GRB Question
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Den Koawl
May 17, 2013, 5:42:55 AM5/17/13
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Hi Folks, When a GRB occurs, would we see the light from it before the energy affects our ionosphere ?
Den
Dave Typinski
May 17, 2013, 12:23:47 PM5/17/13
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GRB as in cosmological gamma ray burst? Those haven't been observed to affect
the ionosphere -- or much of anything else, for that matter. Which is why
nobody even knew they existed until the Vela satellites' bhangmeters started
registering nuclear tests out in space, piquing everyone's curiosity.
A GRB could affect the ionosphere if the emission source were close enough, but
in that case you'd have far more to worry about than HF propagation -- like the
collapse of the planetary food chain as the upper atmosphere was converted to a
brown haze of oxides of nitrogen, blocking the visible solar radiation necessary
for photosynthesis. The ozone layer would also go away, opening up a window for
hard solar UV to fry anything that tried to survive anyway.
Such an event could happen if a nearby binary neutron star system coalesced to
form a black hole. The neutron binaries we do know about are far away. We can
observe them only if at least one of the pulsar beams happens to point toward
us. If they don't, we won't know they exist -- not until we build a
gravitational wave observatory sensitive enough to detect their presence -- and
the jury's still out on whether that's even possible.
This isn't wholly speculative. It's possible that nearby GRB's may have caused
one or more of the mass extinctions we see in our evolutionary record.
http://arxiv.org/abs/astro-ph/9501019
http://arxiv.org/abs/astro-ph/0512013
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the ionosphere -- or much of anything else, for that matter. Which is why
nobody even knew they existed until the Vela satellites' bhangmeters started
registering nuclear tests out in space, piquing everyone's curiosity.
A GRB could affect the ionosphere if the emission source were close enough, but
in that case you'd have far more to worry about than HF propagation -- like the
collapse of the planetary food chain as the upper atmosphere was converted to a
brown haze of oxides of nitrogen, blocking the visible solar radiation necessary
for photosynthesis. The ozone layer would also go away, opening up a window for
hard solar UV to fry anything that tried to survive anyway.
Such an event could happen if a nearby binary neutron star system coalesced to
form a black hole. The neutron binaries we do know about are far away. We can
observe them only if at least one of the pulsar beams happens to point toward
us. If they don't, we won't know they exist -- not until we build a
gravitational wave observatory sensitive enough to detect their presence -- and
the jury's still out on whether that's even possible.
This isn't wholly speculative. It's possible that nearby GRB's may have caused
one or more of the mass extinctions we see in our evolutionary record.
http://arxiv.org/abs/astro-ph/9501019
http://arxiv.org/abs/astro-ph/0512013
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David Fields
May 17, 2013, 12:35:51 PM5/17/13
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Hi Dave,
Wouldn't a GRB produce a Compton pulse as it encountered the atmosphere? If so, we'd see a radio pulse. I think that this is the origin of some radio transients, and that we should watch for correlations. But.... I didn't do it yet.
The GRB itself would reach us ahead of a trailing EM light (radio) pulse, after passing through the interstellar medium and all those free electrons.
Cheers,
David Fields
Wouldn't a GRB produce a Compton pulse as it encountered the atmosphere? If so, we'd see a radio pulse. I think that this is the origin of some radio transients, and that we should watch for correlations. But.... I didn't do it yet.
The GRB itself would reach us ahead of a trailing EM light (radio) pulse, after passing through the interstellar medium and all those free electrons.
Cheers,
David Fields
Steve Berl
May 17, 2013, 1:21:03 PM5/17/13
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If anyone were interested in correlating GRB timing with radio frequency bursts, the data from the ERGO Telescope project might be useful.
--
-steve
Steve
--
-steve
Raydel Abreu (CM2ESP)
May 17, 2013, 1:24:07 PM5/17/13
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That's sound interesting on which frequency band is a greater chance of success with very very limited equipments...
Regards,Dave Typinski
May 17, 2013, 2:35:36 PM5/17/13
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That would be an interesting experiment, David. As Steve pointed out, the ERGO
data may be of use for that.
--
Dave
On 05/17/2013 12:35, David Fields wrote:
> Hi Dave,
> Wouldn't a GRB produce a Compton pulse as it encountered the atmosphere? If so,
> we'd see a radio pulse. I think that this is the origin of some radio
> transients, and thatwe should watch for correlations. But.... I didn't do it yet.
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data may be of use for that.
--
Dave
On 05/17/2013 12:35, David Fields wrote:
> Hi Dave,
> Wouldn't a GRB produce a Compton pulse as it encountered the atmosphere? If so,
> we'd see a radio pulse. I think that this is the origin of some radio
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Robert Fritzius
May 17, 2013, 3:00:11 PM5/17/13
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J...@seti.net
May 17, 2013, 3:02:46 PM5/17/13
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It happens that I am working on the next generation of ERGO telescope
receiver. This one will still use the Russian GM tube but will tag the
arrival time of the event down to the nanosecond using GPS.
http://www.seti.net/Cosmic%20Rays/cosmic_rays.htm
Regards.... Jim
receiver. This one will still use the Russian GM tube but will tag the
arrival time of the event down to the nanosecond using GPS.
http://www.seti.net/Cosmic%20Rays/cosmic_rays.htm
Regards.... Jim
Den Koawl
May 17, 2013, 7:30:25 PM5/17/13
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Tnx to all for your reply...... the reason i ask the question is, on occasion i find very short ( in time ) double spikes in my charts.
See Attachment from 130424...... the main trace is the screen capture and the inset is copied from my excel plot of the 24 hr scan. This type of double spike doesnt happen very often.
The chart is probably best viewed in MS Paint.
Den
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Robert Fritzius
May 18, 2013, 9:04:02 AM5/18/13
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| Dave, and other good guys There may be evidence that could lead to a different conclusion on this. Please see these articles (which I think are related): The Light of 5 Billion Billion Suns http://www.saao.ac.za/no_cache/public-info/news/news/article/117/615/neste/30/?tx_ttnews[pS]=1128161770&cHash=10861ca44e83dd3b311b3df2966db471 The Day the Solar Wind Disappeared http://science1.nasa.gov/science-news/science-at-nasa/1999/ast13dec99_1/ Best I can tell, the solar wind started its downward ramp in density about two hours after the GRB occurred. The sunward side of the earth's magnetosheath expanded five-fold during the disruption. Here's a link to a page of mine that shows a three day solar wind density history bracketing the disruption (with the GRB time overlaid) http://www.datasync.com/~rsf1/vel/aw0912.htm Bob Fritzius --- On Fri, 5/17/13, Dave Typinski <dav...@typnet.net> wrote: |
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John Mannone
May 19, 2013, 3:50:45 PM5/19/13
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Hello David T.,
I read all the responses to Den's question(s)
I beg to differ with your statement about GRB's having no observed effect on our ionosphere. In the 2007 SARA Conference, I presented a paper analyzing the Rhessi data for the SGR1860. Its gamma ray burst lasted several minutes and was clearly detected with a gyratron circuit (and I saw the Colorado data taken by a SARA member whose name escapes me at the moment). Many other GRBs since then have been detected with SID monitors.
Den, the double spike doesn't make sense to me as far as observable phenomena. The negative spike would correspond to a sudden signal attenuation followed by a sudden enhancement. That doesn't make sense. I like Marcus' explanation.
Fritzius (?) mentioned the work of some NASA folks and the ELF waves produced by the solar wind (if I remember correctly). I am very curious to learn more about that those. It is true that the annular cavity waves are ELF--the resonant waves are called Schumann resonances with a fundamental around 7.8Hz. The other waves, however, would dampen out very quickly. They are generally produced by global lightning storms, so I am very interested to learn if indeed they are produced by the solar wind too.
John
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I read all the responses to Den's question(s)
I beg to differ with your statement about GRB's having no observed effect on our ionosphere. In the 2007 SARA Conference, I presented a paper analyzing the Rhessi data for the SGR1860. Its gamma ray burst lasted several minutes and was clearly detected with a gyratron circuit (and I saw the Colorado data taken by a SARA member whose name escapes me at the moment). Many other GRBs since then have been detected with SID monitors.
Den, the double spike doesn't make sense to me as far as observable phenomena. The negative spike would correspond to a sudden signal attenuation followed by a sudden enhancement. That doesn't make sense. I like Marcus' explanation.
Fritzius (?) mentioned the work of some NASA folks and the ELF waves produced by the solar wind (if I remember correctly). I am very curious to learn more about that those. It is true that the annular cavity waves are ELF--the resonant waves are called Schumann resonances with a fundamental around 7.8Hz. The other waves, however, would dampen out very quickly. They are generally produced by global lightning storms, so I am very interested to learn if indeed they are produced by the solar wind too.
John
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Dave Typinski
May 19, 2013, 4:00:40 PM5/19/13
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Well, whaddaya know. That's really interesting. I'd never have imagined that
the gamma flux would be great enough or last long enough to have an observable
effect on terrestrial radio propagation.
Thanks for the correction, John!
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Dave
the gamma flux would be great enough or last long enough to have an observable
effect on terrestrial radio propagation.
Thanks for the correction, John!
--
Dave
Den Koawl
May 19, 2013, 4:10:10 PM5/19/13
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John Hi, yes i have read a book on the various signals which i do encounter here ( near the Arctic Circle ) being the statics, auroral and so on. Marcus does have a good point, but there isnt much in the way of aircraft passing over my area, and there isnt much in the way of the RFI / EMI that the populated areas have.
Possibly these are caused by disturbance to the magnetosphere from a strong solar wind ? I saw a paper somewhere that showed a GRB event captured by a SID monitor, and the plot showed this type of upward / downward spike.
Den
Rodney Howe
May 19, 2013, 4:34:21 PM5/19/13
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John, Dave,
Myself and 12 other VLF folks detected SGR1806-20 December, 27, 2004
SGR1806-20 was detected by Swift satellite on December 27, 2004 at 21:30:26
UT. http://gcn.gsfc.nasa.gov/gcn3/2944.gcn3 AAVSO observers of this event
were as follows:
• Observer Receiver Location Transmitter and Location
• Moos Switzerland FTA - St. Assie, France
• Hill Massachusetts, USA NAA - Cutler, ME, USA
• Winkler Texas, USA NAA - Cutler, ME, USA
• Kielkopf Kentucky, USA NAA - Cutler, ME, USA
• Campbell Alberta, CA NLK - Jim Creek, WA, USA
• Howe Colorado, USA NML - LaMoure, ND, USA
• Mc. Williams Minnesota, USA NML - LaMoure, ND, USA
• Samouce Montana, USA NML - LaMoure, ND, USA
• Kielkopf Kentucky, USA NPM - Lualualei, HI, USA (2nd
receiver)
• Mandaville Arizona, USA NPM - Lualualei, HI, USA
• Lewis California, USA NPM - Lualualei, HI, USA
• Winkler Texas, USA NPM - Lualualei, HI, USA (2nd
receiver)
SGR1806-20 was not a Gamma Ray Burst (GRB), it's a Magnetar (neutron star,
probably in a binary configuration with another star). These are Soft Gamma
Repeaters. They [it] will probably flare again, as it did before in 1998.
The reason these affect the ionosphere it seems is that the SGRs are high
energy events long and hard in the X-ray bands (not so much the gamma-ray
bands) which affect the ionosphere, AND they have to be in the line of sight
with your loop antenna! By long we mean over 10 to 50 seconds in duration.
The most recent request from NASA, Jerry Fishman, was for GRB 130427A ,
however, it was far south in declination (down-under) and even though a hard
burst, it was not long enough for detection, here:
http://gcn.gsfc.nasa.gov/gcn3_archive.html
The older satellites (not SWIFT), but INTEGRAL, HESSI, Beppo Sax, etc. are
likely to detect an SGR as they have detectors which are not tuned so high
in the gamma ray region. Magnetars: http://en.wikipedia.org/wiki/Magnetar
R.
Myself and 12 other VLF folks detected SGR1806-20 December, 27, 2004
SGR1806-20 was detected by Swift satellite on December 27, 2004 at 21:30:26
UT. http://gcn.gsfc.nasa.gov/gcn3/2944.gcn3 AAVSO observers of this event
were as follows:
• Observer Receiver Location Transmitter and Location
• Moos Switzerland FTA - St. Assie, France
• Hill Massachusetts, USA NAA - Cutler, ME, USA
• Winkler Texas, USA NAA - Cutler, ME, USA
• Kielkopf Kentucky, USA NAA - Cutler, ME, USA
• Campbell Alberta, CA NLK - Jim Creek, WA, USA
• Howe Colorado, USA NML - LaMoure, ND, USA
• Mc. Williams Minnesota, USA NML - LaMoure, ND, USA
• Samouce Montana, USA NML - LaMoure, ND, USA
• Kielkopf Kentucky, USA NPM - Lualualei, HI, USA (2nd
receiver)
• Mandaville Arizona, USA NPM - Lualualei, HI, USA
• Lewis California, USA NPM - Lualualei, HI, USA
• Winkler Texas, USA NPM - Lualualei, HI, USA (2nd
receiver)
SGR1806-20 was not a Gamma Ray Burst (GRB), it's a Magnetar (neutron star,
probably in a binary configuration with another star). These are Soft Gamma
Repeaters. They [it] will probably flare again, as it did before in 1998.
The reason these affect the ionosphere it seems is that the SGRs are high
energy events long and hard in the X-ray bands (not so much the gamma-ray
bands) which affect the ionosphere, AND they have to be in the line of sight
with your loop antenna! By long we mean over 10 to 50 seconds in duration.
The most recent request from NASA, Jerry Fishman, was for GRB 130427A ,
however, it was far south in declination (down-under) and even though a hard
burst, it was not long enough for detection, here:
http://gcn.gsfc.nasa.gov/gcn3_archive.html
The older satellites (not SWIFT), but INTEGRAL, HESSI, Beppo Sax, etc. are
likely to detect an SGR as they have detectors which are not tuned so high
in the gamma ray region. Magnetars: http://en.wikipedia.org/wiki/Magnetar
R.
Robert Hart
May 19, 2013, 10:18:59 PM5/19/13
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Gamma ray bursts entertaining the
earth's atmosphere produce Cherenkov radiation which can be
detected at ground level using special telescopes http://en.wikipedia.org/wiki/MAGIC_(telescope)
these telescopes use very high speed detectors (usually PMT), as
the flash of light produced is very brief, only a few nanosecond.
Cosmic Rays can induced radio emissions and are detectable which are also only a few nanoseconds so , https://www.astro.ru.nl/wiki/research/pierre_auger_observatory#auger_engineering_radio_array
The process is known as a geo-synchrotron emission and are in the region of 10-100 MHz, where most power received is at the lower frequencies due to coherence effects and so the spectrum begins to fall off at around 50 MHz. However due to the short duration of the radio pulse typically less than 10nS it becomes increasingly difficult to measure at low frequencies and so most observations of cosmic ray induced radio emissions are made between 40 and 60Mhz.
Robert
Cosmic Rays can induced radio emissions and are detectable which are also only a few nanoseconds so , https://www.astro.ru.nl/wiki/research/pierre_auger_observatory#auger_engineering_radio_array
The process is known as a geo-synchrotron emission and are in the region of 10-100 MHz, where most power received is at the lower frequencies due to coherence effects and so the spectrum begins to fall off at around 50 MHz. However due to the short duration of the radio pulse typically less than 10nS it becomes increasingly difficult to measure at low frequencies and so most observations of cosmic ray induced radio emissions are made between 40 and 60Mhz.
Robert
Den Koawl
May 19, 2013, 10:27:50 PM5/19/13
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Yes you may be right, i understand that the x-rays effect the ionosphere and i should have used a different term in place of GRB. Whatever the source, it is interesting.
Tnx
Den
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David Fields
May 19, 2013, 10:56:42 PM5/19/13
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Hi Robert,
Thanks for the good references. I understand that the cosmic rays, which are particles with mass (protons, mostly) do produce showers of high-velocity recoil particles in the atmosphere that emit Chrenkov radiation when their velocity is high enough. We see this with the PMTs. Gamma rays on the other hand are photons, and do not directly produce Chrenkov radiation. They can, of course, ionize the atmosphere, and we see an SID, as Rodney Howe et al. have seen.
If the gammas are energetic enough, they kick out the electrons (ionization plus a big recoil velocity) and this produces an electrical pulse (Compton pulse) and some whistlers. This is something like an EMP from a nuclear device detonated above the atmosphere. I guess that there is may a small Chrenkov pulse also, from the electrons.
The gammas travel through space at velocity 'c' while the cosmic rays are slower. Any radio signal generated at the same time as the gammas would arrive later. Any radio signal generated at the same time as the cosmic rays would travel faster and in straight lines, but the cosmic rays do not travel in anything like straight paths, due to magnetic fields in space. Their direction of origin usually remains unknown to us. (OK, I know that curved space bends radio, light, gamma, and all EM radiation, but bending of cosmic rays by magnetic fields is much greater).
Cheers,
David
Thanks for the good references. I understand that the cosmic rays, which are particles with mass (protons, mostly) do produce showers of high-velocity recoil particles in the atmosphere that emit Chrenkov radiation when their velocity is high enough. We see this with the PMTs. Gamma rays on the other hand are photons, and do not directly produce Chrenkov radiation. They can, of course, ionize the atmosphere, and we see an SID, as Rodney Howe et al. have seen.
If the gammas are energetic enough, they kick out the electrons (ionization plus a big recoil velocity) and this produces an electrical pulse (Compton pulse) and some whistlers. This is something like an EMP from a nuclear device detonated above the atmosphere. I guess that there is may a small Chrenkov pulse also, from the electrons.
The gammas travel through space at velocity 'c' while the cosmic rays are slower. Any radio signal generated at the same time as the gammas would arrive later. Any radio signal generated at the same time as the cosmic rays would travel faster and in straight lines, but the cosmic rays do not travel in anything like straight paths, due to magnetic fields in space. Their direction of origin usually remains unknown to us. (OK, I know that curved space bends radio, light, gamma, and all EM radiation, but bending of cosmic rays by magnetic fields is much greater).
Cheers,
David
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