Division of Theoretical Physics and Astrophysics


Scientific research in field of astrophysics is theoretical and observational. It includes investigation of atmosphere and circumstellar envelopes of various types of stars, search for extrasolar planets with gravitational microlensing method, and measurement of gamma radiation by detection of Čerenkov radiation.

altSpectroscopic and photometric investigation of stars in various evolutionary phases is focused on circumstellar envelopes that consist of gas and dust. We determine their chemical composition, physical properties, structure, geometry and evolution time of the relevant parameters. In order to analyze large amounts of observational data and to model complex stellar systems we apply existing and develop new computer codes (D. Kotnik-Karuza, T. Jurkić).

altWithin international collaboration PLANET/MicroFUN we use a network of optical telescopes to measure an increase in brightness of stars that results from gravitational microlensing. By comparing simulated and measured light curves we determine whether these stars are orbited by (extrasolar) planets or if they are binary star systems (D. Dominis Prester, K. Lončarić).


altWe investigate cataclysmic variable stars and especially symbiotic stars with spectroscopic and photometric methods. We study variations of helium lines of Sun’s chromosphere and coronal holes observed in microwave spectral range. Properties of the solar velocity field (rotational, meridional and azimuthal flows, their correlation and covariance, Reynolds stress) indicated by motions of the sunspot groups are investigated in order to reveale the transfer of the angular momentum from higher to lower latitudes and to maintain the current differential rotation profile. We study dependence of solar rotation on time and on the phase of the solar cycle, as well as the relationship between solar rotation and activity (R. Jurdana-Šepić, I. Poljančić-Beljan).

Using Čerenkov telescopes MAGIC I and II located at Canary island La Palma (ORM) we observe scattering of gamma rays in Earth’s atmosphere. With analysis of light curves and gamma radiation spectra we model physical phenomena in extreme conditions: pulsars, black holes, active galactic nuclei and starburst galaxies. Department of Physics of University of Rijeka is co-owner of MAGIC telescope and accompanying  experimental equipment (D. Dominis Prester i T. Terzić).

alt

Gamma-ray bursts (GRBs) are among the most fascinating phenomena that high-energy astrophysics has to offer. The new observations in the very high energy range (>10 GeV) are expected with the CTA (Cherenkov Telescope Array) observatory. Gamma-ray burst prompt emission studies (Z. Bosnjak) aim at improving our physical understanding of the phenomenon, and also to bring new constraints on some fundamental processes in high energy astrophysics, such as relativistic ejection or shock acceleration (Ž. Bošnjak).
Cherenkov Telescope Array (CTA) project is an initiative to build the next generation ground-based very high energy gamma-ray instrument. It will serve as an open observatory to a wide astrophysics community and will provide a deep insight into the non-thermal high-energy universe. The LST-1 (Large Size Telescope) prototype of the largest of the CTA telescopes (24m diameter) is currently being built at the ORM, La Palma. Scientists from nine countries, including Croatia, participate in hardware development and Monte Carlo simulations for the LST (D. Dominis Prester, Ž. Bošnjak, T. Terzić).

Scientific research in theoretical physics covers a wide range of phenomena from interactions of electromagnetic fields with surfaces and Compton scattering on atoms, to thermodynamics of black holes and unification of all forces.

Study of interaction of electromagnetic field with matter, especially with surfaces and particles near the surface and study of electrons and electron structure in systems with reduced symmetry is connected with better understanding of specific phenomena, like Casimir effect (Z. Lenac).

alt Research in elementary particle physics is conducted in two connected directions. One is dedicated to unification of forces, altmostly in the framework of superstring theory.  The other is focused on studying the properties of black holes. Besides growing importance in astrophysics, black holes also provide a unique theoretical laboratory for studying microscopic structure of space-time, i.e. quantum gravity which is yet unknown  theory for which superstring theory is the beast candidate at present. This research is also important for understanding early stages of the Universe (Big Bang) and its future (P. Dominis Prester).

We extended the study of Compton scattering on atom with independent particle model to double-ionised helium atoms with corrections from Coulomb and magnetic interaction. We also study scattering on two centres, for example scattering on positronium (Z. Kaliman).

Scientific and expert work in educational physics includes research of the development of physical concepts and interests for physics in children especially in children of young age, and development of educational modules for f2f environment and e-learning (R. Jurdana-Šepić, V. Labinac, N. Erceg).


Membership in International Collaborations


COST projects


Croatian Science Foundation projects
  • GRAPARION - Gravity and parity violation (2014 - 2018); collaborators: P. Dominis Prester and M. Paulišić
  • SOLSTEL - Solar and Stellar Variability (2014 - 2018); collaborators: R. Jurdana-Šepić and I. Poljančić Beljan


Head of the Division of Theoretical Physics and Astrophysics:
Dijana Dominis Prester, associate professor

Research staff:
Predrag Dominis Prester, professor
Zdravko Lenac, professor
Rajka Jurdana-Šepić, associate professor
Zoran Kaliman, associate professor
Dijana Dominis Prester, associate professor 
Tomislav Terzić, assistant professor
Saša Mićanović, assistant professor
Velimir Labinac, senior lecturer
Tomislav Jurkić, lecturer
Ivana Poljančić Beljan, lecturer
Klaudija Lončarić, PhD student
Mateo Paulišić, PhD student

Technical staff:
Mariza Sarta Deković, senior assistant