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tarbag
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What is the relation between gamma ray bursts (GRBs) and supernova?
Thanks
Thanks
The successful discovery of X-ray, optical and radio afterglows of GRB has made possible the identification of host galaxies at cosmological distances. The energy release inferred in these outbursts place them among the most energetic and violent events in the Universe. They are thought to be the outcome of a cataclysmic stellar collapse or compact stellar merger, leading to a relativistically expanding fireball, in which particles are accelerated at shocks and produce nonthermal radiation. The substantial agreement between observations and the theoretical predictions of the fireball shock model provide confirmation of the basic aspects of this scenario. Among recent issues are the collimation of the outflow and its implications for the energetics, the production of prompt bright flashes at wavelenghts much longer than gamma-rays, the time structure of the afterglow, its dependence on the central engine or progenitor system behavior, and the role of the environment on the afterglow.
The connection between the long Gamma Ray Bursts (GRBs) and Type Ic Supernovae (SNe) has revealed interesting diversity. We review the following types of the GRB-SN connection. (1) GRB-SNe: The three SNe all explode with energies much larger than those of typical SNe, thus being called Hypernovae (HNe). They are massive enough for forming black holes. (2) Non-GRB HNe/SNe: Some HNe are not associated with GRBs. (3) XRF-SN: SN 2006aj associated with X-Ray Flash 060218 is dimmer than GRB-SNe and has very weak oxygen lines. Its progenitor mass is estimated to be small enough to form a neutron star rather than a black hole. (4) Non-SN GRB: Two nearby long GRBs were not associated SNe. Such ``dark HNe'' have been predicted in this talk (i.e., just before the discoveries) in order to explain the origin of C-rich (hyper) metal-poor stars. This would be an important confirmation of the Hypernova-First Star connection. We will show our attempt to explain the diversity in a unified manner with the jet-induced explosion model.
tarbag said:Yes , but I don't understood why GRB is short event (small than 200 s) and supernova is long event. Are GRBs produced in the same time as its associeted supernova in all case?
and what about their afterglows in the other electomgnetic bands?
Laura1013 said:A short GRB is under 2 seconds. A 200 second GRB would be a long GRB. No one really understands how that much energy can be released in that short a period of time.
A GRB (gamma-ray burst) is a powerful explosion of high-energy radiation that occurs in distant galaxies. It is believed that these bursts are caused by a supernova, which is the catastrophic explosion of a massive star.
There are several lines of evidence that support the connection between GRBs and supernovae. One of the most compelling is the observation of a supernova occurring in the same location as a GRB, indicating that the two events are physically linked. Additionally, the spectra of GRBs and supernovae have similar characteristics, further supporting their connection.
GRBs are classified based on their duration, with short-duration bursts lasting less than 2 seconds and long-duration bursts lasting more than 2 seconds. Supernovae are classified based on their spectra, with Type I supernovae having no hydrogen lines and Type II supernovae having prominent hydrogen lines.
The most widely accepted theory is that a GRB is produced when a massive star undergoes a supernova explosion, and the energy from the explosion collides with the surrounding gas and dust, producing a burst of gamma-rays. This theory is supported by the observation of supernovae occurring at the same location as GRBs, as well as the similar spectra of the two events.
Yes, the brightness of supernovae can be used as standard candles to measure distances in the universe, and the redshift of GRBs can be used to measure the expansion of the universe. These measurements have provided important insights into the rate of expansion and the properties of dark energy.