Sökning: "gravitational"

Visar resultat 1 - 5 av 164 uppsatser innehållade ordet gravitational.

  1. 1. Gravitational Collapse of a Massless Scalar Field in a Theory of Minimally Modified Gravity

    Master-uppsats, KTH/Fysik

    Författare :Atabak Fathe Jalali; [2024]
    Nyckelord :Theoretical physics; astrophysics; modified gravity; minimally modified gravity; gravitational collapse; VCDM; scalar collapse; apparent horizon; numerical relativity; Teoretisk fysik; astrofysik; modifierad gravitation; minimalt modifierad gravitation; gravitationskollaps; VCDM; skalär kollaps; uppenbar horisont; numerisk relativitet;

    Sammanfattning : This thesis explores the spherically symmetric gravitational collapse of a massless scalar field in a minimally modified gravity theory denoted VCDM (V replaces $\Lambda$ in the $\Lambda$CDM abbreviation), a class of theories propagating the same degrees of freedom as general relativity at the expense of broken 4D diffeomorphism invariance. Numerical evolution of the equations of motion reveals that for small initial scalar profile amplitudes, no black hole forms from the collapse. LÄS MER

  2. 2. Exocomets in the β Pictoris system

    Kandidat-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Författare :Klaudia Jaworska; [2024]
    Nyckelord :Physics and Astronomy;

    Sammanfattning : Comets have been a source of fascination throughout the history of man. In recent years, advances in technology have opened up for the study of extrasolar objects, among them exocomets. The first exocomets were observed in the β Pictoris system almost 50 years ago and the system has been of interest ever since. LÄS MER

  3. 3. Measuring copper abundances in the Galactic Bulge

    Kandidat-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Författare :Nikolei Höglinger; [2024]
    Nyckelord :Copper; Galaxy: abundances; Galaxy: bulge; Chemical Evolution; Physics and Astronomy;

    Sammanfattning : Context: The chemical evolution of Cu in the Galactic bulge have been studied in a few studies using red giant branch stars, but the ages of individual red giant stars are difficult to determine. In addition, the bulge has been a challenging region of the Milky Way galaxy to obtain high-resolution spectra of stars, except when observing through certain few small fields into the bulge that are known to have low extinction. LÄS MER

  4. 4. The quest for a classical bulge - a study of kinematics, abundances, and ages using microlensed dwarf stars and Gaia

    Master-uppsats, Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

    Författare :Calum Kvernes Macpherson; [2023]
    Nyckelord :Bulge; Milky Way; Kinematics; Galpy; Dwarf Stars; Physics and Astronomy;

    Sammanfattning : Context: We present an kinematical analysis of 90 F and G type dwarf, turn-off, and subgiant stars in the Galactic bulge. These stars were observed with high-resolution spectrographs during gravitational microlensing events This allowed for their ages, abundances, and radial velocities to be ascertained while they were significantly brighter. LÄS MER

  5. 5. Exploring New Physics Through Collider and Gravitational Wave Measurements with Artificial Neural Networks: the Case Study of QCD-like Technicolor

    Magister-uppsats, Lunds universitet/Fysiska institutionen; Lunds universitet/Teoretisk partikelfysik - Geonomgår omorganisation

    Författare :Ashar Ahmed Kamal; [2023]
    Nyckelord :Artificial Neural Networks; ANN; Beyond the Standard Model; BSM; parameter space scan; Physics and Astronomy;

    Sammanfattning : With physicists actively exploring Beyond the Standard Model (BSM) theories that may fill in the gaps of the Standard Model (SM), a fundamental question arises: which parameters hold physical significance? In this thesis, we present our initial progress towards the development of a model-independent artificial intelligence framework designed for conducting parameter space scans in BSM scenarios. Our framework incorporates several publicly available high-energy physics packages, namely SPheno, HiggsBounds, HiggsSignals, and CosmoTransitions. LÄS MER