Time-domain astronomy group at Charles University, Prague
I had a great time giving colloquium at the historical library of Hamburg Observatory, talking to many interesting people and enjoying serene grounds and historic telescopes. Thanks Diego Calderón Espinoza for hosting me!
Our PhD student Milan Pešta is spending April at Australian National University in the group of Prof. Yuan-Sen Ting and working on various applications of machine learning in time-domain astronomy.
Our PhD students were successful in obtaining student grants from the Grant Agency of the Charles University. Camille Landri (with Anthony Kirilov as a co-I) won with a project title The impact of binary evolution on common envelope evolution, and Jakub Cehula will work on Baryon ejection in magnetar giant flares: implications for r-process nucleosynthesis and fast radio bursts. Congratulations!
Last week three of our PhD students travelled to New York to a Workshop on stable mass transfer in binaries held at Center for Computational Astrophysics. Milan and Jakub gave contributed talks on contact binaries and a new mass transfer model.
Congratulations to Michal Jireš who defended his Bachelor thesis entitled Simulation of rings surrounding the progenitor of SN1987A. Good luck with future endeavors!
We were again successful in the competition for time on national supercomputer IT4Innovations. PhD student Camille Landri won 20 000 node hours (4.32 million CPU hours) on Barbora cluster and postdoc Damien Gagnier secured 82 000 node hours (10.496 million CPU hours) on Karolina cluster. Both awards are intended for projects involving binary star interactions and common envelope evolution.
In the past two weeks we were visited by Łukasz Wyrzykowski from Warsaw University and Subo Dong and KIAA in Beijing. Both gave seminars and talked to students, postdocs, and staff.
PhD student Jakub Cehula submitted a paper on Dynamics of baryon ejection in magnetar giant flares: implications for radio afterglows, r-process nucleosynthesis, and fast radio bursts written together with Todd Thompson (Ohio State) and Brian Metzger (Columbia/Flatiron). The paper is a result of Jakub’s two month visit at Ohio State earlier this Spring.
It was great to have Philipp Moesta from University of Amsterdam visit us to give a seminar and discuss science.
In his newest paper, Damien Gagnier takes the next step by simulating post-dynamical common envelope evolution with MHD with Athena++. We see amplification of B to similar levels as in other contemporary work, but with a much lower kinetic-to-magnetic energy ratio and no evidence for jets. Magnetic fields have a negligible impact on many features including binary orbit evolution. Damien performed detailed analysis of reservoirs of energy and transfer between them. He also measured α-disk parameter of ≃0.034, but the “viscosity” is not straighforwardly due to B. There is much more – check out the paper at https://arxiv.org/abs/2310.16880, now under review in A&A.
