Modeliranje mase zbijenog tijela u središtu Mliječnoga puta

master's thesis

• Title (english): Modelling the mass of the compact object in the center of the Milky Way
• Author: Marija Horvat
• Mentor: Vernesa Smolčić (mentor)
• Committee member: Vernesa Smolčić (predsjednik povjerenstva)
• Committee member: Matko Milin (član povjerenstva)
• Committee member: Neven Tomičić (član povjerenstva)
• Committee member: Ivica Smolić (član povjerenstva)
• Committee member: Davor Horvatić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2024-09-19, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

U središtu naše galaksije, Mliječni put, otkriven je snažan radioizvor u smjeru zviježda Strijelac. Smatra se da se radi o supermasivnoj crnoj rupi koja nosi naziv Strijelac A* (engl., Sagittarius A*, Sgr A*). Smatra se da se supermasivne crne rupe nalaze u središtima većine galaksija te da su njihove mase povezane sa svojstvima galaksije u kojoj se nalaze. Masu supermasivne crne rupe u središtu galaksije možemo proučavati na nekoliko načina. U tome nam uvelike pomažu zvijezde koje se nalaze u... More neposrednoj blizini središnje supermasivne crne rupe. Mjerenjem orbita tih zvijezda i korištenjem trećeg Keplerovog zakona, možemo izračunati masu središnjeg tijela oko kojeg zvijezde orbitiraju. Mjerenjem disperzija brzina tih zvijezda također možemo doći do iznosa te mase. Postoje i razni modeli kojima možemo opisati ponašanje mase u ovisnosti u udaljenosti od središta Mliječnoga puta. Jedan od poznatijih modela je Plummerov model. često se koristi za teorijsko modeliranje sferno-simetričnih galaksija i kuglastih skupova. U ovom radu bavila sam se istraživanjem mase kompaktnog objekta u središtu Mliječnog puta, koristeći tri različite metode za procjenu te mase. Prva metoda se temelji na podacima o periodima i velikim poluosima orbita zvijezda koje se nalaze u neposrednoj blizini središta. Korištenjem ove metode dobila sam procjenu mase od M = (4.41 ± 0.03)×10^6 M_⊙. Druga metoda oslanja se na analizu brzina zvijezda i disperzije tih brzina, iz koje sam dobila procjenu mase od M = (1.8 ± 0.4)×10^6 M_⊙. Treća metoda uključuje modeliranje raspodjele mase u ovisnosti o udaljenosti od središta galaksije, koristeći Plummerov model s jediničnom masom u središtu. Ova metoda je rezultirala masom od M = (3.0 ± 0.3)×10^6 M_⊙. Provedena analiza također pokazuje potrebu za dodavanjem jedinične mase u središte galaksije. Less

Abstract (english)

In the center of our galaxy, the Milky Way, a powerful radio source has been discovered in the direction of the constellation Sagittarius. It is believed to be a supermassive black hole named Sagittarius A* (Sgr A*). It is believed that supermassive black holes are located in the centers of most galaxies and that their masses are related to the properties of the galaxy in which they are located. We can study the mass of the supermassive black hole at the center of the galaxy in several ways.... More The stars that are located in the immediate vicinity of the central supermassive black hole are used for this. By measuring the orbits of those stars and using the third Kepler’s law, we can calculate the mass of the central body. By measuring the velocity dispersions of these stars, we can also infer the mass. There are also various models that can be used to describe the mass as a function of the distance from the center of the Milky Way. One of the commonly used model is the Plummer model. It has been developed for theoretical modeling of spherically symmetric galaxies and globular clusters. In this paper, I investigated the mass of a compact object in the center of the Milky Way, using three different methods to estimate that mass. The first method is based on the periods and semimajor axes of the orbits of stars located in the immediate vicinity of the center. Using this method, I obtained a mass estimate of M = (4.41 ± 0.03)×10 ^6 M_⊙. The second method relies on the analysis of stellar velocities and the dispersion of these velocities, from which I obtained a mass estimate of M = (1.8 ± 0.4)×10 ^6 M_⊙. The third method relies on modeling the mass distribution as a function of distance from the center of the galaxy, using the Plummer model with unit mass at the center. This method resulted in a mass of M = (3.0 ± 0.3)×10 ^6 M_⊙. The analysis carried out also shows the need to add unit mass to the center of the galaxy. Less

• Keywords: Mliječni put; supermasivna crna rupa; treći Keplerov zakon; Plummerov model
• Keywords (english): Milky Way; supermassive black hole; Kepler’s third law; Plummer’s model
• Language: croatian
• URN:NBN: urn:nbn:hr:217:301371
• Study programme: Title: The University Integrated Undergraduate and Graduate Programme in Physics; Research Physics; specializations in: Research Physics; Course: Research Physics; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: sveučilišni magistar fizike (sveučilišni magistar fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2025-01-31 09:01:32