MG14 - Talk detail |
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Participant |
Piedipalumbo, Ester | |||||||
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Institution |
University Federico II of Naples - via Cintia Complesso MSA - Naples - - Italy | |||||||
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Session |
GB3 |
Accepted |
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Order |
Time |
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Talk |
Oral abstract |
Title |
The calibrated GRBs Hubble diagram through the Ep,i – Eiso correlation: a tool for cosmology | |||||
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Abstract |
The correlation between the peak photon energy of the intrinsic spectrum of radiation emitted by long gamma-ray bursts and the isotropic--equivalent radiated energy is explored, independently from the cosmological model. Using a recently updated data set of 162 high-redshift GRBs, we apply a local regression technique to estimate the distance modulus using the recent Union SNIa sample, containing 580 SNIa spanning the redshift range 0.015 < z < 1.414. The derived calibration parameters are used to construct a calibrated GRBs Hubble diagram, which we adopt as a tool for investigating the dark energy equation of state. We are also looking for signatures of deviation from the Lambda-CDM model. To accomplish this task we focus on the so called Chevalier-Polarski-Linder parametrization and we use the Markov Chain Monte Carlo method to efficiently sample the cosmological parameter space. We have found indications that the dark energy equation of state is evolving. Moreover we test the consistency of these results with a cosmographic approach. Finally we discuss the influence over the cosmological analysis of possible redshift effects. |
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