The high-redshift gamma-ray burst GRB140515A

Understand

High-redshift gamma-ray bursts have several advantages for the study of the distant universe, providing unique information about the structure and properties of the galaxies in which they exploded.

• Spectroscopic identification with large ground-based telescopes has improved our knowledge of the class of such distant events.
• We present the multi-wavelength analysis of the high-$z$ Swift gamma-ray burst GRB140515A ($z = 6.327$).
• The best estimate of the neutral hydrogen fraction of the intergalactic medium (IGM) towards the burst is $x_{HI} \leq 0.002$.