Kilonovas caused by black hole neutron star mergers

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Discussion Overview

The discussion revolves around the phenomena of gamma-ray bursts (GRBs) associated with black hole and neutron star mergers, exploring their characteristics, duration, and implications for cosmic events. Participants examine the effects of cosmic expansion on the observed duration of GRBs and the nature of their frequency emissions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants express concern about the potential for gamma-ray bursts to cause catastrophic effects on Earth, referencing articles on the subject.
  • Questions are raised regarding the duration of a specific gamma-ray burst and whether its observed duration is affected by the expansion of space over a distance of 4 billion light years.
  • There is a discussion about the nature of gamma-ray burst frequencies, with some participants questioning whether they are narrow band or wideband emissions.
  • One participant asserts that the duration of the source radiation is independent of redshift effects during transit.
  • Another participant clarifies that gamma-ray bursts are not narrow band emissions, noting their detection across various frequencies, including visible light.

Areas of Agreement / Disagreement

The discussion contains multiple competing views regarding the effects of redshift on gamma-ray burst duration and the characteristics of their frequency emissions. No consensus is reached on these points.

Contextual Notes

Participants reference the standard model and its predictions regarding gamma-ray bursts, but there are unresolved questions about the specifics of frequency emissions and the impact of cosmic expansion on observed durations.

Tanelorn
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I thought readers would be interested in this interesting article today on black hole and neutron star mergers and the very small possibility of instantaneous sterilization and extinction of all life on earth:http://www.space.com/22231-gamma-ray-bursts-neutron-stars.html

http://news.yahoo.com/kilonova-dead-star-crashes-may-spark-mysterious-cosmic-212239960.htmlAnother on the origin of Gold:

http://www.space.com/21995-gold-origins-neutron-star-collisions.html
 
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Space news on Phys.org
Could anyone please confirm if the duration of the gamma ray burst, lasting 0.09 seconds, is consistent with the stretching of the gamma ray pulse as a result of the expansion of space between us and the object 4 Billion light years away? How long would we expect the gamma ray burst to have lasted at its source? Are Gamma ray burst frequencies very narrow band or even single frequency lines, or are they quite wideband and dispersed?
 
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Are Gamma ray burst frequencies very narrow band or even single frequency lines, or are they quite wideband and dispersed?

yes:

Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. They are the brightest electromagnetic events known to occur in the universe.[1] Bursts can last from ten milliseconds to several minutes. The initial burst is usually followed by a longer-lived "afterglow" emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, microwave and radio).[2]

Most observed GRBs are believed to consist of a narrow beam of intense radiation released during a supernova as a rapidly rotating, high-mass star collapses to form a neutron star, quark star, or black hole.

http://en.wikipedia.org/wiki/Gamma-ray_burst
 
Could anyone please confirm if the duration of the gamma ray burst, lasting 0.09 seconds, is consistent with the stretching of the gamma ray pulse as a result of the expansion of space between us and the object 4 Billion light years away?

The duration of the source radiation has nothing to do with any subsequent redshift during transit...

And there are lots of gamma ray bursts in the universe...fortunately for us it is really, really big and we are really, really small. So if somebody shoots a cannon off in Moscow or Paris or Singapore for example, I fell pretty safe here in NJ.
 
Thanks Naty, I was just curious if there was a change in the duration of the pulse as a result of redshift and if it agreed with any expected change in duration expected by the standard model.
"Are Gamma ray burst frequencies very narrow band or even single frequency lines, or are they quite wideband and dispersed?"

The quote you provided doesn't mention how narrow band the gamma ray pulse is.
Laser light is narrowband, white light is broadband.
 
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GRB's are not narrow band emissions. They peak in gamma frequencies, but, are also detected in visible light frequencies.
 

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