The Astrophysical Journal (Jan 2024)

ULTRASAT: A Wide-field Time-domain UV Space Telescope

  • Y. Shvartzvald,
  • E. Waxman,
  • A. Gal-Yam,
  • E. O. Ofek,
  • S. Ben-Ami,
  • D. Berge,
  • M. Kowalski,
  • R. Bühler,
  • S. Worm,
  • J. E. Rhoads,
  • I. Arcavi,
  • D. Maoz,
  • D. Polishook,
  • N. Stone,
  • B. Trakhtenbrot,
  • M. Ackermann,
  • O. Aharonson,
  • O. Birnholtz,
  • D. Chelouche,
  • D. Guetta,
  • N. Hallakoun,
  • A. Horesh,
  • D. Kushnir,
  • T. Mazeh,
  • J. Nordin,
  • A. Ofir,
  • S. Ohm,
  • D. Parsons,
  • A. Pe’er,
  • H. B. Perets,
  • V. Perdelwitz,
  • D. Poznanski,
  • I. Sadeh,
  • I. Sagiv,
  • S. Shahaf,
  • M. Soumagnac,
  • L. Tal-Or,
  • J. Van Santen,
  • B. Zackay,
  • O. Guttman,
  • P. Rekhi,
  • A. Townsend,
  • A. Weinstein,
  • I. Wold

DOI
https://doi.org/10.3847/1538-4357/ad2704
Journal volume & issue
Vol. 964, no. 1
p. 74

Abstract

Read online

The Ultraviolet Transient Astronomy Satellite (ULTRASAT) is scheduled to be launched to geostationary orbit in 2027. It will carry a telescope with an unprecedentedly large field of view (204 deg ^2 ) and near-ultraviolet (NUV; 230–290 nm) sensitivity (22.5 mag, 5 σ , at 900 s). 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 timescale (months-long light curves with minutes cadence), with an extragalactic volume accessible for the discovery of transient sources that is >300 times larger than that of the Galaxy Evolution Explorer (GALEX) and comparable to that of the Vera Rubin Observatory’s Legacy Survey of Space and Time. ULTRASAT data will be transmitted to the ground in real time, and transient alerts will be distributed to the community in 23.5 AB mag, over 10 times deeper than the GALEX map. Two key science goals of ULTRASAT are the study of mergers of binaries involving neutron stars, and supernovae. With a large fraction (>50%) of the sky instantaneously accessible, fast (minutes) slewing capability, and a field of view that covers the error ellipses expected from gravitational-wave (GW) detectors beyond 2026, ULTRASAT will rapidly detect the electromagnetic emission following binary neutron star/neutron star–black hole mergers identified by GW detectors, and will provide continuous NUV light curves of the events. ULTRASAT will provide early (hour) detection and continuous high-cadence (minutes) NUV light curves for hundreds of core-collapse supernovae, including for rarer supernova progenitor types.

Keywords