Synergies of THESEUS with the large facilities of the 2030s and guest observer opportunities.

The proposed THESEUS mission will vastly expand the capabilities to monitor the high-energy sky. It will specifically exploit large samples of gamma-ray bursts to probe the early universe back to the first generation of stars, and to advance multi-messenger astrophysics by detecting and localizing the counterparts of gravitational waves and cosmic neutrino sources. The combination and coordination of these activities with multi-wavelength, multi-messenger facilities expected to be operating in the 2030s will open new avenues of exploration in many areas of astrophysics, cosmology and fundamental physics, thus adding considerable strength to the overall scientific impact of THESEUS and these facilities. We discuss here a number of these powerful synergies and guest observer opportunities.

[A rest or arrest--asystolic episodes of 7 seconds in a 22-year-old athlete]. / 22-jähriger Sportler mit Sinusarrest und Pausen bis 7 Sekunden.

A 22-year-old athlete with nocturnal asymptomatic episodes of transient sinus arrest/sinoatrial block up to 7.3 s and recurrent inappropriate sinus tachycardias which had been incidentally found during Holter electrocardiography diagnostics is presented. In spite of extensive diagnostic work-up including invasive procedures like coronary angiography and electrophysiological study, no causal etiology was found. Based on the normal findings and the lack of symptoms, we decided not to implant a permanent pacemaker. After 14 months, the patient is still asymptomatic. Howerver, the 24-h Holter electrocardiography shows unchanged frequency of nocturnal transient sinus arrest episodes.