of cold steel equivalent to the entire baryonic mass within the observable universe.

I can think of possibly much larger yield thermonuclear and matter antimatter devices composed of a layered arrangement of fusion or matter antimatter fuels and an exotic theoretical material known as negative mass which has yet to be discovered let alone produced. With judicious layering of fuels and negative mass in an onion like arrangement, in theory devices with infinite mass and infinite yield could be constructed given an infinite amount of time to construct them. If the life time of protons turns out to be finite, one could simply use eternally stable forms of quarkonium.

I do not have any idea why such dangerously large devices would be constructed, but as a thought experiment, the above conjecture shows how humans and/or ETI might be able to effect the universe on cosmic scales

Thanks;

Jim

Afonso March 22, 2008 at 7:00

This event, being visible in the entire universe (at least in the axis GRP/Solar system), is the perfect atention grabber to motivate all METI civilizations on this axis to transmit along this axis soon after…

philw1776 March 22, 2008 at 11:25

Yes, LIGO non-detection should tell us something. Unfortunately the LIGO website doesn’t say anything about G-wave thresholds and their 5 year operational scans. Is there something about current physics and G-wave theory that is wrong given null results?

dad2059 March 22, 2008 at 13:50

It’s amazing that the GRB knew 7.5 billion years ago, that Arthur C. Clarke would die on the day its light would arrive on a tiny planet that did not even exist when the GRB went off.

Just like the coincidence the ‘Star of Bethlehem’ was the sun that went nova killing a race of humanoid beings in Clarke’s ‘The Star’?

Conundrum upon conundrum upon questions.

ljk March 22, 2008 at 23:05

The Galaxy Population Hosting Gamma-Ray Bursts

Authors: S. Savaglio (MPE), K. Glazebrook (Swinburne University), D. Le Borgne (CEA/Saclay)

(Submitted on 18 Mar 2008)

Abstract: We present the most extensive and complete study of the properties for the largest sample (46 objects) of gamma-ray burst (GRB) host galaxies. The redshift interval and the mean redshift of the sample are 0<z<6.3 and z=0.96 (look-back time: 7.2 Gyrs), respectively; 89% of the hosts are at z < 1.6. Optical-NIR photometry and spectroscopy are used to derive stellar masses, star formation rates, dust extinctions and metallicities. The average stellar mass is 10^9.3 M_sun, with a 1 sigma dispersion of 0.8 dex. The average metallicity for a subsample of 17 hosts is about 1/4 solar and the dust extinction in the visual band (for a subsample of 10 hosts) is A_V=0.5. We obtain new relations to derive SFR from [OII] or UV fluxes, when Balmer emission lines are not available. SFRs, corrected for dust extinction, aperture slit loss and stellar Balmer absorption, are in the range 0.01-36 M_sun yr^-1. The median SFR per unit stellar mass (specific star formation rate) is 0.8 Gyr^-1. Equivalently the inverse quantity, the median formation time scale is 1.3 Gyr.

Most GRBs are associated with the death of young massive stars, more common in star-forming galaxies. Therefore GRBs are an effective tool to detect star-forming galaxies in the universe. Star-forming galaxies at z<1.6 are a faint and low-mass population, hard to detect for the deepest conventional optical-NIR surveys possible today, unless a GRB event occurs. There is no compelling evidence that GRB hosts are peculiar galaxies. More data on the sub-class of short GRB are necessary to establish the nature of their hosts.

Comments: 34 pages, 19 figures, 11 tables, submitted to ApJ, revised version after first referee report

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0803.2718v1 [astro-ph]

Submission history

From: Sandra Savaglio [view email]

[v1] Tue, 18 Mar 2008 21:10:24 GMT (1099kb,D)

http://arxiv.org/abs/0803.2718

Paul F. Dietz March 23, 2008 at 11:15

I suppose non-detection is significant as well. Too bad there’s
not one common process within its present detection ability. Billions of
dollars later comes the realization they should have waited for more advanced
technology or space based system.

You are being a bit silly. Physicists often do experiments that yield null results. These are useful, since they can rule out sections of parameter space. There are also often sources that were not predicted. Building LIGO also is a necessary step toward the more advanced technology you advocate.

BTW, space-based gravitational wave detectors will operate at a much lower frequency range than LIGO, so they are not directly comparable.

Is there something about current physics and G-wave theory that is wrong given null results?

LIGO should not have been able to ‘see’ this event at that distance, so no.

James M. Essig March 23, 2008 at 23:54

Hi Folks;

Upon observing and understanding ever more energetic explosions, perhaps we will oneday witness an explosion wherein the energy released is simply too great to be described in terms of complete mass to energy conversion according to the relativistic equation E = M(C exp 2).

The folks at and working with the relativistic heavy ion collider within the U.S. feel strongly about the possibility of additional nuclear forces besides the strong and weak nuclear force as well as perhaps a sub-structure to quarks and/or leptons.

Perhaps finding any additional nuclear forces could entail a gateway to energy releases of E much, much greater than E = M(C exp 2). One way of making such exothermic energy reactions consistent within current theoretical paradimns might be to view the energy as coming from or derived from the zero point energy fields. Another way would simply be to through in the towel for the relation E = M(C exp 2). One can imagine that a new overarching concept of what such third, fourth, or whatever nuclear-force-based energy means. Could there by a real dynamic source that is much more powerful than what we refer to as energy in E = M(C exp 2) that envolves real material as opposed to being strictly only due to virtual particle based energy sources such as zero point vacuum fluctuations? Could our probing to ever higher energies lead to the discovery of a real physical dynamic source that is many, many times greater in magnitude than even the proposed latent energy density in the vacuum state based zero point fields for which some theories embarassingly calculate to be 120 orders of magnitude greater in density than the averaged real mattergy content within our universe.

If we find additional nuclear forces, I can imagine how the application of such forces would facilitate manned interstellar and intergalactic space travel.

Regards;

Jim

ljk March 24, 2008 at 8:36

For those of you looking for a cosmic “tribute” to Clarke much closer
to home, how about the fact that the Moon and Saturn were in a close
conjunction on the day of Clarke’s passing:

http://www.universetoday.com/2008/03/17/moon-and-saturn-team-up-on-march-19/

The symbolic signifigance? In the novel version of 2001: A Space
Odyssey, the Moon is where the first Monolith (TMA-1) was found
(in crater Tycho) and the signal it sent was aimed at the second
Monolith (TMA-2) placed on Iapetus, a moon of Saturn.

Cue Twilight Zone music… or Thus Spake Zarathustra.

dad2059 March 24, 2008 at 12:35

In the novel version of 2001: A Space
Odyssey, the Moon is where the first Monolith (TMA-1) was found
(in crater Tycho) and the signal it sent was aimed at the second
Monolith (TMA-2) placed on Iapetus, a moon of Saturn.

The same Iapetus that sports the nearly symmetrical mountain ridge about its’ equator? ; http://www.solarviews.com/cap/vss/VSS00056.htm

Cue Twilight Zone music… or Thus Spake Zarathustra

I suddenly smell cigarette smoke and hear a raspy baratone voice somewhere…

george scaglione March 24, 2008 at 13:58

jim no doubt about it,everything you surmise might only be tomorrows headlines!!!!!as we learn more and more and delve deeper into the fabric of the cosmos! LHC will not hurt in this regard either. recall when i sugested using the very fabric of the universe as a power source for propulsion? well…maybe the time draws closer.maybe even ftl too as more or less “part and parcel” of the same thing! glad to hear comments,as always,from everyone here! thank you, george

ljk March 24, 2008 at 16:13

I will give you another coincidental point: In the novel, Clarke
said the second Monolith was in a large crater located right on
the border between the light and dark halves of Iapetus.

When the Voyager probes flew by Saturn and its moons in 1980
and 1981, guess what they found…. No word yet on whether a
large black slab was at the crater’s center, though.

In the same novel, Clarke also stated that Saturn had multiple
rings, rather than just the few large ones most astronomers
thought the system consisted of until the Voyager flybys. A
few amateur astronomers claimed to have seen these many
rings going back to at least the 1940s, but the professionals
dismissed them as optical illusions by overeager amateurs.

ljk March 24, 2008 at 23:08

Observations of the Naked-Eye GRB 080319B: Implications of Nature’s Brightest Explosion

Authors: J.S. Bloom (1,2), D. A. Perley (1), W. Li (1), N. R. Butler (1), A. A. Miller (1), D. Kocevski (1), D. A. Kann (3), R. J. Foley (1), H.-W. Chen (4), A. V. Filippenko (1), D. L. Starr (1,5), B. Macomber (1), J. X. Prochaska (6), R. Chornock (1), D. Poznanski (1), S. Klose (3) (1. UCB, 2. Sloan, 3. Tautenburg, 4. U of Chicago, 5. LCOGT, 6. UCO/Lick Observatory)

(Submitted on 24 Mar 2008)

Abstract: The first gamma-ray burst (GRB) confirmed to be bright enough to be seen with the naked eye, GRB 080319B, allowed for exquisite follow-up across the electromagnetic spectrum. We present our detailed optical and infrared observations of the afterglow, consisting of over 5000 images starting 122 s after the GRB trigger, in concert with our own analysis of the Swift UVOT, BAT, and XRT data. The event is extreme not only in observed properties but intrinsically: it was the most luminous ever recorded at optical wavelengths and had an exceedingly high isotropic-equivalent energy release in gamma-rays. At early times, the afterglow evolution is broadly consistent with being reverse-shock dominated, then is subsumed by a forward shock at around 1000 s. Analysis of the forward shock suggests that the remarkable energetics of this burst may be owed largely to extreme collimation. The spectral energy distribution, spanning from ultraviolet through near-infrared, shows no evidence for a significant amount of dust extinction in the host frame. We do find significant color evolution in the optical afterglow: starting at about 1000 s the index shifts blueward before apparently shifting back to the red at late times. Finally, we examine the detectability of such events with current and future facilities and find that such an event could be detected in gamma-rays by BAT out to z = 4.9 (8 sigma), while the nominal EXIST sensitivity would allow detection to z = 12.2. At K-band this source would have been easily detected with meter-class telescopes to z = 17.

Comments: Submitted to ApJ, 42 pages, 6 figures

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0803.3215v1 [astro-ph]

Submission history

From: Weidong Li [view email]

[v1] Mon, 24 Mar 2008 18:29:33 GMT (249kb)

http://arxiv.org/abs/0803.3215

ljk March 26, 2008 at 16:18

This fellow wants to call the GRB the Clarke Event:

http://blogs.earthsky.org/larrysessions/space/032190/why-not-the-clarke-event/

ljk March 26, 2008 at 23:14

Observations of the Naked-Eye GRB 080319B: Implications of Nature’s Brightest Explosion

Authors: J.S. Bloom (1,2), D. A. Perley (1), W. Li (1), N. R. Butler (1), A. A. Miller (1), D. Kocevski (1), D. A. Kann (3), R. J. Foley (1), H.-W. Chen (4), A. V. Filippenko (1), D. L. Starr (1,5), B. Macomber (1), J. X. Prochaska (6), R. Chornock (1), D. Poznanski (1), S. Klose (3) (1. UCB, 2. Sloan, 3. Tautenburg, 4. U of Chicago, 5. LCOGT, 6. UCO/Lick Observatory)

(Submitted on 24 Mar 2008)

Abstract: The first gamma-ray burst (GRB) confirmed to be bright enough to be seen with the naked eye, GRB 080319B, allowed for exquisite follow-up across the electromagnetic spectrum. We present our detailed optical and infrared observations of the afterglow, consisting of over 5000 images starting 122 s after the GRB trigger, in concert with our own analysis of the Swift UVOT, BAT, and XRT data.

The event is extreme not only in observed properties but intrinsically: it was the most luminous ever recorded at optical wavelengths and had an exceedingly high isotropic-equivalent energy release in gamma-rays. At early times, the afterglow evolution is broadly consistent with being reverse-shock dominated, then is subsumed by a forward shock at around 1000 s. Analysis of the forward shock suggests that the remarkable energetics of this burst may be owed largely to extreme collimation. The spectral energy distribution, spanning from ultraviolet through near-infrared, shows no evidence for a significant amount of dust extinction in the host frame.

We do find significant color evolution in the optical afterglow: starting at about 1000 s the index shifts blueward before apparently shifting back to the red at late times. Finally, we examine the detectability of such events with current and future facilities and find that such an event could be detected in gamma-rays by BAT out to z = 4.9 (8 sigma), while the nominal EXIST sensitivity would allow detection to z = 12.2. At K-band this source would have been easily detected with meter-class telescopes to z = 17.

Comments: Submitted to ApJ, 42 pages, 6 figures

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0803.3215v1 [astro-ph]

Submission history

From: Weidong Li [view email]

[v1] Mon, 24 Mar 2008 18:29:33 GMT (249kb)

http://arxiv.org/abs/0803.3215

ljk March 27, 2008 at 13:37

Observations of the Naked-Eye GRB 080319B: Implications of Nature’s
Brightest Explosion

Authors: J.S. Bloom (1,2), D. A. Perley (1), W. Li (1), N. R. Butler (1), A.
A. Miller (1), D. Kocevski (1), D. A. Kann (3), R. J. Foley (1), H.-W. Chen
(4), A. V. Filippenko (1), D. L. Starr (1,5), B. Macomber (1), J. X.
Prochaska (6), R. Chornock (1), D. Poznanski (1), S. Klose (3) (1. UCB, 2.
Sloan, 3. Tautenburg, 4. U of Chicago, 5. LCOGT, 6. UCO/Lick Observatory)

(Submitted on 24 Mar 2008)

Abstract: The first gamma-ray burst (GRB) confirmed to be bright enough to
be seen with the naked eye, GRB 080319B, allowed for exquisite follow-up
across the electromagnetic spectrum. We present our detailed optical and
infrared observations of the afterglow, consisting of over 5000 images
starting 122 s after the GRB trigger, in concert with our own analysis of
the Swift UVOT, BAT, and XRT data.

The event is extreme not only in observed properties but intrinsically: it
was the most luminous ever recorded at optical wavelengths and had an
exceedingly high isotropic-equivalent energy release in gamma-rays. At early
times, the afterglow evolution is broadly consistent with being
reverse-shock dominated, then is subsumed by a forward shock at around 1000
s. Analysis of the forward shock suggests that the remarkable energetics of
this burst may be owed largely to extreme collimation. The spectral energy
distribution, spanning from ultraviolet through near-infrared, shows no
evidence for a significant amount of dust extinction in the host frame.

We do find significant color evolution in the optical afterglow: starting at
about 1000 s the index shifts blueward before apparently shifting back to
the red at late times. Finally, we examine the detectability of such events
with current and future facilities and find that such an event could be
detected in gamma-rays by BAT out to z = 4.9 (8 sigma), while the nominal
EXIST sensitivity would allow detection to z = 12.2. At K-band this source
would have been easily detected with meter-class telescopes to z = 17.

Comments: Submitted to ApJ, 42 pages, 6 figures

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0803.3215v1 [astro-ph]

Philip Tung Yep March 31, 2008 at 10:40

“Coincidentally, the passing of Arthur C. Clarke seems to have set the universe ablaze with gamma-ray bursts.”

or as Shakespeare wrote

“The heavens themselves blaze forth the death of princes.” Julius Caesar (II, ii, 30-31)

george scaglione April 1, 2008 at 8:07

philip,thank you,that comment above is excellent! respectfully your friend george

Administrator April 2, 2008 at 17:11

Philip, anyone who invokes Shakespeare in such a context is most definitely all right with me! Well done.

george scaglione April 3, 2008 at 8:54

it is such a pleasure to hang out here,this is about my fifth comment of the morning! we have such a wealth of intelligent people “hanging around” :) thank you one and all your friend george

ljk April 4, 2008 at 9:10

A Burst to See (ESO 08/08)

On 19 March, Nature was particularly generous and provided
astronomers with the wealth of four gamma-ray bursts on the
same day. But that was not all: one of them is the most
luminous object ever observed in the Universe. Despite being
located in a distant galaxy, billions of light years away, it was
so bright that it could have been seen, for a brief while, with
the unaided eye.

Read more in ESO 08/08 at:

http://www.eso.org/public/outreach/press-rel/pr-2008/pr-08-08.html

ljk April 4, 2008 at 9:20

A Burst to See (ESO 08/08)

On 19 March, Nature was particularly generous and provided
astronomers with the wealth of four gamma-ray bursts on the
same day. But that was not all: one of them is the most
luminous object ever observed in the Universe. Despite being
located in a distant galaxy, billions of light years away, it was
so bright that it could have been seen, for a brief while, with
the unaided eye.

Read more in ESO 08/08 at

http://www.eso.org/public/outreach/press-rel/pr-2008/pr-08-08.html

ljk April 7, 2008 at 13:23

Is there anything special about GRB 080319B?

Authors: Shlomo Dado, Arnon Dar, A. De Rujula

(Submitted on 4 Apr 2008)

Abstract: We show that the properties of gamma ray burst 080319B and its afterglow are well reproduced by the cannonball model of long gamma ray bursts (GRBs). It was an ordinary GRB, produced by a jet of highly relativistic plasmoids (CBs), ejected in a core-collapse supernova (SN) and viewed, as some others before, particularly close to the CB-emission axis. It still remains to be seen whether GRB 080319B was associated with an SN akin to SN1998bw, the SN type ordinarily associated with GRBs, or with a much more luminous SN.

Comments: 8 pages, 4 figures

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0804.0621v1 [astro-ph]

Submission history

From: Arnon Dar [view email]

[v1] Fri, 4 Apr 2008 16:54:19 GMT (46kb)

http://arxiv.org/abs/0804.0621

ljk April 10, 2008 at 15:48

HUBBLE PINPOINTS RECORD-BREAKING EXPLOSION

Peering across 7.5 billion light-years and halfway back to the
Big Bang, NASA’s Hubble Space Telescope has photographed the
fading optical counterpart of a powerful gamma ray burst that holds
the record for being the intrinsically brightest naked-eye object ever
seen from Earth. For nearly a minute this single star was as bright as
10 million galaxies.

Hubble Wide Field and Planetary Camera 2 (WFPC2) images taken
on Monday, April 7 show the fading optical counterpart of the titanic
blast. The object erupted in a brilliant flash of gamma rays and other
electromagnetic radiation at 2:12 a.m. EDT on March 19, and was
detected by Swift, NASA’s gamma ray burst watchdog satellite.

Immediately after the explosion, the gamma ray burst glowed as
a dim 5th magnitude “star” in the spring constellation Bootes.
Designated GRB 080319B, the intergalactic firework has been
fading away ever since then.

Hubble astronomers had hoped to see the host galaxy where the
burst presumably originated, but were taken aback that the light
from the GRB is still drowning out the galaxy’s light even three
weeks after the explosion. This is particularly surprising because
it was such a bright GRB initially.

Previously, bright bursts have tended to fade more rapidly, which
fits in to the theory that brighter GRBs emit their energy in a more
tightly confined beam. The slow fading leaves astronomers puzzling
about just where the energy came from to power this GRB, and
makes Hubble’s next observations of this object in May all the
more crucial.

Called a long-duration gamma ray burst, such events are theorized
to be caused by the death of a very massive star, perhaps weighing
as much as 50 times our Sun. Such explosions, sometimes dubbed “hypernovae,” are more powerful than ordinary supernova
explosions and are far more luminous, in part because their energy
seems to be concentrated into a blowtorch-like beam that, in this
case, was aimed directly at Earth.

The Hubble exposure also shows field galaxies around the fading
optical component of the gamma ray burst, which are probably
unrelated to the burst itself.

Credit: NASA, ESA, N. Tanvir (University of Leicester), and A.
Fruchter (STScI)

For images and additional information about gamma ray burst
080319B, visit:

http://hubblesite.org/news/2008/17

ljk April 10, 2008 at 15:52

I believe it was Arthur C. Clarke used to say these things were
“industrial accidents”.

I am having a hard time believing that even a huge supernova
explosion could create a GRB of that magnitude from that distance.

Ron S April 10, 2008 at 21:21

I suppose it depends on how narrow the beam is and if we’re on axis with the beam. Three weeks on and it’s still outshining its host galaxy. Now that would have to be some extinction event.

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