Essays about: "CDM"

Showing result 1 - 5 of 70 essays containing the word CDM.

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

    University essay from KTH/Fysik

    Author : Atabak Fathe Jalali; [2024]
    Keywords : 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;

    Abstract : 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. READ MORE

  3. 2. Finding new members of the VelHel-4 stream

    University essay from KTH/Skolan för teknikvetenskap (SCI)

    Author : Lucas Johansson; [2023]
    Keywords : Galactic Archaeology; Milky Way; Stellar Streams; Streams; Stellar Halo; Stars; Globular Cluster; Astronomy; Astrophysics; Gaia; Chemical Abundance; Spectroscopy;

    Abstract : According to the paradigm of lambda-CDM cosmology, the stellar halo ofour Galaxy has been built-up over time through the accretion of other galaxiesand star clusters. The remnants of some of these are still observable today asstellar streams, but are typically very faint and difficult to resolve amidst the farmore numerous foreground Milky Way stars. READ MORE

  4. 3. Warm dark matter simulations and 21cm astronomy

    University essay from Uppsala universitet/Institutionen för fysik och astronomi

    Author : Melker Marminge; [2023]
    Keywords : Warm Dark Matter; N-body Simulation; Power Spectrum; Neutral Hydrogen; Cosmology;

    Abstract : The recent boom in 21cm astronomy has piqued the interest of many, especially cosmologists realizing its applications in their field. This study aims to determine if 21cm astronomy is a good tool for testing the validity of keV WDM models, as well as creating a code capable of simulating keV WDM models from an existing CDM code. READ MORE

  5. 4. Thawing, Scaling and Tracking QUintessence in a Phase Space Perspective : and comparisons to the ΛCDM model

    University essay from Karlstads universitet/Institutionen för ingenjörsvetenskap och fysik (from 2013)

    Author : Arvid Ryberg; [2022]
    Keywords : Quintessence; Cosmology; Dark Energy; Astro physics;

    Abstract : This thesis aims to give an introduction to quintessence models as well ascomparing those models with the currently accepted ΛCDM model. We willconsider quintessence in a spatially flat and isotropic Universe and useregular dynamical systems on a bounded three dimensional phase spacewhere we perform numerical calculations. READ MORE

  6. 5. Starbursts at Cosmic Dawn : Formation of Globular Clusters, Ultra-Faint Dwarfs, and Population III star clusters at z > 6

    University essay from Stockholms universitet/Institutionen för astronomi

    Author : Olof Nebrin; [2022]
    Keywords : Cosmology; Galaxy Formation; Globular Clusters; First Stars; Dark Matter; Cosmic Dawn; Reionization; Ultra-Faint Dwarfs;

    Abstract : In the standard model of cosmology (ΛCDM) the first stars, star clusters, and galaxies are expected to have formed in short bursts of star formation in low-mass dark matter halos at high redshifts (). Up to this point, attempts to predict the properties and abundances of these luminous objects have made use of numerically expensive cosmological simulations. READ MORE