ULTRASAT: A wide-field time-domain UV space telescope

Understand

The Ultraviolet Transient Astronomy Satellite (ULTRASAT) is scheduled to be launched to geostationary orbit in 2026.

• It will carry a telescope with an unprecedentedly large field of view (204 deg$^2$) and NUV (230-290nm) sensitivity (22.5 mag, 5$\sigma$, at 900s).
• ULTRASAT will conduct the first wide-field survey of transient and variable NUV sources and will revolutionize our ability to study the hot transient universe: It will explore a new parameter space in energy and time-scale (months long light-curves with minutes cadence), with an extra-Galactic volume accessible for the discovery of transient sources that is $>$300 times larger than that of GALEX and comparable to that of LSST.
• ULTRASAT data will be transmitted to the ground in real-time, and transient alerts will be distributed to the community in $<$15 min, enabling a vigorous ground-based follow-up of ULTRASAT sources.