archive-1: SETI re: [ASTRO] GRB990123
SETI re: [ASTRO] GRB990123
Larry Klaes ( lklaes@bbn.com )
Thu, 28 Jan 1999 12:34:37 -0500
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>Date: Thu, 28 Jan 1999 10:37:59 -0500
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>From: Philip Chien <kc4yer@amsat.org>
>Subject: re: [ASTRO] GRB990123
>Sender: owner-astro@brickbat12.mindspring.com
>Reply-To: Philip Chien <kc4yer@amsat.org>
>
>Tom Droege <droege@wwa.com> said:
>
>>Looks like the GRB mystery is about to be cleared up.
>
>I wouldn't say cleared up. But this is certainly one more piece in the
>puzzle, and a pretty significant first.
>
>
>Cecce, Anthony J wrote:
>>I assume Hubble has been pointed to this location already?
>
>wouldn't do any good. By the time Hubble, or for that matter _ANY_
>telescope where a decision has to be made to make an observation, could
>turn and look it would be all over. One of the key features of GRBs is
>their relatively short duration - blink (figuratively) and it's all over.
>What's fascinating about ROTSE is that its an automated system - once it
>receives notification if it's night time and there's clear viewing
>conditions it slews its cameras and tries to take images under computer
>control.
>
>The reaction time for an amatuer visual GRB search wouldn't be fast enough.
>I suspect (don't know for a fact) the BATSE team would be glad to put you
>on their automated notification list whenever GRBs are detected (roughly
>once per day). By the time the data's gotten to you it's already several
>seconds old (time to detect, time to transmit data from GRO to TDRS to
>White Sands to Goddard, time to krunch the data, time to transmit to you).
>Let's assume that you've got a system where you continiously monitor
>incoming email. You've got an automated program which converts the Ra and
>Dec of the incoming message in to your local azimuth and elevation and
>determine that it's above the horizon and it's night time. You've got some
>setup which determines whether or not the sky's viewable in that direction
>(no clouds, trees, or mountains in the way). To get an image of the burst
>in time you'd need to have a computer-controlled camera with motorized
>actuators to point the camera accurately in the proper direction and start
>taking images. Basically what I've described here is the ROTSE approach.
>There is no conceivbale way you could get a message on your screen telling
>you where to look, grab your camera, go outside, point the camera the
>correct direction and take a photo - by that point it would be all over.
>
>
>Tom Droege <droege@wwa.com>
>
>>Note that they were there 22 seconds late. This on something decaying
>>fast. Possibly it was 100 or 1000 times brighter when it went off. We
>>don't know.
>
>Is there a theory with any model to show how bright the visual counterpart
>to a GRB would be? Or is this just speculation?
>
>>My point is that an amateur can be on close to the
>>same footing as a professional.
><snip>
>>Here is an area where amateurs can compete head on with little disadvantage.
>
>If you want to build your own equivalent of the ROTSE setup, go for it.
>
>>It is quite possible that if we looked, we would frequently see flashes at
>>mag 0. But almost no one is looking.
>
>Again - is this arbitrary (and rather bright) figure speculation or is
>there some basis for it?
>
>>I am furiously building 2k CCD cameras so I can look all the time at large
>>areas of the sky with the tass project. As a side project I have been
>>thinking about taking several of these cameras and putting them behind wide
>>angle camera lenses to look all the time at a really huge area of the sky.
>
>The problem here is the wider your field of view the less pixels per
>object. And with a wide angle lens there's much more likelyhood of
>something which ruins the image (aircraft lights, background lights,
>satellites, flying saucers, etc.)
>
>>GRB happen about once a day. So it should take
>>only 10 or so nights of observing to get one.
>
>GRBs happen about once per day over the entire celestial sphere. For
>obvious reasons statistically half will be blocked by the Earth. On the
>average half will occur during daylight. How often they'll occur over any
>given location under good viewing conditions with enough brigtness to be
>detected is another story all together. If you think you can discover one
>in 10 observing nights or even 1000 - more power to you if you can succeed.
>But I'd suspect (my speculation) the odds are a bit longer.
>
>
>>How do we tell a bright GRB from something else? Well, now we have one to
>>study that was picked up early enough to show some structure. We can now
>>compare the structure of the optical counterpart over time with the gamma
>>rays. Seems to me that that should give the theorists a lot to work with.
>
>That's the key scientific benefit from this "first" IMHO. One of the key
>mysteries of GRBs is they're all different - like fingerprints. If the
>signature of this particular GRB matches the optical counterpart's light
>curve then that's an interesting piece of data. If the signature doesn't
>match then it says something else.
>
>
>"Victor R. Ruiz" <rvr@idecnet.com>
>
>> So many CCDs and so few serious work... :(
>
>My favorite serious amateur astronomy CCD application is astrometry. I've
>seen demonstrations for how to detect and measure the orbits of asteroids
>using hobby-quality CCDs and it's pretty facinating. I'd like to see them
>also used to detect and determine the orbits of U.S. military satellites
>which may or may not exist. ;-)
>
>
>
>Bill Arnett <billa@zNet.com> said:
>
>>My understanding is also that GRBs can be explained perfectly well in
>>the context of current physics. We just don't know which of many
>>possibilities are actually in play.
>
>Just barely. I've attended a couple of AAS papers and lots of press
>conferences where GRBs have been discussed. It really seems to me (a
>layman) that the theroists are grabbing at straws to find some explaination
>which fits within the currently accepted Way the Universe Works (tm). And
>there's nothing wrong with that - neutrinos were originally conceived as a
>mathametical shorthand to make the equations fit.
>
>My personal favorite theory is they're actually relatively small easy to
>explain events at a much much smaller distance, say within the outer outer
>solar system. And the logic goes like this - when the French test their
>nuclear weapons they use an isolated island in the Pacific Ocean as far
>away from Paris as possible (makes sense, why dirty up your own back yard).
>Now we know that the Klingons have scout ships which patrol our solar
>system (as shown in "Star Trek: V" - hmm, how come we haven't seen more of
>them around these parts) so it's quite plausible that they've chosen our
>solar system as the testing grounds for their weapons of mass destruction.
>The problem with this theory is that GRBs do show a significant red shift.
>So the question is are Klingon nuclear weapons that drastically different
>as to give such a signature? ;-)
>
>>Iridium flares can easily be ruled out because they are so
>>predictable. Just check
>> http://www2.gsoc.dlr.de/
>>to see if there was an Iridium flash at the noted time/place.
>
>This only works with the operational satellites. There are several
>'rogues' which do not have stable attitude control and consequently flash
>unpredictably. However they all show a noticable motion, like any other
>low altitude satellites.
>
>> With a little more work, other satellites can also be ruled out.
>
>True. The only major potential source is confusion is with high altitude
>(relatively slow motion) satellites in Molniya and geosync orbits. Geosync
>are relatively easy to isolate because of their tracks across the sky.
>
>
>
>What's interesting is there have been two space instruments to try to
>detect visual counterparts to GRBs. The first was a student project at
>CalTech, GAMCIT. It was a getaway special shuttle payload with a 35 mm.
>camera connected to a gamma ray detector. When the detector spotted a
>burst it was supposed to take a bunch of photos of the same portion of the
>sky. Unfortunately the camera never advanced, but the rest of the
>experiment still returned good data. It flew on the STS-77 mission and
>during the flight 10 GRBs were detected by BATSE, 4 on the same side of the
>Earth as the shuttle. CalTech plans to refly the experiment although I
>haven't heard any recent status reports.
>
>A freeflying MIT satellite, HETE, was designed with the same concept, but
>using an ultraviolet CCD instead of a 35 mm. camera. It was launched a
>couple of years ago, but they forgot to pay the optional payload separation
>fee ;-( so it remained tucked within its canister and attached to the
>launch vehicle's upper stage. HETE-2 is scheduled for launch in October,
>this time presumably they've made arangements with the launch vehicle
>company to actually deploy them once they arrive in orbit. For some reason
>the Pegasus will be staged out of the Kwajalein missile range in the
>Western Pacific.
>
>
>CVA <cvarc@earthlink.net>
>
>>Are there sites where one can bone up on these phenomena?
>
>fearing that I might get confused with Larry Klass ---
>
>
>http://www.batse.com/ Cosmic Gamma Ray Bursts NEWS & RESEARCH
>
>http://science.msfc.nasa.gov/newhome/headlines/ast13oct98_1.htm Gamma-ray
>Bursters cross the 'Line of Death'
>
>http://science.msfc.nasa.gov/newhome/headlines/ast06may98_1.htm Blast from
>the past
>
>http://science.msfc.nasa.gov/newhome/headlines/ast12jan98_1.htm Gamma-ray
>burst identification earns top prize
>
>http://science.msfc.nasa.gov/newhome/headlines/ast19sep97_1.htm Twinkle,
>twinkle, massive fireball
>
>http://science.msfc.nasa.gov/newhome/headlines/ast31mar97_1.htm Discovery
>may be "smoking gun" in gamma-ray mystery
>
>http://www.umich.edu/~rotse/ ROTSE - home page, University of Michigan>
>
>"On the Origin of Gamma Ray Bursts", by Nir J. Shaviv and Arnon Dar. It is
>available on the Los Alamos preprint server, astro-ph@xxx.lanl.gov, number
>9606032, or on the web at http://xxx.lanl.gov/ or http://babbage.sissa.it/.
>
>
>
>Philip Chien, KC4YER
>Earth News
>world (in)famous writer, science fiction fan, ham radio operator,
>all-around nice guy, etc.
>
>
>