Armagh Observatory & Planetarium

The Gravitational-wave Optical Transient Observer (GOTO) Fast Analysis and Spectroscopy of Transients (FAST) Surveys

Abstract The study of young and fast astronomical transients is often limited by the difficulty of acquiring data, particularly spectra, within hours to days of explosion. Historically, follow-up programmes have rarely obtained spectra until many days after discovery; coupled wit...

Surface brightness inhomogeneity on the helium-rich hot subdwarf in the X-ray binary HD 49798

Abstract HD 49798 is an X-ray binary consisting of a hot helium-rich subdwarf primary and an accreting compact companion with an orbital period of 1.55 d. TESS observations of its optical light curve suggest short-period brightenings superimposed on a sinusoidal variation. The la...

TESS Observations of Stochastic Low-frequency Variability in Extreme Helium Stars

Abstract Extreme helium stars (EHes) are low-mass hydrogen-deficient stars thought to be the products of double white dwarf mergers. Despite prolonged ground-based observations, there is no consensus on the properties of their photometric variability. In this article, we present...

Multiwavelength Observations of Substructures in Solar Flare Ribbons

Abstract Solar flare ribbons are extensive brightenings in the chromosphere during flares, often showing fine-scale structuring that reflects the underlying energy release. Using high-cadence imaging from the Swedish 1 m Solar Telescope/CRISP during an X1.5-class limb flare on 20...