2025/12/17 by Melo, Alejandra, Sanchez-Saez, Paula, Ivanov, Valentin D. +13
Physics and Astronomy · #Astronomy and Astrophysical Research #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Radio Astronomy Observations and Technology
paper · doi:10.48550/arxiv.2512.15555
openalex publication_date 2025/12/17 · openalex created_date 2025/12/19 · openalex updated_date 2026/07/28
Time-domain astronomy is entering an era of unprecedented discovery driven by wide-field, high-cadence surveys such as LSST, Roman, Euclid, SKA, and PLATO. While some of these facilities will generate enormous photometric alert streams, the physical interpretation of variability and transients often requires spectroscopy, which encodes changes in ionisation state, kinematics, and accretion that are inaccessible to photometry alone. A critical gap is therefore emerging: next-generation surveys may produce up to ∼109 alerts per year, whereas global spectroscopic follow-up is limited to only ∼104--105 transient spectra annually. We present the concept of spectroscopic alerts: real-time notifications triggered by significant spectral evolution, enabling spectroscopy to act as a discovery channel rather than solely as follow-up. We outline the key science cases enabled by this capability and describe the instrumental and operational requirements of a wide-field, highly multiplexed spectroscopic facility capable of delivering real-time spectral discovery for 2040s time-domain and multi-messenger astronomy.