Prospects in dark energy cosmology through the calibrated Ep,I- Eiso correlation

Institute for Theoretical Physics, University of Warsaw, Pasteura 5, PL-02-093 Warsaw, Poland; Department of Astronomy, Williams College, Williamstown, MA 01267, USA 3 INAF-IASF, Sezione di Bologna, via Gobetti 101, I-40129 Bologna, Italy Using a new sample consisting of 264 GRBs with measured redshifts and spectra, we applied different techniques to calibrate the Ep,I-Eiso correlation against the type Ia SN data to build a calibrated GRB Hubble diagram. We tested the possible redshift dependence of the correlation and its effect on the Hubble diagram to investigate the tension with the flat ΛCDM model and the dark energy equation of state.