| 1. |
- Acuner, Zeynep, et al.
(författare)
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Appearances of the jet photosphere in GRB spectra
- 2018
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Ingår i: 14th Marcel Grossman Meeting On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories, Proceedings. - : World Scientific Publishing Co. Pte. Ltd.. - 9789813226593 ; , s. 2921-2930
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Konferensbidrag (refereegranskat)abstract
- There are several strong arguments for considering photospheric emission in GRBs. Here, we describe the two main appearances of the photospheric emission that are currently discussed. In the multi-component models the photosphere only contributes to a part of the spectrum, while the main part is due to optically-thin synchrotron emission. In the photospheric emission models the whole emission spectrum is from the photosphere: The emission spectrum has been altered due to subphotospheric dissipation and/or off-axis emission. In many cases, though, it is difficult to distinguish between these models on a purely statistical ground. Therefore, more detailed predictions from different physical scenarios should be tested on the observations.
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| 2. |
- Litvinov, D. A., et al.
(författare)
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RadioAstron gravitational redshift experiment: Status update
- 2018
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Ingår i: 14th Marcel Grossman Meeting On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories, Proceedings. - : WORLD SCIENTIFIC. - 9789813226593 ; , s. 3569-3575
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Konferensbidrag (refereegranskat)abstract
- A test of a cornerstone of general relativity, the gravitational redshift effect, is currently being conducted with the RadioAstron spacecraft, which is on a highly eccentric orbit around Earth. Using ground radio telescopes to record the spacecraft signal, synchronized to its ultra-stable on-board H-maser, we can probe the varying flow of time on board with unprecedented accuracy. The observations performed so far, currently being analyzed, have already allowed us to measure the effect with a relative accuracy of 4 × 10−4. We expect to reach 2.5 × 10−5 with additional observations in 2016, an improvement of almost a magnitude over the 40-year old result of the GP-A mission.
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| 3. |
- Napolitano, George M., et al.
(författare)
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Critical line of the Ising model on 2-dimensional CDT and its dual
- 2018
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Ingår i: 14th Marcel Grossman Meeting On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories, Proceedings. - : WORLD SCIENTIFIC. - 9789813226593 ; , s. 3885-3890
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Konferensbidrag (refereegranskat)abstract
- In this paper we study the annealed coupling of an Ising model with 2-dimensional causal dynamical triangulation model. After a short review of previous results, we prove the existence of the so-called critical line and derive its analytical properties and asymptotics. In addition, relations between the model and its dual are investigated.
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| 4. |
- Pe'Er, A., et al.
(författare)
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Photospheric emission in gamma-ray bursts
- 2018
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Ingår i: 14th Marcel Grossman Meeting On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories, Proceedings. - : World Scientific Publishing Co. Pte. Ltd.. - 9789813226593 ; , s. 806-840
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Konferensbidrag (refereegranskat)abstract
- A major breakthrough in our understanding of gamma-ray bursts (GRB) prompt emission physics occurred in the last few years, with the realization that a thermal component accompanies the over-all nonthermal prompt spectra. This thermal part is important by itself, as it provides direct probe of the physics in the innermost outflow regions. It further has an indirect importance, as a source of seed photons for inverse-Compton scattering, thereby it contributes to the nonthermal part as well. In this short review, we highlight some key recent developments. Observationally, although so far it was clearly identified only in a minority of bursts, there is indirect evidence that a thermal component exists in a very large fraction of GRBs, possibly close to 100%. Theoretically, the existence of a thermal component has a large number of implications as a probe of underlying GRB physics. Some surprising implications include its use as a probe of the jet dynamics, geometry and magnetization.
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