Originally Posted by trinitree88

Gamma Ray Bursts, amonst the most energetic things we can observe and contemplate, continue to confuse and elude strict classifications. This hinders our understanding of some of the distant universe. Longs look like shorts and vice versa. Pieces of spectral data seem missing when theory seems to require that it be there. The author, Maxim Lyutikov, summarizes the state of affairs in a conference paper....at "The Shocking Universe" conference. see:http://www.merate.mi.astro.it/docM/O...009/index.html

see:http://arxiv.org/PS_cache/arxiv/pdf/...911.0349v1.pdf

Originally Posted by Don Alexander

Now, I have not read it yet, just looked over it, but...

Maxim is far and away not attacking the basics: GRBs are collimated explosions at cosmological distances, at least some of them are associated with the core collapse of massive stars, and some with galaxies that exhibit no current star formation.

The problems he points out are details in the models.

Originally Posted by Lyutikov

I argue that any present day model of GRBs, especially of Short type, is grossly incomplete.

Originally Posted by Lyutikov

Our lack of understanding of how GRBs work is impeding the progress and applications of GRBs, e.g., to cosmology. One can only hope that GRB theory will not suffer the same destiny as theories of pulsar radio emission: though we do not understand it and basically gave up hopes, pulsars are still very useful probes of interstellar medium and General Relativity. In case of pulsar radio emission, only about one millionth part of energy is emitted as radio waves; this make the problem especially hard. In contrast, in case of GRBs we are dealing with the dominant energy release, of the order of Solar rest mass energy in a matter of seconds. It is frustrating that we have a hard time to understand even the basic elements in such energetic phenomena.

Originally Posted by Savaglio

Gamma-ray bursts (GRBs) are the brightest events in the universe. They have been used in the last five years to study the cosmic chemical evolution, from the local universe to the first stars. The sample size is still relatively small when compared to field galaxy surveys. However, GRBs show a universe that is surprising. At z > 2, the cold interstellar medium in galaxies is chemically evolved, with a mean metallicity of about 1/10 solar. At lower redshift (z < 1), metallicities of the ionized gas are relatively low, on average 1/6 solar. Not only is there no evidence of redshift evolution in the interval 0 < z < 6.3, but also the dispersion in the ~ 30 objects is large. This suggests that the metallicity of host galaxies is not the physical quantity triggering GRB events

Originally Posted by Jerry

Huh? The Title of the paper is 'Going Back to the Blackboard' which is generally what you do when your rocket/theory/pet idea explodes and you have to start over ...

Originally Posted by trinitree88

Gamma Ray Bursts... continue to confuse and elude strict classifications.

Originally Posted by Cougar

Well, there's physics, and everything else is stamp collecting.

Originally Posted by trinitree88

Cougar. Yep. pete

Originally Posted by Jerry

Redshift evolution of metal content is one of the three pillars of the BB.

Originally Posted by trinitree88

Gamma Ray Bursts, amongst the most energetic things we can observe and contemplate, continue to confuse and elude strict classifications. This hinders our understanding of some of the distant universe. Longs look like shorts and vice versa. Pieces of spectral data seem missing when theory seems to require that it be there. The author, Maxim Lyutikov, summarizes the state of affairs in a conference paper....at "The Shocking Universe" conference. see:http://www.merate.mi.astro.it/docM/O...009/index.html

see:http://arxiv.org/PS_cache/arxiv/pdf/...911.0349v1.pdf