Istraživanje zračenja međuzvjezdanog vodika i prašine u Mliječnom putu

master's thesis

• Title (english): A study of interstellar hydrogen and dust emission in the Milky Way
• Author: Nikolina Pajski
• Mentor: Vibor Jelić (mentor)
• Committee member: Vibor Jelić (predsjednik povjerenstva)
• Committee member: Krešimir Pavlovski (član povjerenstva)
• Committee member: Katarina Jeličić (član povjerenstva)
• Committee member: Vernesa Smolčić (član povjerenstva)
• Committee member: Maja Planinić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2022-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

U našoj Galaksiji, Mliječnom putu, prostor između zvijezda prožet je magnetskim poljem, relativističkim kozmičkim zrakama i međuzvjezdanom tvari koja se sastoji od plina u ioniziranom, atomskom i molekularnom stanju te prašine. Zanimljivo je promatrati kako različite faze plina međudjeluju te na koji način magnetsko polje oblikuje difuzni međuzvjezdani plin. U tu svrhu ovaj rad bavi se proučavanjem zračenja neutralnog vodika i prašine te detektiranjem i određivanjem orijentacija linearnih struktura koje će se usporediti međusobno i sa smjerom magnetskog polja. Istraživanja su provedena pomoću magneto-hidrodinamičkih simulacija sudara super-ljusaka na temelju kojih je simulirano sinkrotronsko zračenje naše Galaskije te je predviđeno zračenje vodika i prašine. Linearne strukture dobivene sintetskim promatranjima iznenadujuće nalikuju na filamentarne strukture i depolarizacijske kanale koji se nalaze u stvarnim opažanjima. Analiza sinkrotronskog zračenja provodi se RM sintezom koja raspetljava zračenje po Faradayevim dubinama budući da magneto-ionski medij uzrokuje Faradayevu rotaciju. Za identificiranje i kvantificiranje orijentacije ravnih depolariziranih kanala primjenjuje se Rolling Hough Transform algoritam. Nadalje, iz simulacije se odredi zračenje vodika na temelju čega se prikaže slika temperature sjaja gdje se RHT analizom odredi orijentacija opaženih filamentarnih struktura HI te se također promatra i polarizirano zračenje prašine koje mjeri orijentaciju magnetskog polja. Usporedbom orijentacija linearnih struktura dobiva se da filamenti vodika i depolarizacijski kanali prate orijentaciju magnetskog polja u ravnini neba, a takvi rezultati mogu se pronaći i u stvarnim mjerenjima.

Abstract (english)

In our Galaxy, the Milky Way, the space between the stars is permeated with magnetic field, relativistic cosmic rays and interstellar matter consisting of gas in ionized, atomic, and molecular states, and of dust. It is interesting to observe how different gas phases interact with each other and how magnetic field shapes diffuse interstellar gas. Therefore, in this work we study the radiation of neutral hydrogen and cosmic dust, and determine orientations of linear structures which will then be compared with each other and with the orientation of the magnetic field. Study was conducted using magneto-hydrodynamic simulations of colliding super-shells, based on which was simulated synchrotron emission of our Galaxy and determined emission of neutral hydrogen and dust. The linear structures obtained from the synthetic observations surprisingly resemble the filamentary structures and depolarization canals found in the real data. An analysis of synchrotron radiation is performed by RM synthesis, which untangles the radiation by Faraday depths, since the magneto-ionic medium causes Faraday rotation. To identify and quantify the orientation of straight depolarization canals, the Rolling Hough Transform algorithm is applied. Furthermore, hydrogen emission is determined from MHD simulation. In an image of the temperature brightness the orientation of the observed filamentary HI structures is determined by RHT analysis. The polarized dust emission is also analysed since it measures the orientation of the magnetic field. Comparing orientations of linear structures shows that hydrogen filaments and depolarization canals follow orientation of the magnetic field in the plane of the sky, as found in the real observations.

• Keywords: Mliječni put; meduzvjezdana tvar; MHD simulacija; sinkrotronsko zračenje; zračenje vodika i prašine; RM sinteza; RHT analiza
• Keywords (english): the Milky Way; interstellar medium (ISM); MHD simulation; polarized synchrotron emission; hydrogen and dust emission; RM synthesis; RHT analysis
• Language: croatian
• URN:NBN: urn:nbn:hr:217:195944
• Study programme: Title: Physics; specializations in: Education; Course: Education; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra edukacije fizike (magistar/magistra edukacije fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-10-20 10:15:36