Top PDF Observations of intergalactic heavy-element enrichment in the early universe

Observations of intergalactic heavy-element enrichment in the early universe

Observations of intergalactic heavy-element enrichment in the early universe

In the past decade, new observations have revealed evidence of early interactions between galaxies and intergalactic matter. After the first stars and galaxies were born, they immediately began to alter their surroundings, first by emitting ionizing radiation, and then by dispersing newly minted heavy elements into intergalactic space. When C iv was first discovered in the filaments of the intergalactic medium (IGM) at z ∼ 3 (Meyer & York, 1987a; Cowie et al., 1995a; Tytler et al., 1995), it became clear that simple models where in situ chemical enrichment only occurred within galaxy haloes were incomplete. Metals fused in stars were somehow sown outside of galaxies in the early universe, signifying that the chemical feedback from early star formation was much more efficient than it is today. This vigorous recycling reveals a fundamental difference between typical galaxies at z & 2 and those of the local universe. The aim of this work is to investigate the impact of early galaxies upon the large-scale IGM, using quasar absorption lines to study the dispersal and detailed distribution of heavy elements.
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Conformality Lost: Broken Symmetries in the Early Universe

Conformality Lost: Broken Symmetries in the Early Universe

A central goal of modern cosmology is to understand the physics underlying the evolution of the early universe. At the simplest level, there are two distinct things to which cosmological observations are sensitive—the background cosmological evolution and small perturbations about this background. At the largest scales, the universe is very simple: observations indicate that the universe is very nearly homogeneous, isotropic and flat. Observations of relic Cosmic Microwave Background (CMB) radiation allow us measure small perturbations away from this background and allow us to infer the properties of the component driving the dynamics of the primordial universe. The CMB is homogeneous radiation left over from the hot big bang. Small temperature anisotropies in its spectrum were seeded by quantum fluctuations in the early universe, and measurements of these anisotropies [17–20] allow us to constrain the evolution of the early universe. The perturbations themselves turn out to be nearly the simplest imaginable—very nearly scale invariant and gaussian. Any scenario purporting to describe early universe evolution must address these observations.
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The photometric properties of galaxies in the early Universe

The photometric properties of galaxies in the early Universe

ric properties of galaxies during the epoch of reionization ( z = 8–15). These properties include the rest-frame UV to near-IR broad-band spectral energy distributions, the Lyman continuum (LyC) photon production, the UV star formation rate calibration, and intrinsic UV continuum slope. In particular we focus on exploring the effect of various modelling assumptions, in- cluding the assumed choice of stellar population synthesis (SPS) model, initial mass function, and the escape fraction of LyC photons, upon these quantities. We find that these modelling assumptions can have a dramatic effect on photometric properties leading to consequences for the accurate determination of physical properties from observations. For example, at z = 8 we predict that nebular emission can account for up to 50 per cent of the rest-frame R-band luminosity, while the choice of SPS model can change the LyC production rate up to a factor of ×2.
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Supermassive Black Holes, the Early Universe, and Gamma Ray Bursts

Supermassive Black Holes, the Early Universe, and Gamma Ray Bursts

supermassive black holes were discussed as well. Metal- lic enrichment and virial temperatures were found to play a major role in determining the behavior of gas dynamics in pre-galactic discs, and thus in the subsequent forma- tion of the seeding black holes. Metal-free or metal-poor environments favor the formation of population III stars that end their lives as massive black holes. In this envi- ronment, black holes can also be formed directly out of a dense gas cloud. In metal rich environments, fragmenta- tion and star formation is the dominant mechanism. Black holes are formed in these systems by the collision of stars in clusters and the subsequent sinking to the cen- ter of the pre-galactic disk. Gas dynamical processes can also lead to the formation of supermassive stars that end their lives as massive black holes. Dark stars, as a possi- ble channel leading to the formation of massive black holes, were also discussed. No observational evidence has been found so far for the existence of supersymmet- ric particles, which are presumed to be responsible for producing the necessary heat at the core of dark stars, despite the fact that energies well above that postulated for their existence have been probed. The formation of primordial black holes from the inflationary era was also reviewed. Theoretical studies show that these objects were formed with a wide spectrum of masses. However, it should be kept in mind that distortion signatures in the microwave background radiation set a limit on the masses of primordial black holes. Hawking evaporation is a key element in exploring the validity of primordial black hole models. Recent observations are in favor of their existence. Furthermore, we discussed the important connection between the powerful stellar explosions known as gamma-ray bursts and black holes, and how under- standing one of them may lead to a better understanding of the other.
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On the Origin of the Gamma Ray Burst  Redshift Distribution in the Early Universe

On the Origin of the Gamma Ray Burst Redshift Distribution in the Early Universe

Observations of some long GRBs reveal a supernova connection. The most widely accepted mechanism in- volves the collapse of the core of an extremely massive, low-metallicity, rapidly rotating star to form a black hole [8]. The infalling matter swirls into a high density accretion disk and drives a pair of relativistic jets along the rotation axis [9]. The jets pummel through the stellar envelope and eventually interact with the stellar surface and radiate gamma rays. According to this model, the minimum angular momentum needed is basically the val- ue associated with the last stable orbit around a black hole which, for non-rotating black holes is given by [10]:
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Gedanken Experiment for Degree of Flatness, or Lack of, in Early Universe Conditions

Gedanken Experiment for Degree of Flatness, or Lack of, in Early Universe Conditions

N S will be tied into the presumed results for initial state density, in ways we will comment upon, leading to observations which are supporting the physics given by Equation (26) of this document as with regards to Gravitational waves, from relic conditions. The deviations from flat space may help confirm the conclusions given by Buchert, Carfora, Kolb, and Wiltshire allegedly refuting the claim by Green and Wald that “the standard FLRW model approximates our Universe extremely well on all scales, except close to strong field astrophysical objects”, as well as give additional analysis appropriate for adding detail to expanding experimental procedures for investigating non FLRW models such as the Polynomial Inflation models as given by Kobayashi, and Seto, as well as other nonstandard cosmologies, as brought up by Corda, and other research- ers. As well as improve upon post Bicep 2 measurements which will avoid GW signatures from in- terstellar dust, as opposed to relic GW. We hope that our approach may help in the differentiation between different cosmology models. Most importantly, our procedure may help, with refinement of admissible frequency range, avoid the problem of BICEP 2, which had its presumed GW signals from presumed relic conditions identical to dust induced frequencies, as so identified by the Planck collaboration in reference [25] which we comment upon in the conclusion.
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Basu, Kaustuv
  

(2004):


	CMB observations and the metal enrichment history of the universe.


Dissertation, LMU München: Fakultät für Physik

Basu, Kaustuv (2004): CMB observations and the metal enrichment history of the universe. Dissertation, LMU München: Fakultät für Physik

We will not discuss in detail the origin and ways of enrichment of the inter-galactic gas by heavy elements. This certainly requires existence of massive stars, supernova explosions, stellar and galactic winds, and even jets from disks around young stars with cold molecular gas (Yu, Billawala & Bally 1999). The main goal of this part is to show that the announced sensitivity of PLANCK detectors might permit us to set very strong upper limits to the time of enrichment of inter-galactic gas by heavy elements, the time of reionization, and maybe even to detect the heavy elements in the inter-cluster medium. The census of baryons in the local universe (Fukugita et al. 1998) shows that most of the baryon remains unobserved, and the proposed method might set way to detect its existence at high redshifts, when it had moderate or low temperature. These missing baryons are centainly out of stars, interstellar gas and intergalactic gas in clusters and groups of galaxies. However, we know that such baryons should exist because they have been detected by WMAP at the last scattering surface at z ' 1100, and are also necessary to justify the observed abundance of deuterium and 6 Li in the early universe. Due to the wide range of redshifts under
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Turbulence of weak gravitational waves in the early universe

Turbulence of weak gravitational waves in the early universe

Introduction. — The recent direct observations of gravita- tional waves (GWs) by the LIGO-Virgo collaboration [1], a century after their prediction by Einstein [2], is certainly one of the most important events in astronomy, which opens a new window onto the Universe, the so-called GWastronomy. In the modern Universe, shortly after being excited by a source, e.g., a merger of two black holes, GWs become essentially linear and therefore noninteracting during their subsequent propagation. In the very early Universe, different mechanisms have been proposed for the generation of primordial GWs, like e.g., phase transition [3 – 9], self- ordering scalar fields [10], cosmic strings [11], and cosmic defects [12]. Production of GWs is also expected to have taken place during the cosmological inflation era [13–15], and many efforts are currently made to detect indirectly their existence [16]. The physical origin of the exponential expansion of the early Universe is, however, not clearly explained and still under investigation [17,18]. Formally, it was incorporated into the general relativity equations simply through adding a positive cosmological constant.
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Several Routes to Determining Entropy Generation in the Early Universe

Several Routes to Determining Entropy Generation in the Early Universe

What if we do not have an infinite fifth dimension ? What if it is compactified only ? We then have to change our analysis. Another thing. We place limits on inflationary models; for example, a minimally coupled λφ 4 is disfavored at more than 3 σ. Result? Forget quartic inflationary fields , as has been show by Peiris, Hingshaw et al31. We can realistically hope that WMAP will be able to parse through the race track models to distinguish between the different candidates . So far “First-Year Wilkinson Microwave Anisotropy Probe (WMAP)1 Observations: Implications For Inflation” , is giving chaotic inflation a run for its money. We shall endeavor for numerical work using some of the tools brought up in this present discussion for falsifying or confirming the figures 1 and 2 of this text which show variance in the CMBR spectrum. In doing so, we set the stage for showing how Brane-anti brane models of entropy fare with regards to their more classical counter parts.
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A new paradigm for the dynamics of the early Universe

A new paradigm for the dynamics of the early Universe

In this article we have discussed a new paradigm for exploring a number of puzzling aspects in modern cosmology and their implications for astrophysics and observable astronomy. In this paradigm we argue that an evolutionary description of the Universe is best formulated in terms of a series of successive approximations based on a viable cosmography derived from current observations with a minimum number of phenomenological constraints on the dynamics of the unobservable early Universe. Consequently assumptions about the states of matter during such epochs in our paradigm are replaced by a series of retro-dictions from a coupled system of field equations with initial conditions based on current data. We depart from many standard cosmological models, with their use of different isotropic fluid models in different epochs, by using a single anisotropic material fluid model in an Einstein-Maxwell-vector-scalar-fluid system of master equations. The Maxwell, vector and scalar fields are coupled to gravity and themselves in such a way that an exact analytic approach to a cosmological solution for the spacetime metric, vector, scalar and Maxwell fields can be found without the need to impose any a-priori equation of state for the material fluid. Instead, its equation of state in the cosmological sector is induced from the Einstein equation containing a stress-energy-momentum tensor without a cosmological constant. By establishing all solutions on a spacetime with the topology I × S 3 , I ∈
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The turbulent chiral magnetic cascade in the early universe

The turbulent chiral magnetic cascade in the early universe

energy halos around TeV blazars ( Aharonian et al. 2006 ) . This has been interpreted in terms of magnetic fi elds permeating the intergalactic medium over large scales ( for a review, see Durrer & Neronov 2013 ) . Simultaneous GeV – TeV observations of blazars put lower limits on such fi elds between 10 - 15 G ( Taylor et al. 2011 ) and 10 - 18 G ( Dermer et al. 2011 ) at x ~ 1 Mpc

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Quasifission in heavy and superheavy element formation reactions

Quasifission in heavy and superheavy element formation reactions

(liquid drop) trends are well defined. To define the smooth trends in quasifission dynamics, a large number of MAD measurements have been selected, at beam energies somewhat above the capture barrier (typically by ∼6%). Here the known effects of deformation alignment [9, 10, 14, 16] and shell structure observed in measurements at below-barrier energies [11, 17] are much reduced [10, 18, 19]. However, the beam energies should not be too far above the capture barriers, otherwise high angular momenta would be introduced in the collisions, which would then not be representative of heavy element formation reactions. Using these measured MADS, reaction outcomes (defined for simplicity in terms of the MAD types described above) are plotted against the variables that reflect the balance between nuclear and Coulomb forces during the collision, which are expected to determine a smooth dependence of outcomes of reactions forming very heavy elements. Reference [20] proposed that there should be scaling behavior between reactions, based on the schematic “chaotic regime dynamics” model of fusion of heavy nuclei, which couples shape changes of the nuclear system to internal nucleonic degrees of freedom (one-body dissipation).
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In-beam fission study for Heavy Element Synthesis

In-beam fission study for Heavy Element Synthesis

Special thanks are due to the staff of JAEA Tandem facility for supplying heavy-ion beams. The experiments are carried out under the collaboration with JAEA, Helmholtzzentrum für Schwerionenforschung, Flerov Laboratory of Nuclear Reactions, Tohoku University, Technische Universität München, and High Energy Accelerator Organization.

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Domain Walls and Matter-Antimatter Domains in the Early Universe

Domain Walls and Matter-Antimatter Domains in the Early Universe

According to this scenario the width of the domain wall should grow exponentially to prevent annihilation at the domain boundaries. Though there is a classical result obtained by Basu and Vilenkin that the width of the wall tends to the one of the stationary solution (constant physical width). That is why we considered thick domain walls in a de Sitter universe following paper by Basu and Vilenkin. However, we were interested not only in stationary solutions found therein, but also investigated the general case of domain wall evolution with time. When the wall thickness parameter, δ 0 , is smaller than H −1 / √ 2,
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A Brief Review of  the Dynamical Universe in the Early and Late Stages

A Brief Review of the Dynamical Universe in the Early and Late Stages

During the early age the universe was solely filled up with vacuum energy. The scale factor a ( t ) grew exponentially so that the ratio of the vacuum energy density would rapidly be approaching towards the critical density at this era and thus a well known ‘flatness problem’ could be solved. Such phenomenon of exponential expansion is called inflation. It was A. Guth who first proposed such inflationary model [9, 10] to fix ‘monopole problems’, i.e., why today no magnetic monopole is present. It was soon observed that the inflation could solve other long-standing problems, such as ‘flatness problem’ and ‘horizon problem’. Guth proposed that the scalar fields might get caught in the local minimum of some potential, and then rolled towards a true minimum of the potential. In 1980 Kazanas suggested [11] that an exponential expansion could eliminate the particle horizon. Sato proposed [12] that exponential expansion would be able to eliminate domain walls, another kind of exotic relic. In 1981 Einho et. al. [13] published a model that could solve ‘magnetic monopole puzzle’. It was then realized that model of inflation had fatal problem as the transition from super cooled initial ‘false vacuum’ to the lower energy ‘true vacuum’ cannot occur everywhere simultaneously [14, 15]. Guth's version of inflation theory was replaced by ‘new inflation’ [16, 17, 18], which is termed as ‘slow roll inflation’ A scalar field, called ‘inflation’ was introduced to explain such phenomenon. Coleman and Weinberg introduced the symmetry breaking mechanism to the new inflation model [19]. In the inflation theory Linde added a new dimension by introducing the ‘chaotic inflation [20]
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Symmetry Breaking and the Structure Formation of the Expanded Early Universe

Symmetry Breaking and the Structure Formation of the Expanded Early Universe

The curves show that at the higher temperatures only neutrons and protons exist, with there being more protons than neutrons while with the decrease of temperature, there is an increase amount of deuterium and helium nuclei. Below the temperature of 1 billion degrees there is a significant increase in deuterium and helium and a decrease in the abundance of protons and neutrons [9]. This uses up the all the free neutrons and some of the protons causing the neutron line to drop off, and the proton line to dip. The deuterium abundance increases to a point as it is an intermediate to the formation of helium. With its creation, it is immediately consumed completing the process of helium nucleosynthesis. When all the neutrons have been used up, its presence drops off and the final step in the formation of elements was capture of the proper number of free electrons for forming neutral atoms. Remaining electrons still had plenty of energy and took about 700,000 years of cooling until this was able to occur. The captures of electrons for the formation of atoms are responsible for making some significant changes in the universe [10]. The stretched out photon wavelengths are referred to as the Cosmic Microwave Background, the intensity of this background radiation can be measured which closely supports the "Big Bang" theory of the creation of the universe. Major epochs and the related main events in the history of the Universe is presented in table I.
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Chameleons in the early universe: kicks, rebounds, and particle production

Chameleons in the early universe: kicks, rebounds, and particle production

The chameleon’s behavior in the early Universe was first investigated in Ref. [61]. Of particular concern is how much the chameleon scalar field evolves between the time of BBN and the present day. Large variations in the chameleon’s value can be interpreted as large variations in particle masses, and yet we know that particle masses at the time of BBN do not significantly differ from the masses that we measure today [e.g. 62, 63]. Ref. [61] found that the chameleon is driven toward its current value prior to BBN, thus ensuring that the nucleon masses are sufficiently close to their observed values that BBN is unaffected, regardless of the chameleon’s initial value (but also see Ref. [64]). Although the chameleon is usually light while the Universe is radiation dominated, the field is able to overcome Hubble friction and approach its present-day value because it becomes momentarily heavy whenever the Universe’s temperature equals the mass of a particle species in equilibrium with the radi- ation bath. We will discuss how these mass thresholds dramatically perturb the dynamics of the chameleon field in Section II; in summary, they kick the chameleon scalar field closer to the minimum of its effective potential, thus enabling it to approach the value it holds today.
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Evaluation of intake charge hydrogen enrichment in a heavy duty diesel engine

Evaluation of intake charge hydrogen enrichment in a heavy duty diesel engine

Such powertrain platforms look set to remain the dominant source of heavy duty vehicle propulsion for decades to come. The currently reported work was concerned with experimental evaluation of the potential to partially displace diesel with hydrogen fuel, which continues to attract attention as a potential longer term alternative fuel solution whether produced on-board or remotely via sustainable methods. The single cylinder engine adopted was of 2.0 litre capacity, with common rail diesel fuel injection and EGR typical of current production technology. The work involved fumigation of H2 into the engine intake system at engine loads typically visited under real world driving conditions. Highest practical hydrogen substitution ratios increased indicated efficiency by up to 4.6% at 6bar IMEPn and 2.4% at 12bar IMEPn. In 6bar IMEPn, CO 2 , CO and soot all reduced by 58%, 83% and 58% respectively while the corresponding
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Stabilized finite element methods based on multiscale enrichment for the Stokes problem

Stabilized finite element methods based on multiscale enrichment for the Stokes problem

The purpose of this work is to use the multiscale approach from [21, 20], combined with the static condensation procedure, in order to propose new stabilized finite ele- ment methods for the Stokes problem. We proceed as in [21], defining an enrichment function for the trial space for the velocity that no longer vanishes on the element boundary (and hence it is not a bubble function), and then we split it into a bubble part and a function being a harmonic extension of the boundary condition. This boundary condition comes from the solution of an elliptic ODE containing a part of the differential operator at the boundary, and a jump term as the right-hand side. Depending on the jump term chosen, this procedure will lead to different methods. Both functions are condensed, and hence we obtain a method which includes the usual Galerkin-Least-Squares (GLS) stabilizing terms at the element level, plus a positive jump term on the interelement boundaries, each one with a proper stabilization pa- rameter. One special feature of these new methods is that the previously mentioned ODE at the element boundary may be solved analytically, and hence the stabilization parameter associated with the jump terms is known exactly.
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Biogenic precipitation of manganese oxides and enrichment of heavy metals at acidic soil pH.

Biogenic precipitation of manganese oxides and enrichment of heavy metals at acidic soil pH.

Importantly, in both 470 profiles, these metals are overwhelmingly associated with the Mn oxide fraction in the barrier 471 layers, despite the fact that, based on the total digest resul[r]

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