Publications by authors named "Tom Theuns"

What should the EU do about the fact that some Member States are backsliding on their commitments to democracy, supposedly a fundamental value of the EU? The Treaty provisions under Article 7 TEU are widely criticized for being ineffective in preventing such developments. Are they legitimate? I argue that the ultimate sanction of Article 7 TEU falls into a performative contradiction, which undermines its ability to coherently defend fundamental values. Instead, expulsion from the EU is the appropriate, coherent and legitimate final political sanction for democratic and rule of law backsliding by a Member State.

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We analyze the total and baryonic acceleration profiles of a set of well-resolved galaxies identified in the eagle suite of hydrodynamic simulations. Our runs start from the same initial conditions but adopt different prescriptions for unresolved stellar and active galactic nuclei feedback, resulting in diverse populations of galaxies by the present day. Some of them reproduce observed galaxy scaling relations, while others do not.

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The intergalactic medium was not completely reionized until approximately a billion years after the Big Bang, as revealed by observations of quasars with redshifts of less than 6.5. It has been difficult to probe to higher redshifts, however, because quasars have historically been identified in optical surveys, which are insensitive to sources at redshifts exceeding 6.

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The first stars in the universe form when chemically pristine gas heats as it falls into dark-matter potential wells, cools radiatively because of the formation of molecular hydrogen, and becomes self-gravitating. Using supercomputer simulations, we demonstrated that the stars' properties depend critically on the currently unknown nature of the dark matter. If the dark-matter particles have intrinsic velocities that wipe out small-scale structure, then the first stars form in filaments with lengths on the order of the free-streaming scale, which can be approximately 10(20) meters (approximately 3 kiloparsecs, corresponding to a baryonic mass of approximately 10(7) solar masses) for realistic "warm dark matter" candidates.

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