vestifmИзвестия Национальной академии наук Беларуси. Серия физико-математических наукProceedings of the National Academy of Sciences of Belarus. Physics and Mathematics Series1561-24302524-2415The Republican Unitary Enterprise Publishing House "Belaruskaya Navuka"10.29235/1561-2430-2021-57-1-85-98vestifm-570Research ArticleФИЗИКАPHYSICSДыфузія выпраменьвання ў абалонцы, якая рэлятывісцкі пашыраецца, у дачыненні да гама-ўсплёскаўRadiation diffusion in a ultra-relativistic expanding shell in relation to gamma-ray burstshttps://orcid.org/0000-0001-7802-0691СіўцоўІ. А.SiutsouI. A.

Сіўцоў Іван Аляксандравіч – кандыдат фізікаматэматычных навук, старшы навуковы супрацоўнік

пр. Незалежнасці, 68-2, 220072, г. Мінск

Ivan A. Siutsou – Ph. D. (Physics and Mathematics), Senior Researcher68-2, Nezalezhnasci Ave., 220072, Minsk

siu@tut.byКургузаваА. Э.KurguzavaА. Е.

Кургузава Аксана Эдуардаўна – аспірант, малодшы навуковы супрацоўнік

пр. Незалежнасці, 68-2, 220072, г. Мінск

Aksana E. Kurguzava – Postgraduate Student, Junior Researcher

68-2, Nezalezhnasci Ave., 220072

kuppory@gmail.comІнстытут фізікі імя Б. І. Сцяпанава Нацыянальнай акадэміі навукB. I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus2021010420215718598Copyright © Сіўцоў І.А., Кургузава А.Э., 20212021Сіўцоў І.А., Кургузава А.Э.Siutsou I.A., Kurguzava А.Е.Данная работа распространяется под лицензией Creative Commons Attribution 4.0.This work is licensed under a Creative Commons Attribution 4.0 License.https://vestifm.belnauka.by/jour/article/view/570

Сучасныя назіральныя даныя, якія атрымліваюцца спадарожнікавымі абсерваторыямі, пакрываюць сем дэкад энергіі гама-квантаў, і агульная ўніверсальная мадэль, якая апісвае фарміраванне спектру, адсутнічае. Таму з’яўляецца актуальнаым апісанне пачатковых этапаў распаўсюджвання выпраменьвання ў абалонцы, якая пашыраецца з ультрарэлятывісцкімі хуткасцямі. Мэтай даследавання з’яўлялася атрыманне ўраўненняў распаўсюджвання выпраменьвання ў абалонцы, якая рэлятывісцкі пашыраецца, у дыфузійным прыбліжэнні, іх рашэнне для натуральных пачатковых даных і прыкладанне атрыманых вынікаў да пачатковага выпраменьвання гамаўсплёскаў. Паказана, што пачатковы этап гама-ўсплёску ў фатонна-тонкім выпадку можна апісаць дыфузіяй выпра[1]меньвання ў абалонцы, якая ультрарэлятывісцкі пашыраецца; прамежак часу, пры якім яшчэ магчыма выкарыстанне дыфузійнага прыбліжэння, падаўжаецца з павелічэннем глыбіні ўнутры абалонкі па законе, блізкім да квадратычнай функцыі; пры прыбліжэнні да часу дыфузіі значэнне глыбіні, па-за якой можна выкарыстоўваць дыфузійнае прыбліжэнне, павялічваецца, а значэнне інтэнсіўнасці выпраменьвання памяншаецца; падчас асноўнага выпраменьван[1]ня фатонна-тонкай абалонкі дыфузійнае прыбліжэнне прыдатнае для большай частцы абалонкі. Параметры выпра[1]меньвання блізкія да характэрных велічынь для кароткіх гама-ўсплёскаў.

 The present-day observational data obtained by satellite  observatories cover seven decades of gamma-ray energy, and there is no universal general model describing the formation of the spectrum. Therefore, it is important to describe the initial stages of radiation propagation in an ultrarelativistically expanding shell. The aim of this study was to obtain equations describing the propagation of radiation in a relativistically expanding shell in the diffusion limit, solve them for natural initial data, and apply the results obtained to the initial radiation of gamma-ray bursts. The following results were obtained: the initial stage of the gamma-ray burst in a photon-thin case can be described by radiation diffusion in an ultrarelativistically expanding shell; the time interval at which it is still possible to use the diffusion approximation increases with increasing the depth inside the shell quadratically; the value of the depth beyond which the diffusion approximation can be used increases, and the value of the radiation intensity decreases in diffusion time approaches; during the main radiation of the photon-thin shell, the diffusion approximation is suitable for most of the jet. The parameters of emission are close to the ones of short gamma-ray bursts.

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The authors declare that there are no conflicts of interest present.