Exploration of the high-redshift universe enabled by THESEUS

Understand

At peak, long-duration gamma-ray bursts are the most luminous sources of electromagnetic radiation known.

• Since their progenitors are massive stars, they provide a tracer of star formation and star-forming galaxies over the whole of cosmic history.
• Their bright power-law afterglows provide ideal backlights for absorption studies of the interstellar and intergalactic medium back to the reionization era.
• The proposed THESEUS mission is designed to detect large samples of GRBs at $z>6$ in the 2030s, at a time when supporting observations with major next generation facilities will be possible, thus enabling a range of transformative science.