Record X Ray burst makes Swift blink.

[MeteorWayne]

http://www.space.com/scienceastronomy/b ... 00714.html

A violent cosmic explosion has unleashed the brightest blast of X-rays ever detected from distant space, a signal so bright it temporary blinded the NASA space telescope assigned to spot it.

The powerful explosion, called a gamma-ray burst, was detected by NASA's Swift observatory, scientists announced Wednesday. Gamma-ray bursts are narrow beams of intense radiation shot out when stars explode in supernovas. In addition to gamma-ray light, they also produce X-rays and other forms of radiation, including visible light.

This recent event, dubbed GRB 100621A, was particularly powerful.

 

[michaelmozina]

http://www.space.com/scienceastronomy/brightest-x-rays-blind-telescopes-100714.html

A violent cosmic explosion has unleashed the brightest blast of X-rays ever detected from distant space, a signal so bright it temporary blinded the NASA space telescope assigned to spot it.

The powerful explosion, called a gamma-ray burst, was detected by NASA's Swift observatory, scientists announced Wednesday. Gamma-ray bursts are narrow beams of intense radiation shot out when stars explode in supernovas. In addition to gamma-ray light, they also produce X-rays and other forms of radiation, including visible light.

This recent event, dubbed GRB 100621A, was particularly powerful.

It kind of makes you wonder about the directional nature of some supernova and their ability to effect distant objects. It's hard to believe something so far away could be so bright in x-ray as to completely drown out all the sources in our own galaxy. Wow.

 

[csmyth3025]

The SDC article on this x-ray burst doesn't identify the source. It only describes the object's distance as:

Light from this explosion traveled through space for 5 billion years before slamming into Swift

If this distance estimate represents the light travel time from the time it was emitted to the time it was received (by Swift), how much has it been red-shifted? I ask this because I'm thinking that these x-ray photons must have been much more energetic when they were emitted 5 billion years ago.

A related question would be: If this object had been (anywhere) in the Milky Way and emitted this burst of (gamma?) rays directly towards Earth sometime in the last 100,000 years, would the brief but intense beam of high energy photons be able to significantly effect our atmosphere?

Chris

 

[OleNewt]

A GRB would have to occur within 20k ly to have any effect on Earth beyond a brief "Ooh! Aaah!" moment.

 

[csmyth3025]

A GRB would have to occur within 20k ly to have any effect on Earth beyond a brief "Ooh! Aaah!" moment.

I found the following passage in the Wikipedia article on Gamma Ray Bursts:

A gamma-ray burst in the Milky Way, if close enough to Earth and beamed towards it, could have significant effects on the biosphere. The absorption of radiation in the atmosphere would cause photodissociation of nitrogen, generating nitric oxide that would act as a catalyst to destroy ozone.[74] According to a 2004 study, a GRB at a distance of about a kiloparsec (3,262 light-years) could destroy up to half of Earth's ozone layer; the direct UV irradiation from the burst combined with additional solar UV radiation passing through the diminished ozone layer could then have potentially significant impacts on the food chain and potentially trigger a mass extinction.[2][75] The authors estimate that one such burst is expected per billion years, and hypothesize that the Ordovician-Silurian extinction event could have been the result of such a burst, although there is no current evidence to support this idea.

There are strong indications that long gamma-ray bursts preferentially or exclusively occur in regions of low metallicity. Because the Milky Way has been metal-rich since before the Earth formed, this effect may diminish or even eliminate the possibility that a long gamma-ray burst has occurred within the Milky Way within the past billion years.

It sounds like getting knocked off by a GRB is pretty far down on our List of Things That Can Kill You.

Chris

 

[MeteorWayne]

The SDC article on this x-ray burst doesn't identify the source. It only describes the object's distance as:

Actually it does: GRB 100621A


The name follows the format YYMMDD, and a letter is added if more than one is found on the day, a for the first, b for the second, etc.

Since the source objects are billions of LY away, the progenitor object is rarely explicitly identified.

 

[csmyth3025]

I should have said "source galaxy". When I think about it, though, I'm not sure a galaxy that far would be listed in any published catalogues. Still, since the astronomers are no doubt working hard to pinpoint any candidate source galaxy associated with the co-ordinates and distance of GRB 100621A, they might eventually come up with something.

Chris

 

[CalliArcale]

It sounds like getting knocked off by a GRB is pretty far down on our List of Things That Can Kill You.

Chris

I highly recommend Phil Plait's book "Death from the Skies". It's an entertaining and informative review of the ways the Universe could destroy all life on Earth. He also gives his impression of the actual risks of each. Gamma ray bursts are covered, in part because they are extremely awesome, even though he considers the risk to be virtually nil as no stars within range have any likelihood of producing one in the forseeable future. (At least, as far as we know.) He goes all the way from stuff like asteroid impacts to the eventual death of the Unvierse itself.