Onderzoeksvragen

The atmosphere is the outer boundary of a gas giant exoplanet’s interior. Therefore, compositional changes in the atmosphere can affect interior inferences. Typically, only metallicity is considered in atmospheric boundary conditions, while other elemental ratios, in particular the C/O ratio, are assumed to be solar. In light of the observational constraints now achievable with James…

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In this work, we model the long-term impact of recurrent stellar flares on the atmospheres of metal-rich gaseous exoplanets. Using synthetic flare spectra from a fiducial flare model integrated with a photochemical kinetics code, we track the changes in atmospheric composition with time. We further analyze the spectral variability by feeding these abundance profiles into…

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X-ray observations probe the inner accretion flow within active galactic nuclei, revealing the highest gas column densities and fastest winds. The most diverse winds yet revealed with the Resolve calorimeter spectrometer aboard XRISM are found in NGC 4151, a nearby Seyfert 1 active galactic nucleus (AGN) that may qualify as a changing-look source (CLAGN). Herein,…

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Context. High-resolution X-ray spectroscopy and polarimetry provided by XRISM and IXPE offer new diagnostics of the geometry and kinematics of photoionised plasmas around compact objects. Interpreting reprocessed X-ray emission in such systems requires a full three-dimensional radiative transfer (3D RT) including photon-ion interactions. Aims. We extended the Monte Carlo (MC) RT code SKIRT by implementing…

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We present a detailed spectral analysis of an X-Ray Imaging and Spectroscopy Mission (XRISM) observation of the prototypical Seyfert 1 galaxy NGC 5548. XRISM’s Resolve microcalorimeter reveals, for the first time, highly ionized outflows in this active galactic nucleus (AGN) through the detection of Fe XXV and Fe XXVI absorption lines in the Fe K…

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The Bidirectional Polarization Distribution Function (BPDF) is essential in quantitative remote sensing, particularly for understanding the anisotropy of land surface polarization properties. The widely-used BRDF-BPDF dataset claimed to not corrected for aerosol scattering, which lay a hidden problem for BPDF modeling. In our work, we conducted aerosol correction based on Chinese polarimetric data DPC-2/GF-5(02), and…

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