We survey 223 916 auroral records from the Northern hemisphere observed between 1650 January and 2024 July, making full allowance for the secular change in the geomagnetic field. We generate criteria for defining extreme auroral events that are met on 0.015 per cent and 0.023 per cent of nights since 1650 and 1790, respectively. After discussing

Episodic accretion is a fundamental process in the build-up of the stellar mass. EX Lupi-type eruptive young stars (EXors) represent one of the main types of episodic accretion. We study the recently discovered EXor Gaia23bab during its 2023 outburst. We obtained optical and near-infrared photometry and spectroscopy to probe the variation of the

Context. Spatially resolved maps of stellar populations and nebular emission are key tools for understanding the physical properties and evolutionary stages of galaxies. These maps are commonly derived from integral field spectroscopy (IFS) data or, alternatively, from multiband imaging techniques. Aims. We aim to characterize the spatially

We present the radio continuum counterparts to the enigmatic ultracompact X-ray binaries (UCXBs): a black hole or neutron star accreting from a hydrogen-deficient white dwarf donor star with short orbital periods (<80 minutes). For the sample of UCXBs hosted by globular clusters (GCs), we search for whether certain GC properties are more likely to

Studying the abundances in metal-poor globular clusters is crucial for understanding the formation of the Galaxy and the nucleosynthesis processes in the early Universe. We observed 13 red-giant stars from the metal-poor globular cluster NGC 2298 using the newly commissioned GHOST spectrograph at Gemini South. We derived stellar parameters and

The critical need to study the magnetic field in the solar corona is highlighted by recent observational facilities, such as the Daniel K. Inouye Solar Telescope and Aditya-L1. A powerful tool for probing the magnetism of the solar corona is forward modeling of the intensity and polarization of coronal emission lines in three-dimensional (3D)