Karakterizacija magnetizirane međuzvjezdane materije

master's thesis

• Title (english): Characterisation of the magnetized interstellar medium
• Author: Marta Čolaković-Bencerić
• Mentor: Matko Milin (mentor)
• Committee member: Matko Milin (predsjednik povjerenstva)
• Committee member: Nikola Poljak (član povjerenstva)
• Committee member: Maro Cvitan (član povjerenstva)
• Committee member: Mihael Makek (član povjerenstva)
• Committee member: Ivica Smolić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2020-07-24, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

U ovom radu prikazana je analiza struktura u simuliranim polarimetrijskim opažanjima korištenjem metoda RM sinteze i Rolling Hough transformata. Simulirana su opažanja polariziranog intenziteta na rasponu frekvencija u radio području nekoliko magnetohidrodinamičkih modela kompresibilne turbulentne međuzvjezdane tvari i modela sudara super-ljuski. Pokazano je da je usmjerenost depolariziranih struktura u opažanjima turbulentne meduzvjezdane tvari prisutna samo ako model sadrži homogenu komponentu magnetskog polja, no da su dovoljne vrijednosti jakosti homogene komponente manje od onih opaženih u spiralnim krakovima Mliječnog puta. Nadalje, pokazano je da udio depolariziranih piksela pada povećanjem kinematičke viskoznosti i otpornosti te jakosti homogene komponente magnetskog polja. Naposljetku, pokazano je da su sudari super-ljuski opazivi polarimetrijskim mjerenjima te da izgled struktura ovisi o gustoći elektrona kozmičkih zraka koje uzrokuju emisiju unutar spomenutog modela.

Abstract (english)

In this thesis we present an analysis of structure visible in synthetic polarimetric observations using Rotation measure synthesis and the Rolling Hough transform. We generated synthetic observations of polarized intensity over a range of radio frequencies for multiple magnetohydrodynamic models of compressible turbulent interstellar matter and a single model of a super-shell collision. It was found that depolarized structures in observations of the turbulent ISM show significant alignment only in models with a homogeneous magnetic field component, but that the sufficient strength was lesser than the values observed in the spiral arms of our Galaxy. Furthermore, it was shown that the percentage of depolarized pixels decreases with increasing kinematic viscosity, resistivity and strength of the homogeneous magnetic field component. Lastly, we have shown that super-shell collisions are detectable by radio polarimetric observations and that the visible structure largely depends on the synchrotron emitting local cosmic ray electron density.

• Keywords: radio-polarimetrija; meduzvjezdana tvar; magnetsko polje; magnetohidrodinamičke simulacije
• Keywords (english): radio polarimetry; interstellar medium; magnetic field; magneto-hydrodynamic simulations
• Language: croatian
• URN:NBN: urn:nbn:hr:217:476686
• Study programme: Title: Physics; specializations in: Research; Course: Research; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra fizike (magistar/magistra fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-01-08 09:30:17