Jorge Casares Velázquez

arXiv2026

The GOTO Telescope Control System

The Gravitational-wave Optical Transient Observer (GOTO) operates a network of robotic, wide-field survey telescopes searching for optical transients to gravitational-wave signals and other astronomical events. Since 2023, the network has comprised two antipodal sites in the Canary Islands and Australia, each hosting two independent robotic mounts. The GOTO Telescope Control System (G-TeCS) is a custom Python software package that manages all operational aspects of the network; from alert processing and target scheduling to onsite hardware operations and monitoring. The central system consists of an alert monitor, observation database and scheduler, which issues targets to the four nodes. Each telescope operates using a system of independent control daemons, with a pilot master control program to coordinate nightly operations. This architecture, in development since 2015, provides a flexible and robust system that now successfully operates the fully autonomous network.

astro-ph.IM↗

arXiv2026

Failed jet breakout in the metal-poor broad-lined type Ic supernova 2026gzf

A long-standing question in the death of massive stars is the role of relativistic jets. While many gamma-ray bursts and some fast X-ray transients seem to be associated with broad-lined type Ic supernovae, the opposite is not true. The lack of observable jet emission in those Ic-BL SNe can be explained by invoking off-axis jets, choked jets that inject all their energy into the stellar envelope, baryon-loaded jets for which the prompt high-energy emission is strongly suppressed, or non-jetted SNe. The lack of exact explosion time in the majority of SNe presents an obstacle to distinguish between these scenarios. Here we report the properties of SN 2026gzf associated with the X-ray thermal Einstein Probe shock-breakout EP260321a at z=0.0343. The absence of compelling shocked cocoon and radio emission up to 54 days, combined with initial expansion velocities of ~30,000 km/s and a circumstellar shell of ~0.07 M$_\odot$, favour a scenario for SN 2026gzf in which a jet was choked in the circumstellar shell. Our high-spatial resolution images of the SN environment show that the progenitor was located between two highly star-forming regions with a metallicity lower than any previously known Ic-BL SN. As the first case of a Ic-BL SN associated with high-energy prompt emission without the signature of a jet, SN 2026gzf provides a unique perspective to understand the successful launch of relativistic jets during the deaths of massive stars.

astro-ph.HE↗