A photometric redshift of $z=1.8^{+0.4}_{-0.3}$ for the \agile GRB 080514B

TL;DR

This paper estimates the redshift of GRB 080514B using optical/NIR data, providing the first photometric redshift for this gamma-ray burst with high-energy emission detection.

Contribution

It presents the first photometric redshift estimate for GRB 080514B based on multi-wavelength observations, confirming the burst's redshift and supporting the independence of afterglow properties from prompt emission.

Findings

Photometric redshift of z=1.8^{+0.4}_{-0.3} estimated for GRB 080514B.

Afterglow properties are similar to those of other long gamma-ray bursts.

Redshift estimate is consistent with gamma-ray based pseudo redshift.

Abstract

Aims: The AGILE gamma-ray burst GRB 080514B is the first burst with detected emission above 30 MeV and an optical afterglow. However, no spectroscopic redshift for this burst is known. Methods: We compiled ground-based photometric optical/NIR and millimeter data from several observatories, including the multi-channel imager GROND, as well as ultraviolet \swift UVOT and X-ray XRT observations. The spectral energy distribution of the optical/NIR afterglow shows a sharp drop in the \swift UVOT UV filters that can be utilized for the estimation of a redshift. Results: Fitting the SED from the \swift UVOT $uvw2$ band to the $H$ band, we estimate a photometric redshift of $z=1.8^{+0.4}_{-0.3}$, consistent with the pseudo redshift reported by Pelangeon & Atteia (2008) based on the gamma-ray data. Conclusions: The afterglow properties of GRB 080514B do not differ from those exhibited by the global sample of long bursts, supporting the view that afterglow properties are basically independent of prompt emission properties.