Acceleration of the charged particles due to chaotic scattering in the
... In the processes occurring around black holes the magnetic fields can be relevant due to several reasons. The local magnetic fields in the Keplerian accretion discs are assumed to be the source of the basic viscosity mechanism of accretion due to the magneto-rotational instability [1]. The kinetic d ...
... In the processes occurring around black holes the magnetic fields can be relevant due to several reasons. The local magnetic fields in the Keplerian accretion discs are assumed to be the source of the basic viscosity mechanism of accretion due to the magneto-rotational instability [1]. The kinetic d ...
PS1-10jh: The Disruption of a Main-Sequence Star of Near
... beyond the peak in the accretion rate Ṁpeak . In these encounters, the peak accretion rate is realized only one day after pericenter, and we follow the evolution of the returning debris for a total of 5×105 seconds (about one week). Our hydrodynamical simulations were performed in a module written ...
... beyond the peak in the accretion rate Ṁpeak . In these encounters, the peak accretion rate is realized only one day after pericenter, and we follow the evolution of the returning debris for a total of 5×105 seconds (about one week). Our hydrodynamical simulations were performed in a module written ...
Is there a Supermassive Black Hole at the Center of the Milky Way?
... Very strong sources of radio waves were discovered in the early years of radio astronomy. Accurate positions of these sources revealed that they were often centered on distant galaxies. In the 1950s, radio interferometers revealed a totally unexpected picture of these “radio galaxies.” The radio wav ...
... Very strong sources of radio waves were discovered in the early years of radio astronomy. Accurate positions of these sources revealed that they were often centered on distant galaxies. In the 1950s, radio interferometers revealed a totally unexpected picture of these “radio galaxies.” The radio wav ...
Review: How does a star`s mass determine its life story?
... • Some massive star supernovae can make a black hole if enough mass falls onto core. © 2010 Pearson Education, Inc. ...
... • Some massive star supernovae can make a black hole if enough mass falls onto core. © 2010 Pearson Education, Inc. ...
The fate of black hole singularities and the parameters of the
... Thus, the statement ∗ follows from the postulates we have made concerning the fates of stars that collapse to black holes. We may note that this theory is much stronger than any version of the anthropic principle[6, 4, 5] because it conjectures the existence of an actual ensemble of universes that ...
... Thus, the statement ∗ follows from the postulates we have made concerning the fates of stars that collapse to black holes. We may note that this theory is much stronger than any version of the anthropic principle[6, 4, 5] because it conjectures the existence of an actual ensemble of universes that ...
Roche accretion of stars close to massive black holes
... The gas flowing through L1 will generally have enough angular momentum to form a torus orbiting the hole. A hotspot will be formed where the stream hits the disc. In addition, it is quite possible that one or two spiral arm shock waves will be created in the disc. The hotspot and shocks will orbit t ...
... The gas flowing through L1 will generally have enough angular momentum to form a torus orbiting the hole. A hotspot will be formed where the stream hits the disc. In addition, it is quite possible that one or two spiral arm shock waves will be created in the disc. The hotspot and shocks will orbit t ...
Natasha Wood
... more edge-on view with respect to the accretion disk. If this is the case the reflection component (X-ray emission from the hot corona) which is scattered by the accretion disk or the inside walls of the molecular torus should be more intense in Sy1 than in Sy2. Furthermore, the X-ray spectrum measu ...
... more edge-on view with respect to the accretion disk. If this is the case the reflection component (X-ray emission from the hot corona) which is scattered by the accretion disk or the inside walls of the molecular torus should be more intense in Sy1 than in Sy2. Furthermore, the X-ray spectrum measu ...
Galaxies have different sizes and shapes.
... the Milky Way galaxy. The Sun lies within a galaxy called the Milky Way. Remember that a galaxy is a huge grouping of stars, gas, and dust held together by gravity. Without a telescope, you can only see nearby stars clearly. Those stars are a tiny fraction of the several hundred billion in the Milky ...
... the Milky Way galaxy. The Sun lies within a galaxy called the Milky Way. Remember that a galaxy is a huge grouping of stars, gas, and dust held together by gravity. Without a telescope, you can only see nearby stars clearly. Those stars are a tiny fraction of the several hundred billion in the Milky ...
Transport and percolation in a low-density high
... an insulating state, but rather, the conductivity displays a linear dependence on temperature (i.e. ρ ∝ T −1 ) in the T = 50 − 450 mK range [19]. In this regime of low density, the Fermi temperature is as low as TF ∼ 250mK. The impact of carrier degeneracy and the temperature dependence of ionized i ...
... an insulating state, but rather, the conductivity displays a linear dependence on temperature (i.e. ρ ∝ T −1 ) in the T = 50 − 450 mK range [19]. In this regime of low density, the Fermi temperature is as low as TF ∼ 250mK. The impact of carrier degeneracy and the temperature dependence of ionized i ...
Exciton polarizability in semiconductor nanocrystals
... been examined using Stark shift measurements13–15 . It is desirable to have a direct experimental determination of the polarizability— ...
... been examined using Stark shift measurements13–15 . It is desirable to have a direct experimental determination of the polarizability— ...
Black Hole Formation and Classicalization in
... completion is accomplished by means √ of collective states composed of a large number N ∼ s/MP of soft gravitons of wavelength R ∼ N LP [3] that, in the mean-field approximation, recover the semi-classical behavior of macroscopic black holes [4]. To put it shortly, classicalization replaces the hard ...
... completion is accomplished by means √ of collective states composed of a large number N ∼ s/MP of soft gravitons of wavelength R ∼ N LP [3] that, in the mean-field approximation, recover the semi-classical behavior of macroscopic black holes [4]. To put it shortly, classicalization replaces the hard ...
The basic concepts and properties of black holes in general relativity
... source is given by the Schwarzschild metric. In other words, describes the spacetime in the exterior of any spherical symmetric body of mass M. [Side note: This theorem holds even if the metric is time varying, as long as the variations are spherically symmetric (though details are more complicated) ...
... source is given by the Schwarzschild metric. In other words, describes the spacetime in the exterior of any spherical symmetric body of mass M. [Side note: This theorem holds even if the metric is time varying, as long as the variations are spherically symmetric (though details are more complicated) ...
Lectures on Quantum Gravity and Black Holes
... In D > 2, this term is not renormalizable. This means that the theory is strongly coupled at the Planck scale. If we try to compute scattering amplitudes using Feynman diagrams, we would find non-sensical, non-unitary answers for E & MP . The rules of effective field theory tell us that we must incl ...
... In D > 2, this term is not renormalizable. This means that the theory is strongly coupled at the Planck scale. If we try to compute scattering amplitudes using Feynman diagrams, we would find non-sensical, non-unitary answers for E & MP . The rules of effective field theory tell us that we must incl ...
The Formation and Evolution of Massive Black Holes - Ira-Inaf
... produce a very massive star of up to a few thousand M⊙ before the first supernovae explode. When heavy elements are still rare, just about when the second generation of stars occurs, the final fate of a very massive star is to collapse into a black hole with a mass similar to that of its progenitor. ...
... produce a very massive star of up to a few thousand M⊙ before the first supernovae explode. When heavy elements are still rare, just about when the second generation of stars occurs, the final fate of a very massive star is to collapse into a black hole with a mass similar to that of its progenitor. ...
Controlled Stark shifts in Er -doped crystalline and amorphous
... optical fiber. Our results confirm the potential of erbiumdoped waveguides for CRIB-based data storage. In the presence of an external DC electric field, the energy levels of an atom with a permanent dipole moment are shifted; this phenomenon is known as the linear DC Stark effect. If the dipole moments ...
... optical fiber. Our results confirm the potential of erbiumdoped waveguides for CRIB-based data storage. In the presence of an external DC electric field, the energy levels of an atom with a permanent dipole moment are shifted; this phenomenon is known as the linear DC Stark effect. If the dipole moments ...
Lu_Ye
... Main features of GRB060614 A long GRB with duration of 102 s A low red shift of z=0.125, and not associated with any supernova Interesting substructures: the light curve of BAT reveals a first short episode of emission (lasting 4s) followed by an extended and some softer episode (lasting 100s) ...
... Main features of GRB060614 A long GRB with duration of 102 s A low red shift of z=0.125, and not associated with any supernova Interesting substructures: the light curve of BAT reveals a first short episode of emission (lasting 4s) followed by an extended and some softer episode (lasting 100s) ...
Fundamentals of Blackbody Radiation
... low frequencies (i.e. hν/kB T 1). An example of Planck’s radiation formula is shown in Fig. 3 along with Rayleigh-Jeans and Wien’s approximations for a blackbody of absolute temperature T = 6000◦ K. Having obtained his formula Planck was concerned to discover its physical basis. It was hard to arg ...
... low frequencies (i.e. hν/kB T 1). An example of Planck’s radiation formula is shown in Fig. 3 along with Rayleigh-Jeans and Wien’s approximations for a blackbody of absolute temperature T = 6000◦ K. Having obtained his formula Planck was concerned to discover its physical basis. It was hard to arg ...
Electric fields and quantum wormholes
... the entanglement of quantum fields. In the AdS/CFT context, there appears to be a precise holographic sense in which a classical geometry is “emergent” from quantum entanglement in a dual field theory (see e.g. [1–10]). Recently, Maldacena and Susskind have made a stronger statement: that the link b ...
... the entanglement of quantum fields. In the AdS/CFT context, there appears to be a precise holographic sense in which a classical geometry is “emergent” from quantum entanglement in a dual field theory (see e.g. [1–10]). Recently, Maldacena and Susskind have made a stronger statement: that the link b ...
Active Galactic Nuclei
... 3. The brightness will not change in less than 10 days. 4. The brightness will not change in less than 100 days. ...
... 3. The brightness will not change in less than 10 days. 4. The brightness will not change in less than 100 days. ...
Causal Sets: Discrete Gravity (Notes for the Valdivia Summer School)
... With the subsequent development of physics, more compelling reasons emerged for questioning the continuum, including the singularities and infinities of General Relativity, of Quantum Field Theory (including the standard model), and of black hole thermodynamics. Einstein, for example, voiced doubts ...
... With the subsequent development of physics, more compelling reasons emerged for questioning the continuum, including the singularities and infinities of General Relativity, of Quantum Field Theory (including the standard model), and of black hole thermodynamics. Einstein, for example, voiced doubts ...
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.