The National Centre for Nuclear Research (NCBJ, Warsaw, Poland) was the main organiser of the Gaia Alerts 2025 conference, the 16th Gaia Science Alerts and ACME Time-Domain Workshop, from 29 September to 3 October 2025 at the Instituto de Astrofísica de Canarias (IAC) in La Laguna (Tenerife). The meeting marks a milestone moment for the Gaia mission, celebrating the end of its science observations, and convenes the international community to chart the next decade of discovery in time-domain and multimessenger astrophysics.
Organized by an international committee chaired by Prof. Łukasz Wyrzykowski (BP4, National Centre for Nuclear Research/Astronomical Observatory University of Warsaw, Poland) with co-chairs Dr. Paul Beck (IAC) and Dr. Jaroslav Merc (IAC/Charles University), the meeting gathered nearly 100 attendees (80 on-site), including experts from time-domain surveys and archives such as Gaia, ZTF, OGLE, and LOFAR, as well as analysts and tool-builders who turn alerts into science. Invited speakers included researchers from the European Space Agency ESA, the University of Cambridge, the University of Geneva, NCBJ, IAC, and other leading institutions. A hybrid format enabled broad participation, with on-site sessions complemented by online access. All the sessions were recorded and are available through the YouTube channel of the Astronomical Observatory of the University of Warsaw.
A key focus this year was the BHTOM.space global telescope network, a unique, community-driven infrastructure that coordinates optical follow-up of time-domain events with small and medium-sized telescopes, including facilities in the Canary Islands. Under the ACME grant, BHTOM is expanding to interface with multimessenger alerts, linking optical, radio, X-ray, UV, gravitational-wave, and neutrino detections, and to ease access to rich time-domain archives for the entire community.
The programme featured morning and early-afternoon sessions throughout the week. On Wednesday, the conference participants visited the Teide Observatory and the National Park. On Friday, the final conference day, participants attended a hackathon, a practical session at the IAC Headquarters dedicated to collaborative development and cross-archive/multimessenger workflows within BHTOM.space system.
More details and the workshop programme are available on its webpage: https://meetings.iac.es/gaiaalerts25/.