Wednesday Colloquium


"Kinetic simulations of particle acceleration mechanism at relativistically magnetized jets"

José Ortuño-Macías (CAMK, Warsaw)

Blazar emission present spectra with extreme broadness and power-law appearance, which are signatures of an efficient non-thermal particle acceleration process. It is also characterized by strong variability on timescales ranging from decades to minutes. Relativistic magnetic reconnection has been often proposed as the particle acceleration mechanism due to its high efficiency at highly magnetized plasma; where the generated plasmoids, magnetic islands enclosing energetic particles, are the emission sources. Local inversions of the magnetic field lines are required for magnetic reconnection to occur. They may be caused by internal jet instabilities, which recently have been shown to be able to accelerate particles by means of large-scale induced electric field. I will present the results of kinetic numerical simulations for two particle acceleration mechanisms for relativistically magnetized electron-positron plasma: steady state relativistic magnetic reconnection with efficient synchrotron cooling and current-driven instabilities in cylindrical magnetized jets.


"Genetically modified man"

Ewa Bartnik (Warsaw University)

Genetically modified humans can be found not only in books (Brave New World) and movies (GAATACA), but also there are 3 genetically modified girls in China, who were supposed to become resistant to AIDS, and somewhere there is a boy whose mitochondria do not come from his mother but from a donor. Jennifer Doudna and Emmanuelle Charpentier received the Nobel prize in chemistry in 2020 for the CRISPR-Cas9 technique, which makes genetic modifications possible. But what does this mean for us - what can CRISPR-Cas9 be used for, and for what has it already been used?


"The Rosetta-stone cluster M67 and the Sun"

Andreas Korn (Uppsala University, Sweden)

I report on 10+ plus year of work we have put into understanding the detailed chemical composition of the solar-age, solar-metallicity open cluster M67. Because of its near-solar age and metallicity, this cluster lets us address questions related to the Solar-system's early chemical evolution which seems to have led to a Sun relatively rich in volatile and poor in refractory elements. The physical reason for this chemical oddity in unknown at present, but may very well be connected to (giant) planet formation. This work on M67 thus brings together planetary, stellar and Galactic research in a unique and highly interesting way.