A Legacy of Deep Synoptic Surveys

With a cadenced ultraviolet survey covering the whole sky, UVEX will provide the deep complementary two-band UV data to a host of modern optical and infrared wide-area sky surveys from observatories such as Rubin, Roman, Euclid, and SPHEREx, and probe the changing ultraviolet sky on cadences ranging from 12 hours to six months. Additionally, regardless of the type of observation UVEX is performing at any time, both its wide-field imaging and 1-degree-long spectroscopic slit instruments will operate continuously, providing a wealth of serendipitous data with every pointing. In this way, UVEX will provide the community with a rich legacy of UV data, enabling a broad range of science beyond UVEX’s own science objectives.

The Milky Way Galactic Plane in the ultraviolet

UVEX imaging data will go >110/50 (FUV/NUV) times deeper than GALEX and cover the entire Galactic Plane in both bands for the first time. This opens tremendous possibilities for Galactic science, including using NUV-optical colors to map Milky Way substructure by obtaining metallicity measurements for ~300 million stars, examining accretion at the beginning of the stellar life cycle in high-mass star-forming regions such as the Carina Nebula Complex, and producing next-generation dust maps.

All-Sky Survey

UVEX will perform a deep all-sky survey, imaging the Galactic Plane and the whole of the Magellanic Clouds in both FUV and NUV bands for the first time.

The extragalactic ultraviolet sky

The entire sky will be surveyed by UVEX to a depth >25 AB mag in FUV and NUV, providing an all-new view of the extragalactic ultraviolet sky. Since the ultraviolet is deeply sensitive to star formation, this will open new avenues in the study of galaxy formation and evolution, and in understanding how and why galaxies undergo star formation quenching. The serendipitous spectra taken alongside every imaging field will capture thousands of galaxies and their haloes, shedding light on how they co-evolve. The hot inner disks of active galactic nuclei also peak in the UV, making UVEX well-suited for studying the extremes of supermassive black hole accretion.

UV and Optical galaxy
The optical band traces ~1–5 Gyr of star formation history, whereas the UV traces 100–300 Myr, and can measure small amounts of residual star formation superimposed upon old stellar populations. 

Exploring the ultraviolet time domain

UVEX will provide prompt public alerts of transient events automatically discovered during its surveys, along with timely, calibrated data products with no proprietary period, facilitating the pan-chromatic follow-up of new UV-discovered transients. Additionally, the broad range of cadences probed by UVEX’s surveys will allow the community to explore time-domain phenomena ranging from binary star and eclipsing white dwarf systems in the Magellanic Clouds to the month-to-year-timescale variability of millions of active galactic nuclei.

UV Time Domain - NS merger
Many transient events peak in the ultraviolet, making UVEX and its cadenced sky survey a powerful discovery engine for studying the dynamic sky.