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... the emerging radiation. The latter depends on the poorly constrained efficiency of the energy exchange between electrons and protons in the plasma near the compact object. The values of the electron temperature typically derived from the spectral fits to the hard spectral component in accreting blac ...
... the emerging radiation. The latter depends on the poorly constrained efficiency of the energy exchange between electrons and protons in the plasma near the compact object. The values of the electron temperature typically derived from the spectral fits to the hard spectral component in accreting blac ...
Quasars
... • AGNs turn `on´ and `off´ depending on the available matter • When all surrounding matter is exhausted, the AGN becomes invisible and its host a `normal´ galaxy • AGNs were more numerous in the past • The Milky Way may have experienced a (rather mild) AGN phase in the past Illustration of a black h ...
... • AGNs turn `on´ and `off´ depending on the available matter • When all surrounding matter is exhausted, the AGN becomes invisible and its host a `normal´ galaxy • AGNs were more numerous in the past • The Milky Way may have experienced a (rather mild) AGN phase in the past Illustration of a black h ...
Many-body levels of optically excited and multiply charged InAs nanocrystals... by semiempirical tight binding
... at a time.27 The exciton creation and the electron 共hole兲 addition experiments probe single-particle energies and manybody interactions of the nanocrystals. The many-body interaction involved in the exciton creation is an electron-hole interaction, while that in the electron and hole addition is an ...
... at a time.27 The exciton creation and the electron 共hole兲 addition experiments probe single-particle energies and manybody interactions of the nanocrystals. The many-body interaction involved in the exciton creation is an electron-hole interaction, while that in the electron and hole addition is an ...
Towards a microscopic Description of classical Solutions in Field
... nature is fundamentally quantum. In this thesis we want to take this perspective as a starting point and investigate its consequences. From this point of view, every classical object should be understood as a quantum bound state of proper microscopic degrees of freedom. As a consequence, consistency ...
... nature is fundamentally quantum. In this thesis we want to take this perspective as a starting point and investigate its consequences. From this point of view, every classical object should be understood as a quantum bound state of proper microscopic degrees of freedom. As a consequence, consistency ...
S282_2 Introduction to active galaxies
... these objects only since the 1940s, and the galaxies have been around for at least 1010 years. So the fact that we observe a small percentage of galaxies in an active phase could mean that every galaxy becomes active for the same small percentage of its lifetime, but it could also mean that a small ...
... these objects only since the 1940s, and the galaxies have been around for at least 1010 years. So the fact that we observe a small percentage of galaxies in an active phase could mean that every galaxy becomes active for the same small percentage of its lifetime, but it could also mean that a small ...
Quantum Fields on BTZ Black Holes
... In QFT, besides ground states, equilibrium thermal states are outstanding elements in the theory. So, after studying the mapping of a ground state it is very natural to ask how an equilibrium thermal state maps from the bulk to the boundary of AdS spacetime. This issue is more appealing when one kno ...
... In QFT, besides ground states, equilibrium thermal states are outstanding elements in the theory. So, after studying the mapping of a ground state it is very natural to ask how an equilibrium thermal state maps from the bulk to the boundary of AdS spacetime. This issue is more appealing when one kno ...
Denouement of a wormhole-brane encounter
... points A and A’ in Figure 1) violates the null energy condition within the brane. In this case the structure is a wormhole whose dimensionality matches that of the brane. This wormhole persists in the sense that it presumably remains in the state of partial envelopment and does not, for the reason a ...
... points A and A’ in Figure 1) violates the null energy condition within the brane. In this case the structure is a wormhole whose dimensionality matches that of the brane. This wormhole persists in the sense that it presumably remains in the state of partial envelopment and does not, for the reason a ...
Active Galactic Nuclei
... Merging of host galaxies transports matter to the core Hopkins et al. (2010): uncertainty leaves room for any kind of scenario Kocevski et al. (2012): Chandra detected AGN + control sample: major merger do not trigger AGN at z~2 (but minor merger?) Difference between dry and wet (= gas-rich) ...
... Merging of host galaxies transports matter to the core Hopkins et al. (2010): uncertainty leaves room for any kind of scenario Kocevski et al. (2012): Chandra detected AGN + control sample: major merger do not trigger AGN at z~2 (but minor merger?) Difference between dry and wet (= gas-rich) ...
Angular momentum and the formation of stars and
... dynamics, governing not only the collapse of a molecular cloud or cloud core but also the redistribution of angular momentum within it. Simulations of star formation show the appearance of trailing spiral features within which gravitational torques can transport angular momentum outward, and forming ...
... dynamics, governing not only the collapse of a molecular cloud or cloud core but also the redistribution of angular momentum within it. Simulations of star formation show the appearance of trailing spiral features within which gravitational torques can transport angular momentum outward, and forming ...
Gravitational Lensing with a Large Deflection Angle as a Probe of
... The coordinate of closest approach required to yield a particular bending angle in both the numerical technique and the SDL approximation. The SDL approximation tends to be converge with the numerical technique as x0 approaches the photon sphere, as the SDL approximation loses validity as one moves ...
... The coordinate of closest approach required to yield a particular bending angle in both the numerical technique and the SDL approximation. The SDL approximation tends to be converge with the numerical technique as x0 approaches the photon sphere, as the SDL approximation loses validity as one moves ...
A Brief History of Time
... outermost sphere carried the so-called fixed stars, which always stay in the same positions relative to each other but which rotate together across the sky. What lay beyond the last sphere was never made very clear, but it certainly was not part of mankind’s observable universe. Ptolemy’s model prov ...
... outermost sphere carried the so-called fixed stars, which always stay in the same positions relative to each other but which rotate together across the sky. What lay beyond the last sphere was never made very clear, but it certainly was not part of mankind’s observable universe. Ptolemy’s model prov ...
IXO as an observatory in the large telescopes era
... kind of depth over much larger areas. IXO's combination of huge collecting area and excellent spatial resolution over a large field of view fulfils this requirement (Fig. 1.3). These observations will have enormous constraining power. Current semi-analytic models of galaxy formation in the early Uni ...
... kind of depth over much larger areas. IXO's combination of huge collecting area and excellent spatial resolution over a large field of view fulfils this requirement (Fig. 1.3). These observations will have enormous constraining power. Current semi-analytic models of galaxy formation in the early Uni ...
The hot, early universe - Cosmology Block
... In equilibrium, certain thermodynamical quantities can be introduced, which take on constant values throughout the system. Best-known of those: Temperature T and pressure p. Equilibrium thermodynamics: given energy E, volume V , particle number N , calculate T, p. ...
... In equilibrium, certain thermodynamical quantities can be introduced, which take on constant values throughout the system. Best-known of those: Temperature T and pressure p. Equilibrium thermodynamics: given energy E, volume V , particle number N , calculate T, p. ...
A Brief History of Time - Stephen Hawking
... As far as Kepler was concerned, elliptical orbits were merely an ad hoc hypothesis, and a rather repugnant one at that, because ellipses were clearly less perfect than circles. Having discovered almost by accident that elliptical orbits fit the observations well, he could not reconcile them with his ...
... As far as Kepler was concerned, elliptical orbits were merely an ad hoc hypothesis, and a rather repugnant one at that, because ellipses were clearly less perfect than circles. Having discovered almost by accident that elliptical orbits fit the observations well, he could not reconcile them with his ...
How Massive Single Stars End Their Life - TigerPrints
... neutron star, fallback black hole, and direct black hole formation. For very massive stars, the remnant of the collapsing star depends sensitively on the metallicity. Above 40 M, low-metallicity stars form black holes directly, while at higher metallicities, black holes of smaller mass are produced ...
... neutron star, fallback black hole, and direct black hole formation. For very massive stars, the remnant of the collapsing star depends sensitively on the metallicity. Above 40 M, low-metallicity stars form black holes directly, while at higher metallicities, black holes of smaller mass are produced ...
Lecture 1: Astrophysics
... Astrophysics is a big subject. Sometimes will just flag where a whole (possibly large!) field branches off, e.g. won’t talk about how stars form Sometimes will give qualitative description (with lots of pretty pictures); unless I say otherwise, this is non-examinable A few topics are amenable to ana ...
... Astrophysics is a big subject. Sometimes will just flag where a whole (possibly large!) field branches off, e.g. won’t talk about how stars form Sometimes will give qualitative description (with lots of pretty pictures); unless I say otherwise, this is non-examinable A few topics are amenable to ana ...
Hawking radiation
Hawking radiation is black body radiation that is predicted to be released by black holes, due to quantum effects near the event horizon. It is named after the physicist Stephen Hawking, who provided a theoretical argument for its existence in 1974, and sometimes also after Jacob Bekenstein, who predicted that black holes should have a finite, non-zero temperature and entropy.Hawking's work followed his visit to Moscow in 1973 where the Soviet scientists Yakov Zeldovich and Alexei Starobinsky showed him that, according to the quantum mechanical uncertainty principle, rotating black holes should create and emit particles. Hawking radiation reduces the mass and energy of black holes and is therefore also known as black hole evaporation. Because of this, black holes that lose more mass than they gain through other means are expected to shrink and ultimately vanish. Micro black holes are predicted to be larger net emitters of radiation than larger black holes and should shrink and dissipate faster.In September 2010, a signal that is closely related to black hole Hawking radiation (see analog gravity) was claimed to have been observed in a laboratory experiment involving optical light pulses. However, the results remain unverified and debatable. Other projects have been launched to look for this radiation within the framework of analog gravity. In June 2008, NASA launched the Fermi space telescope, which is searching for the terminal gamma-ray flashes expected from evaporating primordial black holes. In the event that speculative large extra dimension theories are correct, CERN's Large Hadron Collider may be able to create micro black holes and observe their evaporation.