Supernova explosions interacting with aspherical circumstellar material

… and the implications for light curves, spectral line profiles, and polarization.

Evolution of histograms of line-of-sight velocities as a proxy for spectral line profiles.

Paper led by postdoc Petr Kurfürst explores hydrodynamics of spherical supernova interacting with aspherical CSM. We look at circumstellar disk, bipolar lobes, and shells formed in the wind collision region of binary stars and similar process. While interaction with circumstellar disks (and to some extent with bipolar lobes) leads to expected outcome such as increase in luminosity and double-peaked spectral lines, we find that interaction with colliding wind shells is potentially much more complicated with asymmetric and time-changing line profiles. Cool movies are available on Petr’s website.

Dynamical perturbations of triple stellar and planetary systems seen in gravitational waves with LISA

Fourier transform of eccentric triple star system showing a number of peaks.

Congratulations to Matěj Mezera for successfully defending his Bachelor thesis “Dynamical perturbations of triple stellar and planetary systems seen in gravitational waves with LISA”! In the thesis, he combined three-body integration with gravitational wave strain calculation and Fourier transform.

The Explosion Mechanism of Core-Collapse Supernovae and Its Observational Signatures

The book chapter in “Reviews in Frontiers of Modern Astrophysics From Space Debris to Cosmology” has now been published. In addition to basic overview of core-collapse supernova explosion mechanism, the writing includes side-by-side comparisons of predictions of explosion models (explodes yes/no, explosion energy, nickel mass, compact remnant mass) and observational inferences (explosion energy, nickel mass, neutron star mass).

See the full text at

Second round of computing cluster expansion finished

Second (and final) round of computing cluster expansion is finished. Our group now can use a total of 396 cores in 9 normal nodes (each node two 18-core CPUs and 128 GB RAM) and 1 “fat” node (four 18-core CPUs, 512GB RAM). All nodes are connected with 100 Gbps Infiniband and are accessed through a dedicated login node. Big thanks to cluster administrators for trouble-free experience! Picture on the left courtesy of Oldřich Ulrych.

We are hiring PhD students!

As a part of Prague Doctoral Program we seek 1-2 PhD students to work on topics related to the ERC Starting Grant “Catastrophic interactions of binary stars and the associated transients” (Cat-In-hAT). The work will focus on understanding the theory and observational implications of two merging stars, including neutron stars. Depending on the interests of the student, the work could focus on transients from stellar collisions, (magneto)hydrodynamical evolution of merger products, production of dust and molecules, and understanding the observational counterparts (blue stragglers, R CrB stars, FK Com stars, eta Car, progenitor of SN1987A, GW170817, etc.). The work can utilize existing codes or codes under development in the group: 1D stellar evolution, multidimensional low-Mach number magnetohydrodynamics, moving mesh radiation hydrodynamics, or N-body calculations. In addition, the group is a member of All-Sky Automated Survey for Supernovae, and the thesis can include significant observational or data analysis component.

For application instructions, see Prague Doctoral Program.

We are hiring postdoc!

Postdoctoral Research Positions in Computational Astrophysics

Applications are invited for a postdoctoral position in the area of computational astrophysics in the research group of Dr. Ondřej Pejcha at the Institute of Theoretical Physics, Charles University, Prague, Czech Republic. The successful candidates will lead development of new computational abilities to understand multi-dimensional evolution of catastrophic interactions of binary stars (mergers, common envelope, compact objects). The work will be performed within the project “Cat-In-hAT” funded by the ERC Starting Grant. 

The research group has access to a dedicated computer cluster and is connected to observational efforts in time-domain astronomy as part of the All-Sky Automated Survey for Supernovae

The position is initially for one year, renewable for up to three years, based on performance.

Applicants must have a PhD in astronomy, computational physics, or a related field by the start date of the appointment. The position includes competitive salary and research budget comparable to international fellowships.

Application instructions:  please submit CV, list of publications, statement on past research and future interests to before February 29 2020.  Please arrange for 3 letters of recommendation to be delivered to the same email address. Applications will be reviewed immediately as they come and the position will remain open until filled.

Included Benefits: Full Charles University employee benefits: health insurance (no or very small co-pays), 25 vacation days, 3 sick days, contributions to state pension fund, subsidized meals, parental leave, discounts for sports & wellness, Czech language classes, etc.