GRBs and Relativistic Transients in the 2040s

TL;DR

The paper discusses the future of relativistic transient astronomy in the 2040s, emphasizing the need for dedicated large telescopes with rapid response capabilities to fully exploit upcoming discoveries and address fundamental questions about the universe.

Contribution

It highlights the necessity of a dedicated large-aperture, rapid-response telescope for effective follow-up of relativistic transients in the 2040s.

Findings

Upcoming surveys will discover tens of thousands of transients nightly.

High-energy missions like THESEUS will greatly improve monitoring.

A dedicated 10-30 m telescope is essential for rapid spectroscopic follow-up.

Abstract

Relativistic transients such as gamma-ray bursts (GRBs), jetted tidal disruption events, luminous fast blue optical transients, and fast X-ray transients, represent the brightest explosions in the Universe and serve dual roles as laboratories for extreme physics and as cosmic lighthouses probing the earliest epochs of the Universe. The 2040s will bring transformative capabilities: wide-field optical surveys discovering tens of thousands of optical transients nightly, proposed high-energy missions like THESEUS providing 10-100x improved high-energy monitoring, and third-generation gravitational wave detectors identifying $\mathcal{O}(10^5)$ compact object mergers annually, many accompanied by relativistic jets. This industrial-scale discovery rate will enable population studies addressing fundamental questions such as jet launching mechanisms, nucleosynthesis, the first stars, and how progenitor environments shape these transients across cosmic time. However, realizing this science requires overcoming a critical bottleneck: these transients evolve on timescales of seconds to days, with their physics encoded in rapidly-changing multi-wavelength signatures demanding immediate spectroscopic characterization down to m ~ 25. Current facilities, optimized for classical/queue scheduling, do not provide the rapid, flexible, multi-target response necessary for industrial-scale follow-up. This white paper demonstrates that without a dedicated large-aperture (10-30 m effective collecting area) time-domain facility with robotic scheduling and optical-NIR spectroscopic capabilities, the transformative potential of relativistic transient science in the 2040s will be considerably limited.