Istraživanje međuzvjezdane tvari pomoću bljeskova gama-zraka

master's thesis

• Title (english): Probing the interstellar medium with gamma-ray bursts
• Author: Barbara Šiljeg
• Mentor: Željka Marija Bošnjak (mentor)
• Mentor: Vibor Jelić (komentor)
• Committee member: Vibor Jelić (predsjednik povjerenstva)
• Committee member: Željka Marija Bošnjak (član povjerenstva)
• Committee member: Matko Milin (član povjerenstva)
• Committee member: Krešimir Kumerički (član povjerenstva)
• Committee member: Ivica Smolić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2021-07-12, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

U ovom se radu istražuje konzistentnost metode mjerenja udaljenosti do oblaka međuzvjezdane prašine pomoću prstenova X-zračenja koji se formiraju oko bljeskova gama-zračenja raspršenjem na prašini u Mliječnom putu s drugim nezavisnim mjerenjima. Trenutno postoji šest bljeskova gama-zračenja kojima su se precizno odredile udaljenosti za jedan ili više oblaka prašine na njihovim doglednicama. Ove su se udaljenosti usporedile s predviđanjima 3D raspodjela prašine dobivenih promatranjem ekstinkcije velikog broja zvijezda u našoj okolini: Lallement et al. (2019) i Leike et al. (2020). Zaključilo se da su ove metode mjerenja udaljenosti međusobno konzistentne zbog čega su se pokušali predvidjeti novi prstenovi X-zračenja oko nekoliko selektiranih bljeskova gama-zračenja koristeći navedene 3D raspodjele prašine. Za bljesak gama-zračenja GRB 140206A navedene raspodjele predviđaju oblak prašine na udaljenosti od otprilike 300 pc. Provođenjem analize podataka X-zračenja satelita Swift, opazio se slab signal mogućeg prstena kojim se odredila udaljenost do prašine od 320 pc s relativnom pogreškom od 3.1%. Sam signal nije vrlo značajan s obzirom na pozadinu zbog čega možemo zaključiti da je detektirani prsten, u najboljem slučaju, slabo vidljiv. Za dodatnu analizu prašine na doglednici ovog bljeska uzeli su se podaci sinkrotronskog zračenja radioteleskopa LOFAR te infracrveno emisijsko zračenje prašine teleskopa Planck. Pronađeno dobro slaganje orijentacije depolariziranih kanala sinkrotronskog zračenja s orijentacijom magnetskog polja dobivenom teleskopom Planck daje nam indikaciju da detektirane emisije dolaze vjerojatno iz istog oblaka međuzvjezdane tvari te da je udaljenost ovog oblaka . ≲ 500 pc što se slaže s prijašnjim rezultatima. Konzistentnost 3D raspodjela ekstinkcije s mjerenjima udaljenosti pomoću bljeskova gama-zračenja nam omogućava nov način predviđanja potencijalne detekcije prstenova X-zračenja koje se može koristiti za unaprijeđenje selekcije novih bljeskova.

Abstract (english)

This work explores the consistency of measurements of interstellar dust distances using time evolving X-ray halos that form around gamma-ray bursts with other independent measuring techniques. Until now, there has been six gamma-ray bursts which have provided us with the measurements of the distances to dust clouds in their lines of sight. We decided to test these distances using two 3D extinction maps: Lallement et al. (2019) and Leike et al. (2020). Results show very good correlation of the measured distances from the bursts with the differential extinction distributions from these maps. Because of this, we have decided to also analyse such distributions along the lines of sights for a few more selected gamma-ray burst candidates. We have found that both extinciton maps predict a layer of dust at a distance of around 300 pc along the line of sight for GRB 140206A. In light of this, we have also analysed the X-ray data from Swift satellite in order to find the appropriate halo. We have found a faint signal of the halo which provided us with the distance of 320 pc with 3.1% uncertainty. The signal itself was not very significant with respect to the background, so we can conclude that at best, the halo is very faint. To further analyse the dust along this line of sight, we have also used the synchrotron emission data from the radio telescope LOFAR and the infrared emission of dust from the Planck telescope. We found good correlation between the orientations of depolarized canals in synchrotron data and the magnetic field lines from dust emission polarization. This result indicates that these two different emissions are probably coming from the same cloud of interstellar media and that this cloud is located at distances . ≲ 500 pc which is in good agreement with our previous results. The found consistency of the measurements of dust distances using gamma-ray bursts with the 3D extinction maps makes it possible for us to predict the potential detection of the X-ray halo formation. This information can help us to further improve our current selection of new gamma-ray burst candidates.

• Keywords: bljesak gama-zračenja; meduzvjezdana prašina; multifrekvencijska analiza meduzvjezdane tvari
• Keywords (english): gamma-ray burst; interstellar dust; multi-frequency analysis of interstellar medium
• Language: croatian
• URN:NBN: urn:nbn:hr:217:704831
• 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; Embargo expiration date: 2022-07-12
• Created on: 2021-07-23 11:08:18