Constraining GRBs pseudo-redshift using different empirical correlations

TL;DR

This paper evaluates empirical correlations to estimate pseudo-redshifts of Gamma-Ray Bursts, comparing results for bursts with known redshifts and exploring discrepancies for lower luminosity events.

Contribution

It applies multiple empirical correlations to constrain GRB pseudo-redshifts and compares their consistency across different burst samples.

Findings

Consistent pseudo-redshift estimates for high-luminosity GRBs with known redshifts.

Discrepancies in pseudo-redshift ranges for lower luminosity GRBs.

Empirical correlations can be useful but have limitations for certain GRB populations.

Abstract

The determination of distances is highly constrained to a small number of Gamma-Ray Bursts (GRBs) because it requires observations at different wavelengths. Some empirical functions to estimate redshifts have been identified using populations of GRBs with reported redshifts. For example, the Amati correlation relates $E_{peak}$ of the spectrum when modeled with a Band function and the total energy emitted $E_{iso}$ in a time integrated analysis. A multiple-component scenario has been proposed in order to explain GRBs spectra, and in this context when a fine-time spectral analysis is performed a correlation between the non-thermal component's peak energy and the luminosity ($E_{peak,i} - L_i$) appears. This correlation is also used to infer distances to GRBs. In this work we present a sample of bright GRBs and apply these empirical correlations to constrain the pseudo-redshift of the selected burst sample. Our results for GRB080916C, GRB090926A and GRB150214A with reported redshift are totally consistent. Another three bursts with lower luminosities were selected. For these bursts, the pseudo-redshift range obtained with the two correlations are not totally in agreement.