NASA Gamma Ray Burst Notes 11.22.2013

Gamma Ray burst
first in six
observed from underground observatory
Dying star in distant galaxy
one o the brightest we have ever seen
never before seen details challenge our theoretical understanding of how gamma ray bursts work
Charles Dalmer
Astrophysicist in DC, Naval research Laboratory
High energy radiation outbursts
Tom Vestrand
watches night sky for extra terrestrial objects and things that go bump in the night
Rob Triess
University of Alabama astrophysics
GBM triggered on event on april 27
Interesting behaviour on the first burst of the pulse
Jean-pieroo natafili
Italian Astrophysicist
Gamma ray bursts on laser
new development of telescopes
Sylvia Zoo
Astrophysicist, Maryland
Grad Student
High energy emission from Gamma Ray Bursts
Space craft was able to look at the burst as well as the lab
3 Nasa spacecraft observed gamma ray burst
A Gamma Ray Burst: trans insomething burst of gamma ray radiation from some object in space. after decades of research we find that those gamma rays come from birth of black hole in most cases, this was just an imitation, but only through the development of neew ways of looking to reorient space craft very quickly to get a look at these bursts…
Potential damage of a GRB?
Depends on distance, and if it was pointed at earth (unlikely). atmosphere will generally absorb gamma rays, billions of lightyears away normally. if there was a burst in your galaxy, strong possibility of electronic pulses and ionizing radiation, after time the ozone layer would be destroyed, allowing more radiation and nitrogens would be released, leading to a nuclear winter
why is it important to study GRB?
good question but rhetorical. What was the purpose of uranium study in the early 1900’s what was the significance of studying sun burning in the 60’s? We do not think this will change the world, but this is an explosion and explosion studies have intrinsic value in field of particle beams and uses to give us greater appreciation of all that occurs in nature.
Tremendous amount of energy in GRB, where does it come from?
Ill pipe up and say in large part we do not really know. The bright part of 13027A is that we can study the bright parts in detail, made possible by Dr. Goerner and ensure that everything goes according to the radiation. We know that energy is directed very efficiently, and seems to convert energy into radiation naturally. Our attempts to do so have fallen flat.
What do scientist learn from studying this?
We were able to identify the first and by doing this we could find a good position and recht we immediately too that these objects were intergalactic and we understood these were very powerful objects, which is useful. There is the object in the radio, 98 percent of the weere Dja gamma ray bursts, it is the most effective way the band to tell theposition and the other band that peopled can follow with instrumentation.
People relate this amount of energy to an atomic bomb. How many atomic bombs would this be equivalent to?
wikipedia says that the most powerful hydrogen bombs released about 15 megatons of TNT equivalent energy. You would need 10^30 of these bombs to have one of these bursts. 
Are these directed in one direction or omnidirectional?
Highly directional. In this particular case, the relatively narrow beam would have to be pointed directly at us.
OK How did one of these spacecraft target this area dn saw the burst before during and after?
The difference between monocular and technicolor. Multiple observations give you so much more information. The earth was not blocked on 1427A so there was allowed onboard triggering and response to move the spacecraft to view the burst. No imaging to know the counterpart without detailed X-rays and other information
More than the electromagnetic spectrum, we are in the EM channels but as time goes on they behave in different manners. Intimate clothing makes another separate high energy radiation situation. Multiple complicated wavelengths
Can one of these occur in our galaxy?
one ever 100 million or 500 million years. these numbers are not certain, but it is something we can expect.
How frequent are these observed?
We have a good idea from orbiting observatory which except for earth blockage we saw the entire sky with gamma rays neural the entire universe with bursts. One per day per universe. So the universe provides that, but we do not know where or when.
How can these bursts affect us if they happen here?
They can if they are in the Milky Way, and one is not really expected here. Might change the atmosphere, perhaps if close by some minor changes could be expected.
Any plans for gamma ray burst science that is coming up?
We are in kind of a climate where we do not anticipate high energy astrophysics new projects. we have two good observatories in orbit andwe have a good life expectancy. The Chinese are planning a follow up in Guam.
If there is an agreement this would happen 1015 2016 probably
Is there a program in place to find or predict the next event?
Lots of attempts ot find a demonstration, we have been able to identify certain stars that are likely to have such an event in their area. Typically at such large distances we cannot see individual stars. Liklihood of such a program being approved is not very likely.
Model of matter-anti matter shows there is a sizzling layer between the two so there is not lots of emissions except for comets which do not work, i was playing with that.
we have plotted them out and they are isotropic. so that is the challenge of building observatories that can observe these at anytime anywhere. no sweet spot to look at.
When one of these assets is in the GRB, what is implicated?
notices are sent out to subscribing astronomers with the BAT instrument and each is hooked into the service and sends information out to interested astronomers. Remote telescopes pick up these messages from the internet real time and reposition to view what is occurring. One of the interesting observational challenges is looking at the gamma ray burst before the explosion occurred. This happened before the event development through the act.
How often can we expect to see a GRB of this size?
Typical of gamma, what is unusual is how near by this  burst was. Every 60 years or so we can infer this sort of event happens once or twice very unique every century.
Whatis interesting here/?
persistent afterglow (optical) we knew about this but this one is beautifully interesting because there is such persistence of high energy gamma rays. This persistent gamma ray is caused by some shock etc…
how does this GRB compare to photo extinction event?
first one has to convince people studying that a major extinction event was causedby GRB, personally thinks it is due to volcanic activity. within the milky way it would have to oerate.
one thing that is sot interesting is that the cataclysmic event happened over an extended period. but the gamma ray burst would be  a one – two punch. so the cosmic rays can cause global cooling. There are some behavioural extinction that occurs within those patterns. The patterns in the galaxy are so rare and unlikely, we like to think this is not the case despite tantalizing suggestion.
how big can a gamma ray burst get? upper levels?
The seem to originate in massive stars. All the energy that is equivalent to the rest mass of the sun is equivalent to the mass of the sun. these are isotropic events that are equivalent to outflows and jets, the upper limit is determined by the size of the star that is the preginature of the burst.
How does the GRB actually start?
the most energetic GRB: not proven that black holes are the power, could also be certain stars, for example evidence in plateaus from swift telescope. In many occasions this is pullover. can be monitored in terms of absolute energy. Directed into a very small jet we get very small bursts. We have to figure out what we see versus what really is. This is a difficult or tricky situation to evaluate.
How do they Start!
There is a massive star with fuel and that fuel is spent, put under neutrons degeneracy pressure, yields a black hole, natural situation. 
Is the Gamma Ray Radiation so to speak a beam like a laser?
No and no.
Is there enough energy that it fuses the heaviest elements?
Conference in Kudo where modelling of fusing into higher atomic mass elements was assimilated and it seems to a pretty good approximation gives the highest level elements, so the possibility is yes we can produce some fraction of the heavy metals involved. Excellent question because it ties to how these are related. there would not be a supernova formation event. people look at gamma ray events where black hole is forming massive satr.
Why is there a difference?
The optical light is generated often by lower energy particles and maybe accelerated in different ways. From optical illusion, we think they are generated by exactly the same process. With this other type of optical illusion which we see it is kind of the glowing embers of the explosion, if you will. But not at these lower energy gamma ray emissions, we will often see after these GRE.
Terrestrial GRB?
terrestrial gamma ray flashes are by fermee no way to object the fields of electrons over electric storms. and we see energies high enough to produce pares of electrons and positrons. also quite interesting but a completely different phenomenon
What do X-rays bring to the table in GRB study?
We see some evolution occurring. It sees then that whitefish the spectrum doesn ot change over housr minutes and days. it is some level of information from before. even there we thought the spectrum was exactly the same up to 73. but this was also interpretation as well compared to modern interpretation.
anything else?
it was interesting in the lab because it gave us pop to study something far away and normally something this close is weak, but this was more of an ordinary monster, but close to earth. previously we had a model that explains the HEE very well. We did not see things before when the bursts were very close to us. For these events we required that we think back or tweak our models or something. Also because it was so close we had to observe for 20 hours, something with HEGR.
We saw this on 4/27 but how long did it take for that energy to get to us? when was it born?
black hole was born about 3.75 billion years ago, so this was a young burst all the same, because many we see are 5 or 10 billion years old. Because it is young the signal is very strong. when the earth was then, it looked very different and the whole universe looked different.
The important question is how to measure distance and that is astronomy?
Chuck was lost.
Could the GRB signal an extinction event on mars? such as disappearance of an atmosphere?
No, it is very different, off the road ap, very unlikely. 
Can we assume the burst occurs as a creation event of every black hole?
it is very likely that these happen when a very massive star, the core of one into another. highly magnetized neutron star. so not entirely accurate to say each of these has a black hole, and also not true that all black holes come from this.
What is the effect of gravity on this explosion?
detailed modelling of the collapse of a massive star into nothing, yields a lot of damage giving characteristic signature on gamma ray waves. should be simultaneous, and gravity wave radiations.
Vapor with the optical data, if this interpretation is correct we look at less than 3 million degrees. but his is not cut, there is a discussion about it. a few degrees.
Has this burst actually changed any of our understanding about how stars evolve?
no, because apart from the energy emission it is very similar to the other GRB, what is actually this burst, we can see the Supernova, usually associated to very long bursts, much weaker. This is not very far away, and we can see the entirety of the burst, usually one or two up to 6 or 7 or 9 we have seen so far, something supernova.
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