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تسجيل مستخدم جديدOn the future of Gamma-Ray Burst Cosmology
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With the understanding that the enigmatic Gamma-Ray Burts (GRBs) are beamed explosions, and with the recently discovered ``Ghirlanda-relation, the dream of using GRBs as cosmological yardsticks may have come a few steps closer to reality. Assuming the Ghirlanda-relation is real, we have investigated possible constraints on cosmological parameters using a simulated future sample of a large number of GRBs inspired by the ongoing SWIFT mission. Comparing with constraints from a future sample of Type Ia supernovae, we find that GRBs are not efficient in constraining the amount of dark energy or its equation of state. The main reason for this is that very few bursts are available at low redshifts.
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This is a report on the findings of the gamma ray burst working group for the white paper on the status and future of TeV gamma-ray astronomy. The white paper is an APS commissioned document, and the overall version has also been released and can be
found on astro-ph. This detailed section of the white paper discusses the status of past and current attempts to observe gamma ray bursts at GeV-TeV energies. We concentrate on the potential of future ground-based gamma-ray experiments to observe the highest energy emission ever recorded for GRBs, particularly for those that are nearby and have high Lorentz factors in the GRB jet. It is clear that major advances are possible and that the detection of very high energy emission would have strong implications for GRB models, as well as cosmic ray origin.
High-redshift Gamma-Ray Bursts (GRBs) beyond redshift $sim6$ are potentially powerful tools to probe the distant early Universe. Their detections in large numbers and at truly high redshifts call for the next generation of high-energy wide-field inst
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For gamma-ray bursts (GRBs) with a plateau phase in the X-ray afterglow, a so called $L-T-E$ correlation has been found which tightly connects the isotropic energy of the prompt GRB ($E_{gamma,rm{iso}}$) with the end time of the X-ray plateau ($T_{a}
$) and the corresponding X-ray luminosity at the end time ($L_{X}$). Here we show that there is a clear redshift evolution in the correlation. Furthermore, since the power-law indices of $L_{X}$ and $E_{gamma,rm{iso}}$ in the correlation function are almost identical, the $L-T-E$ correlation is insensitive to cosmological parameters and cannot be used as a satisfactory standard candle. On the other hand, based on a sample including 121 long GRBs, we establish a new three parameter correlation that connects $L_{X}$, $T_{a}$ and the spectral peak energy $E_{rm{p}}$, i.e. the $L-T-E_{rm{p}}$ correlation. This correlation strongly supports the so-called Combo-relation established by Izzo et al. (2015). After correcting for the redshift evolution, we show that the de-evolved $L-T-E_{rm{p}}$ correlation can be used as a standard candle. By using this correlation alone, we are able to constrain the cosmological parameters as $Omega_{m}=0.389^{+0.202}_{-0.141}$ ($1sigma$) for the flat $Lambda$CDM model, or $Omega_{m}=0.369^{+0.217}_{-0.191}$, $w=-0.966^{+0.513}_{-0.678}$ ($1sigma$) for the flat $w$CDM model. Combining with other cosmological probes, more accurate constraints on the cosmology models are presented.
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