Section IV High-Energy Astrophysics and Cosmology
... delay between continuum and emission line variations. Determination of the f value is strongly depending on accepted BLR model. Labita et al. [3] found that the model of an isotope BLR fails to reproduce the observed line widths and shapes. They claimed that a disk model is preferred. A disk-like ge ...
... delay between continuum and emission line variations. Determination of the f value is strongly depending on accepted BLR model. Labita et al. [3] found that the model of an isotope BLR fails to reproduce the observed line widths and shapes. They claimed that a disk model is preferred. A disk-like ge ...
Results from the ANTARES Neutrino Telescope Giorgio Giacomelli
... that distributes power and data from/to shore. The instrumented part of each line starts at 100 m above the sea floor, so that Cherenkov light can be seen also from upgoing muons coming from neutrino interactions in the rock below the sea or in the sea water beneath the PMTs. The three dimensional s ...
... that distributes power and data from/to shore. The instrumented part of each line starts at 100 m above the sea floor, so that Cherenkov light can be seen also from upgoing muons coming from neutrino interactions in the rock below the sea or in the sea water beneath the PMTs. The three dimensional s ...
galactic cosmic radiation and solar energetic particles
... intensity is reached around a few hundred MeV/nucleon. Below the maximum, the differential intensity decreases monotonically to a few tens of MeV/nucleon. The primary cosmic radiation spectrum observed for protons and alpha particles in the inner heliosphere around the earth's orbit is shown in Figu ...
... intensity is reached around a few hundred MeV/nucleon. Below the maximum, the differential intensity decreases monotonically to a few tens of MeV/nucleon. The primary cosmic radiation spectrum observed for protons and alpha particles in the inner heliosphere around the earth's orbit is shown in Figu ...
Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Cosmology
... (Page et al. 2006), these degeneracies are now broken (see §3). However, more general models, most notably those with non-flat cosmologies and with richer dark energy or matter content, have strong parameter degeneracies. For models with adiabatic fluctuations, the WMAP data constrains the ratio of th ...
... (Page et al. 2006), these degeneracies are now broken (see §3). However, more general models, most notably those with non-flat cosmologies and with richer dark energy or matter content, have strong parameter degeneracies. For models with adiabatic fluctuations, the WMAP data constrains the ratio of th ...
Cosmological Implications of Trace
... hypothesis will be shown to lead to simple conventional physics explanations for effects commonly attributed to unconventional forms of dark energy or dark matter, often called ΛCDM . For example, the strong jetting observed in AGNs can be created if matter ionizes near the event horizon of a positi ...
... hypothesis will be shown to lead to simple conventional physics explanations for effects commonly attributed to unconventional forms of dark energy or dark matter, often called ΛCDM . For example, the strong jetting observed in AGNs can be created if matter ionizes near the event horizon of a positi ...
A galaxy rapidly forming stars 700 million years after the Big Bang at
... indicate that it is the progenitor of some of the most massive systems in the high-redshift Universe. However, the z 5 7.213 galaxy GN 108036 (ref. 3), also in the GOODS-North field, also has an implied SFR . 100 M[. Although the current statistics are poor, the presence of these two galaxies in a r ...
... indicate that it is the progenitor of some of the most massive systems in the high-redshift Universe. However, the z 5 7.213 galaxy GN 108036 (ref. 3), also in the GOODS-North field, also has an implied SFR . 100 M[. Although the current statistics are poor, the presence of these two galaxies in a r ...
Science Book - Chapter 1: Introduction
... LSST will produce a massive and exquisitely accurate photometric and astrometric data set. Compared to SDSS, the best currently available optical survey, LSST will cover an area more than twice as large, using hundreds of observations of the same region in a given filter instead of one or two, and e ...
... LSST will produce a massive and exquisitely accurate photometric and astrometric data set. Compared to SDSS, the best currently available optical survey, LSST will cover an area more than twice as large, using hundreds of observations of the same region in a given filter instead of one or two, and e ...
LIGO SURF 2006 Lecture 1 - Indico
... Quasar image appears around the central glow formed by nearby galaxy. Such gravitational lensing images are used to detect a ‘dark matter’ body as the central object ...
... Quasar image appears around the central glow formed by nearby galaxy. Such gravitational lensing images are used to detect a ‘dark matter’ body as the central object ...
Georges Lemaître, The beginning of the world from
... to the growth of the entropy. In the direction of increasing time, the universe evolves to a state of infinite entropy, i.e. of complete disorganization. In the direction of the past, the universe would have proceeded from a state of zero entropy. Eddington had wondered whether the moment of zero en ...
... to the growth of the entropy. In the direction of increasing time, the universe evolves to a state of infinite entropy, i.e. of complete disorganization. In the direction of the past, the universe would have proceeded from a state of zero entropy. Eddington had wondered whether the moment of zero en ...
Axion thermalization in the early universe
... since it is different for different PQ-charge assignments to the matter fields. Given this model dependence, we do not include them in our analysis. They would lead to an increase of the numerical value in Eq. 共39兲 by a factor of ⬃2 and consequently would make the range of F a in Eq. 共41兲 larger by ...
... since it is different for different PQ-charge assignments to the matter fields. Given this model dependence, we do not include them in our analysis. They would lead to an increase of the numerical value in Eq. 共39兲 by a factor of ⬃2 and consequently would make the range of F a in Eq. 共41兲 larger by ...
Introduction to Cosmology - Experimental Elementary Particle
... year is approximately equal to 3.2 × 107 s. In cosmological context, a year is frequently an inconveniently short period of time, so cosmologists frequently use gigayears (Gyr), equal to 109 yr, or 3.2 × 1016 s. For example, the age of the Earth is more conveniently written as 4.6 Gyr than as 1.5 × ...
... year is approximately equal to 3.2 × 107 s. In cosmological context, a year is frequently an inconveniently short period of time, so cosmologists frequently use gigayears (Gyr), equal to 109 yr, or 3.2 × 1016 s. For example, the age of the Earth is more conveniently written as 4.6 Gyr than as 1.5 × ...
astro-ph/0311464 PDF
... IIA. How can the bucket be fixed as the universe rotates? By “fix” Mach did not mean “fix with respect to absolute space.” We assume that for Mach, a fixed bucket is one supported without friction and at rest with respect to the fixed stars before the universe is made to rotate. Whether the univers ...
... IIA. How can the bucket be fixed as the universe rotates? By “fix” Mach did not mean “fix with respect to absolute space.” We assume that for Mach, a fixed bucket is one supported without friction and at rest with respect to the fixed stars before the universe is made to rotate. Whether the univers ...
MOND
... and the mass inferred from the visible light. The standard solution to this ”missing matter problem” was to invoke the existence of some putative dark matter particles. But since none of the well motivated candidate particles have yet been detected, it is important not to reject credible alternative ...
... and the mass inferred from the visible light. The standard solution to this ”missing matter problem” was to invoke the existence of some putative dark matter particles. But since none of the well motivated candidate particles have yet been detected, it is important not to reject credible alternative ...
The energy spectrum of cosmic electrons measured with the MAGIC
... Introduction Cosmic rays give us the unique possibility to learn more about our universe at distances out of mankind’s reach. They travel close to the speed of light and can cover huge distances of up to 93 billion light years. However, not all cosmic rays are equally likely to reach the Earth from ...
... Introduction Cosmic rays give us the unique possibility to learn more about our universe at distances out of mankind’s reach. They travel close to the speed of light and can cover huge distances of up to 93 billion light years. However, not all cosmic rays are equally likely to reach the Earth from ...
On the physical basis of cosmic time - Philsci
... the Friedmann-Lemaı̂tre-Robertson-Walker (FLRW) metric, standardly taken to describe the present universe (at large scales), there seems to be no problem in extrapolating this time concept back to t = 0 or, at least, to the Planck time. However, this objection disregards that the FLRW metric is a ma ...
... the Friedmann-Lemaı̂tre-Robertson-Walker (FLRW) metric, standardly taken to describe the present universe (at large scales), there seems to be no problem in extrapolating this time concept back to t = 0 or, at least, to the Planck time. However, this objection disregards that the FLRW metric is a ma ...
Lyman Alpha Forest
... 1). It is the only direct observational evidence we have of the existence and properties of the general INTERGALACTIC MEDIUM, and, as we have reason to believe, of most of the baryonic matter contents of the universe. On its way to us the light of a bright, distant QSO passes through intervening int ...
... 1). It is the only direct observational evidence we have of the existence and properties of the general INTERGALACTIC MEDIUM, and, as we have reason to believe, of most of the baryonic matter contents of the universe. On its way to us the light of a bright, distant QSO passes through intervening int ...
matter and dark energy Gravitational lensing: a unique probe of dark
... gravitational lensing? Zwicky was correct that galaxies and galaxy clusters serve as more probable lenses than individual stars, but even so three factors seriously limit the visibility of lensed images. Firstly, it is useful to introduce the concept of optical depth τ in considering the probability ...
... gravitational lensing? Zwicky was correct that galaxies and galaxy clusters serve as more probable lenses than individual stars, but even so three factors seriously limit the visibility of lensed images. Firstly, it is useful to introduce the concept of optical depth τ in considering the probability ...
Early Star-Forming Galaxies and the Reionisation of the Universe
... forming galaxies is the Lyman α emission line at rest wavelength of 121.6nm, produced internally by gas heated by young stars. The observability of Lyman α emission is sensitive to the ionisation state of the IGM, as the observed line strength can be attenuated by intervening neutral hydrogen. The ...
... forming galaxies is the Lyman α emission line at rest wavelength of 121.6nm, produced internally by gas heated by young stars. The observability of Lyman α emission is sensitive to the ionisation state of the IGM, as the observed line strength can be attenuated by intervening neutral hydrogen. The ...
LIGO I - Indico
... GWs aren’t just a new band, they’re a new spectrum, with very different and complementary properties to EM waves. • Vibrations of space-time, not in space-time • Emitted by coherent motion of huge masses moving at near light-speed; not vibrations of electrons in atoms • Can’t be absorbed, scattered, ...
... GWs aren’t just a new band, they’re a new spectrum, with very different and complementary properties to EM waves. • Vibrations of space-time, not in space-time • Emitted by coherent motion of huge masses moving at near light-speed; not vibrations of electrons in atoms • Can’t be absorbed, scattered, ...
Life, gravity and the second law of thermodynamics
... top of the list is life’s requirement for free energy. Despite uncertainties in the temperature limits of life (< 130 ◦ C?), despite uncertainties in which solvent life can use (water?), despite uncertainties in its chemistry (carbon-based?)— extraterrestrial life, like terrestrial life, will need a ...
... top of the list is life’s requirement for free energy. Despite uncertainties in the temperature limits of life (< 130 ◦ C?), despite uncertainties in which solvent life can use (water?), despite uncertainties in its chemistry (carbon-based?)— extraterrestrial life, like terrestrial life, will need a ...
The Cosmos & the Bible
... The Solution to Olbers' Paradox • Analogous to question of how deep one must go into woods to see only tree trunks all around. • To have a dark sky, universe must not be deep enough to see only star surfaces in all directions. • Thus the universe is of finite age, or finite size, or average star den ...
... The Solution to Olbers' Paradox • Analogous to question of how deep one must go into woods to see only tree trunks all around. • To have a dark sky, universe must not be deep enough to see only star surfaces in all directions. • Thus the universe is of finite age, or finite size, or average star den ...
Spacetime is a manifold that is continuous and differentiable
... by ηµν = diag(−1, +1, +1, +1). For a Riemannian manifold all diagonal elements need to be positive. The signature (the sum of the diagonal elements) of the metric of spacetime is +2, and in our case we refer to the manifold as pseudo-Riemannian. Assume that we draw a coordinate system on the Earth’s ...
... by ηµν = diag(−1, +1, +1, +1). For a Riemannian manifold all diagonal elements need to be positive. The signature (the sum of the diagonal elements) of the metric of spacetime is +2, and in our case we refer to the manifold as pseudo-Riemannian. Assume that we draw a coordinate system on the Earth’s ...
Functions of the Gravitational Potential
... Put the average ground gravitational potential associated with the rest mass of the earth U E 6.24 107 (m / s)2 into formula (4.37) to get a constant speed: VE 20376 m / s which will be interpreted as the speed of a flux associated with the cosmic gravitational field in section 5. If the grav ...
... Put the average ground gravitational potential associated with the rest mass of the earth U E 6.24 107 (m / s)2 into formula (4.37) to get a constant speed: VE 20376 m / s which will be interpreted as the speed of a flux associated with the cosmic gravitational field in section 5. If the grav ...
Ultra-high-energy cosmic-rays
... One will need to significantly increase the statistics at the highest energies, where the number of sources within the GZK horizon is very limited, in order to isolate sources in the sky…! Major challenge for the coming years!! Glasgow, 13 Nov. 20012! ...
... One will need to significantly increase the statistics at the highest energies, where the number of sources within the GZK horizon is very limited, in order to isolate sources in the sky…! Major challenge for the coming years!! Glasgow, 13 Nov. 20012! ...
Cosmic microwave background
The cosmic microwave background (CMB) is the thermal radiation left over from the time of recombination in Big Bang cosmology. In older literature, the CMB is also variously known as cosmic microwave background radiation (CMBR) or ""relic radiation."" The CMB is a cosmic background radiation that is fundamental to observational cosmology because it is the oldest light in the universe, dating to the epoch of recombination. With a traditional optical telescope, the space between stars and galaxies (the background) is completely dark. However, a sufficiently sensitive radio telescope shows a faint background glow, almost exactly the same in all directions, that is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum. The accidental discovery of CMB in 1964 by American radio astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s, and earned the discoverers the 1978 Nobel Prize.The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380,000 years old. It shows tiny temperature fluctuations that correspond to regions of slightly different densities, representing the seeds of all future structure: the stars and galaxies of today.The CMB is well explained as radiation left over from an early stage in the development of the universe, and its discovery is considered a landmark test of the Big Bang model of the universe. When the universe was young, before the formation of stars and planets, it was denser, much hotter, and filled with a uniform glow from a white-hot fog of hydrogen plasma. As the universe expanded, both the plasma and the radiation filling it grew cooler. When the universe cooled enough, protons and electrons combined to form neutral atoms. These atoms could no longer absorb the thermal radiation, and so the universe became transparent instead of being an opaque fog. Cosmologists refer to the time period when neutral atoms first formed as the recombination epoch, and the event shortly afterwards when photons started to travel freely through space rather than constantly being scattered by electrons and protons in plasma is referred to as photon decoupling. The photons that existed at the time of photon decoupling have been propagating ever since, though growing fainter and less energetic, since the expansion of space causes their wavelength to increase over time (and wavelength is inversely proportional to energy according to Planck's relation). This is the source of the alternative term relic radiation. The surface of last scattering refers to the set of points in space at the right distance from us so that we are now receiving photons originally emitted from those points at the time of photon decoupling.Precise measurements of the CMB are critical to cosmology, since any proposed model of the universe must explain this radiation. The CMB has a thermal black body spectrum at a temperature of 7000272548000000000♠2.72548±0.00057 K. The spectral radiance dEν/dν peaks at 160.2 GHz, in the microwave range of frequencies. (Alternatively if spectral radiance is defined as dEλ/dλ then the peak wavelength is 1.063 mm.) The glow is very nearly uniform in all directions, but the tiny residual variations show a very specific pattern, the same as that expected of a fairly uniformly distributed hot gas that has expanded to the current size of the universe. In particular, the spectral radiance at different angles of observation in the sky contains small anisotropies, or irregularities, which vary with the size of the region examined. They have been measured in detail, and match what would be expected if small thermal variations, generated by quantum fluctuations of matter in a very tiny space, had expanded to the size of the observable universe we see today. This is a very active field of study, with scientists seeking both better data (for example, the Planck spacecraft) and better interpretations of the initial conditions of expansion. Although many different processes might produce the general form of a black body spectrum, no model other than the Big Bang has yet explained the fluctuations. As a result, most cosmologists consider the Big Bang model of the universe to be the best explanation for the CMB.The high degree of uniformity throughout the observable universe and its faint but measured anisotropy lend strong support for the Big Bang model in general and the ΛCDM (""Lambda Cold Dark Matter"") model in particular. Moreover, the fluctuations are coherent on angular scales that are larger than the apparent cosmological horizon at recombination. Either such coherence is acausally fine-tuned, or cosmic inflation occurred.