Black holes - Institute of Physics
... the intricacies of how these processes work. By matching X-ray data to theoretical models, Chris Done at Durham University studies the ebb and flow of accretion. Such studies provide a fine probe of black-hole behaviour. It is possible to distinguish between a black hole and a neutron star in an acc ...
... the intricacies of how these processes work. By matching X-ray data to theoretical models, Chris Done at Durham University studies the ebb and flow of accretion. Such studies provide a fine probe of black-hole behaviour. It is possible to distinguish between a black hole and a neutron star in an acc ...
Mysterious transient objects - NCRA
... Flashes of gamma-rays from random directions in sky Few milliseconds to few seconds timescale Even 100 times more energetic than supernovae Brightest sources of cosmic gamma-ray photons in the universe In universe roughly 1 GRB is detected per day Short duration (< 2 sec) and long duration (> ...
... Flashes of gamma-rays from random directions in sky Few milliseconds to few seconds timescale Even 100 times more energetic than supernovae Brightest sources of cosmic gamma-ray photons in the universe In universe roughly 1 GRB is detected per day Short duration (< 2 sec) and long duration (> ...
Hidden Markov model tracking of continuous gravitational waves
... Hidden Markov model (HMM) methods offer one powerful strategy for detecting and tracking a wandering frequency [45]. The essential idea is to model f? (t) probabilistically as a Markov chain of transitions between unobservable (“hidden”) frequency states and relate the hidden states to the observed ...
... Hidden Markov model (HMM) methods offer one powerful strategy for detecting and tracking a wandering frequency [45]. The essential idea is to model f? (t) probabilistically as a Markov chain of transitions between unobservable (“hidden”) frequency states and relate the hidden states to the observed ...
Oscillating Universe like exact solution of the R2 theory of gravity
... the accelerated expansion of the Universe, which is observed today, implies that cosmological dynamics is dominated by the so called Dark Energy, which gives a large negative pressure. This is the standard picture, in which this new ingredient is considered as a source on the right-hand side of the ...
... the accelerated expansion of the Universe, which is observed today, implies that cosmological dynamics is dominated by the so called Dark Energy, which gives a large negative pressure. This is the standard picture, in which this new ingredient is considered as a source on the right-hand side of the ...
Waves EM Maxwell Eqn
... 1. No information can propagate instantaneously 2. The electric field at the time t is determined by the position of the charge at an earlier time, when the charge was at r’, the retarded position. ...
... 1. No information can propagate instantaneously 2. The electric field at the time t is determined by the position of the charge at an earlier time, when the charge was at r’, the retarded position. ...
Compton scattering in strong gravity
... simply as a function of radius and total optical depth. r0 is the radius of the wind base, that is of the black hole horizon in our case, r0 = 2M. Photons are scattered in the wind, but we assume that after 10 such events the photon is lost (it is likely to be absorbed by an ion). To illustrate the ...
... simply as a function of radius and total optical depth. r0 is the radius of the wind base, that is of the black hole horizon in our case, r0 = 2M. Photons are scattered in the wind, but we assume that after 10 such events the photon is lost (it is likely to be absorbed by an ion). To illustrate the ...
Plane Electromagnetic Wave
... practice as creation of such waves are possible with sources of infinite extent. However, at large distances from the source, the wavefront or the surface of the constant phase becomes almost spherical and a small portion of this large sphere can be considered to plane. The characteristics of plane ...
... practice as creation of such waves are possible with sources of infinite extent. However, at large distances from the source, the wavefront or the surface of the constant phase becomes almost spherical and a small portion of this large sphere can be considered to plane. The characteristics of plane ...
Document
... The Pauli exclusion principle makes it energetically favorable for a system of nucleons to have approximately equal number of protons and neutrons. In neutron stars, there is a significant difference between the neutron and proton fraction and this costs energy. This interaction energy is usually ad ...
... The Pauli exclusion principle makes it energetically favorable for a system of nucleons to have approximately equal number of protons and neutrons. In neutron stars, there is a significant difference between the neutron and proton fraction and this costs energy. This interaction energy is usually ad ...
Study of Space by the Electromagnetic Spectrum
... beam of light could travel from New York to Los Angeles and back again nearly 40 times in just one second. Even at that amazing rate, objects in space are so far away that it takes a lot of time for their light to reach us. Even light from the nearest star, our sun, takes about eight minutes to reac ...
... beam of light could travel from New York to Los Angeles and back again nearly 40 times in just one second. Even at that amazing rate, objects in space are so far away that it takes a lot of time for their light to reach us. Even light from the nearest star, our sun, takes about eight minutes to reac ...
Schwarzschild geometry and black holes
... small size, of order a few kilometers, so that to them the calculation was nothing more than an amusing speculation. Today this is far more than an amusing speculation: objects of this size that trap light are being discovered all over the universe, with masses ranging from a few solar masses up to ...
... small size, of order a few kilometers, so that to them the calculation was nothing more than an amusing speculation. Today this is far more than an amusing speculation: objects of this size that trap light are being discovered all over the universe, with masses ranging from a few solar masses up to ...
Dark Matter
... Which of the following statements is incorrect? a) The mass of a galaxy can be measured from its rotation curve. b) More than 90% of the mass of the universe is dark matter c) When Milky Way & Andromeda Galaxy merge, GMC (Giant Molecular Clouds) will collide & lots of new stars will form d) Gal ...
... Which of the following statements is incorrect? a) The mass of a galaxy can be measured from its rotation curve. b) More than 90% of the mass of the universe is dark matter c) When Milky Way & Andromeda Galaxy merge, GMC (Giant Molecular Clouds) will collide & lots of new stars will form d) Gal ...
A minimum column density of 1gcm(
... balance between cosmic-ray heating and molecular and dust cooling. We are interested in the earliest stages of cloud collapse, so we adopt kr 5 1. This puts most of the mass at low density, and is expected if clouds are in rough hydrostatic balance and obey the observed linewidth–size relation12 s / ...
... balance between cosmic-ray heating and molecular and dust cooling. We are interested in the earliest stages of cloud collapse, so we adopt kr 5 1. This puts most of the mass at low density, and is expected if clouds are in rough hydrostatic balance and obey the observed linewidth–size relation12 s / ...
Particle acceleration in superluminal strong waves
... shock of the pulsar wind nebulae. One is the injection problem. In general, to be injected into the shock crossing cycle, the particles have to be supra-thermal when they encounter the shock front. However, in the paper of Kennel & Coroniti (1984a), upstream plasma is assumed to be cold and all part ...
... shock of the pulsar wind nebulae. One is the injection problem. In general, to be injected into the shock crossing cycle, the particles have to be supra-thermal when they encounter the shock front. However, in the paper of Kennel & Coroniti (1984a), upstream plasma is assumed to be cold and all part ...
Notes 26
... 32.22) A sinusoidal electromagnetic wave emitted by a cell phone has a wavelength of 35.4 cm and an electric field amplitude of 5.4 x 10-2 V/m at a distance of 250 m from the antenna. (a) What is the magnetic field amplitude? (b) The intensity? (C) The total average power? ...
... 32.22) A sinusoidal electromagnetic wave emitted by a cell phone has a wavelength of 35.4 cm and an electric field amplitude of 5.4 x 10-2 V/m at a distance of 250 m from the antenna. (a) What is the magnetic field amplitude? (b) The intensity? (C) The total average power? ...
Abstract Non-relativistic Quantum Theory fairly accurately describes
... star. If the star is large enough the heat produced from the collapse will cause protons and electrons to combine into neutrons. Since these neutrons are uncharged, they are able to form a very dense object at the center of the collapse. The neutrons are held apart from one another by degeneracy pre ...
... star. If the star is large enough the heat produced from the collapse will cause protons and electrons to combine into neutrons. Since these neutrons are uncharged, they are able to form a very dense object at the center of the collapse. The neutrons are held apart from one another by degeneracy pre ...
1/2 - Indico
... Big-Bang theory Standard Big-Bang model basic physics: If the recessional velocity of every galaxy remained unchanged through all time, any galaxy now receding from us was once arbitrarily close and the time that has elapsed since then is equal to the ratio of galaxy’s distance and its velocity. Si ...
... Big-Bang theory Standard Big-Bang model basic physics: If the recessional velocity of every galaxy remained unchanged through all time, any galaxy now receding from us was once arbitrarily close and the time that has elapsed since then is equal to the ratio of galaxy’s distance and its velocity. Si ...
11 Solar Masses
... What about rotation? In a calculation that included current approximations to all known mechanisms of angular momentum transport in the study, the final angular momentum in the iron core of the 10 solar mass star when it collapsed was 7 x 1047 erg s This corresponds to a pulsar period of 11 ms, abo ...
... What about rotation? In a calculation that included current approximations to all known mechanisms of angular momentum transport in the study, the final angular momentum in the iron core of the 10 solar mass star when it collapsed was 7 x 1047 erg s This corresponds to a pulsar period of 11 ms, abo ...