Wednesday colloquia

The API colloquia are weekly meetings where people give a 45 minute overview of their work. Afterwards there is time for discussion. At the end of each month the colloquia are jointly held with GRAPPA.

The contact person for the regular API colloquia is Selma de Mink.
The contact person for the joint GRAPPA/API colloquia is Jacco Vink.

Past colloquia

Strange star, pion gas, hydrodynamics, nuclear-particle physics & astrophysics

Jishnu Dey — Presidency College Calcutta

Theoretical intuitive ideas from Fouxon, Betschart and Bekenstein (FBB) and Hod have persuaded many like me that the conjectured KSS bound is true. There have been theoretical calculations in different densities and temperatures , T, in systems like pion gas in simple kinetic theory with interaction (Prakash et al., Phys. Rep. C 227 (1993) 321). We have shown that the bound is saturated when density dependence is properly utilized. On the exotic side strange matter on the surface of a quark star satisfies the bound at a critical T. Other calculations using Chiral perturbation theory and thermo-field dynamics are also remarkable and will be briefly discussed.

The picture shows the theoretical mass-radius relations of compact stars
for various equations of state.

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Friday 28 January 2011, 15:00. Location: C4.172B

A search for a possible variation of the proton-to-electron mass ratio in the sightline towards J2123-0050

Freek van Weerdenburg — API, Mastercolloquium

We report a strong constraint on the variation of the proton-to-electron mass ratio on a cosmological time scale from the analyses of molecular absorption lines in a quasar spectrum.

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Wednesday 26 January 2011, 15:00. Location: C1.112

Astrometry Lost and Regained

Erik Hoeg — Niels Bohr Institute, Copenhagen University, Denmark

From a modest experiment in Copenhagen in 1925 to the Hipparcos and Gaia space missions.

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Wednesday 19 January 2011, 15:00. Location: C1.112

Christmas Colloquium

Sander Bais — UvA

This year's Christmas colloquium will be given by Sander Bais, who received the Stapenning this year, a special UvA honorary award.

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Friday 10 December 2010, 15:00. Location: C4.172B

Modelling and Observing the Gas in Protoplanetary Systems

Peter Woitke — Royal Observatory, Edinburgh

Numerous enigmas still need to be solved, and open questions to be answered, in the field of protoplanetary disc research and planet formation.

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Friday 3 December 2010, 15:00. Location: A1.10

How gamma-rays can probe the early universe

Martin Raue — University Hamburg

The end of the dark-ages of the universe - the epoch of reionization - is a one of the big open questions in cosmology. Reionization likely started with the formation of the first stars (PopIII stars), which are believed to be hotter and (probably) more massive then the second generation stars.

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Friday 26 November 2010, 15:00. Location: C1.112

Master Colloquium: Dynamical scattering of planetesimals by a migrating planet

Sebastiaan Krijt

A small number of young stellar objects show signs of a halo-like structure of optically thin dust, in addition to a circumstellar disk. This halo or torus is located within a few AU of the star but its origin is not yet understood.

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Thursday 25 November 2010, 10:00. Location: A1.10

What's around nearby stars: dust, debris and planets

Mark Wyatt — University of Cambridge

Some 400 nearby stars are known to have orbiting extrasolar planets, and a similar number are known to have orbiting debris, i.e., dust, asteroids and comets. Just as in the Solar System, observations of extrasolar debris disks provide unique information on the structure, formation and evolution of the planetary systems in which they reside.

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Friday 19 November 2010, 15:00. Location: C1.112

Master Colloquium - Superspinning black holes: theory and practice

Peter van Ham

Black holes, as described by Einstein's general theory of relativity, can posses angular momentum, but only a limited amount: too much angular momentum and the event horizon of the black holes disappears, giving rise to a naked singularity, i.e. a singularity not hidden behind an event horizon.

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Thursday 4 November 2010, 15:00. Location: C1.112

The Highly Obscured supergiant High Mass X-ray Binaries: a new class discovered by ESA's INTEGRAL satellite

Ed van den Heuvel — Universiteit van Amsterdam

Since its launch in 2002, the gamma-ray plus hard X-ray satellite INTEGRAL discovered over 500 new X-ray sources. Among these are some 22 new galactic supergiant High Mass X-ray Binaries, three times more than the 7 such systems known in our galaxy before INTEGRAL.

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Friday 29 October 2010, 15:00. Location: C1.112