f(R) Gravity and Cosmology - Workspace
... Einstein believed in a static universe, and sought to show that a static spacetime geometry could solve his field equations, and thus provided a model for the geometry and history of the entire universe[14]. He was unsuccessful - in its original formulation, General Relativity does not permit the ex ...
... Einstein believed in a static universe, and sought to show that a static spacetime geometry could solve his field equations, and thus provided a model for the geometry and history of the entire universe[14]. He was unsuccessful - in its original formulation, General Relativity does not permit the ex ...
Dan Hooper - Indirect Searches For Particle Dark
... •Not a particularly distinctive signal - it is hard to rule out all astrophysical possibilities completely Prospects: •PLANCK should strongly confirm (or refute) the presence of the WMAP haze •GLAST should be capable of detecting gamma rays from the galactic center in this scenario Dan Hooper - Indi ...
... •Not a particularly distinctive signal - it is hard to rule out all astrophysical possibilities completely Prospects: •PLANCK should strongly confirm (or refute) the presence of the WMAP haze •GLAST should be capable of detecting gamma rays from the galactic center in this scenario Dan Hooper - Indi ...
DTU Chap 16 Galaxies v2
... No cluster of galaxies has an observable mass large enough to account for the observed motions of its galaxies; a large amount of unobserved mass must be present between the galaxies. Hot intergalactic gases emit X rays in rich clusters. When two galaxies collide, their stars initially pass each oth ...
... No cluster of galaxies has an observable mass large enough to account for the observed motions of its galaxies; a large amount of unobserved mass must be present between the galaxies. Hot intergalactic gases emit X rays in rich clusters. When two galaxies collide, their stars initially pass each oth ...
Document
... make it the dominant force at large scales. Holds celestial bodies together. Keeps us on the planet, a planet on orbit around a star, a star in a galaxy, a galaxy in a cluster, a cluster in a supercluster, … Also responsible for stellar structure and collapse (supernova) leading formation of neutron ...
... make it the dominant force at large scales. Holds celestial bodies together. Keeps us on the planet, a planet on orbit around a star, a star in a galaxy, a galaxy in a cluster, a cluster in a supercluster, … Also responsible for stellar structure and collapse (supernova) leading formation of neutron ...
Planck 2013 results. XXVI. Background geometry and topology of
... scattering available to date. This allows us to detect possible departures from the standard model of a globally homogeneous and isotropic cosmology on the largest scales. We search for correlations induced by a possible non-trivial topology with a fundamental domain intersecting, or nearly intersec ...
... scattering available to date. This allows us to detect possible departures from the standard model of a globally homogeneous and isotropic cosmology on the largest scales. We search for correlations induced by a possible non-trivial topology with a fundamental domain intersecting, or nearly intersec ...
A New Assessment of Dark Matter in the Milky Way Galaxy
... large distance in a characteristic fashion. Finally, I show that neutrinos, particles that have often been suggested as a component of dark matter, cannot make up more than a very small amount of the galactic dark matter content. Key Words : Galaxy: kinematics and dynamics, Galaxy: structure, dark m ...
... large distance in a characteristic fashion. Finally, I show that neutrinos, particles that have often been suggested as a component of dark matter, cannot make up more than a very small amount of the galactic dark matter content. Key Words : Galaxy: kinematics and dynamics, Galaxy: structure, dark m ...
Sterrenstelsels en Cosmologie Docent: M. Franx, kamer 425
... As can be seen, the galaxy does not really stop ! As the objects are extended, we like to describe the distribution of light on the sky, and not just the total magnitude (which would be appropriate for a star). Hence we measure the amount of light per area on the sky. This is called the surface brig ...
... As can be seen, the galaxy does not really stop ! As the objects are extended, we like to describe the distribution of light on the sky, and not just the total magnitude (which would be appropriate for a star). Hence we measure the amount of light per area on the sky. This is called the surface brig ...
Sterrenstelsels en Cosmologie Docent: M. Franx, kamer 425
... Photometry −> Imaging galaxies and measuring their brightness distribution •Big technical problem: galaxies are really large, and have low surface brightness wings. See the beautiful image of M31 ...
... Photometry −> Imaging galaxies and measuring their brightness distribution •Big technical problem: galaxies are really large, and have low surface brightness wings. See the beautiful image of M31 ...
Cosmic Order out of Primordial Chaos Jones, Bernard JT
... Summary. Nikos Voglis had many astronomical interests, among them was the question of the origin of galactic angular momentum. In this short tribute we review how this subject has changed since the 1970’s and how it has now become evident that gravitational tidal forces have not only caused galaxies ...
... Summary. Nikos Voglis had many astronomical interests, among them was the question of the origin of galactic angular momentum. In this short tribute we review how this subject has changed since the 1970’s and how it has now become evident that gravitational tidal forces have not only caused galaxies ...
Lyman Alpha Forest
... spectrum there is a relative lack of absorption systems close to the redshift of the QSO. This so-called ‘proximity effect’ has been ascribed to the ionizing radiation produced by the QSO itself, which reduces the neutral hydrogen fraction for gas close to the QSO. The effect can be used to measure ...
... spectrum there is a relative lack of absorption systems close to the redshift of the QSO. This so-called ‘proximity effect’ has been ascribed to the ionizing radiation produced by the QSO itself, which reduces the neutral hydrogen fraction for gas close to the QSO. The effect can be used to measure ...
" Galaxy," Defined
... A growing number of low luminosity and low surface brightness astronomical objects challenge traditional notions of both galaxies and star clusters. To address this challenge, we propose a definition of galaxy that does not depend on a cold dark matter model of the universe: A galaxy is a gravitatio ...
... A growing number of low luminosity and low surface brightness astronomical objects challenge traditional notions of both galaxies and star clusters. To address this challenge, we propose a definition of galaxy that does not depend on a cold dark matter model of the universe: A galaxy is a gravitatio ...
Early Star-Forming Galaxies and the Reionisation of the Universe
... was only ~800 million years old. Intense ultraviolet radiation from these early galaxies probably induced a major event in cosmic history: the reionisation of intergalactic hydrogen. New techniques are being developed to understand the properties of these most distant galaxies and determine their in ...
... was only ~800 million years old. Intense ultraviolet radiation from these early galaxies probably induced a major event in cosmic history: the reionisation of intergalactic hydrogen. New techniques are being developed to understand the properties of these most distant galaxies and determine their in ...
Asymmetric Star Formation Efficiency Due to Ram Pressure Stripping
... processes, considering dark matter and gas particles. The gas particles fall into the centres of dark matter haloes, depending on how they have cooled and whether they reach a density greater than a certain threshold, they can be converted into star particles or not. The rate at which stars are form ...
... processes, considering dark matter and gas particles. The gas particles fall into the centres of dark matter haloes, depending on how they have cooled and whether they reach a density greater than a certain threshold, they can be converted into star particles or not. The rate at which stars are form ...
Science Book - Chapter 1: Introduction
... time-volume space a thousand times over current surveys, the most interesting science may well be the discovery of new phenomena. With its repeated, wide-area coverage to deep limiting magnitudes, LSST will enable the discovery and analysis of rare and exotic objects, such as neutron star and black ...
... time-volume space a thousand times over current surveys, the most interesting science may well be the discovery of new phenomena. With its repeated, wide-area coverage to deep limiting magnitudes, LSST will enable the discovery and analysis of rare and exotic objects, such as neutron star and black ...
Galaxies and Active Galaxies
... at great distances from the center (it is said to be “flat”). • This means that the enclosed mass continues to increase even though the amount of visible, luminous matter falls off at large distances from the center. • In elliptical galaxies, the gravity of the visible matter is not strong enough to ...
... at great distances from the center (it is said to be “flat”). • This means that the enclosed mass continues to increase even though the amount of visible, luminous matter falls off at large distances from the center. • In elliptical galaxies, the gravity of the visible matter is not strong enough to ...
Abstracts - Space Telescope Science Institute
... than a decade old. There has been a lot of progress in this area in the intervening years, and detections of many different atoms and molecules have been reported for a number of exoplanets using a wide variety of ground- and space-based telescopes. However, just detecting the atmospheres of these p ...
... than a decade old. There has been a lot of progress in this area in the intervening years, and detections of many different atoms and molecules have been reported for a number of exoplanets using a wide variety of ground- and space-based telescopes. However, just detecting the atmospheres of these p ...
sBzKs
... Massive galaxies are quite rare and likely highly clustered at all redshifts, hence small areas such as those explored so far are subject to large cosmic variance. ...
... Massive galaxies are quite rare and likely highly clustered at all redshifts, hence small areas such as those explored so far are subject to large cosmic variance. ...
An Expanded View of the Universe
... in which chemical elements, including the building blocks of life, are synthesised and recycled: without stars there would be no life. Accordingly, stellar astrophysics has long been a core activity for astronomers. But much remains to be understood. With higher angular resolution and greater sensit ...
... in which chemical elements, including the building blocks of life, are synthesised and recycled: without stars there would be no life. Accordingly, stellar astrophysics has long been a core activity for astronomers. But much remains to be understood. With higher angular resolution and greater sensit ...
A TRANSLUMINAL ENERGY QUANTUM MODEL OF THE COSMIC
... balance the quantity of positive mass energy) and also contain an equal amount of matter and antimatter. Tryon does not give a model of the quantum fluctuation that produced the universe. In 1989 Dehmelt (4) built on Lemaître’s hypothesis. He suggested that a “cosmon, an immensely heavy lower layer ...
... balance the quantity of positive mass energy) and also contain an equal amount of matter and antimatter. Tryon does not give a model of the quantum fluctuation that produced the universe. In 1989 Dehmelt (4) built on Lemaître’s hypothesis. He suggested that a “cosmon, an immensely heavy lower layer ...
Life, gravity and the second law of thermodynamics
... are up to, it can be reduced to physics. However, physics as we know it can also be viewed as a subset of biology since all physicists are the products of biological evolution. Much has been made of our current inability to unify general relativity and quantum mechanics to arrive at a theory of ever ...
... are up to, it can be reduced to physics. However, physics as we know it can also be viewed as a subset of biology since all physicists are the products of biological evolution. Much has been made of our current inability to unify general relativity and quantum mechanics to arrive at a theory of ever ...
Galaxy Classification Much of modern extragalactic astronomy deals
... how galaxies evolve with time. If galactic evolution can be understood, then parameters such as q0 , Ω0 , and Λ will follow, along with data on the initial conditions for the formation of the universe. Before we can study evolution, however, we have to define what a galaxy is, and how it is structur ...
... how galaxies evolve with time. If galactic evolution can be understood, then parameters such as q0 , Ω0 , and Λ will follow, along with data on the initial conditions for the formation of the universe. Before we can study evolution, however, we have to define what a galaxy is, and how it is structur ...
elt science case
... New observational facilities in the coming decade will try to address these questions. Furthermore, new fundamental question may arise: the evidence for dark energy was found only recently, and it added a new component to the Universe, the biggest component in terms of energy density at low redshift ...
... New observational facilities in the coming decade will try to address these questions. Furthermore, new fundamental question may arise: the evidence for dark energy was found only recently, and it added a new component to the Universe, the biggest component in terms of energy density at low redshift ...
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 ...
Master`s thesis: On the investigation of dark matter haloes
... sense that, faint stars have large positive magnitudes and bright stars have low even negative magnitudes. The Greeks not only gave us the magnitude system but also one of the first rational models of the Universe. They believed in the perfection of geometry and that this (divine) geometry also gove ...
... sense that, faint stars have large positive magnitudes and bright stars have low even negative magnitudes. The Greeks not only gave us the magnitude system but also one of the first rational models of the Universe. They believed in the perfection of geometry and that this (divine) geometry also gove ...
Elliptical galaxies
... found that most of the photo-chemical observables, including the Mg/Fe-mass relation can be reproduced in a scenario in which the more massive galaxies formed faster and with a much more efficient star formation process with respect to the low mass objects. PM04 suggested that a single galaxy should ...
... found that most of the photo-chemical observables, including the Mg/Fe-mass relation can be reproduced in a scenario in which the more massive galaxies formed faster and with a much more efficient star formation process with respect to the low mass objects. PM04 suggested that a single galaxy should ...
Big Bang
The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution. The model accounts for the fact that the universe expanded from a very high density and high temperature state, and offers a comprehensive explanation for a broad range of observed phenomena, including the abundance of light elements, the cosmic microwave background, large scale structure, and Hubble's Law. If the known laws of physics are extrapolated beyond where they are valid, there is a singularity. Modern measurements place this moment at approximately 13.8 billion years ago, which is thus considered the age of the universe. After the initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, and later simple atoms. Giant clouds of these primordial elements later coalesced through gravity to form stars and galaxies.Since Georges Lemaître first noted, in 1927, that an expanding universe might be traced back in time to an originating single point, scientists have built on his idea of cosmic expansion. While the scientific community was once divided between supporters of two different expanding universe theories, the Big Bang and the Steady State theory, accumulated empirical evidence provides strong support for the former. In 1929, from analysis of galactic redshifts, Edwin Hubble concluded that galaxies are drifting apart, important observational evidence consistent with the hypothesis of an expanding universe. In 1965, the cosmic microwave background radiation was discovered, which was crucial evidence in favor of the Big Bang model, since that theory predicted the existence of background radiation throughout the universe before it was discovered. More recently, measurements of the redshifts of supernovae indicate that the expansion of the universe is accelerating, an observation attributed to dark energy's existence. The known physical laws of nature can be used to calculate the characteristics of the universe in detail back in time to an initial state of extreme density and temperature.