|
|
Dwarf galaxies with active galactic nucleus
Adamcová, Barbora ; Svoboda, Jiří (advisor) ; Grossová, Romana (referee)
Title: Dwarf galaxies with active galactic nucleus Author: Barbora Adamcová Institute: Astronomical Institute of the Charles University in Prague Supervisor: RNDr. Jiří Svoboda, Ph.D., Astronomical Institute of the Czech Academy of Sciences Abstract: This masters's thesis deals with star-forming dwarf galaxies with an enhanced X-ray luminosity based on the predictions from star-formation processes. We constructed a sample of dwarf galaxies observed with the SDSS telescope in optical light and with the ESA XMM-Newton observatory in X-rays. We compared different methods to predict the X-ray luminosity from star formation processes and compared it to the observed values. We investigated whether the X-ray excess is related to any physical properties of the studied galaxies, such as stellar population, metallicity or specific star formation rate, or can be attributed to active galactic nucleus. We also processed the first X-ray observations of 7 Blueberry galaxies, which are analogues of high redshift galaxies. We found, that their X-ray luminosities are lower than expected, with only 1 source having an X-ray excess, 1 source being detected and for the rest only the upper limits could be constrained. We discuss possible sources for the measured X-ray excess in the dwarf galaxy sample, as well as the implications...
|
|
|
Radiation transfer in protoplanetary disks vs ALMA interferometric observations
Janoška, Ondřej ; Brož, Miroslav (advisor) ; Grossová, Romana (referee)
We study observability of protoplanetary disc structures by the ALMA interferometer. Structures, which planets create in discs have a form of spiral arms, rings or gaps. Our goal is to calculate synthetic images of such discs. For this purpose, we created Faradit, a program for extending a two-dimensional hydrodynamical simulation of a protoplanetary disc to the third, vertical dimension. We studied 5 different cases: a vertically isothermal disc, an optically thick disk, an optically thin disc, a disc with a distribution of grain sizes and a disc with viscous heating and dust grain evaporation. In all of them, we calculated radiation transfer using RADMC-3D program and created ideal images for six different wavelengths. Eventually, we assessed whether these structures are observable, using a simulator of interferometric observations (ALMA OST). Despite the structures induced by protoplanets with masses 3 M⊕ were present, we concluded they are not observable with a realistic signal and noise of ALMA in continuum. The respective disc would have to be more evolved, with an opened gap. 1
|
guest ::
