High Energy Emission From Pulsar Wind Nebulae • What`s new in
... • We apply the model for acceleration of leptons in resonant interactions with the iron nuclei injected by the pulsar (see e.g. Hoshino et al. 1992; Gallant & Arons 1994). • From normalization to the observations of the Crab pulsar, Arons (1998) postulates that the Lorentz factors of iron nuclei in ...
... • We apply the model for acceleration of leptons in resonant interactions with the iron nuclei injected by the pulsar (see e.g. Hoshino et al. 1992; Gallant & Arons 1994). • From normalization to the observations of the Crab pulsar, Arons (1998) postulates that the Lorentz factors of iron nuclei in ...
The energy spectrum of cosmic electrons measured with the MAGIC
... of up to 93 billion light years. However, not all cosmic rays are equally likely to reach the Earth from such distances. In particular the cosmic electrons on which this thesis will focus, reach Earth from much smaller distances. This is due to the strong energy losses they undergo in the magnetic f ...
... of up to 93 billion light years. However, not all cosmic rays are equally likely to reach the Earth from such distances. In particular the cosmic electrons on which this thesis will focus, reach Earth from much smaller distances. This is due to the strong energy losses they undergo in the magnetic f ...
Comparison of atmospheric neutrino flux calculations at low energies
... three-dimensional version of the model of hadronic interactions from BGS. LK also use the same primary spectrum as used by BGS. We have discovered several bugs in the implementation of the LK code. When these are removed, the results of LK are essentially the same as those of BGS in the absence of a ...
... three-dimensional version of the model of hadronic interactions from BGS. LK also use the same primary spectrum as used by BGS. We have discovered several bugs in the implementation of the LK code. When these are removed, the results of LK are essentially the same as those of BGS in the absence of a ...
The hot, early universe - Cosmology Block
... You will calculate some reaction numbers (photon colliding with atom, or with nucleus) in the exercises today. Collision rates will not be a problem — as long as the photons carry sufficient energy to trigger a reaction (ionization, splitting a nucleus...)! ...
... You will calculate some reaction numbers (photon colliding with atom, or with nucleus) in the exercises today. Collision rates will not be a problem — as long as the photons carry sufficient energy to trigger a reaction (ionization, splitting a nucleus...)! ...
J.J. Thomson, Philos. Mag. 44, 293 Cathode Rays. J.J. Thomson
... An objection very generally urged against the view that the cathode rays are negatively electrified particles, is that hitherto no deflexion of the rays has been observed under a small electrostatic force, and though the rays are deflected when they pass near electrodes connected with sources of lar ...
... An objection very generally urged against the view that the cathode rays are negatively electrified particles, is that hitherto no deflexion of the rays has been observed under a small electrostatic force, and though the rays are deflected when they pass near electrodes connected with sources of lar ...
Universitat Autònoma de Barcelona Observing the VHE Gamma Ray Sky
... rays could initiate showers of secondary charged particles, both in cloud chambers and in the atmosphere: in 1938 Pierre Auger using a number of separated detectors discovered (Auger et al., 1938) that some of these air showers could extend over hundreds of meters on the ground and contained million ...
... rays could initiate showers of secondary charged particles, both in cloud chambers and in the atmosphere: in 1938 Pierre Auger using a number of separated detectors discovered (Auger et al., 1938) that some of these air showers could extend over hundreds of meters on the ground and contained million ...
natural gamma ray logs
... electromagnetic wave similar to visible light or X-rays, or as a particle or photon. Gamma rays are electromagnetic radiations emitted from an atomic nucleus during radioactive decay. These radiations are characterized by wave lengths in the range of 1 0 -9 - 1 0 -11 cm, equivalent to frequencies ra ...
... electromagnetic wave similar to visible light or X-rays, or as a particle or photon. Gamma rays are electromagnetic radiations emitted from an atomic nucleus during radioactive decay. These radiations are characterized by wave lengths in the range of 1 0 -9 - 1 0 -11 cm, equivalent to frequencies ra ...
J. J. Thomson (1856
... of German physicists they are due to some process in the aether to which--inasmuch as in a uniform magnetic field their course is circular and not rectilinear--no phenomenon hitherto observed is analogous: another view of these rays is that, so far from being wholly aetherial, they are in fact wholl ...
... of German physicists they are due to some process in the aether to which--inasmuch as in a uniform magnetic field their course is circular and not rectilinear--no phenomenon hitherto observed is analogous: another view of these rays is that, so far from being wholly aetherial, they are in fact wholl ...
Breaks in gamma-ray spectra of distant blazars and transparency of
... absorption. Since the bulk of the data they used correspond to the energies for which the opacity is low, this effect was seen in stacked samples only. This result does not contradict to ours because it does not exclude the opacity below the lowest model and even favours it for high energies, cf. Fi ...
... absorption. Since the bulk of the data they used correspond to the energies for which the opacity is low, this effect was seen in stacked samples only. This result does not contradict to ours because it does not exclude the opacity below the lowest model and even favours it for high energies, cf. Fi ...
The history of a discovery - Institut d`Astrophysique Spatiale
... • the heavy elements (and associated dust) abundance in the universe is increasing with time • a naïve view would thus predict a decreasing FIR/visible ratio with redshift • a few galaxies had been shown to have a large ratio but the bulk of the galaxies were expected to have rather small one (a few ...
... • the heavy elements (and associated dust) abundance in the universe is increasing with time • a naïve view would thus predict a decreasing FIR/visible ratio with redshift • a few galaxies had been shown to have a large ratio but the bulk of the galaxies were expected to have rather small one (a few ...
Review of the Safety of LHC Collisions
... have looked for heavily-ionizing particles as well as for quanta of magnetic charge, and this search will be continued at the LHC. In some grand unified theories, though not in the Standard Model of particle physics, magnetic monopoles might also catalyze nucleon decay, by transforming protons and n ...
... have looked for heavily-ionizing particles as well as for quanta of magnetic charge, and this search will be continued at the LHC. In some grand unified theories, though not in the Standard Model of particle physics, magnetic monopoles might also catalyze nucleon decay, by transforming protons and n ...
Cosmic Strings - University of Amsterdam
... transitions. Topological defects can occur when the field symmetries are broken. This means that the ground state does not exhibit the same symmetry as the full theory. Symmetry breaking happens when the universe cools down below some critical temperature Tc and the field is forced to choose a vacuu ...
... transitions. Topological defects can occur when the field symmetries are broken. This means that the ground state does not exhibit the same symmetry as the full theory. Symmetry breaking happens when the universe cools down below some critical temperature Tc and the field is forced to choose a vacuu ...
Matter and antimatter in the same universe?
... i) the observable universe would be the evolution, through the inflationary expansion, of a ~,bubble- that, by means of a quantum fluctuation, would have traversed the energetic barrier between the ,,false vacuum,~ region of the symmetric era to the real vacuum region of the broken symmetry era and ...
... i) the observable universe would be the evolution, through the inflationary expansion, of a ~,bubble- that, by means of a quantum fluctuation, would have traversed the energetic barrier between the ,,false vacuum,~ region of the symmetric era to the real vacuum region of the broken symmetry era and ...
Comparing an Analytical Cascade Spectrum of High Energy Gamma
... can produce photons in several ways: bremsstrahlung in the ambient medium, synchrotron radiation in local magnetic fields or through inverse Compton scattering. In all cases, electrons transfer a sizeable portion of their energy to a photon which could emerge as a gamma ray. So while cosmic accelera ...
... can produce photons in several ways: bremsstrahlung in the ambient medium, synchrotron radiation in local magnetic fields or through inverse Compton scattering. In all cases, electrons transfer a sizeable portion of their energy to a photon which could emerge as a gamma ray. So while cosmic accelera ...
Abstract - Istituto Nazionale di Fisica Nucleare
... particle can reenter back with higher probability because will remain closer to the border of heliosphere. We can see same results for increasing the value of with fixed interstellar magnetic field B that increases the particle mean free path and decreases the number of reentrant particles in the mo ...
... particle can reenter back with higher probability because will remain closer to the border of heliosphere. We can see same results for increasing the value of with fixed interstellar magnetic field B that increases the particle mean free path and decreases the number of reentrant particles in the mo ...
FINAL PROGRAM - Drifting through the Cosmic Web
... (Poster) Weak Lensing Signatures of the Connexion between Massive Dark Matter Halos and the Cosmic Web ...
... (Poster) Weak Lensing Signatures of the Connexion between Massive Dark Matter Halos and the Cosmic Web ...
T. Thompson, Jan 2007
... • Starbursts: what is the role of the secondary electron/positrons? • Backgrounds: neutrino (MeV to >TeV), -ray, FIR, & radio. • What is the energy density of cosmic rays in starburst galaxies? ...
... • Starbursts: what is the role of the secondary electron/positrons? • Backgrounds: neutrino (MeV to >TeV), -ray, FIR, & radio. • What is the energy density of cosmic rays in starburst galaxies? ...
On the 1932 Discovery of the Positron
... renowned physicist Robert A. Millikan at Caltech, working with a colleague. Using an unmanned balloon they were able to conduct measurements of the ionization at a height of 15 000 m. Even though the measurements were conducted at a higher altitude than the measurements of Hess, the intensity of the ...
... renowned physicist Robert A. Millikan at Caltech, working with a colleague. Using an unmanned balloon they were able to conduct measurements of the ionization at a height of 15 000 m. Even though the measurements were conducted at a higher altitude than the measurements of Hess, the intensity of the ...
Fulltext PDF - Indian Academy of Sciences
... can be understood as follows. A pair of neighbouring rays cross at a point, but this point itself changes as we consider different rays, unlike the case of perfect focusing. The set of these ‘foci’ is a curve which is tangent to these rays, and is called a ‘caustic’. The same word is used for chemic ...
... can be understood as follows. A pair of neighbouring rays cross at a point, but this point itself changes as we consider different rays, unlike the case of perfect focusing. The set of these ‘foci’ is a curve which is tangent to these rays, and is called a ‘caustic’. The same word is used for chemic ...
Thomson first investigated the magnetic deflection
... Experiment to measure the mass to charge ratio of cathode rays In his classic experiment, Thomson measured the mass-to-charge ratio of the cathode rays by measuring how much they were deflected by a magnetic field and comparing this with the electric deflection. He used the same apparatus as in his ...
... Experiment to measure the mass to charge ratio of cathode rays In his classic experiment, Thomson measured the mass-to-charge ratio of the cathode rays by measuring how much they were deflected by a magnetic field and comparing this with the electric deflection. He used the same apparatus as in his ...
galactic cosmic radiation and solar energetic particles
... as the inverse of the solar sunspot number cycle. This is discussed more fully in Section 6.2.2.1. The isotropic flux exposure to galactic cosmic radiation in space at sunspot minimum is - 4 protons cm 2 s' resulting in a yearly integrated exposure of - 1.3 x 108 protons/cm2. The isotropic flux expo ...
... as the inverse of the solar sunspot number cycle. This is discussed more fully in Section 6.2.2.1. The isotropic flux exposure to galactic cosmic radiation in space at sunspot minimum is - 4 protons cm 2 s' resulting in a yearly integrated exposure of - 1.3 x 108 protons/cm2. The isotropic flux expo ...
Diffuse TeV Emission from the Galactic Center
... Flares occur on average once per day Average L ~ 1035 ergs s-1, but last for a few thousand seconds. The constant luminosity of IGR J17456-2901 cannot result from successive flares ...
... Flares occur on average once per day Average L ~ 1035 ergs s-1, but last for a few thousand seconds. The constant luminosity of IGR J17456-2901 cannot result from successive flares ...
Chapter V Conclusions Radioactive isotopes
... Accurate measurement of radioisotope activity coupled with information on shapes, sizes and shielding depths in meteorite bodies provides the starting point for such an approach. The main results and conclusions arrived from the work on these three topics are described below. !\. Average SCR paramet ...
... Accurate measurement of radioisotope activity coupled with information on shapes, sizes and shielding depths in meteorite bodies provides the starting point for such an approach. The main results and conclusions arrived from the work on these three topics are described below. !\. Average SCR paramet ...
Diffusion of cosmic rays at EeV energies in
... The discovery of cosmic rays dates back to the early 1910s. It is remarkable that the cosmic ray spectrum spans almost twelve orders of magnitude, from ∼ 109 eV to ∼ 1021 . Today, more than one century after the first observations of these particles, there are several aspects not fully understood, e ...
... The discovery of cosmic rays dates back to the early 1910s. It is remarkable that the cosmic ray spectrum spans almost twelve orders of magnitude, from ∼ 109 eV to ∼ 1021 . Today, more than one century after the first observations of these particles, there are several aspects not fully understood, e ...
Cosmic ray
Cosmic rays are immensely high-energy radiation, mainly originating outside the Solar System. They may produce showers of secondary particles that penetrate and impact the Earth's atmosphere and sometimes even reach the surface. Composed primarily of high-energy protons and atomic nuclei, they are of mysterious origin. Data from the Fermi space telescope (2013) has been interpreted as evidence that a significant fraction of primary cosmic rays originate from the supernovae of massive stars. However, this is not thought to be their only source. Active galactic nuclei probably also produce cosmic rays.The term ray is a historical accident, as cosmic rays were at first, and wrongly, thought to be mostly electromagnetic radiation. In common scientific usage high-energy particles with intrinsic mass are known as ""cosmic"" rays, and photons, which are quanta of electromagnetic radiation (and so have no intrinsic mass) are known by their common names, such as ""gamma rays"" or ""X-rays"", depending on their origin.Cosmic rays attract great interest practically, due to the damage they inflict on microelectronics and life outside the protection of an atmosphere and magnetic field, and scientifically, because the energies of the most energetic ultra-high-energy cosmic rays (UHECRs) have been observed to approach 3 × 1020 eV, about 40 million times the energy of particles accelerated by the Large Hadron Collider. One can show that such enormous energies might be achieved by means of the Centrifugal mechanism of acceleration in Active galactic nuclei. At 50 J, the highest-energy ultra-high-energy cosmic rays have energies comparable to the kinetic energy of a 90-kilometre-per-hour (56 mph) baseball. As a result of these discoveries, there has been interest in investigating cosmic rays of even greater energies. Most cosmic rays, however, do not have such extreme energies; the energy distribution of cosmic rays peaks at 0.3 gigaelectronvolts (4.8×10−11 J).Of primary cosmic rays, which originate outside of Earth's atmosphere, about 99% are the nuclei (stripped of their electron shells) of well-known atoms, and about 1% are solitary electrons (similar to beta particles). Of the nuclei, about 90% are simple protons, i. e. hydrogen nuclei; 9% are alpha particles, and 1% are the nuclei of heavier elements, called HZE ions. A very small fraction are stable particles of antimatter, such as positrons or antiprotons. The precise nature of this remaining fraction is an area of active research. An active search from Earth orbit for anti-alpha particles has failed to detect them.