Research in galaxy formation

Hot coronae around galaxies

As one of the key predictions of hierarchical structure formation models, the Milky Way-like galaxies are expected to be embedded in hot and diffuse cocoons of gas. These cocoons are thought to be generated outside-in purely by the gravitational compression of gas, not inside-out by the energy injections from exploding stars. I performed and analysed high-resolution simulations of the Milky Way-like galaxies forming in the cosmological framework and predicted the presence of significant hot gas in the halos well before the halos ought to be able to sustain hot mode accretion in the conventional picture. My work provided theoretical foundations for the existance of a previously unknown stage of the coronal formation driven by merger-induced shock heating and supernovae feedback.

Galaxy-Halo connection

In the standard theory of disk galaxy formation the sizes of galaxies an be easily explained if baryons retain their specific angular momentum, initially resulting from tidal torques, as they collapse into the halo centers. One of the major advancements in the systematics of the "galactic zoo" was linking morphologies with stellar angular momentum per unit mass (relationship known as j-M diagram). In this project, high-resolution zoom-in cosmological simulations of late-type galaxies provided a laboratory for studying the evolutionary tracks of gas and stars on the j-M* diagram, as well as the coupling of baryons with dark matter.

Missing baryon problem

Observed baryon fraction of galaxies falls short of the cosmic baryon fraction, which could be explained by ejection of baryons in feedback processes and/or the presence of large reservoir of baryons in a difficult-to-detect form. For example, warmhot gas (10^5-6) within the galaxies or warm-hot intergalactic medium in the cosmic web (WHIM) would be high-energy and diluted, hence difficult to detect with the current instrumentation. In this project, we are interested in how baryons are distributed in the Universe. Therefore we study low-mass systems such as Milky Way analogues in low-density environments and loose groups, as well as high-mass systems (5x10^12Msol). We investigate the relevance of feedback processes at those scales.

Active Galactic Nuclei with VLBI

The RT-4 radio telescope in Torun is a part of the EVN (European Very Long Baseline Interferometry Network), still one of the most significant projects in the field of radio astronomy.

I used the NRAO AIPS, the software package aimed at cleaning, callibrating and analysing data affected by the downsides of the aperture synthesis method, to study a merely known AGN source over multiple epochs of data.
Left: Radio galaxy 0932+075 observed with the VLBI network.