Essays about: "Svarta Hål"

Showing result 1 - 5 of 24 essays containing the words Svarta Hål.

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. Cosmological Horizons and the Unruh Effect

   University essay from Uppsala universitet/Teoretisk fysik

   Author : Niklas Engelhardt Önne; [2023]
   Keywords : Unruh effect; quantum scalar fields; Bogoliubov transformations; accelerated observers; Minkowski spacetime; cosmological horizons; Rindler observers; special relativity; QFT; Unruh-effekten; skalära kvantfält; Bogoliubov-transformationer; accelererande referenssystem; Minkowski rumtid; kosmologiska horisonter; Rindlerobservatörer; speciell relativitetsteori; QFT;

   Abstract : The black hole information paradox, which states that the evaporation of black holes due to Hawking radiation results in a violation of the conservation of quantum information, is arguably one of the most fundamental problems in all of modern physics. Through the equivalence principle, the essence of the problem can be understood and studied in the context of much simpler flat spacetime (described by the theory of special relativity); in this context the Hawking radiation takes the form of the so-called Unruh effect, a thermal effect in the vacuum of a Minkowski quantum field theory that can be measured by accelerated observers. READ MORE

4. 3. Intermediate-mass black hole binary as an origin of super-massive black holes

   University essay from Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

   Author : Isabelle Signe Maj Maria Thord; [2023]
   Keywords : Intermediate-mass black holes; binary; merger; hardening; encounters; Physics and Astronomy;

   Abstract : Galactic nuclei contain super-massive black holes (SMBHs), nuclear stellar clusters (NSCs), or both. In the NSC, intermediate-mass black holes (IMBHs) are likely to reside and form highly eccentric binaries. Over time, the orbit of a binary could harden via interaction with surrounding low-mass stars. READ MORE

5. 4. Hyper-velocity stars from globular clusters hosting intermediate-mass black holes

   University essay from Lunds universitet/Astrofysik; Lunds universitet/Fysiska institutionen

   Author : Matilda Skantz; [2023]
   Keywords : Hypervelocity stars; run-away stars; stellar binary; intermediate mass black hole; globular cluster; Hills mechanism; Physics and Astronomy;

   Abstract : In 1988 Hills proposed that stars can gain velocities above 500 km s−1 if they are in a stellar binary which gets disrupted by a super massive black hole (SMBH). One of the stars would get trapped in an elliptical orbit around the SMBH while the other gets ejected and obtains a relatively high velocity. READ MORE

6. 5. Black Holes and Scalar Fields : A study of a massive scalar field around a black hole

   University essay from Uppsala universitet/Teoretisk fysik

   Author : Abdulmasih Ghazal; [2022]
   Keywords : Black holes; scalar field; General relativity; special relativity; spacetime; cosmology; Schwarzschild; Schrödinger equation; Svart hål; relativitetsteori; skalär fält; rumtid; Shrödinger; Schwarzschild.;

   Abstract : Black holes are one of the most interesting objects in the universe, and studying these objects should give exciting results. This research will investigate the General Theory of Relativity, explaining the essence of the theory needed for deriving solutions for a Schwarzschild black hole. READ MORE