Netherlands Astronomy Conference 2026

Merging galaxy clusters host Megaparsec-scale diffuse radio emission that traces re-accelerated cosmic ray electrons in the intracluster medium. Recent observations report a growing number of enigmatic radio filaments connected to the lobes of cluster radio galaxies, which may transport and preserve relativistic electrons and thereby seed diffuse cluster-scale radio sources. Resolving these...

NICER has enabled mass–radius inferences for pulsars using pulse profile modeling (PPM), providing constraints on the equation of state (EOS) of cold, dense matter. To date, PPM and EOS inference have been carried out as two separate steps, with the former using EOS-agnostic priors. This approach has several drawbacks. Ideally, one would perform a fully hierarchical Bayesian inference where...

Since the launch of the X-ray satellite Einstein Probe (EP) in 2024, we have finally been able to constrain the origins of several fast X-ray transients (FXTs). Astrophysical transients are known across, and beyond, the whole electromagnetic spectrum, including gamma-ray bursts (GRBs) and gravitational waves. But for long our knowledge on the progenitors of FXTs remained poor. Now that we are...

In the past decade, black holes evolved from a theoretical prediction by General Relativity to actually observable objects. In particular, accretion and outflow of plasma leave key signatures across the electromagnetic spectrum, from the Event Horizon Telescope radio observations to X- and γ-rays, from the shadow size to the shape of the spectral energy distribution (SED). These signatures...

We present the development of a resistive-MHD (RMHD) module within the ideal-GRMHD code GRaM-X. GRaM-X (General Relativistic accelerated Magnetohydrodynamics on AMReX) is a new, GPU-accelerated, dynamical-spacetime ideal-GRMHD code that extends the capabilities of the Einstein Toolkit to GPU-based exascale platforms. It features three-dimensional adaptive mesh refinement (AMR) on GPUs through...

Ultraluminous X-ray sources (ULXs) can be considered for the most part an extreme version of X-ray binaries accreting at super-Eddington accretion rates. The most extreme manifestation of this process, other than their abnormally bright X-ray luminosities ($L_\mathrm{X} \gtrsim 10^{39}$ erg/s) occurs in the form of hundred-parsec nebulae of ionized gas surrounding them, offering a nearby...